Stem Cells

Question 1

what occurs in prophase I?

Answer 1

homologous chromosomes pair up, crossing over occurs

Question 2

what happens in metaphase I?

Answer 2

pairs of homologous chromosomes move to the equator

Question 3

what happens in anaphase I?

Answer 3

homologous chromosomes move to opposite poles of the cell

Question 4

how many chromosomes do the daughter cells have in the mitosis?

Answer 4

half of the parent

Question 5

what is synapsis?

Answer 5

pairing of homologous chromosomes

Question 6

what is a tetrad?

Answer 6

two homologous chromosomes with 4 chromatids

Question 7

what does spermatogenesis begin with?

Answer 7

spermatagonium

Question 8

what is formed from a spermatagonium after meiosis I?

Answer 8

2 primary spermatocytes

Question 9

what does meiosis II form from the primary spermatocyte?

Answer 9

two secondary spermatocytes

Question 10

what do the secondary spermatocytes turn into?

Answer 10

2 spermatids from each spermatocyte

Question 11

what is spermiogenesis?

Answer 11

the formation of spermatozoa

Question 12

where does spermiogenesis occur?

Answer 12

in seminiferous tube

Question 13

where are spermatagonia occur?

Answer 13

on the outside of the tube

Question 14

what are sertoli cells?

Answer 14

cells that carry out the production of mature spermatids

Question 15

how are sertoli cells joined?

Answer 15

by tight junctions

Question 16

what do the tight junctions do?

Answer 16

create a blood-testes barrier

Question 17

why is there a blood-testes barrier?

Answer 17

for immune privilege of the sperm

Question 18

what is the purpose of incomplete cytokinesis?

Answer 18

allows synchronisation of the sertoli cells to produce the sperm cells

Question 19

how long does spermatogenesis take?

Answer 19

75-120 days

Question 20

what is the structure of the sperm tail?

Answer 20

microtubules, and anexome with a 9+2 structure

Question 21

what is the mitochondria like in the sperm?

Answer 21

spiral shaped to fit inside the tail

Question 22

what is the DNA like in the sperm?

Answer 22

highly condensed DNA allows it to be stored in the acrosome

Question 23

what drives the production of sperm?

Answer 23

testosterone

Question 24

what does ABP do?

Answer 24

glycoprotein that binds to testosterone that is produced from sertoli cells

Question 25

what does oogenesis begin with?

Answer 25

a primary oocye

Question 26

what is produced from the primary oocyte after meiosis I?

Answer 26

a secondary oocyte and the first polar body

Question 27

what does meiosis II produce in oogenesis?

Answer 27

two polar bodies from the first and one mature ovum and another polar body from the secondary oocye

Question 28

how to the folicles develop during the release of an ovum?

Answer 28

begins with a primary follicle and then into developing follicles, become mature follicles when it becomes a secondary ovum

Question 29

what happens to the follicles once the ovum has been released?

Answer 29

mature follicle ruptures and turns into a corpus luteum

Question 30

when are primary oocytes produced in a foetus?

Answer 30

20 weeks

Question 31

at what stage does the primary oocyte stop developing in a foetus?

Answer 31

prophase I

Question 32

where does a secondary oocyte reach until fertilised?

Answer 32

metaphase II

Question 33

what do thecal cells do?

Answer 33

leteinize and form cells of the corpus luteum

Question 34

what hormones control oogenesis?

Answer 34

FSH and LH

Question 35

what are embryonic stem cells?

Answer 35

come from blastocyst inner cell mass, differentiate into specialised stem cells

Question 36

what are adult stem cells?

Answer 36

for growth and repair, come from bone marrow and fat and the blood

Question 37

what are the features of stem cells?

Answer 37

choose between cellular fates, prolonged self-renewal, differentiate

Question 38

what are totipotent stem cells?

Answer 38

can form a zygote, come from blastocyte

Question 39

what are pluripotent stem cells?

Answer 39

differentiate into 3 germ layers

Question 40

what are multipotent stem cells?

Answer 40

differentiate into several cell types e.g. haemopoietic stem cell

Question 41

what is a unipotent stem cell?

Answer 41

differentiate into a single cell type

Question 42

what is induced pluripotency?

Answer 42

reprogrammed adult stem cells formed using transcription factors

Question 43

what can induced pluripotent stem cells be used for?

Answer 43

to generate stem cells from someones own cell so no rejection

Question 44

how can you identify stem cells?

Answer 44

using specific CD markers for each type of stem cell

Question 45

what is a functional assay?

Answer 45

systematic experiments that are used to determine the involvement of each protein needed for cellular pathways