Chapter 12 (Cell Division)

Question 1

What is the continuity of life-based on?

Answer 1

cell division

Question 2

What is the cell cycle?

Answer 2

life of a cell aka formation to the division

Question 3

What does cell division result in?

Answer 3

two daughter cells that are genetically identical to 1 parent cell

Question 4

What are the types of cells?

Answer 4

somatic cells and gametes

Question 5

What are somatic cells?

Answer 5

non-reproductive cells that are found all over the body and have two sets of chromosomes

Question 6

What is a cell that has two sets of chromosomes called?

Answer 6

diploid cell

Question 7

What are gametes?

Answer 7

reproductive cells (sperm and egg) that have half as many chromosomes

Question 8

What are gametes for?

Answer 8

utilization for the next generation of organisms

Question 9

What is a cell that has half as many chromosomes called?

Answer 9

haploid cell

Question 10

What is chromatin?

Answer 10

DNA that is loosely wrapped around proteins/complex of DNA and proteins

Question 11

Where is chromatin found?

Answer 11

the nucleus

Question 12

What protein is wrapped around the DNA in chromatin?

Answer 12

histone proteins

Question 13

What are chromosomes?

Answer 13

condensed chromatin aka condensed DNA

Question 14

What are chromatids?

Answer 14

the long part that is replicated and attached to the original chromosome

Question 15

What are sister chromatids?

Answer 15

identical copies of chromosomes that is due to the replication of DNA

I (chromosome) —> I.I (sister chromatids) —-> I I distributed

Question 16

What is the centromere?

Answer 16

where two sister chromatids are most closely attached

Question 17

What are the sister chromatids held together at the centromere by?

Answer 17

cohesin proteins

Question 18

What are the two main phases the cell cycle consists of?

Answer 18

mitotic phase (M phase) and Intererphase

Question 19

What are the steps of the M-phase?

Answer 19

Prophase, metaphase, anaphase, telophase, and cytokinesis

Question 20

What is mitosis?

Answer 20

division of the nucleus (a division of the chromosomes)

Question 21

How much of the cell’s life is in the M-phase?

Answer 21

10 percent

Question 22

What is cytokinesis?

Answer 22

division of the rest of the cell and the content within the cytoplasm

Question 23

What is the result of the M-phase?

Answer 23

two daughter cells that go into their own cell cycle

Question 24

What is interphase?

Answer 24

rest of the cell cycle that excludes the M-phase

Question 25

How much of the cell's life is in the Interphase?

Answer 25

90%

Question 26

What are the phases of interphase?

Answer 26

G1, S, and G2

Question 27

What is the G1 and G2 phases of interphase?

Answer 27

cell functioning and growth

Question 28

What is the S (synthesis) phase of the interphase?

Answer 28

DNA replication THAT HAPPENS BEFORE MEIOSIS/MITOSIS so that there is enough genetic material for daughter cells in the cell division

Question 29

When does the S phase happen?

Answer 29

before mitosis/meiosis and in between G1 and G2

Question 30

Does every cell go through an interphase?

Answer 30

no, not every cell goes through it fast and completely

Question 31

How does the cell control its own division?

Answer 31

system of molecular interactions that happens internally in the cell with the help of proteins in the cytoplasm

Question 32

What is the Intrinsic Cell Cycle Checkpoint Pathway?

Answer 32

ensure the orderly progression of cell cycle events and are activated at different transition points to prevent premature entry into the next cell cycle event

Question 33

What are three checkpoints?

Answer 33

G1, G2, Mphase checkpoint

Question 34

What is the G0 checkpoint?

Answer 34

non-dividing state/resting state of a cycle, no more dividing

Question 35

When would a cell go to the G0 checkpoint?

Answer 35

After the G1 checkpoint assessment, cell decides to go to the resting state instead of proceeding to the S-phase

Question 36

What does the G1 checkpoint check for?

Answer 36

if the cell is big enough to divide after duplicating organelles

Question 37

What does the G2 checkpoint check for?

Answer 37

if the DNA is fully replicated

Question 38

What does the M phase checkpoint check for?

Answer 38

if the chromosomes correctly lined up and if there is a spindle formed

Question 39

What are the two types of regulatory proteins in the control checkpoints?

Answer 39

cyclins and cyclin-dependent kinases (cdk)

Question 40

What do cdk's do?

Answer 40

undergo phosphorylation

Question 41

Are cdks usually active or inactive?

Answer 41

inactive

Question 42

Are cdks present in the cell or not?

Answer 42

present

Question 43

Are cyclins present in the cell?

Answer 43

they have to be synthesized and then later they get degraded

Question 44

What is an example of a cyclin-cdk complex?

Answer 44

MPF

Question 45

What does MPF (maturation/mitosis promoting factor) do?

Answer 45

cyclin-cdk complex that phosphorylates proteins of nuclear membrane to begin fragmenting nuclear membrane

Question 46

When is the mitotic spindle formed?

Answer 46

prophase

Question 47

What is the mitotic spindle?

Answer 47

apparatus that allows mitosis to happen and it controls chromosomal movements during mitosis

Question 48

What is the mitotic spindle made up of?

Answer 48

microtubules

Question 49

What is the centrosome?

Answer 49

microtubule-organizing center that starts the process of making the spindle

Question 50

What is a centriole?

Answer 50

found within a centrosome, they are microtubule units (2 cylinders)

Question 51

When the centrioles go towards opposite ends of the cell, what forms around each spindle pole?

Answer 51

an aster

Question 52

What is an aster?

Answer 52

cellular structure shaped like a star, consisting of a centrosome (that bubble around the centrioles)

Question 53

What is the role of an aster?

Answer 53

microtubules that help spindle anchor at one end fo the cell

Question 54

What are the types of spindle microtubules?

Answer 54

kinetochore and non-kinetochore (aka polar microtubules)

Question 55

What do non-kinetochore (aka polar microtubules) do?

Answer 55

pushes spindle apart

Question 56

What do kinetochores do?

Answer 56

attach to the center of a chromosome and are the sites for microtubules to grab on to

Question 57

How is a kinetochore made?

Answer 57

assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle

Question 58

What happens in the prophase?

Answer 58

creation of the spindle apparatus, condensation of chromatins to form chromosomes, the nuclear membrane breaks down, attachment of microtubules from spindle to chromosomes

Question 59

What happens in metaphase?

Answer 59

all chromosomes within a cell line up at the metaphase plate

Question 60

What happens in anaphase?

Answer 60

replicated chromosomes get pulled apart to form separate chromatids, cleavage (cutting) of cohesin proteins

Question 61

During anaphase, what happens to the nonkinetochore microtubules?

Answer 61

they start overlapping and pushing apart to elongate the cell, eventually, they degrade as they separate and motor proteins take over

Question 62

What happens in telophase?

Answer 62

genetically identical nuclei form at opposite ends of cell, nuclear envelope reforms, chromosomes loosen up, spindle broken down

Question 63

What happens in cytokinesis?

Answer 63

already happening by the time anaphase or telophase rolls around, division of cytosol and organelles to form a cleavage furrow based on microfilaments under plasma membrane

Question 64

What does cell division allow for in a multicellular organism?

Answer 64

development from a single fertilized egg and continue to function as cell repair all over the body

Question 65

What is a genome?

Answer 65

cell's DNA/its genome

Question 66

In somatic cells, where are the chromosomes inherited from, and how many?

Answer 66

23 from each parent for a total of 46 chromosomes

Question 67

What units are added to make the spindle fibers elongate?

Answer 67

adding units of tubulin

Question 68

How do spindle fibers shorten?

Answer 68

losing the subunits of tubulin

Question 69

What does a plant cell produce instead of a cleavage furrow?

Answer 69

cell plate

Question 70

Where did mitosis evolve from?

Answer 70

simpler prokaryotic mechanisms of cell | reproduction