lecture 10+ 11+12

Question 1

Difference between somatic and reproductive cell division

Answer 1

Somatic produces diploid, identical daughter cells whereas reproductive produces 4 haploid daughter cells.

Question 2

Cell theory concept

Answer 2

All organisms made of cells which come from pre existing cells

Question 3

Check points of cell cycle

Answer 3

G1, G2, M (during mitosis)

Question 4

Germ line

Answer 4

passed onto future progeny (basically means genetic)

Question 5

types of subsitutions

Answer 5

silent (no effect, same aa coded), missense (effect varies, different aa coded), nonsense (stop codon, truncated protein )

Question 6

Maturation promoting factor (MPF) structure/function

Answer 6

Complex consisting of cyclin and cyclin dependent kinase (cdk), allows for mitosis by phosphorylating many other proteins. The key at G2 checkpoint.

Question 7

interphase components

Answer 7

G1 - cellular activities, length varies depending on cell type; S phase - DNA synthesis; G2 (interphase) - prep for mitosis by producing proteins, enzymes, check correct DNA replication, centrosome replication completed

Question 8

proto-oncogenes

Answer 8

accelerator, promote cell proliferation (e.g. Ras - a GTPase, Myc - a transcription factor)

Question 9

tumour supressor gene

Answer 9

brakes, inhibit cell proliferation (e.g. tp53, BRCA1, BRCA2)

Question 10

Prophase (mitosis)

Answer 10

-chromosomes condense, mitotic spindle begins to form, nuclear envelope begins to break

Question 11

Metaphase (mitosis)

Answer 11

sister chromatids line up at the meta-plate via tug of war

Question 12

Anaphase (mitosis)

Answer 12

Segregation of sister chromatids, start pulling away

Question 13

Telophase (mitosis)

Answer 13

Nuclear envelope starts to reform, cleavage furrow between two forming cells

Question 14

Cytokinesis (mitosis)

Answer 14

Splitting of into two cells, nuclear envelope reformed. Result are two diploid cells identical to parent cell

Question 15

Prophase I compared to II (meiosis)

Answer 15

I: DNA already replicated, spindle forms, nuclear envelope shatters, homologous chromosome tetrads pair up

II: DNA not replicated, spindle forms and envelope shatters, chromatids

Question 16

Metaphase I compared to II (meiosis)

Answer 16

I: Homologous chromosome tetrads line up at meta-plate (synapsis/cross over)

II: chromatids line up at meta-plate

Question 17

Anaphase I compared to II (meiosis)

Answer 17

I: Homologous chromosome pairs start to pull apart

II: sister chromatids start to pull apart

Question 18

Telophase/cytokinesis I compared to II (meiosis)

Answer 18

I: two new cells form from cleavage furrow (diploid), goes into second round of division

II: four new cells form from cleavage furrow (haploid).
Nuclear envelope reformed in both.

Question 19

S phase

Answer 19

DNA replication by breaking of weak hydrogen bonds between nucleotides, each new strand is made from half old half new

Question 20

when does crossing over occur

Answer 20

prophase 1 after synapsis (homologous chromosomes pair up) and joined by chiasmata (crossing over/recombination)

Question 21

Cyclin fluctuation cycle

Answer 21

Cyclin build up when nearing M phase, forms MPF complex with cdk, degraded during M phase.