Section 5: Cell Division Flashcards Preview

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Flashcards in Section 5: Cell Division Deck (73):
1

What is the term for nuclear division?

What follows nuclear division?

Karyokinesis

Cytokinesis

2

In diploid cells, there are 2 copies of every______, forming a pair, which is called a ______

Chromosome

homologous chromosome

3

Humans have ____ chromosomes, ____ homologous pairs, and a total of _____ chromatids

46 chromosomes

23 pairs

92 chromatids (depending upon stage of division 1)

4

These are also known as centrosomes. A pair of them lay outside the nucleus

Microtubule organizing centers

5

In animal cells, each MTOC contains a pair of

Centrioles

6

In this phase of MITOSIS, the nucleus dissassembles

Prophase

7

During prophase of mitosis, the nucleus disassembles and and the ______ appear

What condenses into chromosomes?

What breaks down?

What two things are formed?

Nucleolus

Chromatin

The nuclear envelope

Mitotic Spindle and microtubules

8

What are the microtubules of the mitotic spindle that is formed during prophase of mitosis made of?

Where do they begin to connect with?

Tubulin

Kinetochores

9

The protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.

Kinetochore

10

During this phase of mitosis, chromosomes line up single file at center

Metaphase

11

During the metaphase of mitosis, each chromatid is complete with a ______ and a _____

Once separated, it is a

To keep track of total, count the number of....

Centromere and kinetochore

Chromosome

Centromeres

12

During mitosis, once the chromatid is separated, that is the end of _______

The chromosome number does what during the next phase?

metaphase

Doubles

13

Karyotyping occurs during which phase of mitosis?

Metaphase

14

During this phase of mitosis, microtubules shorten, and each chromosome is pulled apart into two ________

Anaphase

Chromatids

15

Remember that when two DNA molecules are joined together, each molecule is called a chromatid and the two of the molecules are called a duplicated chromosome. When a DNA molecule(and proteins) is not attached to another one then that single molecule of DNA is not a chromatid but an unduplicated chromosome.

!! Important distinction

16

During anaphase of mitosis, what happens to the chromosome number?

It doubles, because duplicated chromosomes are pulled apart to opposite poles

17

What is it called when the chromosomes are pulled to apart to opposite poles of the cell during mitosis?

Disjunction

18

During mitosis, at the end of _______, each pole has a complete set of chromosomes, same as original cell before replication

Anaphase

19

During mitosis, this is the phase of nuclear division

What develops?

The chromosomes uncoil and become...

What reappear?

Telophase

Nuclear envelope

Chromatin

Nucleoli

20

This is a particular region of the nucleus containing chromosomal regions of cells

Nucleolus

21

What begins during the later stages of mitosis, aka at the end of anaphase?

Cytokinesis, the division of cytoplasm to form 2 cells

22

During cytokinesis, these microfilaments shorten, pulling the plasma membrane to the center (animals)

What is this process called?

Actin and myosin

Cleavage furrow

23

During cytokinesis in plants, vesicles from Golgi bodies migrate and fuse to form...

Out growth occurs and merging with the _____ separating the two new cells.

Do cells actually separate?

What cements adjacent cells together, then?

Cell plate

Plasma membrane

No, they are cemented together

Middle Lamella

24

This phase begins after mitosis and cytokinesis are complete, and consists of G1, S, and G2 phases

Interphase

25

What are the phases of the cell cycle in order?

M, G1, S, G2,

26

During the ___ phase of interphase, the second molecule of DNA is replicated from the first, forming sister chromatids

S phase

27

Is more time spent during interphase or mitosis?

Interphase

28

During interphase, does growth only occur during G's?

No, it occurs in all 3 interphases

29

During which interphase are the materials for the next mitotic division prepared?

G2

30

There are checkpoints at each interphase to make sure things are going as planned

Near the end of ____, cell growth is assessed and favorable conditions are checked. If this fails, the cell enters

Near the end of ____, checks for sufficient mitosis promoting factor levels required to proceed

There is an M checkpoint during mitosis that triggers start of...

G1

G0

G2

G1

31

This part of MEIOSIS is reduction division

Meiosis 1

32

In this PHASE of meiosis, homologous chromosomes pair at the plate and migrate to opposite poles

Is there separation of sister chromatids?

What develops?

Microtubules attach to ____

Crossing over means genetic ____

This could change the ___ sequence

Prophase I

No.

Spindle

Kinetochores

recombination

Nucleotide sequnce

33

This is the term for when homologous chromosomes pair up during prophase I of meiosis

The pairs are referred to as ___ or ____

Synapsis

Tetrads or bivalents

34

During prophase I of meiosis, this is the region where crossing over occurs of non-sister chromatids

Chiasmata

35

During prophase I of meiosis, this is the protein structure that temporarily forms between homologous chromosomes: gives rise tothe tetrad w/ chiasmata and crossing over

Synaptonemal complex

36

How many phases does prophase I of meiosis have?

What are they?

5

Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis

37

In this step of prophase I, chromosomes start condensing

Leptotene

38

In this step of prophase I, synapsis beings; the synaptonemal complex is forming

Zygotene

39

In this step of prophase I, synapsis is complete, and crossing over occurs

Pachytene

40

In this step of prophase I, the synaptonemal complex disappears and the chiasma is still present

Diplotene

41

In this step of prophase I, the nuclear envelope fragments, and chromosomes complete condensing, tetrads are ready for metaphase

Diakinesis

42

During this phase of MEIOSIS, homologous pairs are spread across the metaphase plate

_____ are attached to kinetochores of one member of each homologous pair. They one member then attach to the 2nd member of the pair

Metaphase I

Microtubules

43

During this phase of meosis, homologues within tetrads uncouple and are pulled to opposite sides

The term for pulling apart is...

Anaphase I

disjunction

44

During this phase of meiosis, the nuclear membrane develops. Each pole forms a new nucleus

What proportion of chromosomes do the new nucleus' have from the beginning?

Telophase I

Half the chromosomes

45

This is the chromosome reduction phase of meiosis to haploid

Telophase I

46

Depending upon the species, what may occur after telophase I of meiosis?

Interphase

47

In this part of meiosis, chromosomes spread across metaphase plate and sister chromatids separate and migrate to opposite poles. It is
similar to mitosis.

Meiosis II

48

In this phase of meiosis, the nuclear envelope disappears and the spindle develops, etc,

Is there chiasmata or crossing over?

Prophase II

No.

49

During this phase of meiosis, the chromosomes align on a plate like in mitosis but now with half the number of chromosomes (no extra copy)

Metaphase II

50

During this phase of meiosis, each chromosome is pulled into 2 separate chromatids and migrate to opposite poles of the cell

Anaphase II

51

During this phase of meiosis, the nuclear envelope reappears and cytokinesis occurs

How many cells are created?

Are they diploid or haploid?

Telophase II

4

haploid (each chromosome=1 chromatid)

52

What type of cell division occurs in somatic cells?

What type of cell division occurs in gametes?

Mitosis

Meiosis (egg, sperm, pollen)

53

This is the fusion of two haploid gametes

It forms a...

This is meoisis, right?

Fertilization/syngamy

diploid zygote

54

In plants what produces spores?

Are these diploid or haploid?

Spores undergo MEIOSIS/MITOSIS to become multicellular

Once multicellular, they are called

Sporangia

Haploid

Mitosis

Gametophytes

55

Gametophytes are diploid or haploid?

The gametes fuse and produce a

This grows to become a

Haploid, since spores are already haploid

Diploid Zygote (2n)

Sporophyte

56

Cells in the sporophyte (sporangia) undergoes MITOSIS/MEIOSIS to produce haploid spores which germinate and repeat the life cycle

Meiosis (check out diagram in feralis notes)

57

This is a term primarily used to describe the life cycle of plants (taken here to mean the Archaeplastida). A multicellular gametophyte, which is haploid with n chromosomes, alternates with a multicellular sporophyte, which is diploid with 2n chromosomes, made up of n pairs. A mature sporophyte produces spores by meiosis, a process which reduces the number of chromosomes to half, from 2n to n.

Alternation of generations (alternation of diploid and haploid stages in plants)

58

Genetic variation (genetic recombination during meiosis and sexual reproduction) results from 3 events. What are they?

Crossing over during Prophase I

Independent assortment of homologues during metaphase (which chromosome goes into which cell)

Random joining of gamete aka germ cells (which sperm fertilizes which egg)

59

In the regulation of the cell cycle, the volume gets much larger when cells grow. When this value is small, exchange is hard, leading to cell death or cell division to increase surface area. When the value is large, exchange becomes much easier

What is the volume equation?

What is the SA equation?

Surface to volume ratio

4/3πr^3

4πr^2

60

In the regulation of the cell cycle, the genome size remains constant throughout life. As the cell grows, the volume increases.

The value will be small and thus exceed the ability of its genome to produce sufficient amounts of regulator of activites

Genome to volume ratio

61

What do some large cells have to deal with small genome to volume (G/V) ratios?

They are multinucleated (paramecium, human skeletal muscle)

62

In the checkpoints of the cell cycle, this is the restriction point, the most important one. At the end of the phase, if the cell is not ready to divide it may arrest here and never proceed or wait until it is ready

What phase will it go to if it is not ready?

what cells rarely proceed to division after maturing, and therefore go to G0?

G1 checkpoint

G0 phase

Nerve and muscle cells

63

In the checkpoint of the cell cycle, this one evaluates the accuracy of DNA replication and signals whether to begin mitosis

G2 checkpoint

64

In the checkpoints of the cell cycle, this occurs during metaphase and ensure microtubules are properly atteached to kinetochores

M checkpoint

65

These are enzymes that activate proteins that regulate cell cycle by phosphorylation

What are they activated by?

Cyclin-dependent kinases (CDKs)

Cyclin (duh)

66

The plasma membrane has receptors for _______ that stimulate cell for division (such as damaged cell)

growth factors

67

This occurs when cells stop dividing when surrounding cells density reaches maximum.

Density Dependent Inhibition

68

Most cells only divide when attached to an external surface such as neighboring cells or side of culture dish. This regulation is called

Anchorage dependence

69

What type of cells defy all 5 of the cell specific conditions mentioned before (Checkpoint, CDKs, Growth factors, Density dependent inhibition, anchorage dependence)

Cancer cells

70

How many chromosomes are there in the anaphase of mitosis if a cell has 46 chromosomes at the beginning?

What can be counted to give this value?

92

(46 chromosomes made of 2 sister chromatids are pulled apart to give 92 chromosomes)

Centromere

71

At anaphase I, how many chromosomes are there if a cell has 46 chromosomes at the beginning?

46 (23 chromosomes that are pulled to each pole, no separation of sister chromatids at anaphase I)

72

Do plants have centrioles?

Why or why not?

No

The cell plate forms

73

Which has no genetic variation, mitosis or meiosis?

mitosis