3.4 Inheritance

Question 1

What experiments led Mendel to discover the principles of inheritance?

Answer 1

Mendel’s experiments with pea plants, crossing large numbers, revealed inheritance principles.

Question 2

What are Mendel’s principles of inheritance?

Answer 2

Mendel outlined segregation, independent assortment, and dominance.

Question 3

Why do gametes contain only one allele of each gene?

Answer 3

Gametes are haploid, carrying one allele per gene due to meiosis.

Question 4

How do alleles of each gene separate during meiosis?

Answer 4

Alleles segregate into different haploid daughter nuclei during meiosis.

Question 5

What results from the fusion of gametes in terms of zygote’s alleles?

Answer 5

Fusion results in diploid zygotes with two alleles of each gene, same or different.

Question 6

How do dominant and co-dominant alleles affect phenotype?

Answer 6

Dominant alleles mask recessive ones; co-dominant alleles have joint effects.

Question 7

How do you construct Punnett grids for monohybrid crosses?

Answer 7

Punnett grids predict genetic crosses’ outcomes by aligning parents’ alleles.

Question 8

Describe the inheritance of ABO blood groups.

Answer 8

ABO inheritance involves co-dominant (IA, IB) and recessive (i) alleles.

Question 9

What genetic basis underlies many human diseases?

Answer 9

Diseases often stem from recessive autosomal alleles; some involve dominant/co-dominant alleles.

Question 10

Explain the inheritance of sex-linked diseases.

Answer 10

Sex-linked diseases result from alleles on sex chromosomes, affecting males and females differently.

Question 11

How is the inheritance pattern different for sex-linked genes?

Answer 11

Sex-linked inheritance varies with the gene’s sex chromosome location, affecting males and females differently.

Question 12

State the mutation rate increase due to radiation and chemicals.

Answer 12

Radiation and chemicals can significantly elevate mutation rates, leading to diseases and cancer.

Question 13

Outline the consequences of radiation exposure in Hiroshima and Chernobyl.

Answer 13

Radiation caused genetic diseases, cancer, and acute radiation syndrome in affected populations.

Question 14

How do actual genetic cross outcomes compare to predicted ones?

Answer 14

Actual outcomes may differ from predictions due to random genetic events; large sample sizes reduce this discrepancy.

Question 15

What are the principles of inheritance outlined by Mendel?

Answer 15

Mendel’s principles include segregation, independent assortment, and dominance in heredity.

Question 16

What role does meiosis play in genetic diversity?

Answer 16

Meiosis results in haploid gametes with one allele of each gene, leading to genetic diversity.

Question 17

How does the fusion of gametes form zygotes?

Answer 17

Gametes’ fusion forms diploid zygotes, combining two alleles of each gene from each parent.

Question 18

Describe the genetic basis for cystic fibrosis.

Answer 18

Cystic fibrosis is caused by recessive alleles of the CFTR gene on chromosome 7.

Question 19

Explain the genetic mechanism behind Huntington’s disease.

Answer 19

Huntington’s disease results from a dominant allele of the HTT gene on chromosome 4.

Question 20

How are red-green colour blindness and hemophilia inherited?

Answer 20

Both disorders are X-linked, with colour blindness being recessive and hemophilia affecting mostly males.

Question 21

What does analyzing pedigree charts reveal about genetic diseases?

Answer 21

Pedigree charts help deduce inheritance patterns, distinguishing between dominant, recessive, and sex-linked traits.

Question 22

How do mutations lead to genetic diseases and cancer?

Answer 22

Mutations, often caused by radiation and chemicals, can alter DNA, leading to diseases and cancers.

Question 23

Discuss the impact of the Hiroshima bombing and Chernobyl accident on human genetics.

Answer 23

Both events led to increased radiation exposure, causing mutations, genetic diseases, and cancers in affected populations.

Question 24

How does the actual outcome of genetic crosses compare to predicted outcomes?

Answer 24

Actual outcomes may vary due to random genetic variations; large sample sizes can help align predictions with reality.

Question 25

Why are dominant alleles able to mask recessive alleles?

Answer 25

Dominant alleles express their trait even when paired with a different allele, masking recessive alleles’ effects unless in a homozygous recessive pair.

Question 26

How do Punnett grids help predict genetic cross outcomes?

Answer 26

Punnett grids visually represent possible genetic combinations from parents, predicting offspring’s phenotypes.

Question 27

What illustrates the importance of understanding blood group inheritance for transfusions?

Answer 27

Knowing ABO blood group inheritance is crucial for safe blood transfusions, avoiding immune reactions.