GCSE Biology Unit 1 AQA

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Bio 1.1

Healthy Diet

A balanced diet is having the correct amount of these different types of food

Proteins

– Build and repair tissue.

Amino acids are the

building blocks of proteins

Carbs

– Found in rice, bread, pasta. They are needed to provide energy for the body

Fat

– Found in butter, oils, lard. Provide stored energy that will be used when there is a lack of carbs. It

is also there to insulate the

body.

Water

– Hydrates the body and

is important because all

chemical reactions in the body happen in a watery environment. SO you

need it.

Fibre

– Found in fruits, veg and cereals. Helps with the release of faeces.

Vitamins

and Minerals – Certain vitamins and minerals have different jobs. They give you good general health.

Malnutrition

– Can lead to being overweight or underweight.

More energy taken in then lost = gain weight

Less energy taken in then lost = lose weight

Metabolic

rate – The rate at

which chemical reactions take place in your body. Things that affect

this are:

·

Gender

– Males on average have higher metabolic rate

·

Muscle/Fat

Ratio – More muscle to fat means higher metabolic rate

·

Inherited

Genetics

Cholesterol

– Cells use this to produce cell membranes. Too much of this can cause blocked

arteries which can lead to heart attacks.

Type 2

Diabetes – This is a result of insulin not being recognised in the body and it means you can’t control blood sugar levels. Tends to be in overweight people.

There are two types of cholesterol. Good cholesterol and bad

cholesterol. If this balance in the two cholesterols is bad then you can be at

risk of health problems. The liver makes produces cholesterol that you

inherited from your parents. Eating lots of high fat foods can cause the

cholesterol levels to become unbalanced therefore putting you at risk of heart

diseases.

Defence

against Diseases

Microorganisms

– Bacteria, Fungi, Viruses. The Microorganisms that cause disease are called pathogens.

People can pass these pathogens on from person to person.

This makes them Infectious

diseases.

Bacteria

– Produces anti-toxins

(poisons). Single cell living

organisms. Much smaller then plant/animal cells. Many bacteria cells are

harmless and some are actually

beneficial in life. Bacteria multiply by splitting in two.

Viruses

– Gets into the cells and reproduces

rapidly. This causes the cell to be permanently damaged. These microorganisms are much smaller then bacteria cells.

Viruses cause disease in every

single living organism.

Symptoms

– high temperatures,

headaches, and rashes. This is caused by the damage the pathogens do to

your body and also how your body reacts to the toxins they produce.

There are a number of ways in which pathogens can be spread. The most likely ones

are:

·

Droplet Infection – When you cough, sneeze or talk you expel tiny droplets. Other

people breathe these droplets in along with the pathogens they contain, so they

pick up the infection.

·

Direct Contact – When pathogens get in small breaks/cuts in skin. Injecting with

dirty needles, eating raw undercooked food. Spread by direct contact of skin.

Bodies’ defences

Skin

– your skin is your bodies’ main defence when it comes to pathogens. It acts as

a barrier and covers your whole body.

Clots

– When you cut your skin, you blood instantly forms a clot which dries to make a scab. The scab seals

of the cut so pathogens can’t

get into the wound.

Mucus

– When you breathe, you breathe in pathogens. Luckily your body produces mucus. Mucus is a

sticky liquid that pathogens get

stuck in. It covers the lining of your lungs and tubes. You then swallow

the mucus and acid in your

stomach destroys the microorganism.

When your outer body defences fail your white blood cells

take action.

White

blood cells – ingest

pathogens, produce

antibodies or they can produce

antitoxins.

Ingest

microorganisms – They ingest the pathogen. This destroys the pathogen so

they can’t make you ill

Antibodies

– Some white blood cells produce special chemicals called antibodies. There is a different antibody for each pathogen. If

the pathogen gets into your body a second time the antibody can be made very quickly

Antitoxins

– counter act the toxins

that are released by the pathogens.

Drugs to treat

disease

When you get a disease you often take medicines. These medicines rarely effect

the pathogen, they just ease

the symptoms. Paracetamol and aspirin are very useful painkiller. But

they have to effect on the actual virus that entered the body.

Antibiotics

– Antiseptics and disinfectants are used to kill bacteria outside the body but

they are far too poisonous to use inside your body. They would kill the

pathogen and you at the same time. Antibiotics are drugs we use inside the body to kill the bacteria

that causes diseases.

They work by damaging the bacterial cells without harming your own cells. They

have saved many lives. Sadly they are not the full answer. Antibiotics do not kill pathogens caused by

viruses. They can't kill viruses because viruses reproduce inside the cells of our body. It

is extremely difficult to develop drugs that kill viruses without damaging the cells and

tissues of your body at the same time.

Keeping Healthy

Diseases