- Single-celled (unicellular) organisms like amoeba often reproduce asexually by mitosis.
Cancer- Cancer is caused by DNA mutations.
- Abnormal and uncontrolled cell division results in tumour formation.
- Tumours affect the functioning of the tissue or organ.
- Cancer cells can enter the bloodstream or lymph and spread to distant parts of the
body and form new tumours (metastasise). - Cancers are caused by substances called carcinogens.
- Carcinogens such as certain chemicals, radiation, viruses and genetics can be the cause
of certain cancers. - Cancers can be treated by various methods including surgery, radiation, chemotherapy
and traditional medicines.
4.6 End of chapter exercises DUMMY
Exercise 4 – 1:- Multiple answers are provided for each of the questions below. You are required to
choose the most appropriate answer for each question. Write down the letter only.
a) During which stage does DNA replication occur?- A) Prophase
- B) Anaphase
- C) Metaphase
- D) None of the above
b) Which of the following statements is correct?
- A) The chromosomes shorten and thicken during prophase
- B) The nucleolus reappears following telophase
- C) Interphase is characterised by little cellular activity, as the cell is resting to
prepare for the next mitotic event. - D) All of the above
c) Which of the following is not true?- A) Only plant cells grow a cell plate
- B) Animal and plant cells both contain centrioles
- C) Metaphase is is when the chromosomes line up on the equator of the cell
- D) All of the above
d) There are two copies of DNA in the cell during:
- A) G 1 phase
- B) Telophase
- C) G 2 phase
- D) All of the above
112 4.6. End of chapter exercises