Transcript Biology 3 Revision Booster

B3 Revision
Osmosis is the movement of water from a high water
concentration (dilute solution) to a low water concentration
(concentrated solution) through a partially permeable
membrane.
During active transport, carrier proteins in the cell
membrane ‘pick up’ particles and move them against
the concentration gradient.
Requires energy from the cell, which is created by
respiration.
Ventilation is the process of breathing in and
breathing out
Feature
Inhaling
Exhaling
Diaphragm
flat & contracted
domed & relaxed
Volume
increases
decreases
Ribs
up and out
down and in
Intercostal muscle
contracted
relaxed
Pressure
Lungs
decreases
inflated
increases
deflated
Stomata - water
• Guard cells – sensitive to water and light.
• TOO MUCH water – guard cells FULL, PLUMP,
(TURGID)  stomata OPEN for gas exchange
• TOO LITTLE water – guard cells not much
water, (FLACCID),  stomata CLOSE to
prevent water evaporation.
• Increase in light intensity opens stomata
• Decrease in light intensity closes stomata
Transpiration
is the
Evaporation
of Water from
Leaves
Light
- more light = more photosynthesis = more co2 released
through stomata = more H2O lost through stomata =
increased transpiration
Temperature
- More heat = more evaporation = increased transpiration
Humidity
- A lot of water vapour in air = less water loss as air
already saturated with air = decreased transpiration
Wind
- Water vapour in air is replaced with drier air = water
concentration in air is lower than in plant = increased
transpiration
aorta
oxygenated blood to
the body
pulmonary artery
pulmonary vein
valve
left atrium
valve
vena cava
tendon
right atrium
valve
right ventricle
left ventricle
A blood vessel which transports blood away from the heart
A blood vessel which transports blood back to the heart
A permeable blood vessel where gas exchange takes place
Red blood cell not carrying any oxygen
Red blood cell carrying oxygen
Carries deoxygenated blood from the heart to the lungs
Carries oxygenated blood from the lungs to the heart
The main blood vessel transporting deoxygenated blood to
the heart
The main blood vessel transporting oxygenated blood to
the body
Found in the heart and veins to ensure the blood flows in
one direction
Artificial Heart
Mechanical device to pump blood
• ADVANTAGES
• Temporary fix until donor
heart is found
• Some cases permanent
therefore no need for
transplant
• Not rejected by body’s
immune system
• DISADVANTAGES
• Surgery involved
therefore risk of infection
• Don’t work as well as
natural
• Can wear out
• Blood flow is not as
smooth therefore could
get clots
• Drugs to thin blood
Stents are metal
grids which can be
inserted into an
artery to maintain
blood flow by
keeping the artery
open.
Advantages & disadvantages of stents
• Advantages
– No anaesthetic
– Relatively cheap
– Stent does not corrode
• Disadvantages
– Cannot open the most blocked or narrowed arteries
– Can irritate the lining of the blood vessel causing scar
tissue to be formed
– Need to take anti-coagulant drugs
air sac in the
lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
4 the haemoglobin in
the red cells goes
back to the lungs to
pick up more oxygen
2 Haemoglobin and
oxygen join to make
oxyhaemoglobin
3 when the blood flows past
cells with very little oxygen in
them the oxyhaemoglobin
breaks down
oxygen diffuses into the cells of the body
oxygen is used for respiration
Artificial blood products
Advantages
Disadvantages
Cheap
Sides effects
Easily available
Difficult to get in to the system
Don’t need to depend on donors
May rely on blood products
anyway
Good carriage of oxygen
(compared to plasma or saline)
No risk of disease
Broken down rapidly
Long shelf life
Don’t clot blood
Less religious objections
Don’t offer defence against
disease
Don’t carry dissolved food
Kidney Function Summary
• 1 - Filter the blood at high pressure (squeeze
everything into the kidney tubule [except
proteins, blood cells])
• 2 – Reabsorb all the glucose and amino acids
by active transport
• 3 – reabsorb the dissolved ions (as much as
the body needs)
• 4 – reabsorb as much water as the body needs
• 5 – release the urea, excess ions and excess
water as urine.
• Blood leaves the artery and enters the dialysis machine
where the blood flows between partially permeable
membranes.
• The dialysis fluid contains the same concentration of useful
substances as the blood.
• Dialysis fluid contains no urea
at all so urea passes out from
the blood into the dialysis fluid
due to a steep concentration
gradient
• Blood with correct conc of
dissolved substances is returned
Donor rejection
• All your body cells have ANTIGENS (labels to say you
are you!)
• The donor kidney will have DIFFERENT ANTIGENS
• The immune system of the person who receives the
kidney could ATTACK the donor kidney.
• TISSUE TYPE the kidney so its as close a match as
possible
• Immunosuppressant drugs given for life to reduce
chance of rejection
Glucose – a sugar
found in the body.
Glycogen – a
storage of
carbohydrate found
in liver and muscles
Glucagon – converts
glycogen into
glucose.
Insulin – converts
excess glucose into
glycogen for storage
Evaluate the use of insulin injections over
pancreas transplants
• Insulin treatment widely available; relatively
cheap
• Pancreatic transplant good but surgery required;
high risk; expensive; long term
immunosuppressant use and most importantly
not enough donors;
Compare modern insulin treatment with the original
insulin used to treat diabetics and evaluate the two
treatments
Original – from pancreases of cattle and pigs used for
meat ; no control over quantities as used what was
available from slaughterhouses; not genetically identical
to human insulin. Some people disagree with using
animal insulin (ethical/religious issues)
Modern – produced by genetically modified bacteria;
exact quantity and quality control; genetically identical,
however some people disagree with GM insulin, long
term effects unknown
Increased population
• Non-renewable energy resources (such as
coal, oil and natural gas) are being used up
rapidly.
• More land is being used for buildings and
transport networks, quarrying, farming and
dumping waste - reducing the amount of land
available to other animals and plants.
• More waste is being produced - causing more
pollution.
Pollution
• Human activities may pollute:
–Water
• with sewage and fertilisers (eutrophication)
or toxic chemicals
–Air
• with smoke and gases such as sulfur dioxide
which contribute to acid rain
–Land
• with toxic chemicals such as pesticides and
herbicides, which maybe washed from the
land into water
Deforestation
• Is the cutting down of large scale forests,
especially in tropical areas.
• Occurs because land needed for growing
biofuel crops, growing food crops (rice) and
rearing cattle, buildings, wood used for timber
(furniture etc…)
• Causes damage because releases of CO2 when
burned, less CO2 is locked away as wood,
reduced biodiversity, loss of homes of
indigenous people, increased methane release
from rice and cattle fields.
Ethanol can be made by a process called
fermentation. This converts sugar into ethanol
and carbon dioxide if conditions are anaerobic.
Disadvantages
• Greater demand on rainforest land.
• Only grows well in hot countries
• Engine modification is needed
• Although biofuels are in theory carbon neutral, this
does not take into account the carbon dioxide
emissions associated with growing, harvesting and
transporting the crops, or producing the ethanol
from them
Efficiency of food production can be
improved by reducing the number of
levels in the food chain
Animals are kept still and warm so they
transfer less energy as waste heat. The
energy saved can be used to produce more
meat, eggs or milk.
FOOD MILES = The distance our food
travels to get to our homes
• Why do we import food from abroad
Cheaper, want out of season food, bigger profits for
supermarkets, some food cannot be grown in UK
• What are the problems associated with this
Increased fuel consumption = increased CO2
emissions = global warming
• How can we reduce food miles
Buy British food, buy food locally, grow own food
Fishing quotas
- Size of the holes in
nets, so only bigger
fish are caught.
- Bans on fishing during
breeding season.
- Strict limit on the
amount and type of
fish caught.
1. What is mycoprotein?
Substance made from the fungi Fusarium
2. What conditions are needed for its optimum growth?
Aerobic conditions
3. Why is this a good food source?
High protein and low fat meat substitute ideal for
vegetarians and dieters