What function is maintained as a result of the release of HCG?

A. Production of milk by the mammary glands

B. Release of oxytocin by the posterior pituitary gland

C. Production of FSH by the anterior pituitary gland

D. Production of progesterone by the ovary

What sequence shows the route taken by nitrogenous wastes in insects from their production in body cells to their removal from the insect’s body?

A. Hemolymph → Malpighian tubule → hindgut → rectum

B. Hindgut → hemolymph → kidney tubule → bladder

C. Malpighian corpuscle → nephron → ureter → bladder

D. Neonicotinoid → rectum → antagonistic muscles → anus

Which hormone is inhibited during pregnancy in order to prevent contractions of the uterus?

A. Oxytocin

B. Progesterone

C. Estrogen

D. FSH

The diagram represents a sarcomere. Which structure is myosin?

[Source: MPI of Molecular Plant Physiology. [Sarcomere]. [diagram online] Available at: http://www.macroevolution.net/sarcomere.html [accessed 4 April 2019]. Source adapted.]

Which kidney adaptation would be expected in the desert kangaroo rat (Dipodomys deserti)?

A. Increased nephron density
B. Longer proximal convoluted tubule
C. Longer loop of Henle
D. Increased ADH receptors on the collecting duct

 

Hybridoma cells are produced in laboratories for medical diagnostics and treatments. Which two cells are fused to produce a hybridoma cell?

A. Gametes from two phenotypically different parents

B. Two different antigen-secreting cells

C. Two different tumour cells

D. A plasma cell and a tumour cell

Hormones maintain the thickness of the endometrium during pregnancy. However, insufficient levels of hormones in early pregnancy may cause the breakdown of the endometrium, which leads to miscarriage. What could be a cause of miscarriage in early pregnancy?

A. The embryo does not produce enough HCG.

B. The pituitary gland does not produce enough FSH.

C. The endometrium does not produce enough progesterone.

D. The ovarian follicle does not produce enough estrogen.

The pregnancy test for humans is based on detection of the hormone HCG. What is the reason for detection of this hormone indicating pregnancy?

A. HCG is involved in milk production.

B. HCG production is blocked by negative feedback during menstruation.

C. HCG is produced by an embryo.

D. HCG is released during the acrosome reaction.

The micrograph shows a glomerulus and Bowman’s capsule, where ultrafiltration takes place in the kidney.

[Source: MICROSCAPE/SCIENCE PHOTO LIBRARY.]

What facilitates the formation of glomerular filtrate?

A. Many fenestrations in walls of capillaries in the glomerulus

B. High pressure in the Bowman’s capsule

C. ADH secreted by the pituitary gland

D. Osmosis caused by a high concentration of urea in the blood

What is the role of calcium in muscle contraction?

A. To release tropomyosin from myosin

B. To bind to troponin so myosin-binding sites on actin are exposed

C. To bind to tropomyosin so ATP can bind to actin

D. To release ATP from actin so myosin can bind to troponin

The image shows a flow chart.

Which sequence would correspond to the stages shown in the flow chart?

If the ovaries of a pregnant woman have to be removed during the first five months of pregnancy, a miscarriage results and the pregnancy fails. If the ovaries are removed in the last four months of pregnancy, the miscarriage does not occur. What is the reason for this?

A.  After the fifth month, the ovaries can regenerate rapidly.

B.  The pituitary gland takes over the function of sustaining the pregnancy.

C.  The placenta produces sufficient hormones to sustain the pregnancy.

D.  Before removal the ovaries produce sufficient hormones to sustain the pregnancy.

The diagram shows the female reproductive system.

[Source: © International Baccalaureate Organization 2017]

Which structures do K and L identify?