A midwife uses Fig. 1 to explain growth from fertilisation to birth. The diagram shows four stages but the time scale is not uniform. fertilised ovumcells d...
Question 1 Report
A midwife uses Fig. 1 to explain growth from fertilisation to birth. The diagram shows four stages but the time scale is not uniform.
(a) Name the process that causes the fertilised ovum to become a group of cells. [1]
(b) Describe two changes in the developing human between the embryo stage and birth. [2]
(c) Explain why cells in the developing fetus become specialised. [3]
(d) State two substances transferred from the mother to the fetus across the placenta. [2]
(e) Which structure carries blood from the fetus to the placenta? [1]
Answer Details
(a) The fertilised ovum becomes a group of cells by mitosis, or cell division. [1]
(b) Between the embryo stage and birth, the developing human increases greatly in size and organs develop. Development of limbs or other body features, and cell specialisation, are also acceptable changes. [2]
(c) Different types of cells are required to carry out different functions. During development, different genes are switched on, or expressed, in different cells. This produces specialised cells, which form tissues and organs. [3]
(d) Two substances transferred from mother to fetus across the placenta are oxygen and glucose. Amino acids and antibodies are also acceptable. [2]
(e) Blood travels from the fetus to the placenta in the umbilical artery. [1]
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