IGCSE Biology Flashcards (Mocks)

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What is Variation?

the difference between individuals of the same species

What is Phenotypic variation?

difference in features between individuals of the same species

What is Continuous Variation?

is when the individuals in a population have a range of phenotypes which vary between 2 extremes

What is Discontinuous Variation?

is when there are 2 or more distinct categories

What is Phenotypic Variation caused by?

Genetics or environmental

Give 3 examples of Genetic Variation

Eye colour, gender & Blood group

What is variation caused by?

Genes

Characteristics of all species can be affected by environmental factors such as

climate, diet, accidents, culture and lifestyle

What does environmental mean?

Outside of the organism

What is a Continuous feature?

Height

What is a mutation?

a genetic change

Why do mutations occur?

from a gene that results in a different version which is called an allele

Do most mutations do not affect the phenotype?

Yes

The new allele gives the individual a

survival advantage

What harmful changes can mutations cause?

Sickle cell anaemia

What are adaptive features?

characteristics that an organism inherits which will help it to survive and reproduce in its environment

What does “well adapted” mean?

Suited to the environment

Who survives and reproduces the most?

Why do individuals vary?

Different genes

What causes genetic variation?

Different alleles

Why are many offspring produced?

Not all will survive

What happens when too many are born?

Competition

What is the “struggle for survival”?

Competing for resources

What happens to poorly adapted organisms?

They die or reproduce less

Why do some reproduce more?

They are better adapted

How are useful alleles passed on?

By reproduction

What happens to useful alleles over time?

They increase

How does a species change over time?

Becomes better adapted

Why does the next generation have better traits?

The best adapted reproduce

Who developed natural selection?

Charles Darwin

What is “survival of the fittest”?

Best adapted survive

Does “fittest” mean strongest?

No, best adapted

Why is reproduction important in evolution?

It passes on genes

Why is competition important?

Only the best adapted survive

What is the human excretory system?

group of organs which are specialised for the removal of certain excretory products

Which organs does the human excretory system include?

Kidney & Liver

What is excretion?

Removal of the waste substances of metabolic reactions, toxic materials and substances in excess of requirements

Why do the lungs excrete carbon dioxide?

the waste product of aerobic respiration during exhalation

Why do the Kidneys excrete excess water, salts and urea?

Produced in the liver from excess amino acids) through the formation of urine

Why must carbon dioxide be excreted?

it dissolves in water easily to form an acidic solution, which can lower the pH of cells

What is the Kidney?

Two bean-shaped organs that filter the blood

What is the utterer?

Tube connecting the kidney to the bladder

What is the Bladder?

Organ that stores urine

What is the Urethra?

Tube that connects the bladder to the exterior; where urine is released

What is Respiration?

A chemical process that involves the breakdown of nutrient molecules to release the energy

What is respiration controlled by?

Enzymes

Can respiration take place with oxygen and without oxygen?

Yes

Where does respiration take place?

in all living cells

What energy is released when respiration occurs?

Protein synthesis, Growth & Active transport

What is aerobic respiration?

is chemical reaction in cells that use oxygen to break down nutrients and release energy

What is the word equation for aerobic respiration?

glucose + oxygen = carbon dioxide + water

What is anaerobic respiration?

is a series of chemical reactions in cells that break down the nutrient molecules to release energy without oxygen

what’s the word equation for aerobic respiration?

glucose = Lactic acid

Do all gas exchange surfaces have features in common?

Yes

What Features maximise the rate of gas exchange taking place?

Large surface area, Thin walls & Good blood supply

What are the ribs?

Bone structure that protects the internal lungs

What are the intercostal muscles?

Muscles between the ribs which control their movement

What is the diaphragm?

the muscle that allows inhalation and exhalation

what is the Trachea?

windpipe that connects the mouth and nose to the lungs

What is the Larynx?

air passes across here so were able to make sounds

What is the bronchi?

Large tubes benching off the trachea

What is the bronchioles?

Split from smaller tubes called bronchioles in the lungs, connect to the alveoli

What is the alveoli?

Tiny air space where gas exchange takes place

Does exercise increase the breathing rate?

Yes

What is the Job of the lungs?

Transfer oxygen to the blood and remove waste carbon dioxide

What is a pathogen?

is any organism that causes disease

What is a transmissible disease?

disease where the pathogen can be passed from one host to another

How are pathogens spread?

Direct contact & Indirect contact

What is direct contact?

Through the host blood & body fluids

What is indirect contact?

Through contaminated surfaces or food

What are 3 body defences?

Skin, Mucus & stomach acid

Whats the function of the Skin body defence?

Acts as a barrier to pathogens

Whats the function of the Hairs in nose's body defence?

These trap particles from the air that could contain pathogens

Whats the function of the Mucus body defence?

Cells in your trachea and bronchi produces mucus to trap pathogens

How do you control the spread of disease?

Clean water supply, Hygienic food prep & Personal hygiene

How does clean water supply stop the spread of disease?

Having access to clean, Fresh water for drinking and cooking

How does Hygienic food prep supply stop the spread of disease?

Preparing food in clean conditions will stop the spread of pathogens

How does personal hygiene stop the spread of disease?

washing your hands after you go to the bathroom can stop the spread of pathogens

What is passive immunity?

fast-acting, short-term defence against a pathogen by antibodies acquired

How are antibodies passed from the mother to the child?

Breastmilk

What does the body not do?

antibodies and memory cells

How are pathogens destroyed in your body?

by white blood cells

What does cholera cause?

diarrhoea

What is the circulatory system?

A system of blood vessels with a pump and valves to make sure that blood always flows in one direction

What are the components of the circulatory system?

Blood vessels, a pump & Valves

Where is the The Mammalian Heart located?

In the chest

What blood does the right side of the heart receive?

Deoxygenated blood to the lungs

What blood does the left side of the heart receive?

Oxygenated blood to the body

What are the 2 sides of the heart separated by?

Septum

What is the heart made of?

Muscle tissues

How can you monitor the activity of the Heart?

ECG or measuring the pulse rate

What is coronary heart disease?

Where the coronary arteries gets blocked

How do the arteries get blocked?

By fatty materials building up

What are some of the risk factors of coronary heart disease?

Smoking, Gender, Genetics & Age

How can you prevent Coronary heart disease?

Diet, Exercise & Quit smoking

What are the functions of arteries?

To carry blood away from the heart

What is the function of Capillaries?

Transport deoxygenated blood from the arteries to the cells

What is the function of Veins?

These blood vessels carry blood towards the heart at low pressure

What are the wall in the arteries?

Thick and muscluar

What are the walls in the Veins?

Thin