Animal R+D+G Flashcards
(130 cards)
1
Q
define sex
A
the fusion of genetic material from two different parents
2
Q
pros of asexual reproduction
A
higher rate of offspring per organism
no energetic costs
3
Q
cons of asexual reproduction
A
transmits mutations and no genetic variation
4
Q
4 methods of asexual reproduction
A
fragmentation - break body bits and regrow lost parts
binary fission - divide into two creating daughter cells
budding - offspirng grows from parental body cells
parthenogenesis - virgin birth,
5
Q
in stressful conditions _______ is favoured over ______ reproduction because in stress ________ is needed
A
sexual reproduction
asexual reproduction
genetic diversity
6
Q
how old is sexual reproduction
A
1.5 -2 billion
7
Q
3 stages to sexual reproduction
A
gametogenesis
mating
fertilisation
8
Q
both ______ and _____ are highly conserved but ______- has huge variety
A
gametogenesis
fertilisation
mating
9
Q
describe external mating
A
stuck in the same spot e.g. giant clam - cast sperm into environment, more mobile species will put sperm as close as possible to the female
10
Q
_______ is essential for external ferilisation
A
water
11
Q
what are the limits to external fertilisation?
A
cant control the delivery
huge number of gametes required
high energetic cost
12
Q
internal fertilisation can be _______ or _______
A
indirect or direct
13
Q
describe the mating strategy of the Sminthurus virdis
A
a neat spermatophore made from males testes - stalk with spermatophore on top
no courtship ritual
14
Q
desccribe the mating strategy of the Allacma gallica
A
male deposits several spermatophores
- pushes female towards them - increasing likelyhood that a female accepts the spermatohore
- males eat the spermatophore of others males to increase paternity
15
Q
direct transfer of sperm requires an __________ organ
A
intromittent
16
Q
describe sexual dimorphism in the blanket octopus
A
females are up to 2 meters
males are 1mm
males fill sperm n an arm like organ mating arm spits offf and swims towards the` female
17
Q
define hermaphrodite
A
male and female reproductive organs
cant self fertilsie
18
Q
describe the costly mating of the bean weevil (callobrichus)
A
males penis has spines - lacerate the reproductive tract
- shortens life span
- increases time between female copulations
19
Q
describe the costly mating in bed bugs
A
females dont have genital openings
males pierce body and place sperm in the haemocoel
sperm move ton eggs
20
Q
describe sexual canabalism
and why it is adaptive
A
female eats male
- nutritional benefit to female
- maximises paternity by prolonging copulation
- minimise paternity monopolisation
21
Q
three key processes in gametogenesis
A
meiosis
- spermatogenesis in males
- oogenesis in females
22
Q
briefly describe meiosis
A
homologus chromosomes
genetic recombination occurs
two rounds of cell diviision
in meiosis 2 the cell splits and produces 4 gametes
23
Q
in humans sperm is produced in the _________ of the testes, and then is moved to the _______ where they are stored, the ______ transfer sperm to the penis
A
seminiferous tubules
epidiymis
vas deferens
24
Q
seminal fluid makes up ____ of semen
A
90%
25
in fruit fly sperm is formed in the ____ of the testes and picks up seminal fluid from the _____
hub
| accsessory glands
26
spermatogonial stem cells divide by ________ to produce _______ spermatocytes. Then each spermatocyte divides by ______ to form two secondary spermatocytes. Meiosis 2 occurs in which each secondary spermatocyte divides into _________ _______ _______
mitosis
primary
meiosis
four halploid spermatids
27
differences between spermatogenesis in inverts and humans
inverts, cysts within testes
humans - seminferous tubules
inverts - distal to proximal
humans - periphery to lumen
inverts in larval stage
humans - puberty
inverts - few days but 10,0000 per day
mammals - 74 days but 3000 million per day
inverts store in seminal vesicle
humans store in epidiymus
28
```
use the:
- house mouse
- zebra fish
- nematodes
as examples of diverse sper,m
```
house mouse has hooked sperm enables them to move in groups
zebrafish have more mitochondria
nematodes have pseudopodia instead of a tail allowing a crawling movement
29
descrine the sperm heteromorphism adaptation in butterflies
long fertile and short infertile
adaptation for sperm competition
infertile may act as a plug to prevent other males
30
describe oogenesis
primary oocyte divides germinal vesicle breaks down (nucleus)
meiosis 1
metaphase plate moves towards the edge by telophase one of the daughter cells contains very ittle cytoplasm
small cell = firstr polar body
large cell = secondary oocyte
second meiotic division:
polar body divides as well as secondary oocyte makes three polar bodies and one ovum
the ovum has more of the cytoplasm etc
31
compare oogenesis in inverts and humans
inverts: egg develop from distal region to proximal
human: oogenesis within a folicle grows for 2 weeks ruptures to release an egg
inverts: starts in larval stage
humans: 400,000 folicles folicles at birth no ovulation until puberty
inverts: 100 eggs per takes a few to mature an egg
humans : 1 egg matures each month
inverts released into uterus for fertilisation
human: folicle ruptures oocyte enters fallopian tube
inverts: egg develops outside the insect
humans: embeded into uterian wall
32
what hormone is released by females during puberty to start their period ? what does it do?
gondaotrophin releasing hormone
stimulates FSH (folicle stimulating hormone) and LH (lutenising hormone)
33
what happens to males at the start of puberty?
FSH causes the development of leydig cells which secrete testosterone stimulating spermatogenesis
- develops seminferous tubules and spermatogensis
34
what do FSH and LH do in females
FSH - stimulates folicle development and secretion of estrogens
LH - stimulates maturation of follicles and release of ova at ovulation
35
role of oestrogen in females
enhances folicle growth and grows endomethium
36
role of progestrone
grow and maintains endometrieum for pregnanct secretes nutrients to embryo
37
where is gondotrophin releasing hormone released from
hyperthalamus
38
when do LH and FSH peak?
ovulation
39
go through the series of events from release of Gondotrophin to mensruation
GnRH released from anterioir pituritory gland
LH released later
stimulates folicle growth
oestrogen released
LH surge
folicle realses egg
corpus luteium (egg housing) degenerates
protesteone and estorgone released
endometerium expands
if egg is unferilised then menstruation will happen
40
how does the birth control pill work, how effecrtive is it?
synthetic oestrogen and progesterone
no oestrogen peak
changes cervical mucus - more harsh for sperm
41
five stages of development
fertilisation - zygote formed
cleavage - cell division forms blastula
gastrulation - formation of tissue layers and axis
organogenesis - fromation of organs
morphogenesis - body shape formation
42
the mitochondria of the zygote all comes from the ______
mother
43
zygote has two spheres the _______ which contains the ______and the _______ which contains the ______
animal - nucleus
| vegital - nutrients
44
describe the process that occurs after fertilisation in amphibians
vegital clear - animal is opauque
cortex rotates so site of ferilisation is at a junction between the animal and vegital spheres
45
in amphibians where does the crey crescent sit?
opposite the site of fertilisation
46
what is cleavage? what does it form?
a rapid series of cell divisions following fertilisation
- typically double
- each cell = blastomere
- ball of cells = morula
- blastula = hollow ball of cells
47
there is very little _____ during cleavage
growth
48
3 patterns of cleavage what determines the pattern?
complete
incomplete - discoidal
incomplete superficial
determined by the amount of yolk and spindle orientationo
49
when does complete cleavage occur
no or small amount of yolk
| - where no yolk even division occurs
50
when does incomplete discoidal cleavage occur
lots of yolk - cleavage furrows dont penetrate the yolk - blastodisc froms on top of the yolk gives rise to embryo
51
when does incomeplte superficial cleavage occur?
when the yolk sits in the middle of the egg
cytokenesis doesnt follow nucleus division. nuclei migrate to the edges
plasma membranes grows inwards partioning the nuclei
52
when mitotic spindles form at right angles or parallel the cleavage is ?
radial
53
describe the mitotic spindles in rotaional cleavage
first division is parallel to a-v axis second is at right angles
54
in early development cells are _________ . At ________ their fate becomes _______. At _________ th cells become structurally and functionally specialised
totipotent
determination
differentiation
55
what is gastrulation?
where the blastula becomes an embryo
| - tissue layers begin to fall
56
what are the three tissue layers formed by gasturlation?
endoderm - inner layer produces digestive tract
ectoderm - epidermis and nervous system
mesoderm - bone muscle liver, heart and blood vessels
57
describe the process of gasturlation in mammals
blastula invaginates at vegital hemisphere
cells migrate towards the blastocoel and become primary mesenchyme cells
invagination continues - archentron which becomes the gut
secondary mesemchyme cells attach to vegital pole
in protosomes the mouth forms from the blastopore where as deuterosomes the anus forms from the blastopore
58
breief description of early development in birds
cleavage forms a blastodisc
epiblast forms the embryo and hypoblast forms extraembryonic membranes - the blastocoel lies in betweeen the two
gastrulation occurs when hensens node moves across the
59
neurulation
formation of the nervous system, ectoderm thickens above the notochord
edges of thick area continue to thicken to give ridges
60
neural crest cells produce what during neurulation?
peripheral nerves
61
somites produce what during neurulation?
vertebrae ribs, muscles and trunk
62
```
define the following parts of the egg.
- yolk sac
- amnioitic sac
- chorion
allantois
```
yolk sac = nutrient transfer via blood vessels
amniotic sac = protection surronding embryo
chorion = gas and water exchange, surronds embryo and yolk sac
allantois = waste storafe in mammals incorporated into ambilical chord
63
what proportion of sperm survive the virgina
1 in 1 million
64
mammalian egg structure
germinal vesicle = contains nucleus
ooplasm = cytoplasm of egg
viteline layer - cell membrane surronding ooplasm
zona pellucida - extracellular matrix that contains glycoproteins
surronded by corona radiata - layer of folicle cells
65
structure of sperm
head - nucleus
neck - centriole
midpiece - mitochondria which provides energy for movement
tail - drives the sperm forward
66
describe how the sperm penetrates the egg in mammals
vigorous motility to get through corona layer
undergoes acrosome reaction to get through the zona pelcuida
sperm and oocyte plasma membranes fuse - protein recognition and attahcment
sperm nucleus enters ovum
membrane and zp proteins block polyspermy
67
describe how the sperm penetrates and fertilises the egg in sea urhcins
protective jelly coat dissolved by enzymes from sperm
sperm binds to receptors on microvilli which recognise species specific bindin proteins
potrusion from sperm head and membrane fusion occurs
68
how do sea urchins protect themselves from polyspermy?
by changing their electrochemical gradient
69
ZP2 egg protrein is in the top __% of most divergent molecules
5
70
one of the fastest evolving metazoan proteins is ?
lysin - dissolves egg envelope in abalone molluscs
71
three controlers of development
cytoplasm
genes
external environment
72
what is genomic activation?
the transiion from maternal control to embryo control
73
why is early development under maternal control?
in early embryos there is no transcription
all proteins and enzymes come from the cytoplasm
74
differnetiation is caused by _______. How was this proved
differntial gene expressionn
take adult skin cells and mature them in a medium of transcription factors
nucleus of somatic cell transferred into enuclated egg and a normal embryo was produced.
also shows genomic equivalance and that the cytoplasm controls earlt devlelopment
75
what is genomic equivialnce ?
no infomation is lost in the early stages of embryoninc development
76
where are the cytoplasmic factors held? how do we know?
gray crescent
- split the grey cresecent if split in two there are two normal tadpoles
- if split unevenly with all grey crescent on one side then one tadpole and one belly piece
77
desccribe cytoplasmic segregation. and why different segregation results in different outcomes
factor unequally distributed in the cytoplasm and ends up in some daughter cells but not others
most of the nurients are at the vegital poles
- result depends on where the segregation occurs
- horizontal - remain embryonic, only one has nutrients
- vertical - normal but small since both have nutrients
78
what is developmental induction?
where the presence of one tissue effects the development of another
79
give an example of primary induction in birds and amphibians
amphibians - spemann organiser - dorsal lip of blastopore, which induces overlying ecotderm to form neural tissue
hensens node in birds
induced from the central nervous system
80
give an example of secondary induction
forebrain starts to bulge and optical vesicle forms causes lens placode tissue to form
differentiates into a lens indues surface layer to become a cornea and the layers behind it to be an optic cup
81
what morphogen controls the anterior prosterior axis of the limb, how does it do so?
BMP2
| smallest dose of BMP2 causes the growth of the little finger etc
82
male male zygotes wont form a ____ because the inner cell mass is _______ controlled> where as female female zygotes wont produce a ______ becuase this develops from ______ genes
embryo
maternally
placenta
paternal genes
83
demonstarte how the same gene on maternal and paternal chromomes can cause different phneotype
prader willi syndrome - deletion on paternal chromosome 15
- compulsive eaters with learning difficulties
angelman syndrome
deletion in maaternal chromosome 15
- mobility issues and permanet happiness
84
give the four types of genes involved in segmentation and what each one does
gap genes - organise large areas along the anterioir prosterioir axis
pair rule genes - divides each embryo into units of two segments
segmentation polarity genes - determine segment boundries
homeotic genes are expressed along the length of the body and determine what the segments will become
85
homeotic genes are also known as what?
HOX genes
86
apoptosis
programmed cell death
87
how many of c elegans 1090 stomatic cells are programmed to die
131
88
what enzymes stimulates apoptosis in human embryos hands ?
caspase
| - removes webbing between fingers
89
describe the infuence gut bacteria have on mpuse development
induce gene expression in the intestine which is essential for normal capillary development
90
describe spina bifidia and how it is caused
where the neural tube fails to close at the posterioir end - part of the spine doesnt develop properly
91
describe anencephaly
where the tube fails to close at the anterioir end - brain dioesnt develop properly gap in
92
the chances of anencephaly and spina bifidia are redcued by
adequate folic acid when pregnant
93
what causes cretinism, what are the symptoms
lack of iodine
| symptoms include - drawfism and large heads
94
what is sonic the hedgehog protein involved in?
fomration of the neural system
95
what is the average rate of egg failure and what about in kakapos
10-15% average
| 70% for kakapo
96
what are the two major types of cause of egg failure
fertilisation failure
| embryo death
97
ways an egg may fail because of fertilisation
sperm doesnt reach
sperm or ovum dysnfunction
female antisperm response
98
what percentage of sperm that enter vagina female die?
0.00001%
99
what part of the reproductive tract does fertilisation occur in
infundibulum
100
if you bypass the uterus even ____ sperm gets to the egg.
dead
101
describe how you can test the most succsessful bird sperm
female secretes glycoporteins into the outer perivitelline layer that trap sperm
- can see the sperm that made it to the egg
- measure them
102
___ sperm have a competitive advantege over ____ sperm as long as the ______ and the _______ are equal size
long
small
midpiece and tail
103
in birds polyspermy is normal which means?
sperm selection continues after entering the egg
104
polyspermy is required for surivial in many bird eggs whuch part of the extra sperms is needed and how do we know this
injected single sperm with many proteins extracted from over 200 other sperm
only the sperm protein is needed
105
4 mechanisms of cloning
natural
embryo splitting
reprogramming of somatic cells
nuclear transfer
106
describe embryo splitting as a mechanism of cloning - who did it first
bisect the egg of a salamander
manipulatied monozygotic twins
spemann first to do it with a hair from his baby
107
reprogramming of stomatic cell is basically ____________. and involves
revevrsing differntiation
| - take cells and feed specific growth factors
108
why is stomatic cell nuclear transfer controversial
invasive
tech porblems
ethical problems
109
who were the first cloned mammals?
megan and morag the sheep
110
how where megan and morag cloned
arrested embryo cells in G0 of interphase by depriving them of a growth factor
arrested cells into enuclated eggs and stimulated them
planted into surrogate
111
why what was the argument against megan and morag being the first clones?
they had come from an embryo cells - argued that they hadnt lost complete totipotency
112
how was dolly cloned
adult sheep mammary glands arrestred in G0
cells fused with enuclated eggs and transplanted intoo a surrogate
113
why is cloning better than genetic modification of all lambs in an atempt to create theraputic milk
each trasngenic lamb requires 51.4 ewes
each transgenic clone requires 20.8 ewes
114
what disease does polly and her sisters milk help to treat
haemophilia - has blood clotting factor nine
115
first monkey to be cloned
ANDi - rhesus monkey
116
for how long did cloning bring the pyrenean ibex back from extinction?
7 minutes
117
why cant cloning ever bring back a loved one
only dna clones not cytoplasm ones
clones have their own mutations
differnent environments
aging - telemoeres shorten with age- clone has telomere of parent
large foetus syndrome - clones grow larger and need to be implanted into larger surrogates
118
what disease is caused by a lack of dopamine
parkinsons
119
what is evo devo
evolutionary development
- looks at how changes in the genes that regulate development affect the adult forms of organisms and how these changes have occured over the course of evolution
120
what gene codes for eye growth in mice
Pax 6
121
how did darwin know that gosseneck barnacles were crustaceans
by looking at their larval stage
122
describe th emutatioon in the arhtopods that lead to the insects
arthropods have legs on their abdomen
insects have a mutation which produces a protein that represses the distal less gene in the abdomen which is essntial for leg formation
all insects legs orignate on the thorax and not the abdomen
123
describe the roles of both BMP4 and gremlin in forming the ducks webbed feet
BMP4 expressed between the developing toes it insructs the cells to undergo apoptosis which destroys the webs
gremlin is a BMP4 inhibitor expressed around the digits to prevent toe dropping off
in ducks gremlin moves between toes allowing webbed feet
124
describe temporal shifts in expression in bolitoglossa
webs disappear as they mature e.g. rostratus
some e.g. occidentales expression of these genes is slowed down allowing for suction cups enabling arboreal life
125
what triggers egg production in mosquitos
a blood meal
| - stimulates vitellogenin production
126
describe the wet and dry season form of the squinting bush butterfly
dry is darker with less obvious eye spots itcomes out when it is less than 20
more than 24 and the wet form will develop
127
polyphenism
two phylogenetic pathways dependant on climate
128
describe the polyphenism in the moth nemoria arizoniaria
spring larvae feed on oak flowers and look like them
summer form look like oak leaves and eats stems
129
describe the polyphenism in daphina
```
encounter chaoborus (predator) and get spiky helmets
- helmet induction occurs around the larvae of chaoborus it is a trade off since those with helmets produce fewer eggs
```
130
describe the polyphenism in spade foot toads
live in desert ponds
dry up quickly following a rainfall
eat insects and alage meaning slower develoment since poor nutrition
pond could dry up causes tadpoles to have a wider mouth and a stronger jaw
intestines become modified to eat meat
start to eat the other tadpoles
