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CB8H
Pearson GCSE Combined Science Biology Higher
Question | Answer |
---|---|
What do we mean when we talk about the concentration of a substance? | (the amount of the substance in a certain volume (usually of another substance)) |
By what process do particles move from a place of greater concentration to a place of lower concentration? | (diffusion) |
In diffusion, do particles move up or down a concentration gradient? | (down) |
For what process in the body do we need oxygen? | (aerobic respiration) |
What gases are exchanged in the lungs? | (oxygen and carbon dioxide) |
What molecule is used to carry oxygen in red blood cells? | (haemoglobin) |
A cuboid has sides of 4 cm by 4 cm by 5 cm. What units would be used for its surface area? | (cm2) |
A cuboid has sides of 4 cm by 4 cm by 5 cm. What units would be used for its volume? | (cm3) |
A cell has a surface area of 24 cm2 and a volume of 8 cm3. What is the ratio of its surface area to its volume? | (3 : 1, although note that surface area : volume (SA : V) ratios are given as a single figure, 3 = 3 in this case) |
How are the lungs adapted for efficient gas exchange? | (large surface area/alveoli) |
Which organ excretes carbon dioxide in humans? | (lung(s)) |
In what pocket-shaped structures does carbon dioxide excretion occur? | (alveoli) |
Why do alveoli have walls that are only one cell thick? | (to increase the rate of diffusion) |
Which organ excretes urea in humans? | (kidney(s)) |
What do you divide surface area by to calculate a surface area : volume (SA : V) ratio? | (volume) |
Which have the bigger SA : V ratios, smaller cells or larger cells? | (smaller) |
Does diffusion happen up or down a concentration gradient? | (down) |
What are the smallest blood vessels in the body called? | (capillaries) |
What is the name of the blood vessels that carry blood away from the heart? | (arteries) |
What is the function of an erythrocyte? | (to carry oxygen) |
Which blood vessels take blood away from the heart? | (arteries) |
Which blood vessels have thick, elastic walls? | (arteries) |
Which blood vessels contain valves? | (veins) |
Through which blood vessels does diffusion of substances into and out of tissues take place? | (capillaries) |
Which blood cells are adapted to carry oxygen? | (red blood cells, erythrocytes) |
Which blood cells engulf and digest foreign cells? | (phagocytes) |
Which component of the blood carries urea? | (plasma) |
What helps to push blood along veins in the legs? | (skeletal muscles) |
How many chambers does a human heart have? | (four) |
What happens when blood is prevented from reaching heart muscles? | (heart attack) |
What are the lower chambers of the heart called? | (ventricles) |
What stops blood flowing the wrong way in the heart? | (valves) |
Which side of the heart has the thicker muscle walls? | (left side) |
What parts of the body does the right side of the heart supply with blood? | (lungs) |
Which blood vessel carries blood to the left atrium from the lungs? | (pulmonary vein) |
Does the pulmonary artery carry deoxygenated or oxygenated blood? | (deoxygenated) |
Why does heart rate increase during exercise? | (cells in tissues need more oxygen/glucose) |
Jack’s stroke volume is 0.1 litres/beat and his heart rate is 50 beats per minute. What is his cardiac output? | (0.1 × 50 = 5 litres/min) |
What element does aerobic respiration need that anaerobic respiration does not? | (oxygen) |
What happens to energy in an exothermic reaction? | (It is transferred to the surroundings.) |