Chromosomes & The Cell Cycle Flashcards Preview

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Flashcards in Chromosomes & The Cell Cycle Deck (46)
1

Prokaryote vs. eukaryote chromosomes

Prokaryote: short and circular

Eukaryote: long and linear

2

Prokaryote basics

no nucleus

Single celled

Always haploid

3

Eukaryote basics

Have a nucleus

Some single celled, some multicellular

Both haploid and diploid

4

Every cell has it's own ____ and can be ___ or ___

Genes, haploid, diploid

5

Haploid definition

1 copy of every gene

6

Diploid

2 copies of every gene

1 from mom and 1 from dad

7

Mitosis definition

Cell division that makes 2 daughter cells identical to the mother cell--whether haploid or diploid

8

Meiosis definition

Cell division that splits diploid cells into haploid cells

9

Cell division in prokaryotes

Very simple--circular haploid chromosome of DNA duplicates, then cell splits in two

Result: 2 identical haploid daughter cells

10

Human diploid cell chromosome #

23 pairs, or 46 chromosomes

11

After DNA duplication, Human diploid cell chromosome #

23 pairs, or 46 chromosomes

BUT each chromosome has a sister chromatid = 92 chromatids in the cell

12

When the cell is about to divide it first...

Duplicates chromosomes

13

After duplication of chromosomes...

Each chromosome consists of 2 sister chromatids

14

What is a chromosome?

A strand of DNA that carries genetic info in a cell

15

Human haploid and diploid #s

Haploid (N) = 23

Diploid (2N) = 46

16

spindle fiber

long protein molecule (microtubule) that tows chromosomes during division

17

centromere

area of a chromosome where spindle fibers attach during division

18

kinetochore

protein structure on a centromere where spindle fibers attach

19

centrosome

the structure (centriole + aster) where microtubules pull the chromosomes

aka. microtubule organizing center (MTOC)

20

centriole

strange little cylinder made of short microtubules

located at the center of a centrosome

21

aster

cluster of spindle fiber

converge at centrosome

22

bands on chromosomes

numbered in both directions starting at centromere

only visible when chromosomes are stained with a special technique

23

the earlier in ___ the longer the chromosomes are, and more bands are ____

prophase, visible

24

karyotype

visual of a person's 23 chromosome pairs

25

during the mitotic cell cycle a human cell has how many chromosomes?

46 (23 pairs)

26

during the mitotic cell cycle is a human cell always diploid?

yes

27

interphase

happens between cell divisions

chromosomes are decondensed and invisible

3 stages (G1, S, G2)

28

G1

each chromosome consists of 1 chromatid

29

S

DNA is duplicated

30

G2

each chromosome consists of 2 chromatids

31

G0

some cells exist in this state of non-division

may be permanent (nervous cells) or reversible (immune cells)

32

at what stage can you see a karyotype?

at the end of G2 in interphase

33

cytokinesis

dividing the cytoplasm and membrane

34

at mitosis the cell splits each _____ into _____

2-chromatid chromosome, single-chromatid chromosomes

35

higher plants don't have...

centrioles

36

the haploid number of chromosomes is called __ and the diploid number is called ___

N, 2N

37

in simple eukaryotes the ___ stage of life is dominant

haploid

38

fungi spend most of their lives as ____

haploids, growing as little invisible threads called mycelia

39

more complex plants spend most of their lives as ___

diploids

40

animals spend their whole lives as ____ except for the _____ stage

diploids, gamete

41

the diploid stage of any eukaryote begins with ____

syngamy: when two haploid gametes combine to form a diploid cell

42

meiosis can only occur in the ___ stage because...

diploid

it requires a cell with pairs of homologs

43

what are the two types of cells in animals in the diploid stage?

somatic and germline

44

somatic cells

everything other than germline

only go through mitosis

45

germline cells

exist only in the gonads (testes & ovaries)

go through either mitosis OR meiosis

46

what is the important function of meiotic recombination?

to shuffle the genes, making new chromosomes with new combinations of parental alleles