Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a human - Edexcel - GCSE Biology - Question 8 - 2018 - Paper 1
Question 8
Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a human.
(i) These cells are animal cells.
Animal cells do not ha... show full transcript
Worked Solution & Example Answer:Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a human - Edexcel - GCSE Biology - Question 8 - 2018 - Paper 1
Step 1
(i) These cells are animal cells.
Animal cells do not have
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Answer
The correct answer is B a cell wall. Animal cells do not possess a cell wall, which is a characteristic feature of plant cells.
Step 2
(ii) The actual length of the red blood cell from a turtle is 20.5 µm.
Calculate the length of the magnified image of the red blood cell of the turtle when magnified 400x.
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Answer
To find the magnified length, multiply the actual length by the magnification factor:
extMagnifiedLength=20.5imes400=8200extµm
Step 3
(iii) The width of the human red blood cell, when magnified 400x, is 3.08 mm.
Calculate the actual width of the cell and show your answer in standard form.
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Answer
To find the actual width, divide the magnified width by the magnification:
extActualWidth=4003.08extmm=0.0077extmm
This can be recorded in standard form as:
7.7imes10−3extmm
Step 4
(i) Describe a method you could use to see how much the ring of tissue from an artery could stretch before it no longer returns to its original size.
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Answer
Measure the initial length of the tissue ring using a ruler.
Gradually add weights or masses to the ring and measure the extension at each weight.
Remove the weights, and measure the length again after each removal.
Repeat the process until the ring no longer returns to its original length.
Step 5
(ii) Give one safety precaution you need to take when handling animal tissue such as blood vessels.
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Answer
One safety precaution is to wash hands thoroughly after handling the tissue to prevent contamination.
Step 6
Explain why the circulatory system of a frog is less efficient at carrying oxygen to the tissues than the circulatory system of a human.
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Answer
The frog's circulatory system is less efficient because it has only one ventricle and three chambers, allowing for mixing of oxygenated and deoxygenated blood. In contrast, a human's system, with two ventricles and four chambers, keeps these blood types separate, ensuring more efficient oxygen transport to body tissues.
