B5-7 Spec Flashcards
(328 cards)
1
Q
what kind of cells are formed as a result of meiosis
A
non identical cells
2
Q
what kind of cells are formed as a result of mitosis
A
identical cells
3
Q
what is sexual reproduction in terms of cells
A
fusion of male and female gametes
4
Q
what are the two gametes in animals
A
sperm and egg
5
Q
what are the two gametes in plants
A
pollen and egg cells
6
Q
how are gametes formed
A
meiosis
7
Q
in sexual reproduction there is a ___of genetic information which leads to ____in the offspring
A
mixing
variety
8
Q
asexual reproduction has how many parents and how much fusion of gametes and how much mixing of genetic information leading to genetically____offspring and only___is involved
A
1 parent
no fusion of gametes
no mixing of genetic information
identical
mitosis
9
Q
describe meiosis and where does it happen and what does it produce
A
reproductive organs
gametes
normal cell makes copies of genetic information
cell divides twice to form 4 gametes - each with a single set of chromosomes
all gametes are genetically different from each other
10
Q
when meiosis forms gametes are they the same genetically or different?
A
all are different
11
Q
gametes join at ___to restore the __number of chromosomes
A
fertilisation
normal
12
Q
after fertilisation cells divide by ___. as the embryo develops cells ____
A
mitosis - differentiate
13
Q
homeostasis definition
A
regulations of the internal condition of a cell or organism to maintain conditions for function in response to internal and external changes
14
Q
give 2 reasons homeostasis is important
A
to maintain optimum conditions for enzyme activity
and cell function
15
Q
what does homeostasis maintain levels of
A
glucose
water
temperature
16
Q
what things are involved in automatic control systems (two ways of responding to internal or external conditions)
A
nervous responses or chemical responses
17
Q
what is a receptor for
A
to detect stimuli
18
Q
what are coordination centres for
A
receive and process information from receptors
19
Q
what are 3 coordination centres
A
spinal chord
brain
pancreas
20
Q
what are effectors for
A
bring about a response to restore optimum conditions
21
Q
what 2 things could effectors be
A
muscle or gland
22
Q
what does the nervous system allow humans to do
A
react to surroundings and coordinate behaviours
23
Q
reflex arc of touching something hot
A
stimulus of hot thing
receptor of skin
sensory neurone detects it
information passes along the neurones as electrical impulses
CNS (using relay neurones) coordinates the response of the effectors (spinal chord)
motor neurones causes muscles to contract and pull away
24
Q
why are reflexes important
A
to keep us safe from harm and prevent injury
25
how is information transferred between neurones
it passes along neurones as electrical impulses
26
what are reflex actions
do not involve the conscious part of the brain
they are automatic and rapid
27
ruler drop experiment control variables
caffeine intake
sleep
age
eyesight/disabilities
(ensure hand at bottom of ruler)
28
what is a risk of the ruler drop experiment
risk of drinking too much caffeine which could cause unpleasant side effects
29
what is another variation of the ruler drop experiment
use computer software to find reaction time - reaction to a stimulus
30
why are computers more accurate
remove possibility of human error
31
why are computers more precise
computer can record reaction time in milliseconds - kind of interchangeable with the accuracy one
32
3 advantages of sexual reproduction
produces variation
variation gives a survival advantage by natural selection if the environment changes
natural selection can be sped up by humans in selective breeding to increase food production
33
advantages of asexual reproduction
only 1 parent needed
more time and energy efficient (as don't need to find mate)
faster
many identical offspring can be produced - when conditions are favourable
34
how do malarial parasites reproduce in the human host
asexually - as can't get any gals in the human
35
how do malarial parasites reproduce in the mosquito
sexually
36
how do fungi do asexual reproduction
by spores - but they can also reproduce sexually!!
37
give 3 examples of things that can reproduce both sexually and asexually
plants
fungi
malaria
38
how do plants reproduce sexually
using seeds
39
give 2 examples of plants that reproduce asexually - and the process of their asexual reproduction
bulb division such as daffodils
runners such as strawberry plants
40
41
define genome
entire genetic material of an organism
42
what is the structure of DNA
double helix - two strands
43
what type of thing is DNA
polymer
44
what is DNA contained in
the nucleus
chromosomes
45
what is a gene
small section of DNA on a chromosome
46
each gene codes for what
a particular sequence of amino acids to make a specific protein
47
the whole human genome has been what and what is this greatly important for
studied
medicine in the future
48
give 3 reasons it is important to understand the human genome
search for genes linked to different types of disease
understand and treat inherit disorders
trace human migration patterns from the past
49
why is understanding the human genome linked to tracing past migration patterns
understanding common ancestor in Africa
tracing how new populations split off leading to tiny differences in genomes
50
what is DNA made from
4 different nucleotides
51
what is a nucleotide comprised of
sugar - pentagon
phosphate group -cirlce
1 base - square
52
what are the 4 bases
ACTG
53
How many bases in one amino acid
3
54
how do bases control production of a protein
the order controls the order of
amino acids being assembled
55
DNA consists of alternating what
sugar and phosphate sections
56
what is C linked to and what is A
C=G
A=T
57
where are proteins synthesised
ribsomomes
58
how are proteins synthesised
carriers molecules
bring specific amino acids
in the correct order to form a
protein chain
59
when the protein chain is complete what happens
it folds to form a unique shape
60
why is it important that proteins have a unique shape
this enables the proteins to do their job (as enzymes, hormones or structure forming proteins like collagen)
61
give 3 examples of proteins
hormones, enzymes and collagen
62
how often do mutations occur
continuously
63
what do most mutations do
either don't alter protein
or alter so slightly that appearance or function doesn't change
64
give 2 thing that could happen if a mutation changes the shape of a proetin
an enzyme might not fit with the substrate binding site
and the structural protein could lose its strength
65
give an example of a piece of DNA which doesn't code for proteins - what does it do?
non coding DNA - switches genes on and off
66
non coding genes (switching them on and off)could affect what
how the genes are expressed
67
what 2 things could a mutation do
change a coding gene
change a non coding gene - how expressed
could change phenotype or lead to genetic disease like cystic fibrosis
68
what is a gamete
sex cell
69
what is a chromosome
carries the DNA (genetic information)
70
what is an allele
a different version of the same gene
71
what does dominant mean
an allele that is always expressed even if only one copy is present
72
what is a recessive allele
only expressed if the individual has 2 copies of a gene
73
what does homozygous mean
alleles are identical
74
what is a phenotype
the observable physical characteristics of an organism
75
give 2 examples of characteristics controlled by a single gene
fur colour in mice and red green colour blindness in humans
76
what is the genotype
the alleles present
77
most characteristics are from one/many genes interacting
many
78
what is polydactly and what is it caused by
having extra fingers or toes
dominant
79
what is cystic fibrosis and what is it caused by
disorder of cell membranes
recessive
80
give 3 advantages and 3 disadvantages of embryonic screening
3 +
prevents suffering
financial benefits as don't have to pay for long term treatment NHS
embryos in IVF need to be screened to check they are healthy
3 -
ethical concerns with destroying the embryos not used
designer babies
discrimination against characteristics or non designed people
expensive in the short term
81
how many pairs of chromosomes do human body cells have ordinarily
23
82
how many pairs determine sex
1
83
what is sex chromosomes for females
XX
84
sex chromosomes for males
XY
85
give 3 reasons for variations in characteristics of a population
genes
environment
combination of the two
86
how many genes roughly determine phenotype, how many influence it and what do most do
very few
some
no effect
87
what is the theory of evolution
all species evolved from simple life forms (that first developed more than 3 billion years ago)
88
when did simple life forms first develop
3 billion years ago
89
why does a new species happen
two populations of one species become so different in phenotype
that they can no longer interbreed to form fertile offspring
90
stages of evolution answer
mutation
variation (say what the variation is of)
competition
survival and reproduction as __is better suited to its environment!!
the allele is inherited over generations
evolution over time
91
what is selective breeding
when humans breed plants and animals for particular genetic charactertistics
92
when did humans first do selective breeding and give 2 examples
thousands of years ago
food crop breeding from wild plants
and domestication of animals
93
describe the process of selective breeding
choose parents with desired characteristic from a mixed population
breed them together
breed offspring with desired charactertistic together
continues over generations until all offspring show the desired charactertistic
94
give 4 examples of selective breeding for characteristics
disease resistance in food crops
animals producing more meat/milk
domestic dogs with gentle nature
large or unusual flowers
95
what bad thing can selective breeding lead to
inbreeding - where breeds are prone to disease or inherited defects
96
give 2 examples of genetic engineering in plants
engineered for disease resistance
and to produce bigger/better fruits
97
give an example of genetic engineering not in plants
bacterial cells engineered to produce useful substances like human insulin to treat diabetes
98
give 3 characteristics of GM crops
resistance to insect attack
resistance to herbicides
increased yeilds
99
give 2 concerns about GM crops
effects on wild flowers and insects as pollen could be toxic
effects of eating GM crops on human health haven't been fully explored
100
what is modern medical research exploring with regards to genetic modification
exploring its usage to overcome genetic inherited disorders
101
give the 3 steps of genetic engineering
enzymes used to isolate gene
gene inserted into vector
vector inserts gene into cells
genes transferred to cells of organism at an early stage of the organisms development
102
what is used to isolate the required gene
enzymes
103
what is the gene inserted into in genetic engineering and what is this usually
vector - plasmid or virus
104
what is a tissue culture
using small groups of cells from the plant to grow identical new plants
105
give 2 uses of tissue cultures
preserving rare plant species
commercially in nurseries
106
cuttings is a new/old method and who is it used by and what for
old and simple
gardeners
producing many identical new plants from a parent plant
107
what are embryo transplants for cloning
split apart cells from developing animal embryo before specialised
transplant the identical embryos into host mothers
108
give the 5 stages of adult cell cloning
nucleus removed form unfertilised egg cell (enucleated)
nucleus from adult body cell(such as skin cell) inserted into egg cell
electric chock stimulates egg cell to divide into embryo
embryo has same genetic information as adult skin cell
when it has developed into ball it is inserted into womb of adult female to continue development
109
what is used to stimulate a clump of cels to divide into an embryo in adult cell cloning
electric shock
110
give 3 things that led Charles Darwin to his theory of evolution
observations on a round the world expedition
years of experimentation and discussion
linked to developing knowledge of geology and fossils
111
what did Darwin publish his ideas in and when
on the origin of species 1859
112
give 3 reasons there was controversy over evolution theory and it took a while for ideas to be accepted
challenged the idea that god created all animals and plants on earth
insufficient evidence at the time of publishing to convince many scientists
mechanism of inheritance and variation wasn't known until 50 years after theory published
113
how many years after the theory of evolution was published was the mechanism of inheritance and evolution discovered
50
114
what is the theory of another guy around the time of Darwin and what was his name
Jean-Baptiste Lamarck
changes that occur in an organism during its lifetime can be inherited
115
why do we know Lamarck is wrong
for the vast majority of cases his type of inheritance of characteristics acquired in a lifetime cannot occur
116
who independent also proposed evolution by natural selection
Alfred Russel Wallace
117
who proposed joint writings with Darwin and when which promoted Darwin to do what
Alfred russel Wallace
1858
publish on the origin of species the following year
118
what is Alfred Russel Wallace best known for
warning colouration in animals
and speciation
119
what did Alfred Russel Wallace do
worked worldwide gathering evidence for evolutionary theory
120
who pioneered our understanding of speciation
Alfred russel Wallace
121
how does speciation happen
two populations separated
different mutations take place
natural selection makes them evolve differently
interbreeding can't happen as phenotypes are too difference
122
what was Gregor Mendel up to until the mid 1850s
carrying out breeding experiments on plants
123
what was one observation from Gregor mendel
inheritance of characteristics is determined by 'units' that are passed on to descendants unchanged
124
when was the behaviour of chromosomes during cell division observed
the late 1800s
125
when was it observed that Mendel's units and chromosomes behaved in similar ways and what did this lead to
early 1900s
units (genes)were located on chromosomes
126
when was the structure of DNA determined
mid 1900s
127
when was the mechanism of the gene function worked out
mid 20th century
128
give a timeline of gene theory
mendel units - 1850s
chromosomes - late 1800s
units are on chromosomes - early 1900s
mid 1900s - structure of DNA and gene function worked out
129
give 3 pieces of evidence for evolution
anti biotic resistant bacteria evolve
fossil records - show simple life
characteristics of parents are passed onto offspring in genes
130
what are fossils
the remains of organisms from millions of years ago found in rocks
131
give 3 ways fossils could be formed
parts of the organism haven't decayed (as the conditions needed for decay are absent: no oxygen, no water, too cold)
parts of the organism replaced by minerals as they decay
preserved traces of organisms
132
give 3 examples of preserved traces of organisms
footprints,
burrows
rootlet traces
133
why have many early life forms left few traces
soft bodied
traces destroyed by geological activity
134
why can scientists not be certain how life began on earth
few traces of early life forms (as soft bodied and remains destroyed geologically)
135
what can we learn from fossils
how much/little organisms have changed as life developed on earth
136
what is extinction
when there are no remaining indivdiduals of a species alive
137
give 5 reasons for extinction
new disease
new predator
new, more successful competitor
climate change (changes to environment)
single catastrophic event (such as asteroid collision or volcanic eruption)
138
why do bacteria evolve rapidly
they reproduce at a fast rate
139
what do mutations of bacterial pathogens produce
new strains
140
describe the production of anti biotic resistant strains of bacteria
mutations produce new strains
some strains are resistant and not killed
survive and reproducing increasing strain population
resistant strain spread as lack of immunity and treatment
141
give an example of a anti biotic resistant strain of bacteria
MRSA
142
give 3 ways to reduce the rate of development of anti biotic resistant strains of bacteria
don't prescribe antibiotics inappropriately
complete course so all bacteria are killed and none survive and mutate to form resistant strains
agricultural usage of antibiotics restricted
143
give 2 examples of inappropriately prescribing antibiotics
for non serious things
or viral infection
144
the development of new antibiotics is__-and ___and so unlikely to keep up with what
costly and slow
the emergence of new strains
145
what are living things classified into groups based on
structure and characteristics
146
who developed the classification system traditionally used
carl Linnaeus
147
what are the 7 groups of Linnaeus's system of classificantion
kingdom
phylum
class
order
family
genus
species
148
what system are organisms named by
binomial system of genus and species
149
how do developments in biology impact classification systems
internal structures understanding is more developed due to improvements in microscopes
understanding of biochemical processes progressed
new improved models of classification
150
what is the new model for classification due to new ___analysis
chemical
three domain
151
who developed the 3 domain system
Charles Woese
152
what are the 3 groups in the 3 domain system
Achaea
bacteria
eukayota
153
what are archaea
primitive bacteria living in extreme environments
154
what are bacteria
true bacteria
155
what does eukaryota include
fungi protists animals and plants
156
what is an ecosystem
the interaction of a community of living (biotic)and non living(abiotic) parts of the environment
157
give 3 things animals compete for
food, mates, territory
158
give 4 things plants compete for
light, space, water and mineral ions in soil
159
if one species in a community of organisms is removed what happens and what is this called
interdependence it can affect the whole community
160
what is a stable community
all species and environmental factors are in balance so the population size remains fairly constant
161
give 3 examples of interdependence
relying on another species for food, shelter, seed dispersal, pollination
162
how does temperature affect a community
plants grow healthily at optimum temp
163
how can soil pH affect a community
some plants like heathers grow best in acidic soils but some don't like it and are sensitive to that so won't grow as well
164
how can wind intensity and direction affect a community
affects CO2 supply to plants
increases rate of plant transpiration
can mechanically damage plants
165
how can Co2 levels affect plants
more CO2 increases growth and yield as needed for photosynthesis
CO2 is acidic so may not raise yields of all plants as some are sensitive to pH
166
how do oxygen levels affect aquatic animals
oxygen needed for respiration
stagnant and polluted waters have low levels of oxygen
moving lakes have high levels
167
give 4 biotic factors affecting a community
new predators
new pathogens
food availability
competition - outcompeted
168
give 3 types of adaption
structural
behavioural
functional
169
what are extremophiles and give an example
organisms adapted to live in extreme environments
bacteria living in deep sea vents
170
give 3 examples of extreme environments for extremophiles
high temp, pressure or salt conc
171
who are the producers of biomass for life on earth
photosynthetic organisms
172
what do food chains begin with
a producer which synthesises molecules
173
give an example of a typical producer
green plant or alga that makes glucose with photosynthesis
174
what are producers eaten by
primary consumers
175
what are primary consumers eaten by
secondary consumers (then tertiary etc)
176
in a stable community what happens to the levels of predator and prey
they rise and fall in cycles
177
describe a method for measuring population of a species
choose plants or slow moving creatures
image space as a grid
use random numbers to generate a set of coordinates for first quadrant
count number of species in quadrat
repeat 14 times
do this in another area with contrasting environment
or use a transect line running from are with one environment to another one with a contrasting environment. take samples every 1m or so
178
give 2 examples of experimental methods used to measure abundance and distribution of a species
transects and quadrats
179
what is the carbon cycle
returns carbon from organisms to atmosphere where used by plants in photosynthesis
180
what does the water cycle do
provides freshwater for plants and animals on land before draining to seas
181
what are 3 factors affecting rate of decomposition
temp
water
oxygen
182
explain how temp affects decomposition
colder = decomposers less active
rate = low
at too high decomposers killed and it stops
as the decomposers secrete enzymes then absorb the molecules
183
explain how water affects decomposition
too dry = die
as volume of water increases rate increases
184
what is oxygen used for by decomposers
respiring to grow and multiply
185
what is compost used for
a natural fertiliser for growing garden plants or crops
186
what does anaeorobic decay produce
methane gas
187
what is used to make methane into a fuel
biogas generators
188
describe the practical investigating effect of temp on rate of decay of fresh milk by measuring pH change
20 cm cubed of fresh milk into 3 beakers
do 5 degrees, 20, and 35
use Universal indicator solution to check pH
cover with cling film and incubate at appropriate temp
revisit after 24, 48, 72 hours
repeat
189
why does the pH of milk reduce as it decomposes
bacteria in milk carries out a process converting lactose milk to lactic acid
190
4.7.2.4 okay?
191
what is biodiversity
variety of species of organisms in an ecosystem or on earth
192
what is a positive impact of biodiversity
reduces dependence of one species on another for food, shelter and maintenance of physical environment
193
the future of what relies on a good level of biodiversity
THE HUMAN SPECIES ON EARTH
194
give 2 reasons more resources are used and more waste is produced
rapid growth of human population
increase in standard of living
195
Give 3 areas of pollution
water
air
land
196
give 3 causes of water pollution
sewage(pollution is shit) fertiliser and toxic chemicals
197
give 2 causes of air pollution
smoke and acidic gases
198
give 2 causes of land pollution
landfill and toxic chemicals
199
what can pollution reduce
biodiversity as kills plants and animals
200
give 4 ways humans reduce land available to other animals and plants
farming, quarrying, building, dumping waste
201
how can peat bogs release. greenhouses gases and which one
decay or burning
CO2
202
what does the destruction of peat bogs do
reduces area of habitat and hence biodiversity
203
give 2 reasons for large scale deforestation in tropical areas
land for cattle and rice fields provision
growing crops for biofuels
204
why is there consensus around climate change
based on systematic reviews of thousands of peer reviewed publications
205
give 5 programs to reduce negative effects on ecosystems and biodiversity from humans
breeding programmes for endangered species
protection and regeneration of rare habitats
reintroduction of field margins and hedgerows in monocultures
reduction of deforestation and CO2 emissions
recycling
206
what is trophic level 1
plants and algae - producers as make own food
207
what is trophic level 2
primary consumers
herbivores eat plants and algae
208
what is level 3 trophic
carnivores eat herbivores - secondary consumers
209
what is trophic level 4
carnivores eat other carnivores - tertiary consumers
210
what are apex predators
carnivores with no predators
211
how do decomposers break down dead plant and animal matter
secreting enzymes into the environment
small soluble food molecules diffuse into the organism
212
producers transfer ___% of light energy from photosynthesis
1
213
only __% of biomass from each level is transferred to the one above
10
214
give 2 reasons for loss of biomass between levels
lots of glucose used for respiration
not all ingested material is absorbed - some tested as faeces
some is lost as waste water, CO2 or urea
215
what is food security
having enough food to feed a population
216
give 6 biological factors affecting food security
increasing birth rate
changing diet = scarce food resources transported around the world
new pests and pathogens affect farming
if rains fail = widespread famine
cost of agricultural inputs
conflicts
217
what needs to be done to feed people on earth
sustainable methods must be found
218
how can the efficiency of food production be increased
restricting energy transfer from food animals to environment - limiting movement and controlling temperature
219
what are some animals fe dot increase growth
high protein foods
220
evaluate the advantages and disadvantages of modern farming techniques
higher yield
more efficient land use
ethical objections
can increase risk of antibiotic resistance
CONCLUDE
221
what in oceans is declining
fish stocks
222
why is it important to maintain fish stocks at a particular level
a level where breeding continues is important
or some may disappear in some areas
223
give 2 ways to keep fish stocks at a sustainable level;
fishing quotas
control of net size
224
what fungus is used to make food suitable for vegetarians and what is it called
fusarian
mycoprotein
225
how is mycroprotein grown
fungus grown on glucose syrup
in anaerobic conditions
biomass harvested and purified
226
what produces insulin
a genetically modified bacterium
227
what could GM products provide and give an example
more food
food with an improved nutritional value
golden rice
228
what does the brain do
control complex behaviour
229
what is the brain made up of
billions of interconnected neurones
has different regions that carry out different functions
230
identify cerebellum, cerebral cortex and medulla on Brain diagram
231
give 3 ways neuroscientists have mapped regions of the brain to particular functions
studying patients with brain damage
electrical stimulation of different parts of the brain
using MRI scanning
232
give 2 reasons that investigating and treating brain disorders is very difficult
delicacy and complexity of the brain
233
the eye is a __organ
sense
234
give 2 things receptors in the eye are sensitive to
light intensity and colour
235
can you label the eye?
236
what does the retina do
contains receptor cells sensitive to brightness and colour of light
237
what is the optic nerve
carries impulses between the eye and brain
238
what does the cornea do
refracts light as it enters the ey
239
what is the iris doing
controls how much light let into pupil
240
what does the lens do
further refracts light to focus it on the retina
241
what does the sclera do
tough white outer layer
helps protect the eye from injury
242
what is accomodation
the process of changing the shape of a lens to focus on near or distant objects
243
explain what happens to focus on a near object
ciliary muscles contract
suspensory ligaments relax
lens is thicker and refracts light rays more strongly
244
explain what happens to focus on a far object
ciliary muscles relax
suspensory ligaments contract
the lens is pulled thin and only slightly refracts light rays
245
what are 4 ways to correct myopia or hyperopia
spectacle lenses
hard and soft contact lenses
laser surgery to change the shape of the cornea
replacement lenses
246
how do you correct for myopia
hyperopia?
with concave lenses -
convex lenses - as there is an e in hyperopia
247
what is body. temperature monitored by
thermoregulatory centre
248
what is body temperature controlled by
thermoregulatory centre
249
give 2 mechanisms for finding temperature of the body
thermoregulatory centre contains receptors sensitive to the temperature of blood
skin contains temperature receptors and sends nervous impulses to the thermoregulatory centre
250
is body temp is too high what happens
blood vessels dilate - vasodilation
sweat is produced from the sweat glands
causing a transfer of energy from the skin to the environment
251
what 3 things happen if too cold
blood vessels constrict - vasoconstriction
sweating stops
shivering - skeletal muscles contract
252
what muscles contract in shivering
skeletal muscles contract
253
what is the endocrine system composed of and what does it do
glands
secretes chemicals called hormones into the bloodstream
254
describe the process of hormones being released to having an effect
glands secrete hormones into bloodstream
blood carries hormone to a target organ
where it produces and effect
255
how to the effects of the endocrine system compare to the nervous system
the effects are slower but act for longer
256
what is the master gland
the pituitary gland
257
what does the pituitary gland do
secretes several hormones into the blood in response to body conditions
these hormones act on other glands to stimulate other hormones to be released to bring about effects
258
label a diagram of hormonal glands of the body
259
what is blood glucose concentration monitored and controlled by
the pancreas
260
if blood glucose is too high what happens
pancreas produces insulin hormone
that moves glucose from blood to liver and muscle cells where excess glucose is converted to glycogen for storage
261
where is glucose stored in and as what
glycogen - liver and muscle cells
262
what is type 1 diabetes
pancreas fails to produce sufficient insulin
263
what is type 1 diabetes characterised by
uncontrolled high blood glucose levels
264
what is type 1 diabetes treated with
insulin injections
265
what is type 2 diabetes
body cells no longer respond to insulin produced by the pancreas
266
give 2 common treatments for type 2 diabetes
Carbohydrate controlled diet and exercise regime
267
what is a risk factor for type 2 diabetes
obesity
268
is blood glucose is too low what happens
pancreas produces glucagon
which converts glycogen back into glucose
and releases it into blood
269
how does water leave the body
via lungs during exhalation
270
what 3 things are lost from the skin in sweat
water, ions and urea
271
is there any control over water, ion or urea loss by sweat or lungs?
no
272
what 3 things are removed by the kidneys and via what
water, ions and urea
urine
273
what 3 things are in urine
water, ions and urea
274
If body cells gain or lose water too much by osmosis what happens
they don't function effectively
275
how are excess amino acids from the digestion of proteins excreted safely and where
liver
amino acids deaminated to make ammonia
ammonia is toxic
so immediately converted to urea for safe excretion
276
ammonia is____
toxic
277
how do kidneys produce urine
filtration of the blood
selective reabsorption of useful substances such as glucose, some ions and water
278
what is water level in the body controlled by
the hormone ADH acting on kidney tubules
279
what is ADH released by
the pituitary gland - as A is the master
280
describe what happens when there is not enough water in the blood - negative feedback loop
ADH released by pituitary gland
more water reabsorbed back into the blood from the kidney tubules
281
give 2 ways to treat kidney failure
organ transplant
kidney dialysis
282
how does dialysis work
unfiltered blood high in urea
mixed with anti coagulants (blood thinners)
blood and dialysis fluid separated by partially permeable membrane
flowing in opposite directions
exchange over concentration gradient
glucose and ions similar conc in dialysis
but no urea
so urea passes out
283
what does the dialysis fluid have the same conc of
glucose
284
+/- of transplants
+transplants
lead more normal life
cheaper for NHS overall
-transplants
immunosuppressant drugs
shortage of donors
only last 8-9 years
operational risks
285
+/- of dialysis
available to all - no shortage
no need for immunosuppressants
must limit salt and protein intake between dialysis sessions
expensive for NHS
regular sessions impact lifestyle
286
during puberty what causes secondary sex characteristics to develop
reproductive hormones
287
what is oestrogen produced in
the ovary
288
one egg is released every ___days
28
289
what is ovulation
the release of an egg
290
what does testosterone do
stimulate sperm production
291
What does FSH do
matures egg in ovary
292
what does LH do
stimulates the release of an egg
as L - lets it go
293
what do oestrogen and progesterone do
maintain uterus lining
294
what is the start of the cycle
period
295
what does FSH stimulate the release of
oestrogen
296
what stops FSH production
oestrogen
297
what does oestrogen stimulate the pituitary glands to release
LH
298
what is progesterone produced by
follicle - and released by ovaries
299
how do oral contraceptives work
inhibit FSH so eggs c=don't mature
300
what does injection, implant or skin patch of slow release progesterone do to be contraception
inhibits maturation and release of eggs
301
how do barrier methods work
prevent sperm reaching the egg
302
what are 2 ways intrauterine devices can work
prevent implantation of embryo
or release a hromone
303
what do spermicidal agents do
kill or disable sperm
304
when do you abstain from intercourse
when egg might be in the oviduct
305
the progesterone pill - evaluate
free
at least 99% effective
have to take same time each day
no STD protection
some medicines make it less effective
306
evaluate spermicide
short term
non invasive
only 70-80% effective
no STI protection
307
abstinence is very/not very effective
not very
308
condoms are __% effective and have __side effects but give 2 costs
98%
no
costs money
can tear
latex allergies
309
how effective is diaphragm
92%
310
the implant is free/not free NHS
free
311
give costs of the contraceptive implant
disrupted periods
pain on insertion
312
what hormones are in fertility drugs for women
FSH and LH
313
give the 4 stages of IVF
give mother FSH and LH to stimulate the maturation of several eggs
eggs collected and fertilised with father's sperm in lab
fertilised eggs develop into embryos
when tiny balls of cells one or two inserted into uterus (womb)
314
give 3 costs of IVF
very emotionally and physically stressful
success rates low
can lead ti multiple births - risk to baby and mother
315
what is adrenaline produced by and when
adrenal glands
times of fear or stress
316
give 3 things adrenaline does
increases heart rate
boosts delivery of oxygen and glucose to brain and muscles
preparing for fight or flight
317
what is thyroxine from and what does I tdo
thyroid gland
stimulates basal metabolic rate
318
what does basal metabolic rate do
plays a role in growth and development
319
describe what happens when thyroxine conc in blood is too low
production of TSH increases
stimulates thyroxine secretion by thyroid
320
what controls phototropism and gravitropism
plant hormones - unequal distributions of auxin causing unequal growth rates in roots and shoots
321
what hormones are important for seed germination
gibberellins - G G
322
what controls cell division and fruit ripening
ethene
323
give 3 things auxins are used for
weed killers
rooting powers
promoting growth in tissue cultures
324
what is ethene used for
controlling ripening of fruit during storage and transport in the food industry
325
what 3 things can gibberellins be used for
ending seed dormancy
promote flowering
increase fruit size
326
describe the auxins practical method
cotton wool on 3 Petri dishes with same amount of water for each dish
10 seeds per dish and placed somewhere warm
allow to germinate
one in dark, one in light and measure heights
327
which side does auxin gather on for phototropism
shaded side as promotes growth there
328
what do auxins do in gravitropism (negative)
inhibit growth and make root curve down - for positive stimulates growth to serve upwards
