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?
In diffusion, do particles move up or down a concentration gradient?
For what process in the body do we need oxygen?
What gases are exchanged in the lungs?
oxygen and carbon dioxide
What molecule is used to carry oxygen in red blood cells?
A cuboid has sides of 4 cm by 4 cm by 5 cm. What units would be used for its surface area?
A cuboid has sides of 4 cm by 4 cm by 5 cm. What units would be used for its volume?
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, 31 3 in this case
How are the lungs adapted for efficient gas exchange?
large surface area/alveoli
In human lungs, what gas is transported into the blood using gas exchange?
How are alveoli adapted to their function?
they have a large surface area, they have thin walls
For what process does the body need glucose?
By what transport method do carbon dioxide molecules move from the blood into the lungs?
A cube has a volume of 1000 cm3 and surface area of 600 cm2. What is its surface area : volume ratio?
0.6, but accept 3 : 5
How is the SA : V ratio of larger cells different from the SA : V ratio of smaller cells?
larger cells have a smaller SA : V ratio
How is the concentration gradient of oxygen between the inside and the outside of a capillary maintained?
by the flow of blood
What is the unit g/cm3 a measure of?
In what other format can g/cm3 be written?
Which organ excretes carbon dioxide in humans?
In what pocket-shaped structures does carbon dioxide excretion occur?
Why do alveoli have walls that are only one cell thick?
to increase the rate of diffusion
Which organ excretes urea in humans?
What do you divide surface area by to calculate a surface area : volume (SA : V) ratio?
Which have the bigger SA : V ratios, smaller cells or larger cells?
Does diffusion happen up or down a concentration gradient?
What are the smallest blood vessels in the body called?
What is the name of the blood vessels that carry blood away from the heart?
What is the function of an erythrocyte?
to carry oxygen
What is the name of the ‘pockets’ in the lungs where gas exchange occurs?
Which blood vessels take blood away from the heart?
Which blood vessels have thick, elastic walls?
Which blood vessels contain valves?
Through which blood vessels does diffusion of substances into and out of tissues take place?
Which blood cells are adapted to carry oxygen?
red blood cells, erythrocytes
Which blood cells engulf and digest foreign cells?
Which component of the blood carries urea?
What helps to push blood along veins in the legs?
How many chambers does a human heart have?
What happens when blood is prevented from reaching heart muscles?
What are the lower chambers of the heart called?
What stops blood flowing the wrong way in the heart?
Which side of the heart has the thicker muscle walls?
What parts of the body does the right side of the heart supply with blood?
Which blood vessel carries blood to the left atrium from the lungs?
Does the pulmonary artery carry deoxygenated or oxygenated blood?
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?
What happens to energy in an exothermic reaction?
It is transferred to the surroundings.