Reproduction

Question 1

Meiosis

Answer 1

The process that produced gametes

it results in 4 haploid cells, all with different genetic makeup

Question 2

stages of meiosis

Answer 2

interphase
prophase I
metaphase I
anaphase I
telophase I
prophase II
metaphase II
anaphase II
telophase II

Question 3

interphase

Answer 3

interphase - chromosomes duplicate, not visable

Question 4

prophase I

Answer 4

prophase I - “prep phase”: centriole fibres migrate, spindle fibres form, nuclear membrane breaks down

Question 5

metaphase I

Answer 5

metaphase I - homologous chrs line up across equator, centrioles move to opposite sides, spindle fibres attach to chrs

Question 6

anaphase I

Answer 6

anaphase I - homologous chrs pulled to opposite sides of the cell

Question 7

telophase I

Answer 7

cell undergoes cytokinesis - creates 2 separate cells

Question 8

Spermatogenesis

Answer 8

spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid

Question 9

primary spermatocyte

Answer 9

undergoes meiosis I

produces 2 haploid cells

Question 10

secondary spermatocyte

Answer 10

undergoes meiosis II

chromatids are separated to produce 4 haploid cells

Question 11

spermatid

Answer 11

matures in the epididymus

loses some cytoplasm and forms a tail - creates sperm (1n)

Question 12

spermatogonium

Answer 12

diploid cell undergoes mitosis. Sperm move towards seminiferous tubule, become primary spermatocyte

Question 13

Oogenisis

Answer 13

oogonia, primary oocyte, secondary oocyte,ovum

Question 14

oogonia

Answer 14

diploid cell

mitosis occurs before birth

Question 15

primary oocyte

Answer 15

undergoes meiosis I

produces 2 haploid cells - 1st polar body receives half chrs, but less cytoplasm therefore isn’t viable

Question 16

primary oocyte

Answer 16

undergoes meiosis I
chromatids are separated to produce 2 haploid cells
2nd polar body isn’t viable
results in a single ovum

Question 17

ovum

Answer 17

haploid cell

during ovulation, the ovum is released into the fallopian tubes

Question 18

Ovarian cycle

Answer 18

concerned with changes within the ovary

cycle lasts around 28 days

Question 19

Hormonal changes in ovarian cycle

Answer 19

FSH causes a single primary follicle to mature into secondary follicle
Secondary follicle secretes oestrogen, develops into Graafian follicle
Graafian follicle bursts and releases ovum (LH)
corpus luteum secretes progesterone

Question 20

menstrual cycle

Answer 20

concerned with changes in the uterus

Question 21

hormonal changes - menstrual cycle

Answer 21

gonadatrophin factors stimulate the release of FSH and LH
FSH - matures follicle, which secretes oestrogen
Oestrogen thickens endometrium, increased levels cause FSH to drop
Corpus luteum secretes progesterone, maintains the endometrium
corpus luteum amalgamates, shedding endometrium

Question 22

Fertilisation to foetus

Answer 22

1. sperm and ovum meet in the fallopian tubes, forming zygote (single diploid cell)
2. zygote undergoes mitosis resulting in two diploid cells, which moves along the fallopian tubes
3. continues to undergo mitosis travelling into the uterus
4. dividing cell results in a morula after 4-5 days
5. forms a blastocyst after 7 days - cells are identical, undifferentiated
6. implantation
7. differentiation: tri laminar disc (mesoderm, ectoderm, endoderm)

Question 23

Blastocyst

Answer 23

when first formed, all cells are genetically identical and undifferentiated
after implantation, cells begin to differentiate: endoderm, mesoderm, ectoderm

Question 24

ectoderm

Answer 24

gives rise to skin and nervous system

Question 25

mesoderm

Answer 25

gives rise to muscles

Question 26

ectoderm

Answer 26

gives rise to internal organs

Question 27

Umbilical cord

Answer 27

connects the foetus and the placenta | contains two arteries and one vein, carrying blood to and waste from the foetus

Question 28

Stages of birth

Answer 28

1. cervical dilation, contraction of the uterus 2. expulsion of baby 3. expulsion of chorion, placenta

Question 29

foetal blood supply modifications

Answer 29

foreman ovale ductus arteriosis ductus venosus

Question 30

foreman ovale

Answer 30

hole in the septum connecting the the left and right atrium; reduces blood flow to the lungs

Question 31

ductus arteriosis

Answer 31

connects the pulmonary artery to the aorta; blood flow to the lungs is reduced

Question 32

ductus venosus

Answer 32

diverts the oxygenated blood from the umbilical vein to the vena cava, bypassing the liver

Question 33

Artificial insemination

Answer 33

used when sperm can't naturally fertilise an egg | semen sample is placed around vagina around ovulation

Question 34

Assisted fertilisation

Answer 34

drugs used to increase the number of maturing eggs | fertilised by IVF, gamete intrafallopian transfer, intracytoplasmic sperm injection

Question 35

In vitro fertilisation

Answer 35

harvested eggs are combined with semen in a petri dish | resulting embryos are then frozen or implanted into the uterus

Question 36

gamete intrafallopian transfer

Answer 36

harvested eggs are combined with the males sperm | mixture is injected into uterus

Question 37

intracytoplasmic fertilisation

Answer 37

single sperm injected into the egg

Question 38

Components of semen

Answer 38

sperm - produced in the testes alkaline fluid - neutralises acidic vagina, added by prostate nutrients - sugary fluid produced by seminal vesicle lubricating fluid - aids the transportation of sperm, added by Cowper's gland