Ch 10 Meiosis & Sexual Life Cycles

Question 1

gene

Answer 1

discrite unit of hereditary information with specific nucleotide sequence in DNA

Question 2

allele

Answer 2

variation of gene (hair color)

Question 3

asexual reproduction

Answer 3

without fusion of gametes and offspring are genetic copy of parent

Question 4

sexual reproduction

Answer 4

fusion of gametes and offspring have unique combo of parents genes

Question 5

homologous chromosomes

Answer 5

pair of chromosomes with same length, centromere position and staining pattern with genes for same characteristic at same loci

Question 6

meiosis

Answer 6

sexual reproduction of cells

Question 7

what type of cells does meiosis occur

Answer 7

gametes

Question 8

How does meiosis impact chromosome number

Answer 8

chromosome number halved

Question 9

how many nuclear divisions in meiosis

Answer 9

two

Question 10

main purpose of meiosis one

Answer 10

separation of homologous chromosomes

Question 11

main purpose of meiosis two

Answer 11

separation of sister chromatids

Question 12

prophase I

Answer 12

• chromosomes condense

- crossing over begins

Question 13

metaphase I

Answer 13

• centrosomes line up by homologous pair

- nuclear envelope breakdown

Question 14

anaphase I

Answer 14

-homologous pair of chromosomes move toward poles

Question 15

telophase I & cytokines

Answer 15

• two haploid cells form

- each chromosome has 2 sister chromatids

Question 16

prophase II

Answer 16

• spindle apparatus forms

- -later chromosomes move toward metaphase plate

Question 17

metaphase II

Answer 17

• chromosomes at metaphase plate
• because of cross over sister chromosomes not identical
• kinetochores of sister chromatids attach to microtubules to opposite poles

Question 18

anaphase II

Answer 18

• breakdown of proteins holding sister chromatids

- centromere separates

Question 19

telophase II & cytokinesis

Answer 19

• nucli forms

- cytokinesis occurs

Question 20

crossing over

Answer 20

takes place during synapsis and alignment of homologous chromosomes

Question 21

cohesins

Answer 21

hold sister chromatids together
-hold arms together released by middle of prophase leaving sister chromatids connected only by effect of cohesion complexes at centromere

Question 22

synaptomemal complex

Answer 22

protein structure formed between homologous chromosomes in meiosis and moderates chromosome pairing, synapsis & recombination

Question 23

chiama

Answer 23

two homologous non-sister chromatids exchange genetic material during cross over

Question 24

independent assortment

Answer 24

sister chromosomes align randomly at metaphase plate allowing for infinite combination for crossing over, happens in metaphase I

Question 25

random fertilization

Answer 25

each gamate has unique combination of genes that get randomly fertilized

Question 26

meiotic nondisjunction

Answer 26

failure of two members of chromosome pair to separate during meiosis causing both chromosomes to go to single daughter cell *responsible for extra chromosomes in trisomy 21

Question 27

aneuploidy

Answer 27

abnormal number of chromosomes in cell

Question 28

down's syndrome

Answer 28

caused by trisomy 21