NSC Life Sciences Human Reproduction: 3.1 Describe the role of auxins

Question

3.1 Describe the role of auxins in phototropism when a plant is exposed to unilateral light.

3.2 The FSH test is sometimes used to determine the cause of infertility in females. The levels of FSH usually indicate the number of follicles in the ovaries. If the number of follicles are low or depleted, the pituitary gland will secrete more FSH.

An investigation was conducted to compare the average FSH levels in 4 different age groups.

The procedure was done as follows:

1 000 females were asked to participate (250 in each of the four age groups),

The females were all healthy and not using any hormone-based contraceptives.

Their blood FSH levels were measured on day 3 of the menstrual cycle for 5 cycles.

The average FSH levels in their blood were calculated per age group.

The results are shown in the table below:

AGE GROUP        | AVERAGE FSH LEVELS
------------------|-------------------
20–32            | 7,0
33–35            | 7,8
36–40            | 8,0
41–50            | 6,9

3.2.1 State TWO factors, regarding the females, that should have been kept constant during the investigation.

3.2.2 State TWO ways in which the reliability of the results was ensured.

3.2.3 State ONE conclusion that can be drawn from the results.

3.2.4 Explain why the oestrogen levels may remain low in the blood of the females in the 41–50 age group.

3.2.5 Explain why females that were using progesterone-based pills were excluded from the investigation.

3.3 Describe the development of the placenta and umbilical cord from the time of implantation.

3.4 The diagram below represents part of the human ear with a middle-ear infection.

3.4.1 Identify part:

(a) B

(b) D

3.4.2 State ONE function of part A.

3.4.3 Explain how middle-ear infection could affect hearing.

3.4.4 Describe the role of the Eustachian tube.

3.4.5 Name the small device that is used in the treatment of middle-ear infection.

3.4.6 Write down the LETTER of the part where the small device, named in QUESTION 3.4.5, is inserted.

3.4.7 Describe how part E is involved in maintaining balance when there is a change in the speed and direction of movement of the head.

3.5 Type I diabetes mellitus is caused by pancreatic cells which cannot produce insulin.

In type II diabetes mellitus the pancreas does secrete insulin, but the body cells are resistant to the effect of insulin.

To diagnose if a person has type I or type II diabetes mellitus, the following tests may be conducted:

- The blood glucose level is tested after fasting (the person is not allowed to eat or drink for 6 hours before the test). If the blood glucose level is above 126 mg/dl, the person is diabetic.
- The person is then given a glucose solution to drink and the blood glucose level is tested after 2 hours.
- The blood is also tested for the presence of GAD antibodies. The presence of GAD antibodies would indicate that the body is destroying the insulin-producing pancreatic cells.
- The levels of C-peptide are measured. This is a substance produced by the same pancreatic cells that produce insulin. If the levels are below 0,3 ng/ml then the person is diabetic.

3.5.1 Name the cells in the pancreas that secrete insulin.

3.5.2 Explain which type (I or II) of diabetes mellitus would be indicated by:

(a) Presence of GAD antibodies in the blood.

(b) C-peptide levels at below 0,3 ng/ml.

3.5.3 Give ONE reason why a diabetic person may experience hypoglycemia.

3.1 Describe the role of auxins in phototropism when a plant is exposed to unilateral light - NSC Life Sciences - Question 3 - 2022 - Paper 1

Worked Solution & Example Answer:3.1 Describe the role of auxins in phototropism when a plant is exposed to unilateral light - NSC Life Sciences - Question 3 - 2022 - Paper 1