Unit 5

Question 1

Genotype

Answer 1

A combination of alleles an individual has, codes for the phenotype

Question 2

Phenotype

Answer 2

Physical traits of an individual

Question 3

Alleles

Answer 3

Different versions of a gene

Question 4

Heterozygous

Answer 4

Has two different alleles (Ff)

Question 5

Homozygous

Answer 5

Has two of the same allele
There is homozygous dominant (FF) and homozygous recessive (ff)

Question 6

True-breeding

Answer 6

Parents produce offspring that all have the same phenotype, this means the parents are homozygous for every trait

Question 7

Diploid

Answer 7

A cell with two sets of chromosomes

Question 8

Haploid

Answer 8

A cell with one set of chromosomes

Question 9

Homologous chromosomes

Answer 9

2 chromosomes in a pair, code for the same type of phenotype

Question 10

Linked genes

Answer 10

Genes that are close or directly next to each other on the same chromosome and are inherited together

Question 11

Sex-linked genes

Answer 11

Genes located on a sex chromosome

Question 12

What are the similarities between mitosis and meiosis

Answer 12

• Nuclear envelope disappears
• DNA coils into chromosomes
• Chromosomes align in the center of the cell
• Fibers separate chromosomes
  nuclear envelope reappears
• Chromosomes uncoil
• Followed by cytokinesis and the production of daughter cells

Question 13

What are the differences between mitosis and meiosis

Answer 13

Mitosis:
- Creates 2 daughter cells
- Creates cells that are genetically identical to each other and the parent cell
- Conserves the number of chromosome sets
- Sister chromatid cohesins are cleaved at the end of metaphase
Meiosis:
- Creates 4 daughter cells
- Creates cells that are genetically varied
- Reduces the number of chromosome sets from 2 diploid to 1 haploid
- Cohesins between homologs are cleaved in anaphase 1 and between sister chromatids in anaphase 2
- Has synapsis/crossing over in prophase 1
- During metaphase 1 homologous pairs align at the metaphase plate
- During anaphase 1 homologs are separated

Question 14

How does meiosis generate genetic diversity

Answer 14

• independent assortment of chromosomes
• crossing over
• random fertilization

Question 15

What are the advantages of sexual reproduction

Answer 15

Creates genetic variation in offspring

Question 16

How does the environment affect phenotype

Answer 16

The same genotype can have different phenotypes depending on the environment of the individual

Question 17

How does the movement of chromosomes during meiosis explain Mendel’s Law of Segregation of alleles

Answer 17

Law - two alleles for a given trait separate from each other giving the gametes only one allele for the trait. This way offspring inherit one allele from each parent
Meiosis - During anaphase, the chromosomes are pulled apart and separated into different gametes

Question 18

How does the movement of chromosomes during meiosis explain Mendel’s Law of Independent Assortment

Answer 18

Law - Genes separate independently during gamete formation. The allele a gamete receives for one gene doesn’t affect the allele it receives for another gene
Meiosis - During metaphase, the chromosomes randomly line up at the metaphase plate

Question 19

What is responsible for aneuploidy

Answer 19

The fertilization of gametes in which nondisjunction occurred

Question 20

What is nondisjunction

Answer 20

A pair of homologs doesn’t separate normally in meiosis resulting in gametes with two of the same chromosome or none