Chapters 12-15 Flashcards Preview

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Flashcards in Chapters 12-15 Deck (63)
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Gap 1 Phase

growth of cell and synthesis of cytoplasmic organelle

1

Synthesis (S)

DNA replication (DNA replication is the only replication not involved in G1)

2

Gap 2 Phase

synthesis of structures involved in cell division. (Ex. microtubules)

3

Mitosis (M) = Karyokinesis

"chromosome splitting" chromosomes condense and separate into 2 nuclei

4

Cytominesis

"Cell splitting" the cytoplasm separates into 2 cells

5

Interphase

Gap 1, Synthesis and Gap 2 are collectively called this. The cell is very biologically active at this time.

6

how much time do cells spend in mitosis?

5-15% of lifetime but varies among organs.

7

how long do blood marrow cells spend in mitosis?

Divide rapidly to replace worn out blood cells (120 days = life of a red blood cell)

8

How long do neurons (nerve cells) spend in mitosis?

neurons divide very slowly, or not at all in adults. Cycle stops in gap 1 stage (at the Gap 1 checkpoint) and exits the cell cycle into G0 phase.

9

how long do liver cells spend in mitosis?

liver cells divide rapidly to replace missing tissue but slowly otherwise

10

chromosome

a strand of DNA that has wound up tightly causing it to be visible in the microscope

11

centromere

constricted region of the chromosome with associated proteins

12

sister chromatids

2 identical copies of the same chromosome

13

homologous chromosomes

chromosomes that are the same length, have centromeres in the same location, and carry genes for the same traits (e.g. eye color or blood type). One comes from your father, the other comes from your mother.

14

how do you count the number of chromosomes?

count the number of centromeres

15

Interphase role in Mitotic Division

no condensation of chromatin

cant tell the number of chromosomes through a microscope

nuclear envelope present

nucleolus present at nucleolar organizer region

centrosomes paired side-by-side (not found in plants)

16

Prophase

chromatin condenses into chromosomes

chromosomes massed in center of cell

nuclear envelope disappears

nucleolus disappears

spindle fibers, made of microtubules attached end-to-end, form between the migrating centrioles and attach to kinetochores of each sister chromatid.

17

kinetochore

disk-shaped proteins found on the centromere of the chromosome. allows spindle fibers to push and pull the chromosomes into place.

18

metaphase

chromosomes are fully condensed

chromosomes line up at metaphase plate by the spindle fibers in a 1X1 pattern

19

Anaphase

spindle fibers push and pull sister chromatids to separate poles of the cell.

20

Telophase

two nuclei are now forming

chromosomes unwind into chromatin

nuclear envelope reappears

nucleoli reappear

spindle fibers break down

21

Cleavage furrow

where the animal cell pinches off in cytokinesis. made of contractile ring of microfilaments that work like a draw string.

22

cell plate

cytokinesis of plant cells

1. vesicles form
2. vesicles fuse into cell plate
3. cell plate fuses with cell wall

23

meiosis

nuclear division that produces 4 daughter cells that have half the number of chromosomes as the original parent cell.

24

Gametes

egg or sperm. result of meiosis and are haploid.

25

another name for Meiosis

reduction-division because chromosome numbers are reuced by half during Meiosis I, then sister chromatids are separated in Meiosis II.

26

Prophase I

homologous chromosomes (mom and dad) pair up during a process called synapsis

during synapsis some homologous chromosomes break and swap places. this is called recombination

27

chiasmata

location where homologous chromosomes touch. this is where recombination is occuring

28

metaphase I

homologous chromosomes line up at metaphase plate 2-by-2. these sets of homologous chromosomes are called tetrads.

29

Anaphase I

homologous chromosomes are pulled apart to opposite poles of the cell.

sister chromatids are STILL connected.