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Pearson GCSE Combined Science Biology Higher

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.)



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