chapter 12: the cell cycle Flashcards Preview

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Flashcards in chapter 12: the cell cycle Deck (41):
1

the cell theory

all organisms are made of cells, and all cells arise from pre-existing cells

2

Rudolf Virchow

proposed that new cells are formed through cell division

3

cell division

the splitting of pre-existing cells to from new cells

4

embryos

newly developing organisms

5

meiosis

leads to the production of sperm and eggs; results in daughter cells that are genetically different from each other

6

gametes

male and female reproductive cells (sperm and eggs)

7

mitosis

leads to the production of somatic cells (non-reproductivee cells); results in daughter cells that are genetically identical to the parent cell

8

somatic cells

non-reproductive, "body-belonging" cells

9

the two ways that nuclei divide before cell division

meiosis and mitosis

10

cytokinesis

the division of the cytoplasm into two distinct cells

11

basic steps of cellular replication

(1) copying the DNA
(2) separating the copies
(3) dividing the cytoplasms to create two complete cells

12

Walther Flemming

in 1879, observed threadlike structures (chromosomes) in the dividing cells of salamander embryos; coined the term mitosis (from the Greek for "thread")

13

Wilhelm Waldeyer

coined the term chromosome ("colored-body") in 1888

14

chromosome

consists of a single long DNA double helix that is is wrapped around proteins (histones) in a highly organized manner

15

histones

the proteins around which the DNA is wrapped

16

gene

a region of DNA in a chromosome that codes for a particular protein or RNA

17

chromatid

each of the double-stranded DNA copies in a replicated chromosome

18

cohesions

proteins that join the two chromatids along their length

19

centromere

a specialized region of the chromosome where the connection between the two chromatids remains intact

20

sister chromatids

chromatid copies that remain attached at their centromere

21

M phase

occurs when cells are in the process of separating their chromosomes ("M" = mitotic or meiotic)

22

interphase

the phase during which cells spend most of their time; no dramatic changes in the nucleus are visible; chromosomes uncoil into extremely long, thin structures and no longer appear as individual threads; the cell is either growing and preparing to divide or fulfilling its specialized function in a mulitcellular organism

23

Alma Howard and Stephen Pelc

discovered (using what process? p. 255 review) that DNA replication occurs during a period in interphase; coined the term "cell cycle"

24

S (synthesis) phase

the part of interphase during which chromosomes are replicated

25

cell cycle

the orderly sequence of events that leads a eukaryotic cell through the duplication of its chromosomes to the time it divides

26

G1 phase

the gap between the end of M phase and the start of S phase; in multicellular organisms, cells perform their functional roles during this phase

27

G2 phase

the gap between the end of S phase and the start of M phase; cells uses this phase to prepare for M phase

28

chromatin

DNA wrapped around globular histone proteins (what's the difference between this and a chromosome? --- chromosomes consist of chromatin?)

29

the five subphases within M phase

1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase

30

prophase

chromosomes condense into compact structures

31

spindle apparatus

a structure consisting of microtubules that produces mechanical forces that (1) moved replicated chromosomes during early mitosis and (2) pull chromatids apart in late mitosis

32

MTOCs

"microtubule-organizing centers"; MTOCs define the two poles of the spindle apparatus and produce microtubules

33

polar microtubules

during prophase, microtubules, that extend from each spindle pole and overlap with one another

34

centrosome

a structure that contains a pair of centrioles

35

centrioles

two bundles of microtubules contained in the centrosome

36

cytoplasm

all the contents inside the cell membrane, excluding the nucleus

37

pulse-chase experiment

by (step 1) exposing experimental cells to a high concentration of a modified amino acid and then (step 2) washing it away and replacing it with the normal version of the amino acid, a pulse-chase experiment marks a population of molecules at a particular interval (the pulse) and then follows their fate over time (the chase)

38

microtubules

cytoskeletal components composed of alpha-tubulin polypeptides (at the minus end) and beta-tubulins (at the plus end)

39

prometaphase

"before middle-phase"; ...

40

kinetochores

specialized structures at which the cytoplasmic microtubules attach to chromosomes; each sister chromatid has its own kinetochore, which is assembled at the centromere

41

kinetochore microtubules

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