Biology B2 OCR 21st century

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Name two types of Microorganisms that cause disease.
Microorganisms that cause disease include: bacteria, protozoa, viruses and fungi.
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Give two ways in which microorganisms can cause illness.
Microorganisms can cause illness by damaging body cells and producing toxins.
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If a bacterium can grow and divide every 30 minutes and the starting population is 20 what will the population be after 3 hours?
In 2 hours the population would've doubled 6 times 20 x 2^6 = 1,280.
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Which type of white blood cell engulfs and digests bacteria?
Phagocytes are the type of white blood cell that engulf and digest bacteria.
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What does a vaccine contain?
A vaccine contains dead or inactive forms of the pathogen.
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What are antibiotics?
Antibiotics are drugs used to control infections caused by bacteria.
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What problem can the overuse of antibiotics cause?
The overuse of antibiotics can cause the development of antibiotic resistant strains of bacteria.
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Give two reasons why new medical drugs need to be extensively tested and trialled.
New medical drugs need to be extensively tested and trialled to find out if they are safe and effective.
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What is a placebo?
During drug trials some patients are given a placebo, which does not contain the drug to compare them with patients who were actually given the drug.
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Which type of blood vessels carry blood away from the heart?
Arteries are the type of blood vessels that carry blood away from the heart.
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Why do arteries have thick walls containing muscle and elastic fibres?
In the arteries, the blood is under high pressure so they have thick walls containing muscle and elastic fibres to prevent them from bursting.
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Why do capillaries have permeable walls that are only one cell thick?
Capillaries have permeable walls that are only one cell thick for rapid exchange of dissolved substances with the body cells.
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Why is it dangerous to have high blood pressure?
It is dangerous to have high blood pressure because it gives a higher risk of heart disease or stroke.
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What is heart disease?
Heart disease occurs when fatty deposits build up in the blood vessels supplying the heart muscle (coronary blood vessels). If these vessels become blocked it can cause a heart attack.
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What does the term homeostasis mean?
Homeostasis is the maintenance of a stable internal environment.
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Give three conditions that need to be kept constant in the body.
Conditions that need to stay constant within the body include: water levels, blood glucose levels, body temperature, ion content.
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Explain how negative feedback helps to keep conditions stable in the body. (Higher)
If there is a change in a condition away from the constant this is detected by the receptors which then send information to the processing centres. The effectors are then stimulated to bring the condition back to the steady state. Any change in a con
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How is excess water lost from the body?
Any excess water is lost from the body through the kidneys in the urine.
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Why do the kidneys produce a small volume of concentrated urine on hot days?
On hot days the body loses more water through sweating therefore the kidneys conserve more water and produce a small volume of concentrated urine.
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How does the kidney respond to high levels of anti-diuretic hormone (ADH)? (Higher)
The kidney responds to high levels of ADH by reabsorbing more water back into the blood. This results in the production of a smaller volume of more concentrated urine. (Higher)
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Other cards in this set

Card 2

Front

Give two ways in which microorganisms can cause illness.

Back

Microorganisms can cause illness by damaging body cells and producing toxins.

Card 3

Front

If a bacterium can grow and divide every 30 minutes and the starting population is 20 what will the population be after 3 hours?

Back

Preview of the front of card 3

Card 4

Front

Which type of white blood cell engulfs and digests bacteria?

Back

Preview of the front of card 4

Card 5

Front

What does a vaccine contain?

Back

Preview of the front of card 5
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