Bio Chap. 10 Mitosis

Front 1

Genome

Back 1

A cell's total DNA

Front 2

Genome of prokaryotes vs. eukaryotes
What is a variation in each?

Back 2

Prokaryotes: have a single circular DNA
Variation: plasmid= an additional small circular DNA which contains antibiotic resistant genes

Eukaryotes: much more DNA
Variation: number of chromosomes is species specific

Front 3

How many chromosomes does each human cell have?

Back 3

46

Front 4

Somatic cells vs. sex cells

Back 4

Somatic = body cells which contain 46 chromosomes

Sex = gametes (sperm and egg) which contain 23 chromosomes

Front 5

Gametes

Back 5

Sex cells = sperm and egg

Front 6

Why does DNA replicate itself in preparation for mitosis?

Back 6

So that the cell may split into 2 identical cells with the same genetic information

Front 7

Purpose of mitosis
3

Back 7

Growth
Reproduction
Repair

Front 8

5 phases of the cell cycle

Back 8

G1
S phase (DNA synthesis)
G2
Mitosis
Cytokinesis

Front 9

What makes up interphase?

Back 9

G1
S
G2

Front 10

What makes up M phase?

Is it long or short in duration?

Back 10

Mitosis
Cytokinesis

Shortest phase

Front 11

G0 phase
4

Back 11

• Cells that stay in G1 phase
• Stage in which cells are not dividing, but are at rest
• Most cells are in this phase
• some cells remain here permanently

Front 12

G1 phase
3

Back 12

• gap phase 1 = gap between cytokinesis and synthesis
• primary growth phase → regular metabolic functioning
• longest phase

Front 13

S phase
2

Back 13

• DNA synthesis
• replication / duplication

Front 14

G2 phase
3

Back 14

• gap phase 2 = gap between synthesis and mitosis
• second growth phase
• prepares cell for mitosis with centriole duplication

Front 15

Mitosis
What are the 5 stages?

Back 15

Separation of nucleus into 2 daughter genomes
5 stages:
1) prophase
2) prometaphase
3) metaphase
4) anaphase
5) telophase

Front 16

Chromatin
4

Back 16

• loose unfolded DNA bound to proteins
• bowl of spaghetti! Appears very long and thin
• duplicates itself in preparation for mitosis
• exists during interphase

Front 17

Chromosomes
2

Back 17

• supercoiled chromatin (DNA bound to proteins)
• appears during mitosis

Front 18

How many molecules of DNA is each chromosome?

Back 18

1 molecule

Front 19

During which phase does DNA replicate itself?

In which form is DNA in during replication?

Back 19

S phase
b/c S stands for DNA synthesis

DNA is in the form of chromatin

Front 20

Path of chromatin to chromosome
4

Back 20

During G1 and S:
1) Chromatin remains loose and uncoiled

During G2:
2) Chromatin wraps around histones = nucleosomes
3) nucleosomes further coil into solenoid

During mitosis:
4) Wrapping around condensin

Front 21

Histones
What are they?
What do they help in and how?

Back 21

• a cluster of 8 proteins bound to DNA every 200 nucleotides
• "magnetic forms" that help guide the coiling of DNA b/c of their charge
• positively charged b/c they consist mostly of amino acids
• DNA is negatively charged due to phosphate groups, and so histones attract the DNA

Front 22

Nucleosome

Back 22

A complex of DNA and histone proteins

Front 23

Solenoid
AKA

Back 23

• 30nm fiber
• further coiling of nucleosomes

Front 24

Condensin

Back 24

a scaffold protein that supports radial looping of chromatin into chromosome
• occurs during mitosis

Front 25

Karyotype

Back 25

The particular set of 23 homologous chromosome pairs in an individual

Front 26

Haploid
3

Back 26

• a set of 23 unpaired chromosomes
or
• a gamete cell b/c it only has 23 chromosomes
• represented by the letter n

Front 27

Diploid
3

Back 27

• a set of 23 homologous chromosome pairs = 46 chromosomes
• 23 are from mom and 23 from dad
• represented by 2n

Front 28

Homologous pairs
Where they descend from in a cell
Similarities vs. differences
What they make up
Do they have the same roles in mitosis and meiosis

Back 28

• a pair of chromosomes in which one is inherited from mom and the other from dad
• 2 chromosomes of the:
1) Same size
2) Same banding pattern
3) Same genes
4) Different alleles
• they make up a cell's karyotype
• do not have the same roles in mitosis and meiosis. They pair up in meiosis but not in mitosis

Front 29

Chromatids
2 types

Back 29

Each half of a duplicated chromosome held together at the centromere by cohesin

Sister chromatids = identical copies of chromosomes
Non-sister chromatids

Front 30

Cohesin

Back 30

• protein that holds 2 sister chromatids together as a duplicated chromosome
• the glue between them

Front 31

Centromere

Back 31

The middle of the chromosome where the two sister chromatids meet

Front 32

Kinetochores

Back 32

• Proteins at the centromere
• an attachment site for microtubules that separate the sister chromatids to opposite sides of the cell

Front 33

Why must chromosome pairs be held together?

Back 33

• Chromosome pairs must be held together in order to organize the cell for when the cell splits
• this ensures that each daughter cell receives 1 of the sister chromatids

Front 34

What type of chromosomes are paired up in preparation for the cell to split?
Homologous pairs or sister chromatids?

Back 34

Sister chromatids

Each chromosome of a homologous pair replicates itself and is attached to its duplicated chromosome

Front 35

Centrioles

Back 35

A pair of microtubules arranged in a ring inside centrosomes

Front 36

Centrosome
When does it replicate?

Back 36

• A non-membranous organelle which contains the centrioles
• microtubules radiate out of here and bind to the kinetochores of the chromosomes
• replicate in G2

Front 37

Tubulin

Back 37

The protein that forms microtubules

Front 38

Prophase
4

Back 38

Phase 1 of mitosis - longest phase
1) nuclear membrane breaks down
2) chromatin beings to condense into chromosomes
3) centrosomes/centrioles migrate to opposite poles
4) formation of spindle apparatus

Front 39

Spindle apparatus
3 types

Back 39

Microtubules that form during prophase
1) asters
2) kinetochores
3) non-kinetochores

centrioles?

Front 40

Prometaphase
2

Back 40

Phase 2 of mitosis
1) spindles attach to kinetochores; each sister chromatid is connected to a microtubule from opposite sides of cell
2) chromosome pairs begin to move to center of the cell

Front 41

Metaphase
1

Back 41

Phase 3 of mitosis
1) creation of the metaphase plate = chromosomes are lined up at center of cell

Front 42

Anaphase
2

Back 42

Phase 4 of mitosis - shortest phase
1) kinetochore microtubules pull sister chromatids appart and to opposite poles of the cell
2) non-kinetochore microtubules elongate the cell until chromosomes are at opposite poles

Front 43

Telophase
2

Back 43

Phase 5 of mitosis
This is the opposite of prophase
1) nuclear membrane regenerates
2) chromosomes begin de-condensing

Front 44

Cytokenesis
Animal vs. plant cells

Back 44

Separation of cytoplasm into 2 daughter cells

Animal cells:
• cleavage furrow = actin constricts like a drawstring to pinch the cell in two

Plant cells:
• cell plate = divides cell in 2 and forms the new membranes
• cellulose is added between membranes to form cell wall

Front 45

What is the longest phase of the cell cycle?
What is the longest phase of mitosis?

Back 45

Cell replication = G1
Mitosis = prophase (first phase)

Front 46

Binary fission
What is it?
AKA
How is the DNA described and where is it?
How does it occur? 2

Back 46

• Cell division in bacteria
• theta replication b/c looks like a theta symbol
• genome is one circular DNA molecule in the nucleoid region
• DNA replicates at origin site
• septum (a wall of proteins) forms separating cell

Front 47

Checkpoints in cell division
What are they?
How many?
What do they check for?

Back 47

• points in cell cycle where the cell decides whether or not to proceed to next phase
• 3 checkpoints
1) G1/S: growth factors and nutritional state
2) G2/M: successful DNA replication
3) Spindle: spindles attached to all chromosomes at metaphase plate to begin anaphase

Front 48

Kinases (2) and Cyclin-Dependent Kinases (CDK's) (2)

Back 48

Kinases = enzymes for phosphorylation of a protein by ATP
• this phosphorylation activates or deactivates the protein

CDK's = kinases that are activated by cyclin proteins
• regulate checkpoints

Front 49

CDK's and G1/S checkpoint
What is formed here?
What does it do?
What does it initiate/prevent?

Back 49

• G1/S CDK complex = cyclins accumulate and activate CDK's (same as in G2/M)
• this complex phosphorylates and activates proteins involved in DNA synthesis
• S phase is initiated or prevented

Front 50

CDK's and G2/M checkpoint
What is formed here?
What does it do?
What does it initiate/prevent?

Back 50

• mitosis-promoting factor (MPF) = cyclins accumulate and activate CDK's (same as in G1/S)
• MPF's are sensitive to DNA damage, and will deactivate CDK's with inhibitory phosphates
• Mitosis initiated or prevented

Front 51

Anaphase-promoting complex

Back 51

• Mechanism of spindle checkpoint
• activates proteases that break down cohesin, and allows sister chromatids to separate