1. What is a "prokaryotic cell" ?
Answer
Has genetic material not enclosed in a nucleus.
2. Plant and algal cells have cell walls. What is their cell wall made of ?
Answer
It is made of cellulose.
3. What is meant by the "resolution" of a microscope ?
Answer
The resolution is the shortest distance between two points or lines that can be distinguished.
4. The figure below shows a plant cell. Name the structures labelled A, B and C.
Answer
5. Suggest one reason why prokaryotic cells do not have mitochondria.
Answer
Prokaryotic cells are too small to contain mitochondria.
6. Describe two ways that the genetic material is arranged differently in prokaryotic and eukaryotic cells.
Answer
Prokaryotic genetic material is free-floating, often in a single loop with plasmids, while eukaryotic genetic material is enclosed in a nucleus, organized into linear chromosomes and lacks plasmids.
7. Give two reasons why electron microscopes are used to study cells in finer detail than light microscope.
Answer
Electron microscopes have a much higher magnification and a greater resolving power.
8. Describe at least three of the structures and functions of specialised animals cells.
Answer
Sperm cell function is to fertilise an egg cell (ovum) so it has a tail to swim to ovum and large numbers of mitochondria to provide energy for swimming.
Nerve cell function is to conduct electrical impulses so it has a long axon to conduct impulses over long distances and myelin sheath to insulate and speed up nerve impulse.
Muscle cell function is to contract and cause movement so it has many mitochondria to provide energy for contraction.
9. Name the parts of the microscope labelled A–E.
Answer
10. Name the process of simple cell division in bacteria and give two conditions that support rapid division.
Answer
The process is called binary fission. Rapid division happens when there are enough nutrients and a suitable temperature.
11. A student investigates antibiotic effects using an uncontaminated bacterial culture. They place antibiotic-soaked paper discs on an agar plate and measure the zones of inhibition. The bacteria divide every 40 minutes. Starting from one cell, calculate the population after 24 hours. Give your answer in standard form.
Answer
The mean division time is 40 minutes and 24 hours equals 1440 minutes. This means the number of divisions in 24 hours is