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1. DISSOLVED SUBSTANCES
1. What is osmosis? The net movement of water molecules
across a partially permeable membrane from a dilute to a
concentrated solution.
2. What do most soft drinks (and sports drinks) contain and
why? Water sugar and ions to replace the sugar used as an
energy source for respiration and the water and ions lost by
sweating.
3. How does active transport differ from diffusion? Active
transport describes movement against the concentration
gradient and requires energy.
4. List some features of a specialised exchange surface (e.g.
alveoli/villi). 1. Large surface area, 2. Thin to provide a short
diffusion pathway, 3. Having an efficient blood supply (4. being
ventilated – lungs)
5. What do we call the upper part of the body (where the
lungs are) and the lower part (where our intestines are)?
1. Thorax and 2. Abdomen
6. In the process of ventilation, breathing in involves the lungs
moving down and in/up and out, the diaphragm and intercostal
muscles contracting/relaxing, this increases/decreases the
volume of the thorax and reduces/increases the pressure. Air
then moves in because the pressure outside the lungs/body is
higher than inside.
2. EXCHANGE AND TRANSPORT IN PLANTS
1. Carbon dioxide enters (and oxygen leaves) the leaves of a
plants through holes called stomata by diffusion.
2. The holes are opened and closed by guard cells.
3. Water and ions/salts/minerals are absorbed through the
roots which have hairs to increase the surface area.
4. In leaves, their flattened shape and internal air spaces act to
increase the surface area.
5. Water vapour is lost through stomata by evaporation
(transpiration) and is faster in what type of conditions? Hot,
dry, windy
6. What happens to a plant when the rate of water loss is
faster than the rate of water uptake? It wilts
7. In plants xylem tissue transports water and minerals from
roots to stem and leaves.
8. The movement of water through the roots, stem, leaves and
evaporation out the plant is called the transpiration stream.
9. Phloem tissue carries sugars from the leaves to the rest of
the plant (including the growing regions and storage organs).
The sugars are produced in the leaves by photosynthesis.
3. THE BLOOD SYSTEM
1. Name the 4 main components of blood and what their role is. Red blood
cells – carry oxygen, White blood cells – fight infection (immune system),
Platelets – clotting at a wound and Plasma – liquid part of blood.
2. What happens to haemoglobin in the lungs and the body tissues? In
lungs it combines with oxygen to produce oxyhaemoglobin and in the
tissues it releases the oxygen and reforms haemoglobin.
3. As well as the blood, what are the 2 other components of the circulatory
system? Heart and blood vessels
4. What is the heart made from, what is its role and what are the four
chambers called? Muscle – pumps blood around the body – left and right
atria (atrium) and left and right ventricles
5. Which type of blood vessel carries blood away from the heart? Artery
(Aorta and pulmonary arteries)
6. Name the 4 blood vessels attached to the heart and what they do. Aorta
= oxygenated blood away from heart to body tissues, Vena cava =
deoxygenated blood back to heart from body tissues, Pulmonary artery =
deoxygenated blood to lungs, pulmonary vein = oxygenated blood from
lungs to heart.
7. What do veins and the heart both have that are not found in arteries or
capillaries? valves
8. Arteries such as the coronary artery which supplies blood to the heart
muscle can become narrowed by the build up of fatty deposits. What can
be inserted into one to keep it open?
A stent
9. Why have capillaries got very thin walls (one cell thick)?
So that substances such as oxygen, glucose, carbon dioxide etc can pass
easily between the blood and body cells.
4. HOMEOSTASIS – WASTE REMOVAL AND WATER
CONTROL
1. The main two waste products that need to be removed from the body
are (1) carbon dioxide – produced by respiration and removed by breathing
out and (2) urea – produced in the liver by breaking down amino acids and
removed by the kidneys, stored in the bladder.
2. If the water or ion content of the body is not kept constant then cells
may be damaged by gaining/losing water by osmosis.
3. Urine is produced in the kidneys by ultrafiltration and selective
reabsorption. Describe what happens in both.
Ultrafiltration – all small particles, such as water, glucose, salts, urea and
amino acids are filtered out of the blood.
Selective reabsorption – all glucose, some salts, some water BUT no urea is
reabsorbed.
4. The two treatments for kidney failure are either dialysis or transplant.
a) How does a dialysis machine work?
Blood flows through a machine between a partially permeable
membrane and dialysis fluid. Waste substances such as urea pass out by
diffusion into the dialysis fluid from the blood but not useful substances as
the dialysis fluid contains the same concentration of these as the blood.
b) What are some of the disadvantages with dialysis?
Have to be attached to a machine regularly for hours, having to follow
a carefully controlled diet, urea build up between sessions, restrictions to
lifestyle (travel?)
c) What are some of the disadvantages with a transplant?
Rejection, due to antigens on surface of transplanted organ being
foreign – therefore have to take immunosuppressant drugs for ever! Major
operation to go through. Having to wait for a donor.
5. HOMEOSTASIS – TEMPERATURE CONTROL
1. Core body temperature is monitored and controlled by
receptors found where? Thermoregulatory centre in the brain
2. Where else in the body would you find temperature
receptors? Skin
3. What happens to help you cool down when your core body
temperature is too high? Sweating – evaporation of water,
blood vessels supplying skin capillaries dilate, more blood flows
near skin surface, skin looks redder, heat lost by radiation.
4. What happens to help you warm up when your core body
temperature is too low? Blood vessels supplying skin capillaries
constrict, less blood flows near skin surface, skin looks paler,
reduces heat lost by radiation. Also muscles may shiver –
contraction releases some energy through respiration which is
used to warm the body.
6. HOMEOSTASIS – SUGAR CONTROL
1. Blood sugar is both monitored and controlled by the
pancreas which releases the hormones insulin and glucagon.
2. High blood sugar triggers the pancreas to release insulin.
This causes glucose to move into cells from the blood
3. Low blood sugar triggers the pancreas to release glucagon.
This causes glycogen to be converted into glucose and
released into the blood
4. In type 1 diabetes, a person’s blood sugar may rise too
high, why? How can this be treated/controlled? Exercise, diet
and insulin injections
7. HUMANS AND THEIR ENVIRONMENT
1. Water, air and land can be polluted with what? Sewage, fertiliser, toxic
chemicals, smoke, sulfur dioxide, pesticides, herbicides etc.
2. Why is deforestation occurring? More land for farming, housing, roads, wood
for construction
3. How does deforestation contribute to global warming? Cuts down trees, less
photosynthesis (so less CO2 removed and ‘locked up’) burning trees also adds
CO2 to atmosphere. (also reduces biodiversity – but not linked directly with this
question)
4. Why is peat bog destruction a cause for concern? Releases CO2 and reduction
of biodiversity (habitat destruction)
5. What are some of the concerns about global warming?
Climate change, rise in sea level, reduction of biodiversity, migration patterns
change, changes in species distribution.
6. Biogas is mainly methane and can be produced by Anaerobic fermentation of
plant products, animal/plant waste material – i.e. substances containing
carbohydrates. Lots of different type of biogas generator, from small scale to
large factory.
7. Why are shorter food chains more efficient than longer ones? Less stages =
less energy loss as energy is lost at ach stage through processes such as … not
all previous stage eaten, faeces, urine, heat, movement.
8. How can animal farming be ‘improved’ to increase efficiency? Restrict
movement and keep warm – i.e. in barns.
9. What measures are being employed to try to conserve the ocean’s fish stocks?
Setting quotas and net size restrictions
10. What is mycoprotein and how is it produced? Protein produced by fungus
Fusarium suitable for vegetarians. Grown on glucose syrup in aerobic conditions,
with the biomass being harvested and purified.