1. What is heredity?
The transmission of genetic traits from parents to offspring.
2. What is inheritance?
The process by which genetic information is passed from one generation to the next.
3. Who is considered the father of genetics?
Gregor Johann Mendel.
4. What are Mendel’s laws of inheritance?
Law of Segregation, Law of Independent Assortment, and Law of Dominance.
5. What is the Law of Segregation?
Each individual has two alleles for a trait, which segregate during gamete formation, so each gamete carries one allele.
6. What is the Law of Independent Assortment?
Alleles of different genes assort independently during gamete formation, provided the genes are on different chromosomes.
7. What is the Law of Dominance?
In a heterozygous condition, one allele (dominant) masks the expression of the other (recessive).
8. What is an allele?
An alternative form of a gene occupying the same locus on homologous chromosomes.
9. What is a gene?
A segment of DNA that determines a specific trait or function.
10. What is a trait?
A specific characteristic or feature of an organism, e.g., seed color.
11. What is a dominant allele?
An allele that expresses its phenotype even in the presence of a recessive allele.
12. What is a recessive allele?
An allele whose phenotype is masked by a dominant allele in a heterozygote.
13. What is a genotype?
The genetic makeup of an organism, e.g., TT or Tt for a trait.
14. What is a phenotype?
The observable physical or biochemical expression of a genotype, e.g., tall or short.
15. What is a homozygous condition?
Having two identical alleles for a gene, e.g., TT or tt.
16. What is a heterozygous condition?
Having two different alleles for a gene, e.g., Tt.
17. What is a monohybrid cross?
A cross between two individuals differing in one trait, e.g., tall vs. short plants.
18. What is the phenotypic ratio of a monohybrid cross?
3:1 (dominant:recessive) in the F2 generation.
19. What is the genotypic ratio of a monohybrid cross?
1:2:1 (homozygous dominant:heterozygous:homozygous recessive) in the F2 generation.
20. What is a dihybrid cross?
A cross between two individuals differing in two traits, e.g., seed color and shape.
21. What is the phenotypic ratio of a dihybrid cross?
9:3:3:1 in the F2 generation for two independently assorting traits.
22. What organism did Mendel use for his experiments?
Pea plant (Pisum sativum).
23. Why did Mendel choose pea plants for his experiments?
They have short generation time, many traits, and are easy to cross-pollinate.
24. What is a Punnett square?
A diagram used to predict the genotypic and phenotypic outcomes of a genetic cross.
25. What is a test cross?
A cross between an individual with a dominant phenotype and a homozygous recessive to determine its genotype.
26. What is the outcome of a test cross if the individual is heterozygous?
A 1:1 phenotypic ratio (dominant:recessive).
27. What is the outcome of a test cross if the individual is homozygous dominant?
All offspring show the dominant phenotype.
28. What is incomplete dominance?
A condition where neither allele is fully dominant, resulting in an intermediate phenotype in heterozygotes.
29. What is an example of incomplete dominance?
Red and white flowers producing pink flowers in snapdragons.
30. What is the phenotypic ratio in a monohybrid cross with incomplete dominance?
1:2:1 (homozygous dominant:heterozygous:homozygous recessive).
31. What is codominance?
A condition where both alleles in a heterozygote are fully expressed, showing both phenotypes.
32. What is an example of codominance?
AB blood group in humans, expressing both A and B antigens.
33. What is the phenotypic ratio in a monohybrid cross with codominance?
1:2:1, with the heterozygous phenotype showing both traits.
34. What is multiple allelism?
The presence of more than two alleles for a gene in a population.
35. What is an example of multiple allelism?
ABO blood groups in humans (A, B, O alleles).
36. How many genotypes are possible in the ABO blood group system?
Six genotypes: AA, AO, BB, BO, AB, OO.
37. What is the phenotype of the AB blood group?
Both A and B antigens are expressed (codominance).
38. What is the phenotype of the O blood group?
No A or B antigens (homozygous recessive).
39. What is polygenic inheritance?
Inheritance of a trait controlled by multiple genes, resulting in continuous variation.
40. What is an example of polygenic inheritance?
Human skin color, influenced by multiple genes.
41. What is the phenotypic pattern in polygenic inheritance?
A bell-shaped curve due to continuous variation.
42. What is pleiotropy?
A single gene influencing multiple, unrelated phenotypic traits.
43. What is an example of pleiotropy?
Sickle-cell anemia gene affecting red blood cells and causing multiple symptoms.
44. What is the chromosomal theory of inheritance?
Genes are located on chromosomes, and their behavior during meiosis explains inheritance patterns.
45. Who proposed the chromosomal theory of inheritance?
Walter Sutton and Theodor Boveri.
46. What is linkage?
The tendency of genes on the same chromosome to be inherited together.
47. What is genetic recombination?
The exchange of genetic material between homologous chromosomes during crossing over.
48. What is crossing over?
The exchange of segments between non-sister chromatids during meiosis.
49. What is the significance of crossing over?
Increases genetic diversity by producing new allele combinations.
50. What is a linkage map?
A map showing the relative positions of genes on a chromosome based on recombination frequency.
51. What is recombination frequency?
The percentage of recombinant offspring, indicating the distance between genes.
52. What is one map unit in a linkage map?
1% recombination frequency between two genes.
53. Who developed the concept of genetic linkage maps?
Thomas Hunt Morgan and Alfred Sturtevant.
54. What organism was used by Morgan for linkage studies?
Fruit fly (Drosophila melanogaster).
55. What is sex-linked inheritance?
Inheritance of traits controlled by genes on sex chromosomes, primarily the X chromosome.
56. What is an example of a sex-linked trait?
Color blindness, caused by a recessive gene on the X chromosome.
57. Why are males more affected by X-linked recessive disorders?
Males have one X chromosome, so a single recessive allele expresses the trait.
58. What is hemophilia?
A sex-linked recessive disorder causing impaired blood clotting.
59. What is the genotype of a female carrier for hemophilia?
X^H X^h (heterozygous).
60. What is the genotype of a male with hemophilia?
X^h Y.
61. What is color blindness?
A sex-linked recessive disorder impairing the ability to distinguish colors, usually red-green.
62. What is the inheritance pattern of color blindness?
Recessive, X-linked, more common in males.
63. What is a Barr body?
An inactivated X chromosome in female somatic cells.
64. What is the significance of X-chromosome inactivation?
Equalizes gene expression between males (XY) and females (XX).
65. What is sex determination?
The genetic or environmental process determining an organism’s sex.
66. What is the sex determination system in humans?
XX-XY system, where XX is female and XY is male.
67. What is the role of the SRY gene in sex determination?
The Sex-determining Region Y gene triggers male development in XY individuals.
68. What is the sex determination system in birds?
ZW-ZZ system, where ZW is female and ZZ is male.
69. What is the sex determination system in honeybees?
Haplodiploidy, where fertilized eggs become females and unfertilized eggs become males.
70. What is a mutation?
A permanent change in the DNA sequence of a gene or chromosome.
71. What are the types of mutations?
Gene mutations and chromosomal mutations.
72. What is a gene mutation?
A change in the nucleotide sequence of a gene, e.g., point mutation.
73. What is a point mutation?
A change in a single nucleotide base pair in DNA.
74. What is an example of a point mutation?
Sickle-cell anemia, caused by a single base substitution in the hemoglobin gene.
75. What is a frameshift mutation?
Insertion or deletion of nucleotides that shifts the reading frame of a gene.
76. What is a chromosomal mutation?
A change in the structure or number of chromosomes.
77. What are the types of chromosomal mutations?
Deletion, duplication, inversion, and translocation.
78. What is deletion in chromosomal mutation?
Loss of a chromosome segment.
79. What is duplication in chromosomal mutation?
Repetition of a chromosome segment.
80. What is inversion in chromosomal mutation?
Reversal of a chromosome segment’s orientation.
81. What is translocation in chromosomal mutation?
Transfer of a chromosome segment to a non-homologous chromosome.
82. What is aneuploidy?
An abnormal number of chromosomes, e.g., trisomy or monosomy.
83. What is trisomy?
Presence of three copies of a chromosome instead of two.
84. What is monosomy?
Presence of only one copy of a chromosome instead of two.
85. What is polyploidy?
Presence of more than two complete sets of chromosomes, common in plants.
86. What is a genetic disorder?
A disease caused by abnormalities in an individual’s genetic material.
87. What is a Mendelian disorder?
A genetic disorder caused by a single gene mutation, following Mendelian inheritance.
88. What is an example of a Mendelian disorder?
Sickle-cell anemia, caused by a recessive gene mutation.
89. What is sickle-cell anemia?
A recessive disorder causing abnormal hemoglobin, leading to sickle-shaped red blood cells.
90. What are the symptoms of sickle-cell anemia?
Anemia, pain crises, and increased infection risk.
91. What is the genotype of a sickle-cell anemia patient?
Hb^S Hb^S (homozygous recessive).
92. What is the advantage of being a sickle-cell carrier?
Resistance to malaria in heterozygous individuals (Hb^A Hb^S).
93. What is thalassemia?
A recessive disorder affecting hemoglobin production, leading to anemia.
94. What are the types of thalassemia?
Alpha-thalassemia and beta-thalassemia, based on affected globin chains.
95. What are the symptoms of thalassemia?
Severe anemia, fatigue, and bone deformities in major cases.
96. What is the treatment for thalassemia?
Blood transfusions, chelation therapy, or bone marrow transplant.
97. What is phenylketonuria (PKU)?
A recessive disorder causing inability to metabolize phenylalanine, leading to intellectual disability.
98. What is the cause of phenylketonuria?
Mutation in the PAH gene, impairing phenylalanine hydroxylase enzyme.
99. What is the treatment for phenylketonuria?
A low-phenylalanine diet and enzyme supplements.
100. What is a chromosomal disorder?
A genetic disorder caused by abnormalities in chromosome number or structure.
101. What is Down syndrome?
A chromosomal disorder caused by trisomy 21, leading to intellectual disability and physical abnormalities.
102. What are the symptoms of Down syndrome?
Flattened face, slanted eyes, short stature, and developmental delays.
103. What is the cause of Down syndrome?
Nondisjunction during meiosis, resulting in an extra chromosome 21.
104. What is nondisjunction?
Failure of chromosomes to separate properly during cell division.
105. What is Klinefelter syndrome?
A chromosomal disorder in males with an extra X chromosome (XXY), causing infertility and reduced testosterone.
106. What are the symptoms of Klinefelter syndrome?
Tall stature, reduced body hair, and gynecomastia.
107. What is Turner syndrome?
A chromosomal disorder in females with a missing X chromosome (XO), causing short stature and infertility.
108. What are the symptoms of Turner syndrome?
Webbed neck, low hairline, and ovarian dysfunction.
109. What is a karyotype?
A visual profile of an individual’s chromosomes, used to detect abnormalities.
110. What is the role of pedigree analysis?
Traces inheritance patterns of traits in families to predict genetic disorders.
111. What is a pedigree chart?
A diagram showing the occurrence of a trait across generations in a family.
112. What symbol represents a male in a pedigree chart?
A square.
113. What symbol represents a female in a pedigree chart?
A circle.
114. What does a shaded symbol indicate in a pedigree chart?
An individual affected by the trait or disorder.
115. What is an autosomal dominant disorder?
A disorder caused by a dominant allele on an autosome, expressed in heterozygotes.
116. What is an example of an autosomal dominant disorder?
Huntington’s disease, causing progressive neurological degeneration.
117. What is an autosomal recessive disorder?
A disorder caused by a recessive allele on an autosome, expressed only in homozygotes.
118. What is the inheritance pattern of autosomal dominant disorders?
Affected individuals have at least one affected parent; appears in every generation.
119. What is the inheritance pattern of autosomal recessive disorders?
Affected individuals often have unaffected parents; may skip generations.
120. What is a carrier in genetics?
A heterozygous individual carrying a recessive allele without expressing the trait.
121. What is the probability of two carriers of a recessive disorder having an affected child?
25% (1/4).
122. What is a sex-linked recessive disorder?
A disorder caused by a recessive allele on the X chromosome, e.g., hemophilia.
123. What is the inheritance pattern of X-linked recessive disorders?
More common in males; females are often carriers.
124. What is a sex-linked dominant disorder?
A disorder caused by a dominant allele on the X chromosome, e.g., hypophosphatemic rickets.
125. What is the inheritance pattern of X-linked dominant disorders?
Affects both males and females; passed from affected mothers to all daughters and sons.
126. What is a Y-linked disorder?
A disorder caused by a gene on the Y chromosome, affecting only males.
127. What is an example of a Y-linked trait?
Hairy ears, though rare and poorly documented.
128. What is genetic counseling?
A process to assess and advise on the risk of genetic disorders in families.
129. What is the role of a genetic counselor?
Interprets genetic test results and guides families on inheritance risks.
130. What is amniocentesis?
A prenatal test analyzing amniotic fluid to detect chromosomal abnormalities.
131. What is chorionic villus sampling (CVS)?
A prenatal test analyzing placental tissue to detect genetic disorders.
132. What is the risk of amniocentesis?
A small risk of miscarriage or infection.
133. What is the advantage of CVS over amniocentesis?
Can be performed earlier in pregnancy (10–13 weeks).
134. What is a genetic marker?
A DNA sequence used to identify a gene or chromosome region associated with a trait.
135. What is the significance of Mendel’s experiments?
Established the basic principles of inheritance, forming the foundation of genetics.
136. What is a true-breeding line?
A population that produces only one phenotype when self-pollinated, e.g., TT or tt.
137. What is the F1 generation?
The first filial generation, offspring of the parental (P) generation cross.
138. What is the F2 generation?
The second filial generation, offspring of the F1 generation cross.
139. What is the parental generation (P)?
The initial organisms crossed in a genetic experiment.
140. What is the significance of Mendel’s monohybrid cross?
Demonstrated the Law of Segregation and dominance.
141. What is the significance of Mendel’s dihybrid cross?
Demonstrated the Law of Independent Assortment.
142. What is a backcross?
A cross between an F1 individual and one of the parental types.
143. What is the purpose of a backcross?
To determine the genotype of an individual or reinforce desired traits.
144. What is epistasis?
A gene interaction where one gene masks or modifies the expression of another.
145. What is an example of epistasis?
Coat color in mice, where one gene determines pigment presence and another its type.
146. What is dominant epistasis?
A dominant allele at one locus suppresses the expression of alleles at another locus.
147. What is recessive epistasis?
A homozygous recessive genotype at one locus masks the expression of another gene.
148. What is the phenotypic ratio in dominant epistasis?
12:3:1 in a dihybrid cross, instead of 9:3:3:1.
149. What is the phenotypic ratio in recessive epistasis?
9:3:4 in a dihybrid cross, instead of 9:3:3:1.
150. What is complementary gene action?
Two genes work together to produce a phenotype, requiring both dominant alleles.
151. What is an example of complementary gene action?
Purple flower color in peas, requiring dominant alleles of two genes.
152. What is the phenotypic ratio in complementary gene action?
9:7 in a dihybrid cross, instead of 9:3:3:1.
153. What is duplicate gene action?
Two genes produce the same phenotype, requiring at least one dominant allele.
154. What is the phenotypic ratio in duplicate gene action?
15:1 in a dihybrid cross, instead of 9:3:3:1.
155. What is quantitative inheritance?
Inheritance of traits controlled by multiple genes, showing continuous variation.
156. What is an example of quantitative inheritance?
Height in humans, influenced by multiple genes and environment.
157. What is the role of environment in quantitative traits?
Modifies phenotypic expression, e.g., nutrition affecting height.
158. What is a multifactorial trait?
A trait influenced by multiple genes and environmental factors.
159. What is an example of a multifactorial trait?
Heart disease, influenced by genetics and lifestyle.
160. What is heritability?
The proportion of phenotypic variation in a population due to genetic factors.
161. What is broad-sense heritability?
The ratio of total genetic variance to total phenotypic variance.
162. What is narrow-sense heritability?
The ratio of additive genetic variance to total phenotypic variance.
163. What is the significance of heritability?
Helps predict the response to selection in breeding programs.
164. What is a lethal allele?
An allele causing death, often in homozygous condition.
165. What is an example of a lethal allele?
The Manx cat tailless allele, lethal in homozygotes.
166. What is a conditional lethal allele?
An allele causing death only under specific conditions, e.g., temperature.
167. What is a semi-lethal allele?
An allele reducing viability but not always causing death.
168. What is a genetic mosaic?
An organism with cells of different genotypes, e.g., due to X-inactivation.
169. What is chimerism?
A condition where an organism has cells from two different zygotes.
170. What is the difference between mosaicism and chimerism?
Mosaicism arises from mutations in one zygote; chimerism from fusion of two zygotes.
171. What is the Hardy-Weinberg principle in genetics?
Allele and genotype frequencies remain constant in a population without evolutionary forces.
172. What are the conditions for Hardy-Weinberg equilibrium?
Large population, random mating, no mutation, no migration, no selection.
173. What is the significance of Hardy-Weinberg equilibrium?
Provides a baseline to detect evolutionary changes in populations.
174. What is the formula for Hardy-Weinberg equilibrium?
p^2 + 2pq + q^2
175. What does p^2 represent in Hardy-Weinberg equilibrium?
The frequency of the homozygous dominant genotype.
176. What does 2pq represent in Hardy-Weinberg equilibrium?
The frequency of the heterozygous genotype.
177. What does q^2 represent in Hardy-Weinberg equilibrium?
The frequency of the homozygous recessive genotype.
178. What is genetic drift in the context of inheritance?
Random changes in allele frequencies, affecting inheritance in small populations.
179. What is the bottleneck effect?
A reduction in genetic diversity due to a drastic population decrease.
180. What is the founder effect?
Reduced genetic diversity when a small group establishes a new population.
181. What is an example of the founder effect?
High prevalence of genetic disorders in isolated communities, e.g., Amish.
182. What is gene flow in genetics?
The transfer of alleles between populations, affecting inheritance patterns.
183. What is the effect of gene flow on genetic variation?
Increases genetic similarity between populations, reducing divergence.
184. What is a population in genetics?
A group of interbreeding individuals sharing a common gene pool.
185. What is a gene pool?
The total collection of alleles in a population.
186. What is allele frequency?
The proportion of a specific allele in a population’s gene pool.
187. What is the role of mutations in inheritance?
Introduce new alleles, altering inheritance patterns and genetic variation.
188. What is a spontaneous mutation?
A mutation occurring naturally without external agents.
189. What is an induced mutation?
A mutation caused by external agents like radiation or chemicals.
190. What is a somatic mutation?
A mutation in body cells, not passed to offspring.
191. What is a germline mutation?
A mutation in reproductive cells, passed to offspring.
192. What is the significance of germline mutations?
Can cause hereditary disorders or contribute to evolution.
193. What is a missense mutation?
A point mutation causing a single amino acid change in a protein.
194. What is a nonsense mutation?
A point mutation creating a stop codon, truncating the protein.
195. What is a silent mutation?
A point mutation that does not change the amino acid sequence.
196. What is the role of genetic drift in Mendelian disorders?
Can increase the frequency of harmful alleles in small populations.
197. What is consanguinity?
Marriage between close relatives, increasing recessive disorder risk.
198. What is the effect of consanguinity on genetic disorders?
Increases the chance of homozygous recessive genotypes, causing disorders.
199. What is a genetic screen?
A test to identify individuals with specific genetic traits or disorders.
200. What is newborn screening?
Testing infants for genetic disorders like PKU to enable early treatment.
201. What is carrier screening?
Testing individuals for recessive alleles to assess disorder risk in offspring.
202. What is prenatal screening?
Testing a fetus for genetic abnormalities during pregnancy.
203. What is the role of family history in genetics?
Helps identify inheritance patterns and disorder risks.
204. What is a proband in pedigree analysis?
The individual through whom a pedigree is initiated, often affected.
205. What is a consanguineous mating symbol in a pedigree?
A double line between mating individuals.
206. What is a sibship in a pedigree?
A group of siblings in a family, connected by a horizontal line.
207. What is a multifactorial disorder?
A disorder caused by multiple genes and environmental factors, e.g., diabetes.
208. What is the difference between Mendelian and multifactorial disorders?
Mendelian disorders follow single-gene patterns; multifactorial involve multiple genes and environment.
209. What is the role of twin studies in genetics?
Compare identical and fraternal twins to estimate genetic vs. environmental contributions.
210. What is concordance rate in twin studies?
The probability that both twins share a trait or disorder.
211. What is the significance of higher concordance in identical twins?
Indicates a stronger genetic influence on the trait.
212. What is a monozygotic twin?
Identical twins from a single fertilized egg, sharing nearly identical DNA.
213. What is a dizygotic twin?
Fraternal twins from two separate eggs, sharing about 50% of DNA.
214. What is the role of adoption studies in genetics?
Separate genetic and environmental influences by studying adopted individuals.
215. What is the significance of Mendel’s use of large sample sizes?
Ensured reliable statistical data for inheritance patterns.
216. What is the role of probability in genetics?
Predicts the likelihood of inheriting specific genotypes or phenotypes.
217. What is the product rule in genetics?
The probability of two independent events occurring together is the product of their individual probabilities.
218. What is the sum rule in genetics?
The probability of either of two mutually exclusive events occurring is the sum of their probabilities.
219. What is the chi-square test in genetics?
A statistical test to compare observed and expected genetic cross outcomes.
220. What is the significance of the chi-square test?
Determines if observed deviations from expected ratios are due to chance.
221. What is a null hypothesis in genetic experiments?
Assumes no significant difference between observed and expected results.
222. What is a p-value in genetic studies?
The probability that observed results occurred by chance under the null hypothesis.
223. What is a linkage group?
All genes on a single chromosome that tend to be inherited together.
224. What is the maximum recombination frequency between two genes?
50%, indicating they assort independently (unlinked).
225. What is a three-point cross?
A genetic cross involving three linked genes to map their relative positions.
226. What is the advantage of a three-point cross?
Provides more accurate gene mapping by analyzing multiple recombination events.
227. What is interference in genetics?
The effect of one crossover event reducing the likelihood of another nearby.
228. What is the coefficient of coincidence?
The ratio of observed to expected double crossover events.
229. What is the role of polytene chromosomes in genetics?
Allow visualization of gene locations due to their large size in certain cells.
230. What is a balancer chromosome?
A chromosome with inversions to prevent recombination, used in genetic studies.
231. What is a genetic marker in linkage studies?
A known DNA sequence used to track inheritance of nearby genes.
232. What is a restriction fragment length polymorphism (RFLP)?
A genetic marker based on variations in DNA fragment lengths after restriction enzyme digestion.
233. What is the role of RFLPs in genetics?
Used to map genes and diagnose genetic disorders.
234. What is a single nucleotide polymorphism (SNP)?
A variation at a single nucleotide position in the genome.
235. What is the significance of SNPs in genetics?
Serve as markers for disease-associated genes and population studies.
236. What is a haplotype?
A set of alleles inherited together on a chromosome segment.
237. What is linkage disequilibrium?
Non-random association of alleles at different loci, often due to linkage.
238. What is the role of linkage disequilibrium in genetics?
Aids in mapping disease genes by identifying associated markers.
239. What is a genetic map unit (cM)?
A centiMorgan, representing 1% recombination frequency between genes.
240. What is the difference between genetic and physical maps?
Genetic maps show recombination distances; physical maps show actual DNA base pair distances.
241. What is a quantitative trait locus (QTL)?
A genomic region contributing to a polygenic trait’s variation.
242. What is the role of QTL mapping?
Identifies genes influencing complex traits like height or yield.
243. What is a genome-wide association study (GWAS)?
A study identifying genetic variants associated with traits or diseases across the genome.
244. What is the significance of GWAS in genetics?
Links SNPs to diseases, aiding in personalized medicine.
245. What is a candidate gene?
A gene suspected to influence a trait based on its function or location.
246. What is a knockout mutation?
A mutation that inactivates a gene to study its function.
247. What is a transgenic organism?
An organism with a foreign gene introduced into its genome.
248. What is the role of transgenic organisms in genetics?
Study gene functions or model human genetic disorders.
249. What is a model organism in genetics?
An organism like Drosophila or mice used to study genetic principles.
250. Why is Drosophila a model organism?
Short generation time, large offspring, and easily observable traits.
251. What is the role of Arabidopsis in plant genetics?
A model plant for studying inheritance and gene function.
252. What is a genetic stock center?
A facility maintaining strains with specific genotypes for research.
253. What is a mutant phenotype?
An altered trait resulting from a genetic mutation.
254. What is a wild-type phenotype?
The standard or most common phenotype in a population.
255. What is a suppressor mutation?
A second mutation that restores the function lost by an initial mutation.
256. What is an enhancer mutation?
A second mutation that increases the severity of an initial mutation.
257. What is a synthetic lethal mutation?
A combination of two mutations that is lethal, though each alone is not.
258. What is the role of mutations in genetic disorders?
Cause abnormal gene function, leading to disease phenotypes.
259. What is a gain-of-function mutation?
A mutation increasing a gene’s activity or creating a new function.
260. What is a loss-of-function mutation?
A mutation reducing or eliminating a gene’s function.
261. What is a dominant negative mutation?
A mutation producing a defective protein that disrupts normal protein function.
262. What is a haploinsufficiency?
A condition where one functional allele is insufficient for normal function.
263. What is the role of genetic imprinting in inheritance?
Genes are expressed differently based on parental origin.
264. What is an example of genetic imprinting?
Prader-Willi and Angelman syndromes, caused by deletions in chromosome 15.
265. What is Prader-Willi syndrome?
A disorder caused by paternal chromosome 15 deletion, leading to obesity and intellectual disability.
266. What is Angelman syndrome?
A disorder caused by maternal chromosome 15 deletion, causing seizures and developmental delays.
267. What is uniparental disomy?
Inheriting both copies of a chromosome from one parent, potentially causing disorders.
268. What is the role of epigenetics in inheritance?
Heritable changes in gene expression without DNA sequence changes, e.g., methylation.
269. What is DNA methylation?
Addition of methyl groups to DNA, silencing gene expression.
270. What is histone modification?
Chemical changes to histone proteins, affecting gene accessibility.
271. What is the significance of epigenetics in genetic disorders?
Can alter gene expression, contributing to diseases like cancer.
272. What is a trinucleotide repeat expansion?
An increase in repeated three-nucleotide sequences, causing disorders.
273. What is an example of a trinucleotide repeat disorder?
Huntington’s disease, caused by CAG repeat expansion.
274. What is anticipation in genetics?
Increased severity or earlier onset of a disorder in successive generations.
275. What is the cause of anticipation?
Expansion of trinucleotide repeats during gamete formation.
276. What is Fragile X syndrome?
A disorder caused by CGG repeat expansion, leading to intellectual disability.
277. What is the inheritance pattern of Fragile X syndrome?
X-linked dominant with variable penetrance.
278. What is myotonic dystrophy?
A disorder caused by CTG repeat expansion, causing muscle weakness.
279. What is the role of genetic testing?
Identifies mutations to diagnose or predict genetic disorders.
280. What is direct-to-consumer genetic testing?
Commercial tests providing genetic information without medical supervision.
281. What is the ethical concern with genetic testing?
Privacy, discrimination, and psychological impact of results.
282. What is the Genetic Information Nondiscrimination Act (GINA)?
A U.S. law preventing discrimination based on genetic information.
283. What is preimplantation genetic diagnosis (PGD)?
Testing embryos for genetic disorders before implantation in IVF.
284. What is the advantage of PGD?
Prevents transmission of severe genetic disorders to offspring.
285. What is a genetic predisposition?
An increased likelihood of developing a disorder due to genetic factors.
286. What is an example of a genetic predisposition?
BRCA1/2 mutations increasing breast cancer risk.
287. What is the role of genetic diversity in populations?
Enhances adaptability and survival against environmental changes.
288. What is the role of inbreeding in genetics?
Increases homozygosity, raising recessive disorder risk.
289. What is outbreeding?
Mating between unrelated individuals, increasing heterozygosity.
290. What is hybrid vigor?
Enhanced traits in offspring from outbreeding, also called heterosis.
291. What is an example of hybrid vigor?
Increased yield in hybrid corn varieties.
292. What is the role of selective breeding in genetics?
Enhances desired traits through controlled mating, e.g., in crops or livestock.
293. What is the role of genetic drift in small populations?
Can fix or eliminate alleles, affecting inheritance patterns.
294. What is the role of natural selection in inheritance?
Favors alleles enhancing survival, shaping inheritance patterns.
295. What is stabilizing selection?
Selection favoring intermediate traits, maintaining genetic stability.
296. What is an example of stabilizing selection?
Human birth weight, where average weights are optimal.
297. What is directional selection?
Selection favoring one extreme trait, shifting allele frequencies.
298. What is an example of directional selection?
Antibiotic resistance in bacteria, favoring resistant alleles.
299. What is disruptive selection?
Selection favoring extreme traits, increasing genetic variation.
300. What is an example of disruptive selection?
Beak size in finches, favoring large or small beaks.
301. What is balancing selection?
Selection maintaining genetic diversity, e.g., heterozygote advantage.
302. What is an example of balancing selection?
Sickle-cell trait, providing malaria resistance in heterozygotes.
303. What is sexual selection?
Selection based on traits improving mating success, influencing inheritance.
304. What is an example of sexual selection?
Bright plumage in male peacocks, preferred by females.
305. What is intrasexual selection?
Competition within a sex for mating opportunities, e.g., male combat.
306. What is intersexual selection?
Mate choice by one sex based on traits of the other, e.g., female choice.
307. What is the role of assortative mating in genetics?
Non-random mating based on traits, altering allele frequencies.
308. What is an example of assortative mating?
Humans choosing partners based on similar height or intelligence.
309. What is the role of random mating in genetics?
Maintains genetic equilibrium by preventing allele frequency changes.
310. What is the role of population size in inheritance?
Small populations are more susceptible to genetic drift, altering inheritance.
311. What is inbreeding depression?
Reduced fitness due to increased homozygosity in inbred populations.
312. What is an example of inbreeding depression?
Reduced fertility in captive cheetah populations.
313. What is the role of genetic load?
Accumulation of deleterious alleles reducing population fitness.
314. What is the role of genetic counseling in inheritance?
Helps families understand and manage inherited disorder risks.
315. What is the role of genetic engineering in inheritance?
Modifies genes to alter inheritance patterns, e.g., in GMOs.
316. What is an example of genetic engineering affecting inheritance?
Introduction of pest-resistant genes in crops, passed to offspring.
317. What is the role of CRISPR in genetics?
A precise gene-editing tool to modify DNA, affecting inheritance.
318. What is the ethical concern with CRISPR?
Potential for unintended genetic changes or designer babies.
319. What is the role of gene therapy in genetic disorders?
Introduces functional genes to correct defective ones, altering inheritance.
320. What is an example of gene therapy?
Treatment for severe combined immunodeficiency (SCID) using viral vectors.
321. What is the role of pharmacogenomics?
Studies how genes affect drug response, tailoring treatments.
322. What is an example of pharmacogenomics?
Testing for CYP2C19 gene variants to guide anticoagulant dosing.
323. What is the role of population genetics?
Studies allele frequency changes to understand inheritance patterns.
324. What is the role of conservation genetics?
Preserves genetic diversity to maintain healthy populations.
325. What is an example of conservation genetics?
Managing breeding programs for endangered species like pandas.
326. What is the role of forensic genetics?
Uses DNA to identify individuals or solve paternity disputes.
327. What is a DNA fingerprint?
A unique pattern of DNA markers used for identification.
328. What is the role of mitochondrial DNA in inheritance?
Inherited maternally, used to trace lineage or diagnose disorders.
329. What is a mitochondrial disorder?
A disorder caused by mutations in mitochondrial DNA, e.g., LHON.
330. What is Leber’s Hereditary Optic Neuropathy (LHON)?
A mitochondrial disorder causing vision loss, inherited maternally.
331. What is the inheritance pattern of mitochondrial disorders?
Maternal inheritance, as mitochondria are passed via the egg.
332. What is heteroplasmy?
Presence of both normal and mutated mitochondrial DNA in cells.
333. What is the significance of heteroplasmy?
Influences the severity of mitochondrial disorders.
334. What is a pedigree-based disease risk?
The likelihood of inheriting a disorder based on family history.
335. What is the role of genetic databases?
Store genetic data for research, diagnosis, and population studies.
336. What is the Human Genome Project?
A global effort to sequence the entire human genome, aiding genetic studies.
337. What is the significance of the Human Genome Project?
Identified genes and variants linked to disorders, improving diagnostics.
338. What is a genome?
The complete set of genetic material in an organism.
339. What is genomics?
The study of genomes, including structure, function, and inheritance.
340. What is functional genomics?
Studies gene functions and interactions to understand inheritance.
341. What is comparative genomics?
Compares genomes across species to study evolutionary inheritance.
342. What is the role of bioinformatics in genetics?
Analyzes genetic data to identify inheritance patterns and mutations.
343. What is a genetic algorithm?
A computational method inspired by natural selection to solve problems.
344. What is the role of genetic algorithms in research?
Optimize models for predicting inheritance or disease risk.
345. What is the role of genetic variation in evolution?
Provides raw material for natural selection and adaptation.
346. What is the role of genetic variation in medicine?
Influences disease susceptibility and drug response.
347. What is the role of genetic variation in agriculture?
Enables breeding for improved traits like yield or resistance.
348. What is the role of genetic variation in conservation?
Ensures population resilience against environmental changes.
349. What is a genetic bottleneck?
A sharp reduction in population size, reducing genetic variation.
350. What is an example of a genetic bottleneck?
Northern elephant seals, with low diversity due to past hunting.
351. What is the role of genetic drift in conservation?
Can reduce variation in small populations, increasing extinction risk.
352. What is the minimum viable population size?
The smallest population needed to avoid inbreeding and maintain variation.
353. What is genetic rescue?
Introducing genetic variation to boost fitness in endangered populations.
354. What is an example of genetic rescue?
Translocating individuals to increase diversity in isolated wolf populations.
355. What is the role of genetic markers in breeding?
Identify desirable traits for selective breeding programs.
356. What is marker-assisted selection?
Using genetic markers to select individuals with desired traits.
357. What is the advantage of marker-assisted selection?
Increases breeding efficiency by targeting specific genes.
358. What is the role of genetic diversity in crop improvement?
Provides alleles for resistance to pests, diseases, or climate stress.
359. What is the role of landraces in agriculture?
Traditional crop varieties with high genetic diversity for breeding.
360. What is the role of gene banks?
Store genetic material to preserve diversity for future breeding.
361. What is the role of genetic studies in anthropology?
Trace human migration and population history through inheritance.
362. What is the role of genetic studies in forensics?
Use DNA to resolve paternity, identity, or criminal cases.
363. What is the role of genetic studies in personalized medicine?
Tailor treatments based on individual genetic profiles.
364. What is the role of genetic studies in biotechnology?
Develop genetically modified organisms with desired traits.
365. What is the role of genetic studies in evolutionary biology?
Understand how inheritance drives species diversification.
366. What is the role of genetic studies in ecology?
Analyze population structure and adaptation to environments.
367. What is the role of genetic studies in conservation biology?
Guide strategies to maintain genetic diversity in endangered species.
368. What is the future of genetic studies in inheritance?
Advancements in gene editing, genomics, and personalized medicine.
369. What is the role of public awareness in genetics?
Promotes informed decisions on genetic testing and GMOs.
370. What is the role of ethics in genetics?
Addresses concerns like genetic privacy, discrimination, and modification.
371. What is the role of genetic literacy?
Enables understanding of inheritance and its societal implications.
372. What is the role of genetic research in policy?
Informs regulations on genetic testing, GMOs, and conservation.
373. What is the role of interdisciplinary approaches in genetics?
Combines biology, computing, and ethics for comprehensive insights.
374. What is the role of genetic education in schools?
Builds foundational knowledge of inheritance for future generations.
375. What is the role of genetic counseling in public health?
Reduces the burden of genetic disorders through early intervention.
376. What is the role of genetic research in global health?
Addresses inherited diseases and population-specific health risks.
377. What is the role of genetic research in sustainable development?
Enhances crop resilience and biodiversity for food security.
378. What is the role of genetic research in addressing climate change?
Develops organisms adapted to changing environments.
379. What is the role of genetic research in understanding aging?
Identifies genes influencing longevity and age-related disorders.
380. What is an example of a gene linked to aging?
FOXO3, associated with longevity in humans.
381. What is the role of genetic research in understanding behavior?
Links genes to traits like aggression or intelligence.
382. What is an example of a behavior-linked gene?
MAOA gene, associated with aggression in some studies.
383. What is the role of genetic research in understanding disease?
Identifies mutations causing or predisposing to disorders.
384. What is the role of genetic research in understanding diversity?
Explains variation in traits across populations and species.
385. What is the role of genetic research in understanding adaptation?
Identifies genes enabling organisms to survive specific environments.
386. What is an example of an adaptation-linked gene?
EPAS1, enabling high-altitude adaptation in Tibetans.
387. What is the role of genetic research in understanding reproduction?
Studies genes controlling fertility and inheritance patterns.
388. What is the role of genetic research in understanding development?
Identifies genes regulating growth and differentiation.
389. What is an example of a developmental gene?
Hox genes, controlling body segmentation.
390. What is the role of genetic research in understanding immunity?
Links genes to immune responses and disease resistance.
391. What is an example of an immunity-linked gene?
HLA genes, influencing immune system diversity.
392. What is the role of genetic research in understanding evolution?
Traces inheritance patterns to explain species divergence.
393. What is the role of genetic research in understanding ecosystems?
Studies genetic interactions shaping ecological communities.
394. What is the role of genetic research in understanding conservation?
Guides preservation of genetic diversity for ecosystem stability.
395. What is the role of genetic research in understanding agriculture?
Improves crops and livestock through targeted breeding.
396. What is the role of genetic research in understanding medicine?
Develops diagnostics and treatments for genetic disorders.
397. What is the role of genetic research in understanding biotechnology?
Drives innovation in gene editing and synthetic biology.
398. What is the role of genetic research in understanding society?
Explains inherited traits influencing culture and behavior.
399. What is the role of genetic research in understanding the future?
Predicts how genetic advances will shape health and technology.
400. What is the molecular basis of inheritance?
The process by which genetic information encoded in DNA is passed from one generation to the next.
401. What is DNA?
Deoxyribonucleic acid, a double-stranded molecule carrying genetic information.
402. What is the role of DNA in inheritance?
Stores and transmits genetic information from parents to offspring.
403. What are the components of a DNA nucleotide?
A sugar (deoxyribose), a phosphate group, and a nitrogenous base.
404. What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
405. What is the structure of DNA?
A double helix with two antiparallel strands held by hydrogen bonds between bases.
406. Who proposed the double helix model of DNA?
James Watson and Francis Crick in 1953.
407. What is base pairing in DNA?
Adenine pairs with Thymine (A-T) and Guanine pairs with Cytosine (G-C).
408. How many hydrogen bonds are between A-T base pairs?
Two hydrogen bonds.
409. How many hydrogen bonds are between G-C base pairs?
Three hydrogen bonds.
410. What is the sugar-phosphate backbone in DNA?
Alternating sugar and phosphate groups forming the structural framework of DNA strands.
411. What is the significance of the antiparallel nature of DNA strands?
One strand runs 5’ to 3’, the other 3’ to 5’, enabling accurate replication.
412. What is a genome?
413. What is chromatin?
A complex of DNA and proteins (histones) in the nucleus of eukaryotic cells.
414. What is a nucleosome?
DNA wrapped around histone proteins, the basic unit of chromatin.
415. What is the role of histones in DNA packaging?
Compact DNA into chromatin, making it fit within the nucleus.
416. What is a chromosome?
A condensed structure of DNA and proteins carrying genetic information.
417. How many chromosomes are present in a human somatic cell?
46 chromosomes (23 pairs).
418. What is a gene?
A segment of DNA that codes for a functional product, usually a protein.
419. What is the central dogma of molecular biology?
Genetic information flows from DNA to RNA to protein.
420. Who proposed the central dogma?
Francis Crick.
421. What is DNA replication?
The process of copying DNA to produce two identical daughter strands.
422. What is the significance of DNA replication?
Ensures genetic information is passed to daughter cells during cell division.
423. What is the mode of DNA replication?
Semi-conservative, where each new DNA molecule contains one parental and one new strand.
424. Who demonstrated the semi-conservative nature of DNA replication?
Matthew Meselson and Franklin Stahl in 1958.
425. What is the role of the origin of replication?
The specific site on DNA where replication begins.
426. What is a replication fork?
The Y-shaped region where DNA strands are separated during replication.
427. What enzyme unwinds the DNA double helix during replication?
DNA helicase.
428. What is the role of single-strand binding proteins in replication?
Stabilize separated DNA strands to prevent reannealing.
429. What enzyme relieves the tension caused by DNA unwinding?
Topoisomerase (e.g., DNA gyrase).
430. What is a primer in DNA replication?
A short RNA sequence providing a starting point for DNA synthesis.
431. What enzyme synthesizes the RNA primer?
Primase.
432. What is the main enzyme in DNA replication?
DNA polymerase.
433. What is the role of DNA polymerase III in bacteria?
Synthesizes new DNA strands by adding nucleotides in the 5’ to 3’ direction.
434. What is the leading strand in DNA replication?
The strand synthesized continuously in the 5’ to 3’ direction toward the replication fork.
435. What is the lagging strand in DNA replication?
The strand synthesized discontinuously in short fragments away from the replication fork.
436. What are Okazaki fragments?
Short DNA segments synthesized on the lagging strand during replication.
437. What enzyme joins Okazaki fragments?
DNA ligase.
438. What is the role of DNA polymerase I in bacteria?
Removes RNA primers and replaces them with DNA.
439. What is proofreading in DNA replication?
The process by which DNA polymerase corrects mismatched nucleotides.
440. What is the fidelity of DNA replication?
The high accuracy of DNA replication due to proofreading and repair mechanisms.
441. What is a telomere?
The repetitive DNA sequence at the ends of eukaryotic chromosomes.
442. What is the role of telomeres?
Protect chromosome ends from degradation and fusion.
443. What is telomerase?
An enzyme that adds telomeric DNA to chromosome ends, preventing shortening.
444. What is the significance of telomerase in cancer cells?
Enables unlimited cell division by maintaining telomere length.
445. What is RNA?
Ribonucleic acid, a single-stranded molecule involved in gene expression.
446. What are the differences between DNA and RNA?
DNA has deoxyribose and thymine; RNA has ribose and uracil.
447. What are the types of RNA?
Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
448. What is the role of mRNA?
Carries genetic information from DNA to ribosomes for protein synthesis.
449. What is the role of tRNA?
Transports amino acids to ribosomes during translation.
450. What is the role of rRNA?
Forms the structural and catalytic core of ribosomes.
451. What is transcription?
The synthesis of RNA from a DNA template.
452. What is the template strand in transcription?
The DNA strand used as a template for RNA synthesis.
453. What is the coding strand in transcription?
The DNA strand with the same sequence as the RNA (except T for U).
454. What enzyme catalyzes transcription?
RNA polymerase.
455. What are the stages of transcription?
Initiation, elongation, and termination.
456. What is a promoter in transcription?
A DNA sequence where RNA polymerase binds to initiate transcription.
457. What is the role of the sigma factor in bacterial transcription?
Helps RNA polymerase bind to the promoter.
458. What is the transcription unit?
The DNA segment transcribed into a single RNA molecule, including promoter and terminator.
459. What happens during transcription initiation?
RNA polymerase binds to the promoter and unwinds DNA.
460. What happens during transcription elongation?
RNA polymerase synthesizes RNA in the 5’ to 3’ direction.
461. What happens during transcription termination?
RNA polymerase releases the RNA and detaches from DNA.
462. What is a terminator sequence?
A DNA sequence signaling the end of transcription.
463. What is the difference between prokaryotic and eukaryotic transcription?
Prokaryotes have one RNA polymerase; eukaryotes have three and require transcription factors.
464. What are transcription factors?
Proteins that help RNA polymerase bind to eukaryotic promoters.
465. What is RNA polymerase II in eukaryotes?
The enzyme transcribing mRNA and some non-coding RNAs.
466. What is RNA processing in eukaryotes?
Modification of pre-mRNA before it becomes mature mRNA.
467. What are the steps of RNA processing in eukaryotes?
5’ capping, polyadenylation, and splicing.
468. What is the 5’ cap in RNA processing?
A modified guanine nucleotide added to the 5’ end of mRNA.
469. What is the role of the 5’ cap?
Protects mRNA from degradation and aids ribosome binding.
470. What is polyadenylation?
Addition of a poly-A tail (adenine nucleotides) to the 3’ end of mRNA.
471. What is the role of the poly-A tail?
Enhances mRNA stability and export from the nucleus.
472. What is splicing in RNA processing?
Removal of introns and joining of exons in pre-mRNA.
473. What are introns?
Non-coding sequences in eukaryotic genes that are removed during splicing.
474. What are exons?
Coding sequences in eukaryotic genes that are retained in mature mRNA.
475. What is the spliceosome?
A complex of proteins and small nuclear RNAs (snRNAs) that performs splicing.
476. What is alternative splicing?
The process of producing different mRNAs from the same gene by varying exon inclusion.
477. What is the significance of alternative splicing?
Increases protein diversity from a single gene.
478. What is translation?
The synthesis of a protein from mRNA at the ribosome.
479. What is the genetic code?
The set of rules by which codons in mRNA are translated into amino acids.
480. What is a codon?
A sequence of three nucleotides in mRNA that specifies an amino acid or stop signal.
481. How many codons are in the genetic code?
64 codons (61 for amino acids, 3 stop codons).
482. What is the start codon?
AUG, which codes for methionine and initiates translation.
483. What are stop codons?
UAA, UAG, and UGA, which signal the end of translation.
484. What is the characteristic of the genetic code?
Universal, specific, degenerate, and non-overlapping.
485. What does degenerate mean in the genetic code?
Multiple codons can code for the same amino acid.
486. What is a ribosome?
A cellular structure where translation occurs, composed of rRNA and proteins.
487. What are the subunits of a eukaryotic ribosome?
60S (large) and 40S (small), forming an 80S ribosome.
488. What are the subunits of a prokaryotic ribosome?
50S (large) and 30S (small), forming a 70S ribosome.
489. What are the stages of translation?
490. What happens during translation initiation?
The ribosome assembles on mRNA, and tRNA brings the start codon’s amino acid.
491. What is the role of the initiator tRNA?
Carries methionine (in eukaryotes) to the start codon.
492. What is the P site in a ribosome?
The peptidyl site, holding the tRNA with the growing polypeptide chain.
493. What is the A site in a ribosome?
The aminoacyl site, holding the incoming tRNA with its amino acid.
494. What is the E site in a ribosome?
The exit site, where tRNA leaves after releasing its amino acid.
495. What happens during translation elongation?
Amino acids are added to the polypeptide chain as the ribosome moves along mRNA.
496. What enzyme catalyzes peptide bond formation during translation?
Peptidyl transferase, part of the ribosome’s large subunit.
497. What is the role of elongation factors in translation?
Assist in tRNA binding and ribosome movement along mRNA.
498. What happens during translation termination?
A stop codon is reached, and the polypeptide is released.
499. What are release factors?
Proteins that recognize stop codons and trigger polypeptide release.
500. What is a polysome?
Multiple ribosomes translating the same mRNA simultaneously.
501. What is the significance of polysomes?
Increases the efficiency of protein synthesis.
502. What is post-translational modification?
Chemical changes to proteins after translation, e.g., phosphorylation or glycosylation.
503. What is the role of post-translational modification?
Regulates protein function, stability, or localization.
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