FINALS CHAPTER 12: GENETICS

Question 1

Define allele

Answer 1

Different forms of a gene

Question 2

What is a dominant allele?

Answer 2

A gene that carries a trait that will always be expressed

Question 3

What is a recessive allele?

Answer 3

A gene that carries a trait that will only be expressed when there is no dominant trait present

Question 4

Define homozygous

Answer 4

Having two identical alleles for a gene (GG or gg)

Question 5

Define heterozygous

Answer 5

Having two different alleles for a gene (Gg)

Question 6

Are homozygous genes dominant or recessive?

Answer 6

Either; can have both dominant or both recessive alleles

Question 7

Are heterozygous genes dominant or recessive?

Answer 7

Dominant; has to carry at least 1 dominant allele

Question 8

Define genotype

Answer 8

The genetic make up of an organism or what alleles are present in a gene

Question 9

Examples of genotypes

Answer 9

Homozygous and heterozygous

Question 10

Define phenotype

Answer 10

What physical trait an organism expresses

Question 11

Examples of phenotypes

Answer 11

Green vs yellow pea pods
Brown vs blue eyes

Question 12

Can organisms have the same phenotype but different genotypes?

Answer 12

Yes; Homozygous dominant and heterozygous genotypes will both give you the dominant phenotype

Question 13

Can organisms have the same genotype but different phenotypes?

Answer 13

No; each genotype will give you either the dominant or recessive phenotype

Question 14

Define gamete

Answer 14

Sex cells that contain half the normal number of chromosomes

Question 15

Define diploid

Answer 15

A cell containing both sets of chromosomes

Question 16

What symbol is used to represent a diploid cell?

Answer 16

2N

Question 17

Define haploid

Answer 17

Cells containing only one version of the chromosome

Question 18

What symbol is used to represent a haploid cell?

Answer 18

1N or N

Question 19

What are the two main phases of meiosis?

Answer 19

Meiosis I and meiosis II

Question 20

When does interphase occur in meiosis?

Answer 20

Before meiosis I

Question 21

Why does interphase only occur once in meiosis?

Answer 21

Don’t want to replicate the DNA twice

Question 22

What are the stages of meiosis I? (4)

Answer 22

Prophase I
Metaphase I
Anaphase I
Telophase I
Cytokinesis

Question 23

What happens in prophase I? (5)

Answer 23

Spindles form
Chromosomes become visible
Nucleus disappears
Homologous chromosomes pair up
Crossing over can occur

Question 24

What are homologous chromosomes?

Answer 24

Chromosomes that have the same genes and are the same size

Question 25

Where do homologous chromosomes come from?

Answer 25

One comes from mom, one comes from dad

Question 26

Define crossing over

Answer 26

When homologous pairs swap genes

Question 27

What happens in metaphase I?

Answer 27

Homologous pairs line up down the middle of the cell (appears to be two-by-two)

Question 28

What happens in anaphase I?

Answer 28

Homologous pairs get pulled to opposite sides of the cell

Question 29

What happens in telophase I? (4)

Answer 29

Nucleus reforms Chromosomes are no longer visible Pinching occurs for cytokinesis Spindles disappear

Question 30

What happens in cytokinesis? (meiosis I)

Answer 30

Cytoplasm splits, producing 2 haploid daughter cells

Question 31

What happens to the 2 cells produced in meiosis I?

Answer 31

They go through meiosis II

Question 32

What are the stages of meiosis I? (4)

Answer 32

Prophase II Metaphase II Anaphase II Telophase II Cytokinesis

Question 33

What happens in prophase II? (3)

Answer 33

Spindle fibers form Chromosomes become visible Nucleus disappears

Question 34

What happens in metaphase II? (2)

Answer 34

Chromosomes line up single file down the center of the cell Spindles attach to the centromere of the sister chromatids

Question 35

What happens in anaphase II?

Answer 35

Sister chromatids get separated and pulled to opposite sides of the cell

Question 36

What happens in telophase II?

Answer 36

Spindles disappear Chromosomes are no longer visible Nucleus reappears Pinching occurs to start cytokinesis

Question 37

What happens in cytokinesis? (meiosis II)

Answer 37

Cytoplasm splits, forming 4 haploid daughter cells that have half the normal number of chromosomes