Extension Worksheet Chapter 11

Cambridge Biology for the IB Diploma

Extension worksheet – Chapter 11

1Copy and complete the following paragraph, which describes spermatogenesis and oogenesis, by filling in the missing words. (15)

Sperm formation takes place in the walls of the ______of the ______. Outer cells multiply by ______, and then undergo a period of growth before undergoing division by ______. The developing sperm cells complete their development while attached to ______cells. Spermatogenesis is a continuous process that begins at ______and continues until death.

In oogenesis, the multiplication phase takes place in the ______of the fetus. Several thousand primary oocytes are produced and remain in ______. No further development occurs until ______, when the menstrual cycle begins. Each month, one or two ______develop into mature follicles. At ______, a mature follicle ______and releases the ______into the oviduct. This will only undergo the second division of meiosis to become a haploid ovum if ______occurs. Oogenesis in women ceases after the ______.

2The graph below shows how concentrations of antibiotic in infected tissue vary over time for three different methods of administration.

aSuggest reasons for the different patterns of concentration in infected tissue that result from giving the person the antibiotic in different ways. (3)

bDistinguish between the terms ‘antibody’ and ‘antibiotic’.(2)

cExplain why antibodies may sometimes be injected into a person.(2)

3aThe sliding filament hypothesis proposes a mechanism for muscle contraction. Copy and complete the paragraph, which describes the process. (7)

Prior to muscle contraction, ATP binds to heads of ______so they are primed. When an action potential arrives, ______ions are released from the ______. These ions cause the removal of blocking molecules so that ______can bind to the ______filament. As a muscle contracts, ______filaments slide past ______filaments towards the centre of the sarcomere.

bDraw a diagram to show the appearance of the banding pattern in a myofibril before and after the events described above. (3)

4The kidney is important in both excretion and osmoregulation.

aCopy and complete the table to identify the region or regions of the kidney nephrons where various processes occur. (4)

Process / Region(s) of the kidney
water regulation influenced by ADH
selective reabsorption of glucose and amino acids
water reabsorption
ultrafiltration

bDiabetes insipidus is a type of diabetes caused by a lack of ADH. Predict the symptoms of this disease from your knowledge of the function of the kidney and the role of ADH.
(2)

5aThe concentrations of FSH and LH in the blood of a woman increase when the ovaries are removed or after menopause. Suggest a reason for this. (1)

bCompare the structures of the human sperm cell and egg cell and give a reason for each difference. (4)