Gametogenesis Part 1

Question 1

what is gametogenesis

Answer 1

production of sex cells

haploid (n) - diploid (2n) through meiosis

Question 2

these are the progenitor cells of gametes

Answer 2

primordial germ cells or primary undifferentiated stem cells

Question 3

the primordial germ cell appears at _______ and migrates to ______

Answer 3

wall of yolk sac at 3rd wk of development

migrates to gonads at 4th-5th wk

Question 4

discuss the concept of mitosis

Answer 4

cell duplication for SOMATIC CELLS - replaces worn out cells

= 2 identical daughter cells

interphase - prophase - metaphase - anaphase - telophase

Question 5

INTERPHASE of mitosis

Answer 5

chromosomes become double stranded

Question 6

PROPHASE of mitosis

Answer 6

chromatid + chromatid = chromosome joined by centromere - begins to condense and thicken

starts to move towards opposite poles

microtubules produce mitotic spindles that attach to centrosomes

Question 7

PROMETAPHASE of mitosis

Answer 7

mitotic spindle attaches to kinetochores

nuclear membrane breaks down allows fibers to attach to side of chromosomes at kinetochore

Question 8

METAPHASE of mitosis

Answer 8

chromosomes are line up at equatorial plane at METAPHASE PLATE

centrioles have finished moving to opposite sides of cell

Question 9

ANAPHASE of mitosis

Answer 9

centromeres split in 2 - spindle fibers contract and moves toward opposite poles

sister chromatids become chromosomes

Question 10

TELOPHASE of mitosis

Answer 10

chromosomes arrive at opposite poles - decondenses, uncoils and lengthens

nuclear envelope material surrounds each set

Question 11

CYTOKINESIS of mitosis

Answer 11

division of cytoplasm

begins at anaphase but ends after telophase

Question 12

what is meiosis

Answer 12

division in germ cells to produce gametes

2 cell divisions - meiosis 1 and 2 para haploid

46 - 23

Question 13

PROPHASE 1 of meiosis 1

Answer 13

1. leptotene: chromosomes condense = 2 sister chromatids and centromere
2. zygotene: 2 chromosome in each pair associate via synapsis
3. pachytene - the pair trades DNA via crossing over
4. diplotene: synapsis ends c disappearance of synaptonemal complex but homologous pairs still attached via chiasmata
5. diakinesis: chromosomes are full condensed and nuclear membrane disintegrates

Question 14

METAPHASE 1 of meiosis 1

Answer 14

microtubules emerge from spindle and attach to kinetochore and aligns at equator

attaches to maternal and paternal of homologous chromosome

Question 15

METAPHASE 1 of meiosis 1

Answer 15

each homologous chromosome is pulled towards opposite poles - equal division of DNA

each daughter cells has half of chromosome from patent

Question 16

TELOPHASE 1 of meiosis 1

Answer 16

nuclear envelope and spindle fibers disappear and cytokinesis 1 starts = 2 haploid daughter cells

2C = 1N

Question 17

MEIOSIS 2

Answer 17

same lang but produces 2 non identical haploid daughter cells

MEIOSIS 1 2 daughter = 4 MEIOSIS 2 daughters

1C = 1N