deck_691868

Question 2

regulate passage through the cell cycle

Answer 2

cyclin-CDK complexes - G1: cyclin D -> pass restriction point- S-Phase: Cyclin E -> initiates DNA replication- M-phase (mitotic): Cyclin B -> promotes mitosis

Question 3

Activation of CDK’s

Answer 3

cycling binding -> cyclin-CDK activation -> cyclin is degredated -> continuation of cell cycle

Question 4

Interphase

Answer 4

Increases cell size, chromosomes and centrosomes replicate- G1 (longest phase) 2N, 2C- S (DNA Synthesis) 2N, 4C- G2 - 2N, 4CG1 and G2 are gaps between DNA replication and Mitosis

Question 5

Mitosis/M-Phase

Answer 5

lasts a couple hours Prophase - Prometaphase -  Metaphase -  Anaphase A  Anaphase B Telophase

Question 6

Static cells

Answer 6

no longer dividing, post mitotic, long lived - in G0 ex. CNS cells, skeletal or cardiac muscle cells

Question 7

Stable Cells

Answer 7

divide episodically to maintain tissue/organ structure ex. Periosteal/perichondreal cells, smooth muscle cells, endothelial cells, fibroblasts

Question 8

Renewing Cells

Answer 8

display regular mitotic activity, daughter cells will either differentiate of remain as stem cells- Differentiating cells may be lost from the body- Slowly renewing cells (may increase in size) – smooth mm of hollow organs, fibroblasts in uterine wall, lens epithelial cells, slow growing tumor cells- Rapidly renewing cells – blood cells, epithelial cells of skin, mucosal lining of GI tract, tumor cells

Question 9

Prophase

Answer 9

replicated chromosome condense due to phosphorylation of histones; spindles begin to assemble

Question 10

Prometaphase

Answer 10

abrupt break down of nuclear envelope (phosphorylation of nuclear lamins

Question 11

Metaphase

Answer 11

• chromosomes line up and kinetochore microtubules on each chromosome attach to spindle

Question 12

Anaphase A -

Answer 12

kinetochore microtubules depolymerize/get shorter pulling chromatids apart

Question 13

Anaphase B

Answer 13

• spindle poles push apart pulling chromatids apart

Question 14

Telophase -

Answer 14

new nuclear envelopes form and contractile ring forms

Question 15

classes of microtubules in a mitotic spindle

Answer 15

1) Astral (unattached)  radiate from MTOC to cortical cytoskeleton – acts as anchor (probably actin)2) Polar  from centrioles to equator3) Kinetochore  from centrioles to kinetochores of condensed chromosomes

Question 16

Mitosis and meiosis differences

Answer 16

Diploid Cells -> 2 diploid Daughter CellsDiploid cell -> 4 haploid cells-1 cell division-2 cell divisions-Both have 1 S phase-No pairing of homologous chrom.’s in prophase-synapsis of homologous chromosomes in prophase-Non recombinant in prophase-Recombination b/w sister chromatids-Sister chromatids separated in metaphase-Sister chromatids remain together during metaphase 1 and seperate in metaphase 2-Centromeres divide at anaphase-centromeres divide at anaphase 2 not 1-Conservative process (daughter cells identical to parent)-promotes variation

Question 17

Meiosis in males

Answer 17

even distribution of cytoplasm among cells

Question 18

Meiosis in females

Answer 18

uneven distribution of cytoplasm b/w ovum and polar bodiesbegins as fetus then arrests (in prophase1)begins again in pubertyarrests again at menopause

Question 19

First meiotic division

Answer 19

DNA content 4C -> 2C and chromosome # is 46 (2N) -> 23 (1N)Prophase I • Leptotene – condensation, assembly of lateral elements of SC• Zygotene – assembly of central elements of SC• Pachytene – homologous recombination• Diplotene/diakinesis – female – decondensation, transcription especially of rRNA: translation especially of egg specific proteins

Question 20

Second meiotic division

Answer 20

DNA content 2C -> 1C; chromosome # 23 -> 23 (1N)Just like mitosis

Question 21

Mechanisms to mix genes

Answer 21

• Independent assortment of maternal and paternal homologos - meiotic div. I- Crossing over - meiotic prophase I

Question 22

bivalent

Answer 22

tetrad or four chromatids  the way chromosomes line up during metaphase 1 of meiosis