Cells, Digestion, Photosynthesis, Respiration, Circulation, Ecology, Muscles, Bones & Joints and Inheritance.

How to revise and where to get help. The definitive guide for GCSE students today.

Page Index

  1. How to Revise
  2. Where to get help
  3. Cells
  4. Digestion
  5. Photosynthesis
  6. Respiration
  7. Circulation
  8. Ecology
  9. Muscles
  10. Bones (& joints)
  11. Inheritance

How to Revise

Firstly here are a few DOs and DON’Ts.


  1. panic
  2. just stare at the pages
  3. copy out your text book
  4. think you can do it all tomorrow
  5. expect someone else to do it for you

What you should be doing:

  1. keep calm
  2. do what you can
  3. use your time sensibly
  4. write three lists of topics which you
  5. know understand and have memorized
  6. understand and need to memorize
  7. need help with
  8. plan when you will do some memorizing
  9. get help from a science teacher//parent//friend
  10. try some past papers

This is the kind of thing you should end up with:

“I can label a diagram of the human digestive system and get it all correct every time because I have memorized it. I must memorize the names of the enzymes in the mouth and stomach, I understand what they do but I didn’t bother to memorize it for homework last year. I will do this next Tuesday evening. I really don’t understand what happens to the food after it has been digested; I know I need help; I will go and ask teacher XY tomorrow (I will get help from any science teacher who I can find its what they are paid for). When I have done this I will tick it off my lists.”

Where to get help ——— Any Science teacher will help if you ask nicely.

  1. Exercise books
  2. Text books
  3. Science teachers
  4. The Open Learning Centre
  5. The Internet
  6. These pages ~ ask your questions using the form on any page in this website!
  7. E-mail a science teacher


Here are some key words — do you know their meanings?

  1. Nucleus//DNA
  2. Cytoplasm
  3. Cell membrane
  4. Cell wall
  5. Chloroplast//photosynthesis
  6. Vacuole
  7. Osmosis
  8. Plasmolysis
  9. Turgor//turgid
  10. Flaccid
  11. Osmosis

Do you know the differences between animal and plant cells? I do!

one has:

  1. nucleus
  2. cytoplasm and
  3. cell membrane ONLY
  4. an irregular shape

the other has:

  1. nucleus
  2. cytoplasm
  3. cell membrane AND
  4. a regular shape because it has a cell wall
  5. chloroplasts so it can carry out photosynthesis

Can you give some examples of different kinds of cells?

Just think about your own body!

  1. brain// sensory & motor neurons
  2. bone// osteocytes = bone cells
  3. muscle// muscle cells
  4. liver// liver cells
  5. blood// red blood cells & white blood cells

Now find out about Prokaryotes and Eukaryotes

OR have a look at my new pages on animal cells and plant cells

AND there is a page about osmosis


What you might know already:

  1. A balanced diet has – carbohydrate, protein, fat, vitamins, mineral salts & fibre;
  2. Carbohydrate gives you energy;
  3. Protein is needed for growth & repair;
  4. Fats contain fat soluble vitamins;
  5. Vitamins are essential in SMALL quantities;
  6. Mineral salts are also essential, e.g. Calcium, Iron & Iodine;
  7. Enzymes are needed to digest carbohydrate, proteins and fats;
  8. Enzymes are substrate specific;
  9. Enzymes work better at body temperature;
  10. Enzymes only work at their optimum pH;
  11. Villi absorb glucose, amino-acids, fatty acids, glycerol, vitamins and minerals;
  12. Villi have a large surface area.

Now is the time to make sure that you know the names of the enzymes which digest different kinds of food chemicals.

Can you know the explain the lock and key model of enzymes? I can!

Make a jump to enzymes now.

More information about a balanced diet has been here for some time now.

Find out about pH now.


I am sure that you already know that:

  1. Green plants contain a chemical called chlorophyll;
  2. Chlorophyll is used in photosynthesis;
  3. Photosynthesis uses light energy to make glucose;
  4. Photosynthesis takes place in the mesophyll of a leaf;
  5. Photosynthesis also requires Carbon Dioxide and water;
  6. Glucose can be used in respiration or stored as starch;
  7. Iodine and starch turn black;
  8. Green light is not used in photosynthesis;
  9. Increasing the light intensity will make photosynthesis faster.

Please make sure that you have memorized the word equation for photosynthesis, and the balanced chemical equation if you are doing the higher papers. You can find these equations and an explanation of how to balance chemical equations here.

Could you label a diagram of a leaf? This would take me 30 seconds!


You should know the difference between aerobic and anaerobic respiration. You should also know word equations for these. If you hope to get a grade A or B you should also be able to write the balanced chemical equations for these reactions.

  1. Aerobic respiration requires Oxygen.
  2. Anaerobic respiration does not require Oxygen.
  3. Glucose + Oxygen = Carbon Dioxide + Water + ENERGY
  4. Glucose = Carbon Dioxide + Ethanol + ENERGY ( in yeast).
  5. Glucose = Lactic Acid + ENERGY (you will get cramp if you make too much).

What is the purpose of respiration? NOT to get rid of glucose! NOT to make Carbon Dioxide either! The purpose of respiration is to release energy for other things like movement. So know you know why we breathe.

Make a Jump to the Respiration page or have a look at  balanced chemical equations for respiration.


You should know about the composition and functions of blood, the structure and functions of blood vessels (arteries, veins, portal veins, and capillaries), and you should know about the heart.

Could you label a diagram of the heart? This would take me two minutes!

Go and have a look at my pages on the heart or blood now.


Ecology is an interesting language. You may already know the answers to lots of the ecology questions e.g.

  1. What happens to the squirrels if the oak trees don’t produce any acorns?
  2. What happens to the greenfly if there are more ladybirds?

However if you do not use the correct language you will not score so many marks. PLEASE, PLEASE, PLEASE use words like:

  1. Population,
  2. Predation,
  3. Community,
  4. Ecosystem,
  5. Pollution,
  6. Grazing,
  7. Climatic factors,
  8. Biotic factors.

SO don’t say that all the squirrels will die if there are no acorns: what will happen is the squirrel population will decrease.

DON’T say that the ladybirds will eat all of the greenfly. Think about it; more people in the town does not mean that there will be no chips left in the chip shop! If there are more ladybirds then the greenfly population will decrease in size.

More information is available for GCSE and “A” Level students in my ecology web. There is a page which provides you with definitions and explanations of all the key words you need to know for the ecology section of your GCSE biology.

There is a whole section of this website devoted to Ecology.


Do you know what antagonistic muscles are?

Well this topic is really quite straightforward. Muscles can contract and they can relax, but muscles cannot stretch themselves or make themselves longer. What must happen after a muscle has contracted is that it must BE stretched. This can only happen when a muscle relaxes and another muscle pulls it longer. So muscles always work in pairs. Nothing happens if BOTH muscles contract, nothing happens if BOTH muscles relax, but when one muscle contracts and the other muscle relaxes movement occurs. Such pairs of muscles are called “antagonistic muscles” E.g. the biceps and the triceps. When the biceps flexes (bends) the elbow the triceps is stretched, and when the triceps extends (straightens) the elbow the biceps is stretched.

PLEASE make sure that you can label a diagram of the elbow or knee: bones & muscles.

Make a jump to my page about Muscles.

Bones & Joints

Another easy one! You should know that:

Bones are rigid tissues (they are living and they do not bend);
Bone supports your body, acts as a system of levers, and protects vital organs.

You should be able to label a diagram of a synovial joint. My joints are held together by ligaments, they contain synovial fluid which lubricates them, the synovial capsule holds the fluid in, they contain cartilage which acts as a shock absorber. If you play “kickball” you might have damaged your cartilage and had some of it removed. I don’t so I am still nice and bouncy and my bones do not get damaged when I run and jump.

Tendons connect my muscles to my bones, so that when I contract my muscles my bones are moved. Fortunately my tendons and ligaments are inelastic, i.e they do NOT stretch.

Unfortunately I broke a ligament in one of my knees so that knee is a bit wobbly.

Did you know that my knees and elbows work like a hinge, they can bend and straighten; but my hips and shoulders works like ball and sockets so they can move in more than one plane AND they can swivel.

I expect that you body works just like mine so why not take it into the exam with you, it might help to remind you about the different parts and this is not really cheating!

Now take a jump to my muscles page to see how the biceps and triceps flex and extend your elbow joint.


You need to know about

  1. DNA ~ Deoxyribonucleic Acid
  2. Genes
  3. Alleles
  4. Chromosomes
  5. X and Y chromosomes
  6. How inheritance works
  7. An example of inheritance
  8. About Mendel’s work

Jump to my page on Genetics page

You will find all the information that you need in my biology and ecology sections.