Cell Division

Front 1

Diploidy

Back 1

-state where every chromosome has a homologue "2n"

Front 2

Haploidy

Back 2

-single chromosomes with no homologues "n"

Front 3

The function of cell division include:

Back 3

-growth
-repair
-reproduction

Front 4

Mitosis

Back 4

-Produces two genetically identical daughter cells
-Occurs in all somatic cells

Front 5

Meiosis

Back 5

-Reduction division in two consecutive rounds
-Produces four haploid gametes from one diploid cell

Front 6

Sister Chromatid

Back 6

Identical halves of a signle chromosome
-become individual chromosomes when split at the centromere

Front 7

Centromere

Back 7

Part of chromosome that links sister chromatids

Front 8

Kinetochore

Back 8

Associated with the centromeres and interacts with mitotic spindle, moving around the chromosomes

Front 9

More than 90% of cell life is spent in which phase?

Back 9

Interphase

Front 10

What can be seen in a non-dividing cell during interphase?

Back 10

-decondensed chromatin
-more than one nucleoli
-pair of MTOC's and centrioles

Front 11

Prophase (prophase II)

Back 11

-Chromosomes condense
-nucleolus & nuclear membrane slowly disappear
-mitotic spindle forms at the MTOCs which begin to move to opposite poles
-microtubles start to grow at + ends of MTOC
-star-shaped aster fibers form around centriole
-
-

Front 12

Metaphase (Metaphase II)

Back 12

Early: Nuclear membrane totally disappears
-kinetochores produce movement and start to break the centromeres of the sister chromatids
-chromosomes align on the metaphase plate assisted by kinetochores for maintenance

Front 13

Anaphase (Anaphase II)

Back 13

-Microtubules shorten by uncoupling polymers, effectively pulling sister chromatids towards opposite poles
-Each sister chromatid is now called a daughter chromosome

Front 14

Telophase

Back 14

-daughter chromosomes position at opposite poles
-kinetochore fibers disappear
-chromosomes decondense
-nucleolus (nucleoli) and nuclear membrane reappear

Front 15

Cytokinesis

Back 15

Cleavage furrow that formed by actin and myosin microfilaments and pinches cytoplasm until it ultimately divides. "like a purse bag"

Front 16

Cytokinesis in Plants

Back 16

Golgi body vesicles migrate to equator and form a "cell plate" during telophase where they cemented by the middle lamella

Front 17

Middle Lamella

Back 17

A pectin layer which cements the cell walls of two adjoining cells together.

Front 18

What does meiosis I separate?

Back 18

Pairs of homologous chromosomes

Front 19

The divisions of meiosis II and mitosis are similar (T/F)

Back 19

True. Except that the gametes formed in meiosis will contain only 1/2 of the parents genetic information.

Front 20

Prophase I of meiosis

Back 20

Begins like prophase of mitosis except:
-synapsis=the pairing of homologues, "tetrads or bivalents"
-chiasmatas=site where genetic info is exchanged between nonsister homologous chromatids called "crossing-over"
-longest phase

Front 21

Synaptomeal Complex

Back 21

A protein structure that forms between homologous chromosomes (two pairs of sister chromatids) during meiosis and mediates chromosome pairing, synapsis, and recombination (crossing-over).
*It is now evident that the synaptonemal complex is not required for genetic recombination*

Front 22

Metaphase I of meiosis

Back 22

-Homologous pairs of chromosomes are lined up double file along the metaphase plate
-Spindle fibers from the poles attach to the kinetchores via centromeres of each pair of homologues

Front 23

Anaphase I of meiosis

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-Homologous chromosome pairs separate to opposite poles.
-Centromeres DO NOT SPLIT! ---each pole contains one chromosome from each pair of homologues

Front 24

Telophase I of meiosis

Back 24

-nuclear envelope reappears
-cytoplasm divides, leaving genetic material from ONLY one pair of homologous chromosomes "n"

Front 25

Centromeres break after anaphase I (T/F)

Back 25

False. Centromeres do not split; two chromatids belonging to a single chromosome remain attached

Front 26

Meiosis II is like mitosis cell division (T/F)

Back 26

True. Except that one results in 4 haploid gametes and the other produces 2 identical diploid daughter cells

Front 27

Daughter cells inherit homologues identical of the parent cell in meiosis (T/F)

Back 27

False.
-Receives 2 copies of only one member of the each homologous pair

Front 28

Fundamental differences between mitosis and meiosis.

Back 28

-Mitosis: 2 daughter cells with 1 copy of all chromosomes
-Meiosis: 4 haploid gametes with 1 copy of 1 member of each homologous pair
*All begins with tetrad formation during prophase I*

Front 29

What type of cell division is asexual reproduction?

Back 29

Mitosis

Front 30

3 types of genetic variation

Back 30

1) Independent assortment
2) Crossing over
3) Random fertilization

Front 31

Independent assortment

Back 31

Separation of homologous chromosomes depending on the random way in which they line up on the metaphase plate during metaphase I.
Ex: 2 possible orientations so 50% chance.
Combo of maternal and paternal chromosomes in each gamete is 2^23=~8 million

Front 32

Two functional limitations for cell size limit growth or influence the start of a new cell division:

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1) Surface-to-volume ratio (S/V)
-V ↑ by radius cubed, SA ↑ by radius squared
-large S/V ratio is need for cell to effectively exchange nutrients and waste with environment

2) Genome-to-volume ratio (G/V)
-Large G/V ratio needed for nucleus to provide enough substances (enyzmes, biosynthetic) for growing cell
*reason why some large cells (muscle) are multi-nucleated*

Front 33

Cell-specific factors that influence the onset of cell division (5)

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1) Checkpoints
2) Cyclin-dependent kinases (Cdk's)
3) Growth Factors
4) Density-dependent inhibition
5) Anchorage dependence

Front 34

Checkpoints

Back 34

Specific stop-points during cell cycle that evaluates internal/external condition to determine whether cell or not to continue through cell cycle

Front 35

G1 checkpoint

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-Occurs near end of G1 phase
-If conditions are unfavorable or cell is genetically programmed not to divide: G0 state

Front 36

G2 checkpoint

Back 36

-Occurs at the end of G2 phase
-Evaluates accuracy of DNA replication and signals whether or not to begin mitosis

Front 37

M checkpoint

Back 37

-Occurring during metaphase
-Ensures that microtubles (spindle) are properly attached to all kinetochroes at the metaphase plate before division continues with anaphase

Front 38

Cyclin-dependent kinases Cdk's

Back 38

-Phosphorylate proteins that regulate cell cycle
Cyclin----> Cdk's----> cell cycle reg. proteins
*presence of cyclin varies during the different phases

Front 39

Growth factors

Back 39

Naturally occurring substances capable of stimulating cellular growth, proliferation and cellular differentiation
I.e. cytokines, TGF-B, hormones (erythropoietin)

Front 40

Density-dependent inhibition
(contact inhibition)

Back 40

When cells stop dividing because surrounding cell density reaches a certain maximum "overcrowding"

Front 41

Anchorage dependence

Back 41

Most cells (animal) divide when anchored to an external surface such as: petri dish (in vitro), membrane (in vivo)

Front 42

Cancer

Back 42

Uncontrolled cell growth and division. Proliferate without regard to cell cycle regulation and factors.
"Disease of the Cell Cycle"

Front 43

Spermatogonia (-ium)

Back 43

Undifferentiated diploid cells

Front 44

What do spermatogonia become after multiplying, enlarging, and undergoing genomic replication?

Back 44

Primary Spermatocytes (diploid)

Front 45

Spermatids

Back 45

-Immature sperm cells that differentiate in mature spermatazoon with: head (acrosome from golgi), midpiece, and tail.
-Released from sertoli cells and travel to epididymis to gain motility

Front 46

Pathway of sperm cells during ejaculation from testes

Back 46

seminiferous tubules--> epididymis ---> vas or ductus diferens ---> ejaculatory duct ----> urethra

Front 47

Difference between the products of the 1st and 2nd meiotic divisions in males and females?

Back 47

Unequal division of cytoplasm between progeny producing polar bodies in females
(1st= 1 polar body, 2nd= 2 polar bodies)

Front 48

What forms the outer and inner layer of an ovum after released from follicle?

Back 48

Outer- corona radiata
Inner- zona pellucida in mammals aka vitelline membrane

Front 49

When is fertilization complete?

Back 49

When sperm and ovum nuclei fuse to form a zygote

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Placenta

Back 50

-complex mix of embryonic/maternal tissue develops @ site of implantation
-transfers nutrients, waste, gas (O2, CO2) between fetus and mother