Biology GCSE - Part 1A

RESPONDING TO CHANGE

Key points :-

• Control of your body's functions and response involves hormones (chemicals) and the nervous system (electrical impulses)

Key words :- gland, hormone, impulse, nervous system

Examiners Tips:-

• Remember impulses are transmitted by chemicals in the hormone system and electrical impulses in the nervous system
• There are often questions about the difference between the hormone system and the nervous system - make sure you know

REFLEX ACTIONS

Key points:-

• Reflex actions are responses that are rapid and automatic
• Reflex actions do not involve the brain

Key words :- effector, receptor, neurone, synapse, stimulus

Examiners tips:-

• There is nearly always a question about reflexes.
•  Questions usually apply your knowledge to a new situation.
  •  Don't Panic - if the question is set in a new situation you haven't come across before. 
• Make sure you understand how reflex actions work then any new information needed will be supplied in the question
• Do not talk about 'messages' being transmitted, talk about impulses!

THE MENSTRUAL CYCLE

Key points:-

• The cycle takes 28 days with ovulation about 14 days into the cycle
• The cycle is controlled by three hormones

Key words:- stimulate, inhibit, womb, mature

Examiners tips:-

• Many students remember the effect each hormone has on egg production but forget how each hormone affects the production of others. Make sure you know.
• Remember what each hormone does during the cycle, especially the effect each one has on the production of other hormones 

THE ARTIFICIAL CONTROL OF FERTILITY

Key points:-

• The contraceptive pill contains oestrogen that prevents pregnancy
• FSH can be given to a woman to help her produce eggs

Key words:- contraception, fertility treatment

Examiners tips:-

• There are usually issues involving contraception and fertility treatment. Make sure you can offer opinions on these issues in an examination. If you only offer a 'one-sided' argument, you may lose up to half your marks  

CONTROLLING CONDITIONS

Key points:-

• It is important that the internal conditions of the  body are kept within certain limits
• Water and ion content, as well as temperature and blood sugar level, are all carefully controlled

Key words:- internal conditions, blood sugar, ions

Examiners tips:-

DIET AND EXERCISE

Key points:-

• A healthy diet is made up from the 'right' balance of the different foods you need
• You are malnourished if you do not have a balanced diet
• If you take in more energy than you need you may become fat, and this may result in health problems

Key words:- energy, metabolic rate, chemical reactions, malnourished

Examiners tips:-

• The word 'rate' often confuses students in an exam. Rate simply means how fast something is taking place. If you run, the rate at which you use energy increases
• Your metabiloc rate is a measure of how quickly your cells are converting food into energy

WEIGHT PROBLEMS

Key points:-

• If you eat more food than you need you will put on weight
• If you are very fat you are said to be obese

Key words:- obese, arthritis, diabetes, blood pressure, heart disease

Examiners tips:-

• When asked for a list, many students will remember one or two things - try to remember three and pick up the extra mark

FAST FOOD

Key points:-

• Fast food is food that has already been prepared. It often contains too much fat and salt
• Too much fast food is likely to result in health problems

Key words:- cholesterol, lipoprotein, saturated, mono-unsaturated fats, poly-unsaturated, statin

Examiners tips:-

• Make sure you know which lipoprotein  is the good one and which one is the bad one. It is equally important to know which of the three types of fat increase choleterol levels in your body

DRUGS

Key points:-

• All drugs can cause problems whether they are legal or illegal
• Many drugs are addictive. If you try to stop taking them this can result in severe withdrawal symptoms

Key words:- illegal, addictive, withdrawal, recreational, indigenous

Examiners tips:-

• Many problems today are caused by legal drugs, e.g. tobacco and alchohol because they are so widely used (and abused)
• You may get a question asking whether  taking cannabis leads to taking harder drugs - You must try to make both sides of the argument as there is no 'right' answer. If you only make an argument for or against, you will lose up to half your marks

LEGAL AND ILLEGAL DRUGS

Key points:-

• There are both legal drugs and illegal drugs
• There are both medicinal drugs and recreational drugs
• Some legal drugs can be used illegally

Examiners tips:-

• Make sure you know the difference between a drug used as a medicine and a drug used simply for pleasure (recreational).
• Make sure you know the difference between legal and illegal drugs

ALCOHOL - THE ACCEPTABLE DRUG?

Key points:-

• Alcohol is a legal drug that can be bought by anyone over the age of 18 in the UK
• Alcohol causes serious health issues for some that use it
• Alcohol is a recreational drug

Key words:- alcohol, coma, liver damage, brain damage

Examiners tips:-

• Remember that alcohol is legal. However, it still causes many more problems in our society than illegal drugs such as heroin and cocaine as it is much more widely used.

SMOKING AND HEALTH

Key points:-

• Smoking tobacco is legal for anyone over 16 years of age in the UK
• The use of tobacco causes a range of health problems and will probably lead to early death

Key words:- nicotine, tobacco, carcinogen, carbon monoxide

Examiners tips:-

• Remember it is the nicotine in tobacco smoke that is addictive and the other chemicals in the smoke that cause cancer.
• Babies born to mothers who smoke have low birth weights. The babies receive less oxygen to release the energy from food (in respiration) that they need to grow properly

PATHOGENS

Key points:-

• Pathogens are micro-organisms that cause infectious disease
• Key words:- pathogen, bacteria, virus, toxin, infectious

Examiners tips:-

• Remember, in an exam answer, that pathogens reproduce before they make enough toxins to make you feel ill
• You will bump up your grade in an exam from C to A by not just knowing what Semmelweiss discovered about the transfer of infection, but why it took so long for his ideas to be accepted 

DEFENCE MECHANISMS

Key points:-

• It is best to stop pathogens getting into your body in the first place, e.g. having no cuts on the skin or trapping pathogens in the mucus in your nose
• If pathogens do get in, then the white blood cells help us defend ourselves

Key words:- white blood cell, ingest, antibody, antitoxin

Examiners tips:-

• Never write down in an exam that the white blood cells eat pathogens! They ingest them
• In the exam most students will only remember one or, at most, two things  that white blood cells do. Try to remember all three - ingest, produce antibodies, produce antitoxins

USING DRUGS TO TREAT DISEASE

Key points :-

• Antibiotics can be used to kill bacteria
• It is much more difficult to kill viruses

Key words:- antibiotic, penicillin, painkiller

Examiners tips:-

• Viruses are harder to get rid of, as they reproduce inside cells, If you destroy the virus, you can easily destroy the cell as well
• Remember that painkillers only relieve the symptoms of the disease  

CHANGING PATHOGENS

Key points:-

• If a pathogen changes by mutating or through natural selection, then it can be very difficult to control

Key words:- natural selection, mutation, epedeminc, pandemic

Examiners tips :-

• Mutation takes place in an instant, whereas natural selection is a gradual process over many years
• Remember that bacteria don't 'want' to develop resistance - they just do!
• Make sure you understand how bacteria become resistant to antibiotics through natural selection

DEVELOPING NEW MEDICINES

Key points:-

• A new medicine must be effective, safe and it must be able to be stored for a period of time
• New medicines are tested in laboratories to see if they are toxic and on human volunteers to see if they work

Key words:- toxic, side effects, thalidomide

Examiners  tips:-

• It is important to test new medicines on animals first to see if they are toxic. Some people are against the use of animals for this. In an examination be prepared to argue the case for and against the use of animals in testing new medicines
• A good medicine is effective, safe, stable, successfully taken into and removed from the body

IMMUNITY

Key points :-

• You can be immunised to help stop you getting a disease

Key words:- vaccines, immune

Examiners tips :-

• A vaccine is made from dead or inactive forms of pathogen