d3.1 reproduction Flashcards
(145 cards)
1
Q
differences between asexual reproduction and sexual reproduction [4]
A
- no. of parents
- a- mitosis used throughout life cycle
s- meiosis used once per generation - a- offspring is genetically identical to each other + parent
s- offspring genetically different from each other and their parents - a- no genetic variation generated
s- genetic variation generated
2
Q
eg of asexual reproduction
A
bacteria- binary fission
3
Q
pros of asexual reproduction [1]
A
fast and efficient
4
Q
cons of asexual reproduction [1]
A
lack of genetic diversity
5
Q
consequences of lack of genetic diversity
A
- more likely to all die from disease
less adapted against extinction
6
Q
pros of sexual reproduction [1]
A
generates genetic variation
7
Q
what does genetic variation allow for
A
natural selection
8
Q
cons of sexual reproduction [1]
A
slow
9
Q
difference between male and female gametes [4]
A
- motility
m- travel to female
f- sessile - size
- food reserves
m- only enough for the gamete
f- enough for development of an embryo - numbers produced
10
Q
ovulation
A
egg has been developed and released in oviduct
11
Q
another name for egg
A
oocyte
12
Q
what does uterus do when egg is developing
A
prepares for the arrival of a fertilised egg
13
Q
where does the egg develop
A
ovary
14
Q
stages of the menstrual cycle [4]
A
- follicular phase
- ovulation
- luteal phase
- menstruation
15
Q
follicle definition
A
an egg surrounded by a small group of cells
16
Q
what is the group of follicles stimulated by
A
FSH (follicle stimulating hormone)
17
Q
where is FSH released from
A
pituitary gland
18
Q
what does developing follicles release
A
oestradiol
19
Q
purpose of oestradiol
A
thickens the endometrium (uterus lining)
20
Q
what does high amount of oestrogen do
A
inhibit FSH secretion
stimulates LH secretion
21
Q
eg of negative feedback
A
high amount of oestrogen → inhibit FSH secretion
22
Q
what does oestradiol do
A
increase number of FSH receptors on follicle cells- more responsive to FSH and releases more oestrogen
23
Q
eg of positive feedback
A
increase number of FSH receptors on follicle cells- more responsive to FSH and releases more oestrogen
24
Q
what happens if theres too much FSH
A
too many eggs released
25
where does developing follicles move to
edge of the ovary
- bigger ones that contains the egg
26
which days are LH released in huge amounts
days 12-14
27
where is LH released from
pituitary gland
28
what happens on the 14th day
one of the biggest follicle- bursts
29
why does the follicle burst
bc high amount of LH
30
what happens after the follicle bursts [2]
- releases an oocyte into the oviduct
- other follicles degenerates
31
how long does an egg last after ovulation
less than 48 hours
32
what happens at the start of luteal phase
follicle forms corpus luteum and releases progesterone and oestradiol
33
purpose of progesterone
thicken the endometrium further
34
what does oestradiol do in luteal phase
stimulate LH secretion from pituitary gland
35
what does progesterone effect
inhibits both LH and FSH secretion
36
why does LH level drop in luteal phase
mroe progesterone is released than oestrogen
37
why cant a zygote implant
only one cell- need at least 100 cells to implant
38
what happens if theres no implantation [5]
1. unfertilised oocyte leaves via the vagina
2. corpus luteum breaks down after 2 weeks
3. no more progesterone
4. endometrium breaks down (released during menstruation)
5. no progesterone- release FSH again
39
after menstruation stops [4]
1. blood loss stops
2. endometrium builds up
3. FSH stimulates oestradiol release
4. another group of follicles in the ovary will develop
40
what will the embryo release
hCG (human chronic gonatropin)
41
function of hCG
keep corpus luteum active so it can keep making progesterone to thicken the endometrium further
42
reason for pituitary gland not secreting FSH
progesterone is present
43
few weeks after implantation
corpus luteum will degrade
44
function of placenta [2]
1. release progesterone
2. pass nutrients and waste back to mother
45
overall 2 cycles
1. ovarian cycle
- follicle phase
- luteal phase
2. uterine cycle
- changes to the endometrium during menstrual cycle
46
graph of hormones in the menstrual cycle
check notes
47
why does the uterus need to be thickens to prepare for pregnancy
so fetus can be implanted
48
what hormone is responsible for stimulating follicle development?
FSH
49
which hormone stimulates ovulation?
LH
50
what is the name of the hormone that maintains the thickening of the endometrium?
progesterone
51
why would the endometrium collapse and break down if theres no implantation?
no more progesterone
52
what inhibits FSH and stimulate LH
oestradiol
53
what inhibits FSH and LH secretion
progesterone
54
epididymis
where sperm matures and is stored
55
seminal vesicle function
makes seminal fluid
- contains fructose (energy source)
56
testicle function
- male gonads
- make testosterone and sperm (male gametes)
57
prostate gland function
alkaline for the semen for sperms to survive
58
ovary function
- female gonads
- produces oestrogen , progesterone and eggs
59
endometrium (uterus) function
allows for implantation of fetus
60
fallopian tube function
- oviduct
-pathway for egg to uterus
61
sperm diagram
notes
62
egg diagram
notes
63
process of fertilisation (humans) [5]
1. one sperm reaches the zona pellucida
2. acrosome reaction occurs- enzymes in head of the sperm digest through the zona
- takes more than one sperm to digest the zona pelucida
3. plasma membranes of the sperm and the egg fuse
4. stimulates release of Ca2+ in the egg, stimulating meiosis II in the nucleus
5. cortical reaction- at the same time, the cortical granules fuses with the egg plasma membrane, releasing its contents
64
why is it important that the zona pellucida cant bind w sperm
- no more sperm can enter- prevent polyspermy
65
how does structure of zona pelucida change
acrosome is an enzyme
- when active site changes- cant enter anymore
66
what happens when zygote undergoes first mitosis
male and female nuclei fuse- joint mitosis
=> 2 genetically identical diploids
67
what stays out of egg
midpiece and tail of sperm
68
importance of midpiece and tail of sperm not entering egg
male mitochondria never enters
69
ifv process
1. down-regulation
- injection every day for 2 wks- stop the pituitary gland from secreting FSH or LH
- secretion of oesteradiol and progesterone also stops
- allows doctors to control the timing and amount of egg production
2. intramuscular injections of FSH
- stimulates follicles to develop
- aim- generate a higher FSH concentration
- more follicles than usual develop
3. when follicles are 18mm- stimulated to mature by injection of hCG
- signals to the mother that the embryo is in need of sustenance from the endometrium
4. egg collection
- draw the eggs out of the follicles
5. mixed with sperm cells in a shallow dish + incubated
6. extra progesterone given to ensure that uterus lining is maintained
7. if implantation occurs- normal pregnancy
70
petal function
attracts pollinators
71
stigma function
pollen binding site
72
style function
pollen tube grows down style from stigma to ovary
73
ovary function
contains ovules (female gametes)
74
sepals function
protect developing flower
75
filament function
supports anther
76
anther function
contains pollen
77
female name for plant reproduction system
carpel
78
male name for plant reproduction system
stamen
79
why is carpel longer than stamens
- avoid self pollination and increase genetic variety
- offsprings- varied genotype
80
why pollen grains dont simply fall off the stigma after pollination
- different shapes
- water- hydrate the pollen so causes surface tension
- fructose: makes it more sticky
81
why a pollen grain knows when to grow a pollen tube down the style
- hydration from the water
- compatibility- if it recognise that its from itself- wont grow or grow then killed halfway
- temperature
- chemicals to attract the tube to find the ovule
82
micropyle
opening of the micropyle allows the pollen to enter the ovule for fertilisation
83
product of plant fertilisation
zygote: develops into an embryo with an embryo root, embryo shoot and either one or two embryo leaves
84
why 2 male gametes
one- seed, one- endosperm
85
adv of self pollination
ensures survival even when population is scarce
86
disadv of self pollination
disadv- increases the change of recessive alleles of rare diseases being inherited
87
why would want to self pollinate
gardener- rare and pure breed of flower then would want to self pollinate
88
adv cross pollination
1. genetic variation so the offsprings are better adapted to the changing environment
2. promotes hybrid vigour (offsprings of crosses between genetically unrelated plants tend to be healthily and grow strongly)
89
methods to promote cross pollination [4]
1. anthers and stigmas have different maturing times
2. separate male and female flowers
3. separate male and female plants
4. self incompatibility gene
90
anthers maturing first
protandrya
91
stigma maturing first
protogny
92
eg of male and female in the same flower
corn
93
eg of separate male and female plants
ginko tree
94
word for male and female flower on separate plants
dioecious
95
how does self incompatibility gene work
when the pollen lands onto the stigma, the plant will see whether it contains the same allele as the style
96
difference between pollination and seed dispersal
- pollination- transfer of pollen from anther to stigma
- seed dispersal- spread out to avoid competition of sunlight, water, minerals
97
why radicle out first than plumule
- water can get in seed first
dont need sun to germinate
98
ideal conditions for germination + explanation
1. water- taken in thru plumule + used to activate the seed
2. oxygen- respiration
3. ideal temp and pH- enzyme activity
99
is light needed for seed germination
depends on the species
100
why seeds need water to germinate
- stored food inside is starch
- breaks it down into glucose and used for respiration
101
process of seed germination [6]
1. water is absorbed through the micropyle and activates cells
2. synthesis of gibberellins (plant growth hormones)
3. gibberellins cause synthesis of amylase (enzyme)
4. amylase hydrolyses stored starch to maltose
5. maltose absorbed by plumule and radicle
6. further hydrolysis breaks maltose into glucose, which is used for respiration in the growing tissues
102
when is light needed in the process of seed germination
when stored food runs out
103
puberty definition
sequence of developmental changes that form the transition between childhood and sexual maturity
104
where is the GnRH released from
hypothalamus
105
how does fsh and lh secretion secretion by the pituitary gland affect females
oestradiol secretion by the ovaries
106
how does fsh and lh secretion by the pituitary gland affect males
testosterone secretion by the testes
107
what does GnRH stand for
gonadotropin-releasing hormone
108
what does low level frequency stimulate
fsh secretion
109
what does high level frequency stimulate
lh secretion
110
fsh in males
stimulates testis growth
111
lh in males
stimulates testosterone secretion by Leydig cells in the testis
112
lh and fsh in males
development of secondary sexual characteristics
113
fsh in females
development of follicles in the ovary
114
what does wall of follicle do
secretes oestradiol
115
lh in females
stimulates development of the follicle wall into the corpus luteum after ovulation
116
what does corpus luteum secrete
oestradiol and progesterone
117
function of testosterone
development of secondary sexual characteristics
118
function of oestradiol
causes development of secondary sexual characteristics
119
function of progesterone
stimulates developmental changes in the breasts
120
germinal epithelium function
contains the stem cells that makes the primary follicles
121
primary follicles function
location for development of oocyte, surrounded by support cells
- eggs inside not ready
122
mature follicle
contains secondary oocyte
- gamete that fetal makes
123
secondary oocyte
haploid gamete
- final stage of meiosis occurs after fertilisation
124
medula function
nutrients for follicles and nerves
125
differences between spermatogenesis and oogenesis [5]
1. number of gametes (4:1)
2. rate of gamete production
3. timing of release
4. timing of production and release of gametes
5. amount of cytoplasm
126
how pregnancy testing works
127
placenta function
- releases progesterone and oestrogen
- exchange of materials between maternal and fetal blood
128
which hormones are given during hormone replacement therapy
oestrogen and progesterone
129
hormone replacement therapy function
relieve menopausal symptoms
130
cortical granules
releases enzymes to modify zona pellucida- prevent polyspermy
131
function of Leydig cells
produce testosterone
132
name of gaps between seminiferous tubules
interstices
133
origin of spermatogonia
germinal epithelial cells
134
function of Sertoli cells
noursih developing spermatozoa
135
important of meiosis in sexual reproduction
- make haploid gametes
- genetical difference
136
genetic variation in meiosis due to [3]
1. cross over at prophase i
2. random orientation at metaphase i and ii
3. random assortment at anaphase i and ii
137
why fusion of gametes important for sexual life cycle
ensure diploid number of chromosome in offsprings
138
large size of egg as adaptation
energy storage during early stage of embryo development
- before implantation to the uterus lining
139
jelly coat as adaptation
change structure after first sperm penetration into the egg- prevents polyspermy
140
flagellum as adaptation
allow for movement
141
mitochondrion as adaptation
respire to release energy for movement
142
enzyme in acrosome
break down zona pellucida of ovum
143
flowering plants that contain both male and female sexual reproductive system
hermaphroditic plant
144
name of small tubules in testes
seminiferous tubules
145
what are in between seminiferous tubules
Leydig cells
