Cell Unit 2 - Mitosis/meiosis

Front 1

What are the basic stages of the cell cycle?

Back 1

Interphase (G1, S, G2 phase)

Mitosis (prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis)

Front 2

What are the basic stages of meiosis I and II?

Back 2

PMAT I, PMAT II and cytokinesis

Front 3

What are the stages within in Meiosis I, Prophase I (5)?

Back 3

Leptotene

Zygotene

Pachytene

Diplotene

Diakinesis

Front 4

What are the two major events in the cell cycle?

Back 4

1. Interphase - long; cell incr size and content; replication of genetic material

2. Mitosis - short; cell divides nucleus and cytoplasm to give rise to two daughter cells.

Front 5

What kind of cells enter the G0 phase?

Back 5

G0 phase - resting/outside phase

*Cells that are highly differentiated

*Permanent or temporary

Front 6

What happens in cell cycle, G1 phase (6)

Back 6

Period of cell growth and synthesis of macromolecules necessary for DNA duplication

*RNA

*Regulatory proteins for DNA duplication

*Enzymes for DNA duplication

*Restoration of cell volume

*Nucleoli reestablished

*Centriole duplication

Front 7

What happens in cell cycle, S phase

Back 7

DNA duplication occurs

*nucleoproteins (including histones) imported into nucleus

*Chromatin (DNA + histones) formed

*DNA synthesis!

*DNA content becomes 4n

*Chromosome stays at 2n

Front 8

What happens in cell cycle, G2 phase (4)

Back 8

Cell undergoes preparation for mitosis

*RNA and proteins for cell division synthesized

*Energy for mitosis is stored

*Tubulin synthesized for microtubules

*DNA synthesized in analyzed for errors/corrected

Front 9

3 Steps in mitosis induction pathways

Back 9

1. Ligands bind to surface receptor proteins, activating signal transduction pathways

2. Cascade of protein kinases activate intranuclear transcription factors

3. Proto-oncogenes that regular cell division become expressed

Front 10

What groups of proteins regulate cell division?

Back 10

Cyclins + cyclin-dependent kinases (CDKs)

Front 11

What are the cyclin-CDK pairs in G1?

Role(s)?

Back 11

*Permit cell to enter S phase*

Cyclin D-CDK4

Cyclin D-CDK6

Cyclin E-CDK2

Front 12

What are the cyclin-CDK pairs in S?

Role(s)?

Back 12

*Permits cell to progress to G2*

Cyclin A-CDK2

Cyclin A-CDK1

Cyclin B forms

Front 13

What are the cyclin-CDK pairs in G2?

Role(s)?

Back 13

Cyclin B-CDK1

*Permits mitosis to begin*

Front 14

What are the 3 checkpoints for cell cycle?

Back 14

1. Adequate cell growth

2. Correct DNA synthesis

3. Proper chromosomal segregation

Front 15

What is the division of:

--nuclear material

--cytoplasm

Back 15

Karyokinesis

Cytokinesis

Front 16

What happens in cell cycle, Prophase (4)?

Back 16

*Chromosomes condense/become visible

*Sister chromatids joined at centromere

*Nucleolus disappear

*Centrosomes divide into two regions

Front 17

What are centrosomes made of (2)?

Back 17

*Pair of centrioles

*MTOC (microtubule organizing centers)

Front 18

Each MTOC give rise to ___ ___ ___, which consist of two things...

Back 18

Mitotic spindle apparatus

1. Astral rays - MTs; radiate from pole of spindle; assist in orienting MTOC at the pole of cell

2. Spindle fibers - MTs; attach to centromere; assist in directing chromosome migration

Front 19

A new MTOC, the ___, forms at the centromere of each sister chromatid.

Spindle fibers bind to this for ___

Back 19

Kinetichore

Karyokinesis

Front 20

What happens if centrioles are not present?

Back 20

Astral rays and spindle fibers do not form properly

Mitosis fails

Front 21

What happens in cell cycle, prometaphase?

Back 21

*Begins when nuclear lamins phosphorylated

*Nuclear envelope disappears

*Chromosomes remain randomly arranged in cytosol

*Microtubules are attached where they need to be

Front 22

Microtubules attached to kinetichores are ___ ___ __ and assist in:

Microtubules not attached are ___ ___ and assist in:

Back 22

Mitotic spindle MTs - migration of chromosome; proper chromosome orientation and alignment with mitotic spindle

Polar MTs - maintain spacing between poles

Front 23

What happens during cell cycle, metaphase (1)?

Back 23

*Chromosomes condense and line up at the metphase plate

Front 24

What happens during cell cycle, anaphase (2)?

Back 24

*Sister chromatids are pulled apart towards opposite poles of mitotic spindle

*In late anaphase, cleavage furrow forms

Front 25

Disappearance of ___ proteins allows for anaphase

Back 25

Cohesion

Front 26

During anaphase, the ___ site leads and ___ trail

Back 26

Spindle/kinetichore

Chromatid arms

Front 27

Movement of chromatids towards poles due to ___ microtubules by depolymerization at ___ end.

Back 27

shortening

kinetichore

Front 28

What happens during cell cycle, telophase (5)?

Back 28

*Chromosomal set at poles

*Nuclear lamin dephosph

*Nuclear envelope reappears

*Chromosome uncoil into hetero or euchromatin

*NORs (nucleolus organizing regions) form nucleoli on each five pairs of chromosomes

Front 29

What happens during cell cycle, cytokinesis (4)?

Back 29

*Cleavage furrow deepens until only midbody and remaining polar MTs connect two cells

*Contractile ring separate cells

*Depolymerizations of spindle MTs

*Remaining MTs disassemble

Front 30

What is the contractile ring in cytokinesis made of (2)?

Back 30

Actin and myosin filaments

Front 31

What is the chromosome ploidy of a cell before and after mitosis?

Back 31

2n --> 2n

Front 32

What is the chromosome ploidy of a cell before and after Meiosis I and II?

What about DNA ploidy?

Back 32

2n --> 1n --> 1n???

4n --> 2n--> 1n???

Front 33

Recombination in meiosis ensures ____ and ____

Back 33

Genetic variability

Gene pool diversity

Front 34

Meiosis I - ____ division

Meiosis II - ____ division

Back 34

Reductional

Equatorial

Front 35

Which one is longer: prophase I or II?

Back 35

I

Front 36

What happens during each of the five phases in Prophase I?

Back 36

Leptotene - sister chromatids condense

Zygotene - homologous pairs line up; tetrads form via synaptonemal complex

Pachytene - condense and form chiasmata

Diplotene - condense more + sep a little-Diakinesis - nucleus/nucleolus disappear

Front 37

In metaphase I, homologous pairs line up ___ to ensure reshuffling of maternal/paternal DNA

What else happens?

Back 37

Spindle fibers attach to kinetochores

Front 38

At the end of anaphase I, each chromosome still consists of ___

Back 38

two chromatids

Front 39

Meiosis I begins with/without DNA synthesis

Meiosis II begins with/without DNA syntesis

Back 39

With

Without

Front 40

What are the phases of meiosis ii?

Back 40

PMAT

Front 41

At the end of meiosis, the __#__ resulting daughter cells are genetically identical/distinct from ____ of chromosomes and ____

Back 41

4

Distinct

Chromosome reshuffling

Crossover