chapter 13: meiosis

Question 1

genome

Answer 1

all the chromosomes in the nucleus of a cell

Question 2

karyotype

Answer 2

number and visual appearance of the chromosomes in the cell nuclei of an organism

Question 3

what does a genome contain?

Answer 3

all protein-making information for an organism

Question 4

what determines how a cell and organism functions?

Answer 4

genes and proteins

Question 5

phenotypes

Answer 5

characteristics of an organism based on genetic information

Question 6

gene

Answer 6

coding regions of DNA
- code for mRNA that is made into proteins

Question 7

homologous chromosomes

Answer 7

contain the same genes in the same location, but have different version of the genes

Question 8

alleles

Answer 8

alternative versions of the same gene, in pairs

Question 9

genotype

Answer 9

which alleles are present at a gene locus

Question 10

gene locus

Answer 10

the location of a specific pair of genes

Question 11

where do homologous chromosomes come from?

Answer 11

maternal chromosomes and paternal chromosomes

Question 12

how do asexual species reproduce?

Answer 12

by making clones of itself

Question 13

what is required for sexual reproduction?

Answer 13

gametes (egg cell and sperm cell)

Question 14

diploid

Answer 14

2n: 2 versions of each chromosome

Question 15

example of diploid

Answer 15

body cell

Question 16

haploid

Answer 16

1n: one version of each chromosome

Question 17

example of haploid

Answer 17

gametes

Question 18

how is a new organism created?

Answer 18

a gamete cell fuses with another gamete cell
- haplod + haploid = diploid

Question 19

how are gametes created?

Answer 19

meiosis of germ cell into gamete
2n –> 1n

Question 20

meiosis

Answer 20

going from diploid to haploid needs 2 rounds of cell division after S phase

Question 21

meiosis I

Answer 21

parent cell is diploid (2n) and contains a homologous pair of replicated chromosomes and the homologs get split to create two daughter cells containing one homolog (1n)

Question 22

meiosis II

Answer 22

daughter cells that are haploid and contain one homolog get split into 4 daughter cells after sister chromatids split

Question 23

what is created by the end of meiosis

Answer 23

four daughter cells containing one unreplicated chromosome each

Question 24

where do meiosis and mitosis differ?

Answer 24

metaphase

Question 25

what occurs during metaphase I of meiosis I?

Answer 25

crossing over and independent assortment

Question 26

what is crossing over?

Answer 26

exchange of genes between homologous chromosomes

Question 27

what is the purpose of crossing over?

Answer 27

an organisms can produce gametes with recombinant genotypes

Question 28

bivalent

Answer 28

in meiosis, replicated chromosomes pair up and attach to their homologous chromosome

Question 29

what happens during bivalent formation?

Answer 29

non-sister chromatids swap regions of DNA - maternal and paternal chromosomes swap DNA

Question 30

what is formed between non-sister chromatids in bivalent formation?

Answer 30

chiasma forms

Question 31

what is the result of crossing over?

Answer 31

recombinant chromatids

Question 32

after bivalent formation, what happens?

Answer 32

1. meiotic spindles attach to chromosomes 2. spindles pull chromosomes to middle of dividing cell in a vertical line on the metaphase plate 3. they split into 2 daughter cells 4. meiosis II occurs and they split into 4 daughter cells

Question 33

how are the chromosomes sorted?

Answer 33

by random assortment

Question 34

dominant trait

Answer 34

capital letters

Question 35

recessive trait

Answer 35

lowercase letters

Question 36

homozygous

Answer 36

all dominant or all recessive

Question 37

heterozygous

Answer 37

one dominant and one recessive

Question 38

how is wildtype indicated

Answer 38

by a +

Question 39

how is wildtype formatted when it is the dominant allele?

Answer 39

lowercase letters

Question 40

how is mutation formatted when it is the dominant allele?

Answer 40

capital letters

Question 41

where does the chiasma have to be for chromosomes to be recombinant?

Answer 41

in between genes on chromosomes

Question 42

what do nondisjunction events cause?

Answer 42

deviations in chromosome numbers

Question 43

when does nondisjunction occur?

Answer 43

meiosis I or meiosis II

Question 44

nondisjunction events increase with ____

Answer 44

parent age increasing