all Flashcards
1
Q
what is development?
A
series of progressive changes in form and function usually in early part of organisms life cycle
2
Q
what is cleavage?
A
division of cells to form blastula
3
Q
what is gastrulation?
A
formation of tissue layer and axis
blastula transformed into embryo with 3 tissue layers
4
Q
what is organogenesis?
A
formation of organs
5
Q
what is morphogenesis?
A
mechanism of body shape formation
cell differentiation and growth to form complex adult shape
6
Q
what is fertilisation?
A
maternal and paternal genetic material fuse forming diploid
rapid divisions producing a multicellular embryo
7
Q
in the zygote where is the nucleus of egg and nutrients located?
A
nucleus- animal hemisphere
nutrients- vegetal hemisphere
8
Q
in amphibians what happens what happens once the sperm enters the animal hemisphere?
A
cortex rotates exposing the grey crescent- the proteins here control what form the cells will take
9
Q
at each cleavage what happens?
A
cells double in number and divide at the cleavage furrow
10
Q
what do the 3 cleavage patterns depend on?
A
amount of yolk and spindle formation
11
Q
what are the 3 cleavage patterns?
A
complete
- can be no yolk and cells are equal in size
- yolk cn impede/obstruct cleaving furrow so cells divide asymmetrically
incomplete discoidal
- birds
- lots of yolk
- cleavage furrows don’t penetrate yolk
- blastodisc forms on top of yolk
incomplete superficial
- insects
- nuclei migrate to edge and membrane grows inwards
12
Q
what happens if the insects yolk is in the middle of the egg
A
there is no cytokinesis
13
Q
what is radial cleavage?
A
mitotic spindles form at high angles parallel to animal vegetal axis
14
Q
what is spiral cleavage?
A
mitotic spindles form at oblique angles to a-v axis
spiral cell pattern
15
Q
what is rotational cleavage?
A
first division parallel to a-v xis
second division at right angles
16
Q
what happens at determination?
A
cells fate becomes fixed
17
Q
what is the endoderm of mammals?
A
inner layer
digestive tract, circulatory tract, respiratory tract
18
Q
what is the ectoderm of mammals?
A
outer layer
epidermis, nervous system
19
Q
what is the mesoderm of mammals?
A
middle layer
bone, muscle, liver, heart, blood vessels
20
Q
what 2 things does the blastodisc in birds contain and what are they and which one is at the top of the blastocyst?
A
- epiblast (embryo)
- hypoblast (extraembryonic membranes)
epiblast t top
21
Q
in gastrulation in mammals what 2 things can the blastula become?
A
- trophoblast (placenta)
- inner cell mass (epiblast and hypoblast)
22
Q
what is neurulation?
A
occurs early in organogenesis
begins formation of nervous system in vertebrates
23
Q
what are somites?
A
blocks of mesoderm
produce vertebrae, ribs, muscles
24
Q
what do neural crest cells produce?
A
peripheral nerves
25
in an egg what is at the top, below it and to the right and what is directly around the 3 structures?
top: amnion
below: yolk sac
right: allantois
surrounded by chorion
26
what are the 3 extraembryonic membranes supporting the embryo and what do each of these do?
1. yolk sac- nutrient transfer
2. amnion- protection
3. chorion- gas/water exchange
4. allantois- waste storage
27
where is the allantois in mammals?
incorporated into the umbilical cord
28
what 3 epigenetic factors control development?
1. cytoplasm
2. genes
3. external environment
29
what controls early embryonic development and does transcription occur at this point?
nuclear DNA
| no transcription
30
in embryos what does the cytoplasm provide/control?
provide enzymes and proteins
| controls metabolic cycles and instructions for cell division and the fate of the nucleus
31
what is genomic activation?
transition from maternal control to embryo control
32
why does cell division slow down in embryos and what can this help us work out?
slows down due to transcription and protein production taking time
helps work out timing of genomic activation
33
what does differentiation result from?
differential gene expression
| influenced by extracellular environment
34
describe the stages of the frog experiment for developmental control
1. dissociate and culture in medium adult skin cells from epidermis
2. obtain the nucleus from these cells
3. activate and enucleate a frog egg cell
4. combine nucleus and enucleated egg
5. cleavage
6. clone (genetic info- nucleus, cytoplasm- egg)
35
what in the gray crescent is needed for development?
cytoplasmic factors
36
a) what are cytoplasmic factors?
| b) what are the 2 main types?
a) chemical signals involved in cell differentiation
b) cytoplasmic segregation
induction
37
what is cytoplasmic segregation?
- factor unequally distributed in cytoplasm in zygote so ends up in some daughter cells but not others
- differences in cytoplasmic makeup cause differentiation of cells
38
what is primary induction in amphibians and birds?
amphibians: cells move over dorsal lip of blastopore which induces ectoderm to form neural tissue
birds: cells moving under hensons node are induced to form CNS
39
what is secondary induction in the vertebrate eye?
lens placode tissue induces optical vesicles to form a cup shape this induces surface tissue to form lens
40
how can cells interpret positional information?
positional information is given by conc gradient of a morphogen
amount of morphogen determines signal
41
when is a cell considered to be a morphogen?
- if directly affects target cells
| - if different conc. cause different effects
42
in terms of morphogens how is the hand formed?
cells at base of bud make a morphogen (BMP2) whos gradient determines anterior-posterior axis of limb
highest dose= thumb
lowest dose= little finger
43
what is genomic imprinting?
genes only active if specifically from a male or a female
44
is the development of internal cell mass controlled by maternal or paternal genes?
maternal
45
is the trophoblast that is part of the placenta controlled by maternal or paternal genes?
paternal
46
what are the 4 types of segmentation genes?
1. gap genes- organise areas along anterior-posterior axis
2. pair rule genes- divide embryo into units of 2 segments each
3. segment polarity genes- determine segment boundaries
4. homeotic genes- along length of body and determine what segments will become
47
in mice where will the first and last hox genes on the chromosome be expressed?
first: head
last: tail
48
what does a mutation in homeotic genes mean?
there is a change in the identity of the segement
49
in fruit flies what do the mutant homeotic genes do?
a) antennapedia
b) bithorax
a) legs grow instead of antennae
| b) an extra thorax
50
what is apoptosis?
programmed cell death caused by activation of 'death' genes
51
in humans which enzyme stimulates apoptosis for webbed feet and toes?
caspase
52
what do mice raised in microbe free environments lack and what does this result in?
lack gut bacteria
gut bacteria needed as it induces gene expression in intestine which is needed for capillary development
so normal capillaries dont develop
53
in the human neural tube what is it known as if there is a failure to close at the posterior end?
spina bifida
54
in the human neural tube what is it known as if there is a failure to close at the anterior end?
anencephaly
55
in tibetans what does a lack of iodine result in for adults and babies?
adults: goitre
babies: cretinism
56
what does cyclopamine in corn lily plants do?
causes birth defects in lambs
| inhibits action of sonic hedgehog protein and so neural system may not form properly
57
what is a clone and what are the 4 main types of cloning mechanisms?
an individual that is genetically identical to another
- natural
- embryo splitting
- reprogramming somatic cells
- nuclear transfer
58
if splitting occurs too late in embryo formation what can result?
conjoined twins
59
how are monozygotic twins formed and what do they have?
blastomeres in 2 cell embryo separate naturally early on
| have their own nutrients (no competition)
60
can differentiation be reversible?
yes
61
why is cloning by somatic cell nuclear transfer controversial?
- invasive technique
- technical problems
- ethical dilemma
62
what 2 features allow SCNT to occur?
1. nucleus of every somatic cell has a complete copy of the individuals genome
2. fertilised egg is totipotent
63
what are megan and morag and what happened in 1995?
first mammals cloned from cultured differential embryo cells
- wilmut and campbell
- sheep embryo cells deprived of growth factor
- DNA transferred to cytoplasts (enucleated eggs) stimulated to develop
- embryos placed in surrogate
64
what was dolly and what happened in 1996?
first mammal cloned from adult cells
- wilmut and cambell
- deprived adult mammary glands of growth factor
- cells fused with enucleated egg, stimulated
- placed into surrogate
- dolly genetically identical to mammary gland sheep
65
what was polly and why was she created?
first transgenic mammal clone
aim to produce a flock of transgenic sheep that could produce therapeutically useful proteins (such as human gene for clotting factor 1X in milk used to treat haemophilia
66
give 5 potential uses of cloning
- developmental research
- conservation
- cloning elite livestock
- disease resistant farming
- therapeutic cloning
67
what is pharming and xenotransplantation?
pharming: G.M farm animals produce pharmaceuticals in milk
xenotransplantation: using animal organs for transplant
68
what are 7 issues with cloning?
- who decides what species should be cloned?
- wont bring back a loved one
- aging (telomeres shorten, age quickly)
- low success rate
- large foetus syndrome
- prolonged gestation
- lack of genetic variation so disease vulnerability
69
a) what are stem cells?
b) what do they produce?
c) what are fibroblasts?
a) undifferentiated cells capable of extensive proliferation
b) other stem cells, differentiated progeny cells
d) feeder cells on which cells are grown in vitro
70
what forms when stem cells are given vitamin A derivatives?
nerve cells
71
what happens in the brain of people with parkinsons?
dopamine producing cells slowly die
72
what does phenotype result from?
interaction of genes, gene products, environment
73
what are these due to:
a) similarities
b) differences
a) due to having a common ancestor
| b) due to natural selection, adapting them to different environments
74
what did Darwin recognise relationships in organisms could be deduced from?
similarities among embryos
75
what will changes in developmental processes do over evolutionary time?
modify form of adult organism
76
a) what is evolutionary developmental biology a combo of?
| b) what does it study?
a) genetics and embryology
b) - how changes in genes regulating development affect adult forms of organisms
- how these genes have changed over evolution
- how these changes have influenced evolution
77
if a mouse pax6 gene is expressed in a fruit fly what happens?
an eye will develop instead of a leg
78
in which 2 groups does the same set of hox genes provide anterior-posterior info?
mammals and insects
79
where are drosophila gap genes and homologous vertebrate genes expressed?
in anterior region of the brain
80
what 3 things can morphological changes result from?
1. mutation in genes regulating development
2. changes in spatial (where) expression of developmental genes
3. changes in temporal (when) expression of developmental genes
81
what does modularity mean?
developing embryos are modular- have self contained units that can be changed independently of each other
82
what happens if there is a mutation in the ubx gene in insects?
mutated gene expressed in abdomen represses d11 gene for leg formation
so legs dont form on abdomens
83
a) what does BMP4 do in birds?
b) what is gremlin?
c) what kind of expression change is this?
a) expressed between developing toes instructs cells to undergo apoptosis
b) inhibits apoptosis on toes not webs which protects them
c) spatial
84
what is heterochrony ?
that modularity allows the timing of developmental processes to shift independently causing changes in size and shape
85
what is an example of a temporal expression change?
if expression of genes dissolving webs delayed digits dont grow
juvenile webbed feet form with suction cups for arboreal way of life
86
what 2 environmental cues determine development?
1. cues necessary for normal development
| 2. signals closely correlated with future conditions
87
in mosquitos after a blood meal how is egg production stimulated?
prior to meal no vitellogenin yolk protein made
after meal brain stimulated to secrete egg development hormones stimulating ovaries to produce compounds stimulating fat body cells to release an egg
88
what is the symbiotic relationship between grasshoppers and bacteria?
bacteria live in egg cytoplasm and can only multiply here
| hosts embryogenesis dependent on them
89
in W.african butterfly whats the difference between dry and wet season forms?
dry: <20c, less distal, darker
wet: >24c, more distal, lighter
90
what is polyphenism?
2 different forms depending on phylogenetic path animal follows
91
how do the larvae of N.arizonaria differ between spring and summer?
spring: feed on oak flowers
summer: feed on oak leaves
92
in daphnia what do they do when they encounter predator chaoborus but what is a drawback?
increase helmet size
| produce fewer eggs
93
in spadefoot toads what happens to the tadpoles if the ponds dry up?
- develop a wider mouth, powerful jaw, modified intestine
| - eat other tadpoles to develop quicker (transition to carnivorous diet)
94
whats the difference between sex and reproduction?
reproduction: offspring production
sex: fusion of genetic material from 2 different parents
95
give 5 features of asexual reproduction in general
1. all genes from 1 parent
2. all offspring genetically identical
3. easy, cheap, straightforward
4. transmits intact parental genome successfully
5. mutations transmitted
96
in what way do strawberries reproduce asexually and sexually?
asexual: runners
sexual: seeds on outside, flowers, pollen exchange
97
describe the 4 asexual reproduction types
1. fragmentation/regeneration
- body broken into pieces, can develop into adults
- body parts can regrow
2. binary fission
- single cells divide in 2
3. budding
- offspring grow from body of parent
- masses from parents can become offspring
4. parthenogenesis
- unfertilised eggs develop into offspring
- not haploid
- not in mammals (genomic imprinting)
98
in which stress condition os asexual or sexual more likely?
low stress: asexual
| high stress: sexual
99
give 4 features of sexual reproduction in general
- union of 2 parental genomes
- 1.5-2 bn years
- 2 gamete and 2 mating types
- meiosis, recombination, segregation
100
what are the 3 main fundamental processes of sexual reproduction
1. gametogenesis
2. mating (gamete transfer)
3. fertilisation
101
describe external fertilisation and the problems with it
```
eggs and sperm mix and fuse in aquatic environment (requires water)
issues:
- cant control delivery
- lots of gametes needed
- egg predation
```
102
what are the 2 types of internal fertilisation?
indirect- spermatophore deposited for femle
| direct- sperm directly transferred into female
103
explain the 4 min issues with copulation (direct)
1. damage
- bean weevils wound females internally killing them
2. traumatic insemination
- bed bug females have no opening so male pierces membrane to place sperm
3. sexual cannibalism
- females kill mate
- nutrition, prevent paternity monopolisation
4. sexual reproduction hijacked
- can leave individuals vulnerable to sexually transmissible patterns
104
what are gonads?
specialised organs producing gametes
105
describe the general process of spermatogenesis
1. sperm produced from spermatogonial stem cells
2. cells divide by mitosis producing diploid spermatocytes
3. meiosis 1 occurs producing diploid secondary spermatocytes
4. meiosis 2 occurs producing haploid spermatids and them 4 sperm cells
106
give 7 features of spermatogenesis in fruit flies (insects)
- in cysts
- distal to proximal
- larval stage
- sperm produced in a few days
- <10,000 sperm per day
- stored in seminal vesicle
- semen from accessory glands
107
give 7 features of spermatogenesis in humans (mammal0
- in seminiferous tubules
- periphery to lumen
- puberty
- produced 74 days
- 300 million sperm per day
- stored in epididymis
- semen from seminal vesicles and prostate gland
108
what is sperm a) gigantism and b) heteromorphism
a) varying lengths
| b) varying shapes and sizes
109
how does oogenesis differ from spermatogenesis?
oogenesis has placement of metaphase plate
110
explain the general process of oogenesis
1. in meiosis 1 diploid primary oocyte splits into secondary oocyte and polar body
2. in meiosis 2 it is split into an ovum and polar bodies and then a haploid ovum
111
give 5 features of oogenesis in fruit flies (insects)
- distal to proximal
- larval
- eggs produced in a few days
- <100 per day
- released into uterus
- oviparous (no pregnancy)
112
give 6 features of oogenesis in humans (mammals)
- within follicle
- 400,00 follicles at birth
- starts at population
- 1 per month
- follicle ruptures, oocyte into fallopian tube
- if not fertilised uterus lining degenerates
113
at puberty what does the hypothalamus secrete and what does this stimulate?
GnRH
| stimulates FSH and LH from anterior pituitary gland
114
in spermatogenesis what do these stimulate?
a) LH
b) FSH
a) stimulates development of seminiferous tubules and sertoli cells
b) stimulates leydig cells to secrete testosterone
115
in oogenesis what do these stimulate?
a) FSH
b) LH
a) stimulates follicle development and estrogen secretion
| b) stimulates follicles maturation and ova release
116
what does estrogen do?
enhances follicle and endometrium growth
117
what does progesterone do?
grows and maintains endometrium, secretes nutrients for embryo
118
what are the stages of the female reproductive cycle beginning with the release of GnRH from the hypothalamus ?
1. FSH and LH released from anterior pituitary gland
2. these stimulate follicle to grow
3. estrogen secreted by growing follicle
4. progesterone and estrogen secreted by corpus luteum
5. peak causes LH surge
6. surge triggers ovulation
7. transition from follicular phase to luteal
8. progesterone and estrogen promote thickening of endometrium
119
in the whole menstrual cycle what are the 3 main stages?
menstrual
proliferative
secretory
120
how do birth control pills work?
by negative feedback of FSH and LH
- synthetic estrogen and progesterone
- body doesn't experience a sudden rise of estrogen so no ovulation or egg release
- cervical mucus altered
- uterus lining inhospitable
121
beginning at the centre and working outwards what are all the layers of the egg?
```
germinal spot
germinal vesicle
ooplasm
vitelline membrane
zona pellucida
corona radiata
```
122
what is the corona radiata of the egg?
layer of follicle cells
123
what is the zona pellucida?
protects egg
| extracellular matrix with glycoproteins
124
what is the vitteline membrane?
cell membrane surrounding ooplasm
125
what is the germinal vesicle and germinal spot?
vesicle- nucleus with DNA
| spot- proteins and RNA concentrated nucleolus
126
what are the 4 main structures of a sperm cell and what does each do?
head:
-nucleus with DNA capped with acrosome with enzymes to penetrate egg
neck:
- centriole for tail formation and embryo development
mid-piece:
- mitochondria providing energy for movement
tail
127
what are the stages of sperm penetration of the ovum?
1. sperm binds to zona pellucida and penetrates cumulus cell layer, using vigorous movements to burrow through follicle cells
2. acrosome reaction to penetrate z. pellucida
3. sperm and oocyte p.membranes fuse
4. sperm nucleus enters ovum
128
describe sperm penetration in sea urchins
- protective jelly coat with chemoattractive properties so sperm migrate to signals
- the chemoattractants attract mates with compatible nuclear and mitochondrial genes
129
in sea urchin sperm penetration what does the sea urchin have and what contacts with this?
egg plasma membrane with microvilli with protein receptors
| acrosomal process contacts, its binding proteins are detected by protein receptors on the egg
130
what is lysin?
sperm protein that dissolves egg envelope
131
what % of bird species eggs fail to hatch?
10%
132
why do eggs fail to hatch?
```
fertilisation failure
- sperm may not reach egg
- sperm or ovum dysfunction
embryo death
- male or female factors
- incompatibility
- external factors
```
133
what must sperm be to be successful?
motile to make it through vagina
134
what is the fastest shaped sperm?
short mid piece and long tail
135
in mammals what happens if polyspermy occurs?
could destroy egg
136
what is an adaptation?
trait that increases fitness of an organism in its environment
137
what is hibernation?
extended period of sleep allowing for survival in winter extremes
metabolic rate and body temp decrease
138
what is acclimation?
physiological response to experimental environmental change
- short term
- not heritable
139
what is acclimatisation?
physiological response to natural environmental change
140
what is plasticity?
ability of organisms to change their state in response to stimuli
141
at high altitudes what is the barometric pressure and atmospheric O2 like?
low barometric pressure
| low atmospheric O2
142
how is O2 transported around the body?
red blood cells transport it in the form of haemoglobin
O2 from lungs binds to haem group
O2 bonded with haemoglobin
O2 released fro it into tissues that need it
143
what is O2 saturation?
% haemoglobin binding sites that carry O2
144
whats the difference between lungs and tissues on the O2 saturation curve?
lungs: high pO2, high Hb affinity, O2 readily binds
tissues: low pO2, low Hb affinity, O2 released
145
what is hypoxia?
deficiency of O2 reaching tissues
146
in terms of haemoglobin concentration and O2 saturation describe what was found for the Tibetan and Andean populations?
andeans:
- higher [Hb] the ancestors
- higher [Hb] than lowlanders
- low O2 sat. higher than tibetans (less stressed by hypoxia) (not heritable)
tibetans
- no difference in [Hb] between them and ancestors
- similar [Hb] to lowlanders
- low O2 sat. lower than andeans (heritable)
- dominant autosomal gene for O2 saturation
147
what do [Hb] and O2 sat determine?
determine arterial O2 content
148
what are the downstream consequences of an increases in [Hb]?
increase [Hb] --> viscous blood --> strains heart --> better to deal with hypoxia but is a trade off
149
for the Tibetan and Andean populations were any associations found between female fertility and O2 saturation and [Hb]?
- none for O2 sat gene and no. of births
- homozygous recessive mothers had lower curving children than mothers with O2 sat gene
- more infant mortality in homozygous recessive
150
what is homeostasis?
self regulating proceed where biological systems maintain stability and adjust to varying environmental conditions
151
a) what does having a steady set mean?
| b) and why maintain it?
a) stable internal environment, dynamic equilibrium, usually uniform conditions
b) enzymes usually heat activated, chemical reactions temp dependent, proteins denature at high temp
152
what do each of these control mechanisms do?
a) receptor
b) control centre
c) effector
a) monitors internal environment
b) sends message to effector via nervous/ endocrine system
c) re-establishes internal environment
153
give 2 examples of positive feedback
- blood clotting
| - birth in mammals
154
what do hummingbirds do to conserve energy?
- at night/ in the cold enter torpor
- body temp drops from 38-40c to 18-20c
- heart rate drops from 1200 to 50 bpm
155
a) what is doping
| b) give 5 reasons why people may do it
a) the use of banned performance enhancing drugs
b)
- build muscle mass and strength
- increase O2 delivery to exercising tissue
- mask pain/ injury
- decrease weight
- hide use of other drugs
156
a) what can EPO (erythropoietin) be used for?
b) whats the cycle it goes through?
c) whats the stimuli for it?
d) what can it increase O2 supply by?
e) what are 3 side effects from it?
a) to dope
b) fall in blood O2 levels -->kidney releases EPO --> stimulates red bone marrow --> increases in red blood cell count
c) low atmospheric O2, increase in red blood cell count
d) 7-10%
e) blood thickens, heart works harder, increased risk of heart attack and stroke
157
what are the medical uses of meldonium?
- treat corona artery disease
- increases blood flow
- increases flow of O2
158
what do larger animals tend to be/do?
- move slowly
- slower digestion
- slower respiration
- lose heat and water to environment slower
159
a) what is allometry?
| b) what are the 3 types?
a) study of how biological traits scale with body size
study of differential growth
b) ontogenetic, static, evolutionary
160
what is ontogenetic allometry?
compares relative size of body parts of an organism over its lifespan
161
what is isometric scaling?
everything grows in proportion
| b=1
162
what is static allometry?
between different individuals at same development
163
what is evolutionary allometry?
between individuals of different species
164
what do each of the parts mean in the equation?
| y= ax^b
```
y= size of body part
x= measure of whole body size
a= initial growth index when x=1
b= scaling exponent proportional change
```
165
what is the value of b in +ve allometry and -ve ?
+ve: b>1
| -ve: b<1
166
what are larger individuals skeletons like?
more robust and larger
167
with an isometric doubling what happens to SA and length?
X4 SA
| X8 V
168
order in terms of metabolic rate:
a) unicellular, endotherm, ectotherm
b) terrestrial mammals, marsupials, marine mammals
a) endotherm (highest) , ectotherm, unicellular
| b) marine mammals, terrestrial mammals, marsupials
169
how do you calculate metabolic rate and how else can this be written?
body weight (W)
= W^0.75
= W^ -0.25
170
if body temp too low what 4 things happen?
- slow metabolism
- molecules have less kinetic energy
- cells freeze
- inadequate O2 supply
171
if body temp too high what 4 things happen?
- vibrating molecules, H bonds break
- proteins denature
- inadequate O2 supply
- membrane structure alterations
172
in what 4 ways can heat be exchanged and in what % is heat lost from each?
1. radiation- transfer of heat via electromagnetic waves
- 60% heat loss
2. conduction- direct contact
- 3%
3. convection- movement of air/ fluid over body surface
- 15%
4. evaporation- water from body surface
- 22%
173
what kind of conductivity do insulators have and does water or air have a higher conductivity?
low thermal conductivity
| water higher than air
174
what are ectotherms?
conformers
heat derived from environment
body temp fluctuates with environment
175
what are endotherms?
regulators
constant body temp
heat from metabolism
176
give 4 +ves of ectotherms?
- metabolic rate 5X slower than endotherms
- less energy= less food= less H2O
- lots of energy into reproduction
- colonise poor/arid environments
177
give 4 +ves of endotherms?
- high activity bursts
- nocturnal activity
- can exploit colder environments
- migrate over long distances
178
give 4 -ves of ectotherms?
- no nocturnal niches
- can't sustain high activity bursts
- anaerobic so rapid fatigue
- susceptible to sustained predation
179
give 4 -ves of endotherms?
- large body size with low SA:V
- metabolic rate 5X faster
- more energy= more food= more H2O
- little energy in reproduction
180
what is the thermoneutral zone?
range of temps where animal doesn't expend energy to maintain temp, restricted by upper and lower critical limits
181
what is vasoconstriction?
- diameter of blood vessel decreases
- less blood flow to skin
- skin cools
- less heat lost to environment
182
what is shivering?
rapid contraction of skeletal muscles
consumes ATP
increases heat production by 500%
when glycogen runs out proteins and lipids used
183
what does thyroxine do?
increases basal metabolic rate
184
explain the 3 types of insulation
1. brown fat
- -> brown adipose tissue
- mitochondria breakdown fuel into heat
- rich blood supply
- rapid heat production
- -> white adipose tissue
- little blood supply
2. blubber
- thick layer of vascularised adipose tissue
- low thermal conductivity
3. fur/hair/feathers
- reduces convection
- traps warm air
185
what is vasodilation?
- diameter of blood vessels increases
- blood flow increases
- skin heats up
- more heat lost to environment by radiation, conduction, convection
186
what is perspiration?
skin glands secrete sweat for evaporative cooling
| - water absorbs heat and releases it through evaporation
187
what is panting?
evaporation of water from mouth and tongue
| hot air in lungs exchanged with cool external air
188
explain each mechanism of how birds stay cool as they can't sweat:
a) gular flutter
b) urohidrosis
a) rapidly flap membrane in throat to increase evaporation
| b) defecate on legs for evaporative cooling
189
if metabolic heat production can't compensate for heat loss what occurs?
hypothermia
190
if evaporative cooling can't counteract heat gain what occurs?
hyperthermia
191
if there is a decrease in the conc. of water molecules in external environment what happens to the cell?
net movement of water moves out of cells so cells shrivel and can't function
192
if there is a increase in the conc. of water molecules in external environment what happens to the cell?
net movement of water into cells so cells expand and may burst
193
is the movement active or passive?
a) solutes
b) water
a) either
| b) passive
194
what is osmoregulation?
process balancing uptake and loss of water
195
what 4 things influence the passive rate?
- temp (higher= higher rate)
- electric ion charge may prevent passage
- particle size (smaller= faster rate)
- conc gradient (higher gradient= higher rate)
196
a) what is osmolarity?
| b) whats the equation?
a) measure of osmotic pressure exerted by a solution across semi permeable membrane compared to pure water
b) (no. of particles/ molecule of solute) X (moles/litre)
197
if 2 solutions have equal osmolarity what are they?
iso-osmotic
198
mr NaCl = 58.44
| if dissolve 58.44g in 1L water, what is the osmolarity?
```
58.44 in 1L= 1 mole
dissociates into Na+ and Cl-
no. of particles/ molecule= 2
2 X 1mole= 2
so osmolarity= 2 osm/L
```
199
what is tonicity and what 2 things does it depend on?
effect of a solution on cell volume
- membrane permeability
- solutes
200
when hypertonic what happens
| when hypotonic what happens
hyper: solution has higher solute conc so water leaves and cell shrivels
hypo: water moves into cell
201
whats the difference between tonicity and osmolarity?
osmolarity- measure of solute conc
| tonicity- effect of solution on cell volume
202
is it osmoconformer, osmoregulator?
- graph with diagonal line (proportional)
- graph with straight horizontal line
- osmoconformer
| - osmoregulator
203
which species group have limited osmoregulation?
amphibians
204
if osmolarity of freshwater is lower than body fluid what is is?
freshwater is hypo-osmotic to the organisms body fluid
205
what is a teleost?
bony fish
206
a) in a marine environment with low water conc and high sat conc, is the fish hyper or hypo osmotic?
b) how are salts and water gained/ lost?
c) what is the urine like?
d) how is salt gotten rid of, in terms of pumps?
a) hypo osmotic
b) salt:
- diffuses in through gills and in sea water and food
- is actively extruded
water:
- lost by osmosis through gills and skin
- in through sea water and food
c) little and concentrated
d)
- Na/K ATPase provides Na gradient in chloride cell and pumps Na out of cell
- Cl transported due to Na gradient, by Cl/ Na symporters
- Cl diffuses out as it builds up in the cell
- Na can sneak out through leaky cell junctions
207
a) in a freshwater environment with high water conc and low sat conc, is the fish hyper or hypo osmotic?
b) how are salts and water gained/ lost?
c) whats the urine like?
d) how is salt gotten rid of, in terms of pumps?
a) hyper
b) salt:
- lost by gill diffusion and in faeces
- in via active transport at gills and by food
water:
- lost in faeces
- in via food and osmosis at the gills
c) lots and dilute
d)
- apical membranes have ion pumps to pump ions in
- cell cytoplasm low in Na and Cl
- lots of mitochondria
- tight cell junctions so no ion leaks
208
what generates nitrogenous waste and in what 3 ways does this occur?
breakdown of proteins and nucleic acids
- digestive system
- energy/ fat conversion
- amino group removed
209
what happens when proteins/ nucleic acids break down and the amino group is removed?
NH2 combines with hydrogen forming toxic ammonia
210
why is ammonia considered toxic?
it raises ph of body fluids which inhibits key enzymes
211
explain each of the 3 types of nitrogenous waste products and examples of each
1. ammonia
- bony fish, aquatic amphibians and invertebrates
- toxic
- no energy to produce
- small so rapid diffusion
- water soluble
2. urea
- mammals, amphibians, cartilaginous fish
- in liver from ammonia and CO2
- 1000X less toxic than ammonia
- less water needed
- energy needed
3. uric acid
- birds, insects, reptiles
- insoluble
- even less toxic than urea
- 3X more energy than urea needed
- egg development
212
whats the difference between tadpoles and adult frogs in what they excrete?
tadpoles: ammonia
frogs: urea
213
whats the difference between terrestrial and aquatic turtles in what they excrete?
terrestrial: uric acid
aquatic: urea and ammonia
214
what does the west African lungfish excrete on land and on water?
land: urea
water: ammonia
215
what structures do each of these have for excretion:
a) protozoa
b) annelids and molluscs
c) insects
d) vertebrates
e) fish
f) seabirds
a) contractile vacuole
b) nephridia
c) malpighian tubules
d) kidneys
e) gills
f) salt glands
216
a) in insects what is excreted to conserve water?
b) what kind of circulatory system is it?
c) describe the process of the excretory system
a) uric acid
b) open
c) - salts and nitrogenous waste actively transported into gut lumen through tubules
- water by osmosis
- rectum reabsorbs
- salts and organic molecules back into haemlymph and water
- uric acid eliminated as dry matter with faeces
217
what are Malpighian tubules?
blind ended tubules in insects
1 cell thick walls
between mid and hind gut
float in haemolymph
218
which is on the 'right' the renal vein or artery?
artery
219
what are the 4 main stages of excretion in humans?
- filtration
- reabsorption
- secretion
- excretion of filtrate
220
what happens in the medulla and what in the cortex?
medulla: regulates water and salt in blood
cortex: ultrafiltration
221
what is the nephron known as and why?
countercurrent multiplier system
- steep osmotic gradient created
- tubule fluid in descending limb flows in opposite direction to ascending
222
what is ultrafiltration in the nephron?
high blood pressure in glomerulus forces fluid into lumen of bowman capsule
non selective filtration
osmolarity of blood and filtrate the same
223
what occurs at each stage in the nephron:
a) proximal tubule
b) descending limb
c) ascending limb
d) distal tubule
a) water and salt reabsorbed (no osmolarity change)
b) water leaves filtrate (filtrate osmolarity increases)
c) salt leaves filtrate, impermeable to water (filtrate osmolarity decreases)
d) salt conc, ph and water balance regulated
224
what do the loops of henle increase?
increase solute potential of tissue fluid so conc gradient set up
225
tolerances ranges can..
-
-
-
- narrow/ broad
- differ between and within population
- differ between seasons. life stages
226
what is the zone of tolerance?
where the organism is most comfortable and can survive for an indefinite period, bounded by upper and lower zones pf physiological stress
227
what 2 things affect tolerance?
- thermal history
| - exposure to seasonal changes
228
what are the 5 main functions of heat shock proteins?
- promote proper folding/refolding of protein
- prevent damaging interactions with proteins
- aid in disassembly of protein aggregation formations
- help to present antigens from diseased cells to T cells
- act as a warning signal
229
what are molecular chaperones?
- stabilise other proteins
- minimise probability of inappropriate interactions
- successful folding, assembly, degradation
230
what are 4 major stresses?
- hypoxia
- temp extremes
- physical stress
- pollution
231
what are the 4 stages of how heat shock proteins work/ when they are needed?
1. stressful conditions cause proteins to denature and unfold so can no longer function
2. denatured proteins detected
3. heat shock proteins produced
4. heat shock proteins refold denatured proteins acting as a molecular chaperone
232
why don't heat shock proteins denature?
- better H bonds
| - better secondary structure
233
what happens to cells when external fluid freezes?
solute conc of external fluid increases
water leaves cells by osmosis
cells shrinks
234
whats the difference between slow and fast cooling?
slow; cellular death from dehydration
| fast: cellular death from internal ice crystal damage
235
describe the 3 ways freeze avoidance works
1. select dry hibernation site where no ice nucleation
2. physical barrier like wax cuticle to protect from external ice
3. decrease temp that body temp freezes
- super cooling
- cryoprotectant synthesis
236
what is supercooling?
freeze avoidance tactic
- ice nucleating agents removed/ inactivated
- water cools below freezing without changing phase as no nucleation source
- can cool to -42c without freezing
237
what is cryoprotectant synthesis?
freeze avoidance tactic
- biochemistry alteration
- increased solute conc
- lower freezing point
- glycerol
238
what is freeze tolerance and what are the 3 types?
cope with damage caused by ice crystal formation
1. limit supercooling, initiate freezing at higher temp
2. ice structuring proteins produced (antifreeze) which bind/adsorb to small ice crystal to stop further growth
3. ice nucleating proteins produced to control ice crystal formation, induce growth of single ice crystal
239
how does the arctic woolly bear moth show freeze tolerance tactics?
accumulate cryoprotectants
form hibernaculum to emanate nucleators
can withstand -70c
240
how does the golden rod gall moth larvae show freeze avoidance?
water content decreased
glycerol content increased
supercooling point to -38c
241
how does the wood frog display a strategy combo for dealing with cold temps?
super cools to -3c
| surveys at -8c with 48% body water as ice
242
how does the red bark beetle display a strategy combo for dealing with cold temps?
ice structuring proteins
tissues dehydrate so glassy substance forms instead of freezing
glycerol
can withstand -150c
243
aerobic respiration equation?
C6H1206 + 6O2 ---> 6CO2 + 6H2O +ATP
244
what 3 things does the rate of diffusion depend on?
- SA of surface
- thickness of surface
- metabolic demands
245
whats the equation for rate of diffusion ?
r= [(change in P) X (A)] / D
P- change in partial pressure
A- surface area
D- distance
246
what 3 components are needed for a respiratory system?
- gas exchange surface
- circulatory mechanism
- breathing mechanism
247
how do insects respiratory systems work?
- air enters through spiracles
- diffuses into trachae and tracheoles
- trachae inflate and deflate to pump air
- tidal ventilation
248
how do insects balance water loss and oxygen availability?
- can close spiracles
- hairs around spiracles trap air
- air sacs store air
249
what does increasing temp do to affinity for O2?
decreases affinity
250
what does decreasing ph do to affinity for O2?
decreases affinity
251
what happens when CO2 mixes with H2O?
carbonic acid forms which lowers ph
252
does fetal haemoglobin have higher/ lower affinity for O2 than adults and why?
fetal- higher
| so can take O2 from mothers blood more efficiently
253
what kind of flow of water is it over the gills in fish?
unidirectional flow
254
what are the gills made up of and what are 3 features of these?
gill filaments
- thin membranes for short diffusion distance
- capillary network to take O2 away
- large SA
255
what are the inhales/ exhales like for birds and how many per breath?
```
2 inhalations and exhalations per breath
1st inhale: to posterior air sac
1st exhale: moves to lungs
2nd inhale: moves to anterior air sac
2nd exhale: out through trachea
```
256
what kind of air flow do birds have?
cross current- blood flow perpendicular to air flow
257
what enables birds to breathe at high altitudes?
low O2 partial pressure
258
what are the steps of inhalation in mammals?
intercostal muscles contract
diaphragm contracts and moves down
pressure decreases
259
as CO2 increases in atmosphere what happens to seawater CO2 levels and ph?
increased seawater CO2
| decreases ph
260
what are each of these on the thermal performance curve?
- Topt
- CTmin and CTmax
- temp with highest performance
| - breadth of temp organisms can tolerate
261
do endotherms or ectotherms have a wider thermal tolerance range?
endotherms
262
what % of species are experiencing max temp above upper tolerance and what will the % be by 2080 for:
a) birds
b) mammals
a) current: 15%
2080: 36%
b) current: 16%
2080: 47%
263
where may species that can detect climate change go?
move pole-wards and to higher altitudes
264
what is phenotypic plasticity?
ability of single genotype to produce different phenotypes when exposed to different environments
265
in a study of physiology of those in water warmed by nuclear plant and those not what was found?
the increase in temp increases O2 consumption
| but if under heat for a longer period, use less O2 than those immediately exposed, as have acclimatised
266
what 4 reasons make it hard to predict future climates?
1. depends on future emission rates
2. depends on extreme climatic events
3. depends on how close species are to their thermal tolerance limits
4. depends on species interactions
267
how may cell embryo for:
a) pigs and rats
b) humans and cattle
c) frog
a) 4-8
b) 8
c) 3,000-4,000
268
what is genomic equivalence?
no info is lost in early stages of embryonic development
269
what is induction?
factor is secreted by cells to induce other cells to differentiate
270
what is the spemann organiser?
the dorsal lip of the blastopore
271
where is the deletion for prayer will syndrome?
deletion on paternal chromosome
272
where is the deletion for angel man syndrome?
on maternal chromosome
273
how many c.elegans somatic cells re programmed to die?
131
274
how can neural tube defects be reduced ?
if pregnant women receive adequate folic acid
275
describe the example with mice and fruit flys for highly conserved genes
same genes drive development of fruit flys compound eye and house mouses camera like eye
276
in the Euscelis leafhopper what is the gut bacteria necessary for?
normal abdomen development
277
whats an example of a species that uses indirect transfer for reproduction?
springtails
278
if fertilised what do embryonic placental cells do?
secrete Gn to rescue corpus leteum and maintain its function
279
what are ovary and uterus coordinated by?
hormonal feedback
280
what is another word for :
- poikiotherms
- homeotherms
- ectotherms
| - endotherms
281
what is the metabolic regulation below LCT?
vasoconstriction
282
how do hypo osmotic fish get rid of salt?
Na/K ATPase builds NA+ gradient
Cl- transported using this gradient
Cl- builds up and diffuses out
Na+ sneaks through leaky cell junctions
283
at the proximal tubule what 5 things are reabsorbed and what 2 enter the tubule fluid?
- HCO3- NaCl H2O K+ nutrients
| - H+ K+
284
at the distal tubule what 3 things are reabsorbed and what 2 enter the tubule fluid?
- NaCl H2O HCO3
| - H+ K+
285
what kind of urine can be produced and whats the solute concentration like?
hyperosmotic
| higher solute conc than body fluids
286
what was the consequence of drosophila larvae with more hsp genes?
greater mortality and slower development
287
whats the snow fleas way of dealing with colder temperatures and what can be synthetically made?
can synthesise antifreeze protein
| can be synthetically made to extend storage life of donor organs
288
what is the Bohr effect?
higher CO2 partial pressure decreases blood Ph which decreases Hb affinity for O2
289
what 3 things are changes in space constrained by?
dispersal ability, habitat availability, connectivity
290
what does increasing temp do to O2 levels In the ocean?
decreases
291
in ectotherms what happens to metabolic rate as environmental temp increases?
increases
292
which group are closet to their thermal limit?
insects
293
briefly what is thermoregulation?
animals maintain body temp within normal range
294
whats the integumentary system?
outer covering of the body
295
why may oily substances be secreted?
to repel water and protect insulating capacity of fur/feathers
296
what is metabolic rate definition?
sum of all energy an animal uses in a given interval
297
as body size decreases what happens to energy cost of tissues?
increases
298
what 3 types of synchrony aren't needed for asexual reproduction?
behavioural, ecological and physiological synchrony
299
where is the zygote cytoplasm from?
mothers egg
300
what do pharming and xenotransplantation need?
genetic modification
301
what is double fertilisation in plants?
1 sperm nucleus with egg and the other with 2 poor nuclei and a diploid embryo forms
