Question

Multiple choice:

1- Which of the following is a component of the total variability of a trait?

A. additive effects of alleles

B. dominance interactions among alleles

C. environmental effects

D. epistatic relationships among alleles

E. all of the above

2- Which of the following is not an example of a multifactorial disorder?

A. cystic fibrosis

B. diabetes        

C. hypertension             

D. obesity          

E. partial epilepsy

3- Cells with four of each of the basic chromosome number are:

A. tetraploid (2N).

4- What is the chromosomal basis for Mendel's principles of segregation and independent assortment?

A. independent behavior of pairs of chromosomes during the first meiotic division

B. disjunction of chromosomes during meiosis

C. during anaphase of the first meiotic division chromosomes join

D. all of the above

E. A and B

B. haploid (N).               

C. diploid (4N).              

D. tetraploid (4N).                                                                                       

E. diploid (2N).

Answer 1

1- Which of the following is a component of the total variability of a trait?

answer- Option E

reason-  total variance (V_t) of a quantitative trait in an outbred population into variance due to environment (V_e), additive genetic effects (V_a), dominance (V_d), and epistasis (V_I).

2..Which of the following is not an example of a multifactorial disorder?

Answeris option A

Reason:cystic fibrosis is a autosomal recessive disorder.All others like diabetes hypertension,obesity and partial epilepsy result due a number of risk factors.

3- Cells with four of each of the basic chromosome number are:

answer is Option D- TETRAPLOID (4N)

When there is a single set of chromosome - HAPLOID(N)

When there is a two set of identical chromosome-DIPLOID(2N)

When there is a 3 set of identical chromosome -TRIPLOID(3N)

When there is 4 set of identical chromosome - TETRAPLOID (4N)

4- What is the chromosomal basis for Mendel's principles of segregation and independent assortment?

Answer- Option C - BOTH A AND B

REASON-

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop.

The pulling apart of either homologous chromosomes or sister chromatids is called disjunction and occurs during anaphase of meiosis I or meiosis II.