Download Biology TOPIC 2 – Cells

Solutions to Review Questions
1.
a. Answer: The cell would belong to kingdom Bacteria
Explanation: The cell lacks membrane bound organelles and possesses a single circular
chromosome.
b. Answer: Ribosomes
Explanation: Ribosomes are not membrane-bound so are found in prokaryotic cells.
c. Answer: Yes
Explanation: Enzymes are proteins, as ribosomes are the site of protein production the cell would
still be able to make enzymes
2. Answer: An autotroph is able to produce organic molecules from inorganic reactions while a heterotroph
has to consume other organisms to obtain organic molecules.
3. Answer: A
Explanation: Prokaryotic cells possess a single circular chromosome.
4. Answer: A
Explanation: Plant cells have a cell wall and contain a large central vacuole that pushes all of the other
organelles to the extremities of the cell.
5. Answer: B
Explanation: This is the large central vacuole, which takes up the majority of space inside a plant cell.
6. Answer: Apoptosis does not cause inflammation in surrounding cells due to the release of cytokines, it
also does not cause the cell to burst as the rupturing of the plasma membrane is controlled during
apoptosis. This means that nearby cells are less likely to be damaged.
7. Answer: Apoptosis is programmed cell death. In the formation of a tumour apoptosis is occurring at a
slower rate than the reproduction of new cells, which means that there is a buildup of cells, the tumour.
8. Answer: Phagocytes engulf and break down non-nuclear organelles, which help the body to dispose of
the cell without causing harm to the organism.
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9. Answer: B
Explanation: Some cells that are still able to function normally still undergo apoptosis such as in the
development of fingers and toes, which develop within groups of cells. The cells between the fingers and
toes are no longer necessary and as a result receive an external message to undergo apoptosis.
10.
a. Answer: Animal cell
Explanation: It lacks a cell wall so it is likely to be an animal cell. It could be a protist but it is
unlikely that you would be asked to identify a protist as they do not follow specific rules so it is
most likely to be an animal cell.
b. Answer: Mitochondria
Explanation: An organelle made up of folded membranes that are the site of cellular respiration.
c. Answer: Ribosome
Explanation: Ribosomes are small organelles that are not membrane bound. They are either
located in the cytosol or associated with endoplasmic reticulum. They are sites of protein
production.
11.
a. Answer: It is the site of photosynthesis
Explanation: As it is a green organelle, it is likely to be a chloroplast.
b. Answer: It provides the cell with structure and prevents the organism from collapsing.
Explanation: As it contains cellulose it would be the cell wall.
12. Answer: B
Explanation: The mitochondria are the site of cellular respiration which produces energy in the form of
ATP.
13. Answer: D
Explanation: Ribosomes are the smallest organelles and are thus the most difficult to observe under a
microscope.
14. Answer: Animal cells have lysosomes and centrioles, which are lacking in plant cells. This means that if
either of these are present the cell would be an animal cell.
15. Answer: D
Explanation: Not all plant cells have chloroplasts but all plant cells and no animal cell have cell walls.
16. Answer: A
Explanation: Lysosomes are membrane-bound vesicles that contain enzymes involved in the breakdown
of foreign material and are present in most animal cells.
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