AQA Biology Unit 3 Notes

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BIOLOGY 3 NOTES
ACTIVE TRANSPORT B3 1.1
Substances get in and out of cells through:
-Diffusion-
-Osmosis-
-Active Transport
Concentration Gradient-The difference in concentration between the
two areas where the substance is present
DIFFUSION-
-The net movement of particles from an area of higher concentration to an area
of lower concentration. Results of the random movements of the particles of a
gas or of a substance in solution- this is a PASSIVE PROCESS
Factors affecting the rate of diffusion:
-Diffusion Pathway- the shorter the diffusion pathway, the faster the rate of
diffusion (less distance)
-Concentration Gradient- Steeper the concentration gradient, the faster the
rate of diffusion
-Temperature- increase temperature increases the rate of diffusion
-SA: Volume Ratio- increased surface area increases rate of diffusion
-MOIST SURFACE AREA DOES NOT EFFECT THE RATE OF DIFFUSION
OSMOSIS-
-The net movement of particles from an area of high water concentration an
area of low water concentration across a `partially permeable' membrane
-Partially permeable membrane-only allows certain molecules to pass

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BIOLOGY 3 NOTES
ACTIVE TRANSPORT
-When a cell needs to take up a substance against the concentration gradient,
this involves energy and is called `active transport'
Active Transport:
-Goes against the concentration gradient
-Requires energy from respiration-mitochondria
-Is across a living cell membrane
-Requires a transport protein
Active transport is present in:
-Moving mineral ions into plant root cells
-In the kidneys
-In the salt glands of marine animals because they live in salt-water
EXCHANGE OF GASES IN THE LUNGS B3 1.…read more

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BIOLOGY 3 NOTES
EXCHANGE OF MATERIALS IN OTHER ORGANISMS B3 1.…read more

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BIOLOGY 3 NOTES
THE CIRCULATORY SYSTEM B3 2.…read more

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BIOLOGY 3 NOTES
TRANSPORT IN THE BLOOD-(approx. 5 litres in the body)
Constituents of the Blood Function
Red Blood Cells Involved In transport of oxygen
(-Short diffusion pathway around the body.…read more

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BIOLOGY 3 NOTES
Long Term benefits from regular exercise:
-Muscle hypertrophy
-Increased Alveoli
-Lower resting breathing rate
-Increased stroke volume
-Bigger Lungs
-Increased Vo2 Max
-Quicker recovery rate
ANAEROBIC RESPIRATION
Aerobic Respiration Anaerobic Respiration
-With oxygen -Without oxygen
-Products: CO2 and H2 0 -Product: Lactic acid
-More energy released -Less energy released
-Occurs in mitochondria of every living -Occurs in cytoplasm in every living cell
cell
Oxygen Debt- When lactic acid is produced during anaerobic respiration, oxygen is
needed to break it down to produce…read more

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BIOLOGY 3 NOTES
Ureter-tube through which urine passes from the kidney bladder
Renal Artery-brings blood containing urea & other substances in solution to
the kidney
Renal Vein- carries blood away from the kidney, after urea & other substances
have been removed from the blood by the kidney
Bladder-stores urine
Urethra-tube through which urine passes to the outside of the body
Pelvis-the central chamber where the urine arrives from the collecting ducts
Ureter-tube through which urine passes from the kidney bladder
Cortex-dark red-contains lots of capillaries…read more

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BIOLOGY 3 NOTES
-Needs to be done regularly to avoid the build up of urea
KIDNEY TRANSPLANTS
-Failed kidneys replaced by single healthy kidney from donor
-Donor usually dead, but may be alive
-Patient needs to be healthy to undergo surgery
-To prevent rejection by the immune system:
Kidney needs to be a close match as possible
Patient must take immunosuppressant drugs for life
Dialysis or Transplant?
Dialysis Transplant
Machines usually available No special diet required
No problem with tissue matching No sessions of dialysis…read more

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BIOLOGY 3 NOTES
FOOD PRODUCTION USING YEAST
-Single celled organism
-Used to make alcoholic drinks, e.g.…read more

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BIOLOGY 3 NOTES
LARGE-SCALE MICROBE PRODUCTION
-Microorganisms can be grown on a large scale in industrial fermenters
-The conditions in a fermenter must be very carefully controlled
-A mycoprotein can be produced using the fungus Fusarium
-pH are also monitored closely in a fermenter
-A fermenter needs to be kept cool to avoid the enzymes from denaturing
-Mycoprotein is valuable to grow as it can be eaten by both vegetarians and
slimmer's
ANTIOBIOTIC PRODUCTION
-Antibiotics are produced in fermenters
-The mould Penicillium produces the antibiotic…read more

Comments

Katie789

thanks, this was really useful.

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