Biology revision cards B1

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Keeping Healthy

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Keeping Healthy

Exercise increases metabolic rate which means that the chemical reactions in cells work faster.

What can effect your metaboli rate?

-inherited factors

-proportion of muscle to fat

Good cholesteorl is needed for your cell membranes and to make vital substances.

Bad cholesterol leads to heart disease.

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Keeping Healthy

By exercising reguarly you can increase metabolic rate and lower high cholesterol levels.

What are pathogens?

Tiny microorganisms that cause infectious diseases, usually a bacteria or virus.

Viruses are much smaller than bacteria and reproduce inside cells.

Semmelweiss discovered that infection can be transfered from person to person and told people to wash their hands.

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Keeping Healthy

The skin prevents pathoegens getting into the body.

Pathogens are also trapped by mucas and killed by stomach acid.

What are the three things that white blood cells do to defend the body?

1- They ingest pathogens.

2- They produce antibodies to help destroy particular pathogens.

3- The produce antitoxins to counteract the toxins that pathogens produce.

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Keeping Healthy

What do Antibiotics kill?

-Infective bacteria in the body.

Who discovered Penicillin?

Alexander Fleming in 1928.

Penicillin is an antibiotic . 

Viruses are difficult to kill because they reproduce inside the body cells.

Painkillers relieve symptoms of a disease byt do not kill the pathogen.

Your immune system will usually overcome the viral pathogens.

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Keeping Healthy

What do Antibiotics kill?

-Infective bacteria in the body.

Who discovered Penicillin?

Alexander Fleming in 1928.

Penicillin is an antibiotic . 

Viruses are difficult to kill because they reproduce inside the body cells.

Painkillers relieve symptoms of a disease byt do not kill the pathogen.

Your immune system will usually overcome the viral pathogens.

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Keeping Healthy

Bacteria can be grown on agar jelly.

Contamination might come from your skin, the air, the soil or the water around you.

Some pathogens can mutate (change) resulting in a new form called a mutation.

What is the name given to diseases spreading within a country?


Diseases that spread across countries result in a pandemic.

The MRSA is a bacterium that has evolved through the natural selection. They have become resistance to the common antibiotics.

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Keeping Healthy

Dead or innactive froms of a pathogen are used to make a vaccine.

White blood cells react by producing antibodies.

Antibodies recognise antigens on the pathogen.

What does MMR prevents?

Measles, mumps, rubella.

Vaccination protects individuals and society from the effects of disease.

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Coordination and control

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Coordination and control

The nervous system has receptors to detect stimuli.

The receptors are found in sense organs (eye, ear, nose, tongue and skin).

Electrical impulses pass to the brain along neurons (nerve cells).

What forms the central nervous system?

Brain and spinal cord.

Receptors detect external stimuli.

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Coordination and control

The main steps involved in reflect actions:

1- A receptor detects a stimulus (e.g a sharp pain)

2- A sensory neurone transmits the impulse to the CNS.

3- A relay neuron passes the impulse on.

4- A motor neuron is stimulated.

5- The impulse passes to an effector (muscle/gland)

6- Action is taken (the response)


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Coordination and control

What is at the junction between two neurons?


Menstural Cycle-

Follicle stimulating hormones (FSH)- made by the pituitary gland and causes egg to mature and oestogen is produced.

Oestrogen- produced by ovaries and stops further production of FSH.Stimulates production of LH and womb lining to develop to recieve egg.

Luteinising hormone (LH)- made by pituitary gland and stimulates the mature egg to be released from the ovary.

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Coordination and control

The contraceptive pill may contain oestrogen and progesterone.

Contraceptive pill prevents production of FSH so no egg matures.

What does FSH cause?

-The egg to mature.

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Coordination and control

We must keep our temperature constant, otherwise the enzymes in the body will not work properly.

Sugar in the blood is energy source for cells.

What controls our level of sugar in the blood?


Phototropism- plant shoots grow towards the light.

Gravitropism- Roots grow down towards gravity.

Auxin is the hormone which controls phototropism and gravitropism.

Plants growth can be used as weed killers and to stimulate root growth.

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Coordination and control

Using Hormones

In women-

-contraceptive pill.

-help get pregnant.

-help older women have babies.


In plants-


-encourage fruit to ripen.

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Medicine and drugs

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Medicine and drugs

Placebos- do not contain the drug.

Double blind trial- the patient nor doctor know who has the real drug.

Thalidomide was developed as a sleeping pill, it helped morning sickeness for prenant women and left babies born deformed. It now treats Leprosy. 

What are statins?

Drugs that lower bad cholesterol.

St John`s wort treats depression.

Recreational drugs are used by people for pleasure e.g heroin.

If you try to stop taking addictive drugs you will suffer withdrawal symptoms.

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Coordination and control

As recreational drugs affect the nervous system it is very easy to become addicted to them.

What are Steroids?

-Drugs which build up muscle mass.

Using perfomance enharncing drugs can damage the body permanently and even lead to death.

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Adaptation for survival

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Adaptation for survival

Plants need light, carbon dioxide, water, oxygen and nutrients to survive. 

Special features of organisms are called adaptations.

What is a herbivore?

Animals that eat plants.

Extremeophiles are microorganisms which are adapted to live in conditions where enzymes won`t usually work because they would denature.

Bigger animals have smaller surface area compared to their volume, this means that they can conserve enerfy more easily.

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Adaptation for survival

Plants can lose water as water vapour through holes in the leaves called Stomata.

Water can be conserved if the plant has very small or waxy leaves.

Animals are in competition with each other.

Some plants use animals to spread their fruits and seeds. Others use the wind or mini-explosions to spread their seeds.

Give exaples of non-living factors: 

Temp, rainfall, light, oxyegn levels

Give examples of living factors: 

Arrival of new predator, diseases, introduction of new plants

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Energy in biomass

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Energy in biomass

Biomass is the mass of living material in plants and animals.

A pyramid of biomass represents the mass of the organisms at each stage in a food chain.

There is energy wastage between each stage of a food chain.

Some of biomass is used for respiration and the energy released in this is transferred to the surroundings.

Detritus feeders may start the process of decay. 

Decay organisms are bacteria and fungi. They are called decomposers.

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Energy in biomass

Carbon Cycle

Recyling of carbon involves both photosynthesis and respiration.

Photosynthesis removes CO2 from the atmosphere.

Green plants respire, returning CO2 to the atmosphere.

Animals eat green plants and build the carbon into their bofdies. When plants or animals die microorganisms release the CO2 back into the atmosphere by respiration.

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Variation, reproduction and new tech

The nucleus of a cell contains chromosomes.

This chromosome carries genes.

What are s*x cells called?


Genetic info is passed on by reproduction.

As*xual Reproduction- only involves one parent, no fusion of gametes is made.

S*xual Reproduction- involes two parents, fusion of gametes is made.

Identical copies of as*xual reproduction is called clones.

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Variation, reproduction and new tech

Differences in the characteristics of the same species may be due to:

-differences in genes

-conditions in which they have developed


If a mother smokes or drinks alcohol through the pregnancy the baby may have a small birth weight.

Why is cloning used?

To produce new individuals that are useful in farming and agriculture.

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Variation, reproduction and new tech

Embryo transplants are used to clone animals. The embryo with unspecialised cells is split into smaller groups of cells. Each group of genetically identical cells is transplanted and allowed to develop in a host animal.

Animals or plants are genetically modified to produce useful substances before they are cloned.

In adult cell cloning the nucleus of an adult cell e.g skin cell, replaces the nucleus of an egg cell.

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Variation, reproduction and new tech

Genetic engineering involes changing the genetic make-up of an organism.

A gene is cut out of the chromosome of an organism using an enzyme. The gene is then places in the chromosome of another organism.

Crops with changed genes are called genetically modified crop plants.

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Variation, reproduction and new tech


Cloning cattle can produce cattle with usefull characteristics. 

Used to make the best copies of animals.

Cure genetic disorders.

Medicines can be made from Genetic engineering.

GM crops include ones which are resistant to herbicides of insects.

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Variation, reproduction and new tech


GM crops have a bigger yield, but farmers have to buy new GM seeds every year.

People are concerned about accidently introducing genes into wild flower populations.

Insects may be affected by GM crops.

Effects of eating GM crops on human health.


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Jean-Baptiste Lamarck- `the inheritance of acquired characteristics`. Characteristics developed during organisms lifetime can be passed on to the next generation.

Charles Darwin- `natural selection`. Small changes in organisms took place over a very long time.

Charles Darwin visited the Galapagos Islands and recorded observations of finches.

Natural classification system- system to classify organisms.

Evolutionary trees- models that can be drawn to show relationship between different groups of organisms.


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Typo of cholesterol 


Typo of cholesterol 


Typo of metabolic


Typo of metabolic


brill these really helped me thanks

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