WJEC GCSE Biology 3 revision Guide (In detail)

This is a GCSE WJEC Biology 3 (triple science award) revision guide for higher tier.  I've tried to write it so that it is of genuine use for anyone doing the course (because i know that they don't do triple science revision guides -_- ). If you spot any inaccuracies please tell me because obviously I'm not 100% sure that it's all right. I hope it's useful for you :) update it's now 100% complete :)

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  • Created by: Evan
  • Created on: 01-04-13 19:57
Preview of WJEC GCSE Biology 3 revision Guide (In detail)

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"Candidates should: understand why water is important to plants and its use in
photosynthesis, transport of minerals and support."
Plants need water for structural support, growth, photosynthesis and for the transport
of minerals.
Structural support ­ a plant consists of 90% water. The internal pressure of
water in a plant allows it to hold its shape and not wilt (hence why a dry plant
will wilt).
Growth ­ Cells grow by taking in water, causing them to expand. Without water,
cells diminish which stunts the plant's growth.
Photosynthesis ­ Water is a crucial part of the photosynthesis equation (carbon
dioxide + water » Oxygen + glucose). Without water, photosynthesis cannot take
Mineral transportation ­ Dissolved minerals in water (such as magnesium) are
absorbed into the plant by the roots. Water acts as a vehicle of transportation for
"Candidates should: investigate water loss in plants, for instance using a bell jar, and
use of a simple potometer to investigate the effect of different environmental
conditions on the rate of transpiration from a plant cutting."
The amount of water lost by a plant can be measured by a device called a potometer.
A bubble is introduced to the capillary tube; as water is taken up by the plant, the
bubble moves from right to left. By marking the bubbles position at set intervals on the
tube, it is possible to measure the water lost by the plant.
"Candidates should: observe root hairs and understand their significance increasing
the area for absorption. Understand the role of osmosis in the uptake and movement of
water through a plant and understand that mineral salts are taken up by root hairs by
active transport."
Osmosis' role in the uptake of water ­ Water is taken into the plant by the
process of osmosis, using the root cells as a semi permeable membrane.

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Osmosis occurs as there is higher concentration of water outside the root than
there is inside the root, therefore water moves through the membrane into the
Osmosis' role in the movement of water through a plant ­ osmosis is an
important part of the transpiration stream (see below).
How root hair cells are adapted for the process of osmosis ­ Root hair cells are
adapted for osmosis as they have an elongation which increases their overall
surface area.…read more

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Candidates should: recognise and label on a given diagram of a T.S. leaf: cuticle,
epidermis, stomata, palisade layer, spongy layer, xylem and phloem. Structure of
stomata to include guard cells and stoma. Understand that stomata can open and
close to regulate transpiration."
Diagram of a TS leaf's structure:
How the stomata controls transpiration ­ the degree at which the stomata opens
directly controls the amount of water that leaves the plant.…read more

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Phosphate Creates strong roots.
Potassium Creates good flowers and many seeds.
Calcium Creates strong stems.
Nitrate Creates the components to make healthy
plant cells. (E.g. stem, leaves etc.)
Effects of deficiencies in nutrients ­
1. Potassium: The leaves of the plant begin to show a yellow colour.
2. Phosphate: The roots of the plant do not grow well.
3. Nitrate: The plant has poor overall growth.
KPN fertilisers ­ This is a common and basic fertiliser that contains Potassium
(K), phosphate (P) and nitrate (N).…read more

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White blood cell diagram -
Red blood cell
diagram -
Red blood cells ­ They contain haemoglobin. The
function of a red blood cell is to transport oxygen from the lungs to the other
parts of the body and carry carbon dioxide back to the lungs. Red blood cells
don't have a nucleus to allow more space for oxygen; they also have a large
surface area to increase the diffusion rate of oxygen.…read more

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Structure of arteries and veins is not required.)"
The muscle imbalance of the heart ­ As the distance that blood is pumped
along the systemic system is further than the distance of the pulmonary
system, more muscle is required to maintain the blood pressure of the
systemic system. Therefore the left hand side of the heart is more muscular
as this side sends the blood through the systemic circulation system.…read more

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Cornea It refracts light - bends it as it enters the eye
"Candidates should: understand that the brain, spinal cord and nerves form the
nervous system and the central nervous system consists of the brain and spinal cord."
The central nervous system ­ This consists of the brain and spinal cord. The
brain processes and interprets sensory information sent from the spinal cord.
The nervous system ­ This consists of the brain, nerves and spinal cord.…read more

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"Candidates should: know that the kidneys regulate the water content of the blood and
remove waste products from the blood and understand why this is necessary."
Why it is necessary for the kidneys to regulate the water content of blood - The
kidneys control the water content of the plasma in our blood. For the cells of our
body to function properly and to remain healthy, it is important that their water
content is maintained at the correct level.…read more

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