Question 1
The diagram below shows the exchange site between circulatory system and body cells
a) State two adaptations of the capillaries
b) (i) Name the blood cells labeled B.
(ii) State the gas that diffuses from B to the tissue cells.
c) State two functions of the part labeled A.
d) Name the blood vessel with the highest concentration of;
(i) Oxygen.
(ii) Urea
Answer
a)
- Their walls are made up of an endothelium only which allows only part of the blood to move into the intercellular spaces
- Have narrow lumen that maintains high blood pressure
b) (i) Red blood cells;
(ii) Oxygen gas;
c) (i) Transport of food nutrients;Metabolic wastes;antibodies involved in defense against diseases;
(ii) Distribution of body heat
d) (i) Pulmonary vein;
(ii) Hepatic vein;
- Have narrow lumen that maintains high blood pressure
b) (i) Red blood cells;
(ii) Oxygen gas;
c) (i) Transport of food nutrients;Metabolic wastes;antibodies involved in defense against diseases;
(ii) Distribution of body heat
d) (i) Pulmonary vein;
(ii) Hepatic vein;
Question 2.
The diagram below shows how blood glucose in mammalian body is regulated
(a) Name the hormone X and Y
(b) State two ways by which hormone X lowers glucose level in the blood when it rises above 90mg/100ml
(c) Name the organ that produces hormone Y
(d) Suppose there is deficiency of hormone X, state the disease the person would suffer from
(e) Explain how the disease mentioned in (d) above can be controlled
Answer
(a) X – Insulin;
Y – Glucagon
(b) – Stimulates conversion of glucose to glycogen/fats;
– Oxidation of glucose to release energy
(c) Pancreas
(d) Diabetes mellitus
(e) Regular insulin injection; with controlled diet and exercise
Y – Glucagon
(b) – Stimulates conversion of glucose to glycogen/fats;
– Oxidation of glucose to release energy
(c) Pancreas
(d) Diabetes mellitus
(e) Regular insulin injection; with controlled diet and exercise
Question 3
In human beings, a downward pointed frontal hairline (“windows peak”) is a heritable trait. A person with windows peak always has at least one parent who has his trait; whereas persons with frontal hairline may occur in families in which one or even both parents have windows peak. Using B and b to symbolize genes for this trait.
a) Determination the f1 generation if a homozygous windows peak male parent is married to a Homozygous frontal hairline female parent
b) State two causes of variations.
c) Name two examples of discontinuous variation.
Answer
a)
b) - Gamete formation-independent assortment;
- Crossing over;
c) - Tongue rolling;
- Sex;
d) Are genes located on the sex chromosomes and are transmitted together with those that are transmitted together with those that determine sex
b) - Gamete formation-independent assortment;
- Crossing over;
c) - Tongue rolling;
- Sex;
d) Are genes located on the sex chromosomes and are transmitted together with those that are transmitted together with those that determine sex
Question 4
4. The drawing below represents a mature bread mould (rhizopus).Study it and answer the questions which follow.
a) Name the structures labeled A, B and C.
b) Identify the type of asexual reproduction represented in the diagram
c) Give one function of structure C
d) Define the term fertilization
e) Compare an ovum cell and a zygote
Answer
(a)
A - Sporangium;
B - Spore;
C - Rhizoid;
b) Sporulation/spore formation
c) Absorption of water and mineral nutrients from decaying materials
d) (i) Process by which female and male gamete nuclei fuse to form a diploid zygote
(ii)
A - Sporangium;
B - Spore;
C - Rhizoid;
b) Sporulation/spore formation
c) Absorption of water and mineral nutrients from decaying materials
d) (i) Process by which female and male gamete nuclei fuse to form a diploid zygote
(ii)
Question 5
The diagram below shows three different types of neurons along a reflex
a) Identify the neuron labeled 1, 2 and 3
b) Using arrow show the direction of impulse transmission on the diagram
c) Name the part of the spinal cord where the cell bodies of neuron 2 and 3 are located.
d) Describe the transmission impulses across the part labeled P
Answer
(a)
1 - Sensory /Afferent Neuron
2 - Relay/intermediate Neuron
3 - Motor/Efferent Neuron
b)
c) Grey matter
d) Impulse reaching the dendrite end of relay neuron causes the synaptic vesicle to release a acetylcholine;(transmitter substance) that diffuse across the cliff and causes the depolarization of the motor neuron
1 - Sensory /Afferent Neuron
2 - Relay/intermediate Neuron
3 - Motor/Efferent Neuron
b)
c) Grey matter
d) Impulse reaching the dendrite end of relay neuron causes the synaptic vesicle to release a acetylcholine;(transmitter substance) that diffuse across the cliff and causes the depolarization of the motor neuron