Biology 106 KEY Dr. Dudash

Study Questions Fall 1999

Study Questions Set #1 - Handed out September 8, 1999.

Due: In Lab the following week.

All answers MUST be TYPED unless mathematical computation is needed.

Use no more than 3/4 of a page of single spaced typed text.

Please answer 3 of the following questions:

1. What are the evolutionary implications of meiosis?

A. Reassortment of genetic material produces a tremendous amount of genetic variability.

B. Reassortment occurs in two ways: (1) x-over , and (2) random alignment of chromo. before division.

C. Potential Genetic Variability? GREAT!!!!!

2. How does Meiosis differ from Mitosis? List three ways.

1. Homologous chromosomes pair lengthwise and chromatids exchange genetic material by x-over.

2. Sister chromatids do not separate from one another in the first nuclear division.

3. Chromosomes do not replicate between the two nuclear divisions.

3. What are Mendel's Laws of Inheritance? How are they related to each other?

Mendel's Law of Segregation: The alternative forms of a gene (alleles) are discrete and do not blend. Alleles segregate from each other during gamete formation, so that each gamete carries only one allele of each gene pair

Mendel's Law of Independent Assortment: In dihybrid crosses the gene pairs for two different traits are distributed to gametes independently. Genes do not remain in same combination as parents

Both alleles of any given gene and multiple genes for a trait act independently.

4. What is the Product Rule/Law? Provide an example to demonstrate how to apply it.

Product Rule or Law: based on probability of independent events

ex., Dihybrid Cross:

Hybrid heterozygous for two traits

Round & yellow seed x wrinkled & green

RRYY x rryy Parents

RrYy F1

3/4 Round x 3/4 Yellow = 9/16 F2 are Round and Yellow

5. List/describe three types of mutations.

1. Gene mutations

a. point mutation (single amino acid change in protein)

b. frame-shift mutations (many changes in protein)

c. unequal crossing over

2. Chromosome mutations

a. chromosomal rearrangements; 1. inversions (change in gene order):

3. Translocations (movement of chromosome parts to other chromosomes)