Isotonic solution;
sharon kalunda answered the question on May 27, 2019 at 12:58
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An experiment was carried out in which red blood cells were put in salt solutions of different concentrations. The table below shows the percentage of...
(Solved)
An experiment was carried out in which red blood cells were put in salt solutions of different concentrations. The table below shows the percentage of cells which were destroyed by haemolysis in different salt concentration.
(a) Draw a graph of percentage of red blood cells haemolysed against salt concentration.
(b) Explain haemolysis of red blood cells.
(c) From the graph, state:
(i) the salt concentration at which 50% red blood cells were haemolysed.
(ii) the highest salt concentration when the largest number of red blood cells were haemolysed.
(d) (i) Suggest the normal salt concentration in the blood of the mammal from which the red blood cells were obtained.
(ii) Give a reason for your answer in (d) (i) above.
Date posted:
May 27, 2019
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Answers (1)
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A pea plant with smooth seeds was crossed with one with wrinkled seeds. The gene for smooth seeds is dorminant over that for wrinkled seeds....
(Solved)
A pea plant with smooth seeds was crossed with one with wrinkled seeds. The gene for smooth seeds is dorminant over that for wrinkled seeds. Use letter R to represent the dorminant.
(a) State the genotype of the parents if the plant with smooth seeds was heterozygous.
(b) State the gametes produced by the smooth seeds and wrinkled seeds parents.
(c) State the genotype and phenotype of F1 generation. Show your working.
Date posted:
May 27, 2019
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Answers (1)
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The table below shows the number of Leopards and Impala in a grassland park over a period of six years.
(a) (i) What is the average...
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The table below shows the number of Leopards and Impala in a grassland park over a period of six years.
(a) (i) What is the average number of Impala in the park during the six years.
(ii) Account for the decrease in the number of leopards between the 4th and 6th year?
(b) Identify the trophic level occupied by
(i) Leopards
(ii) Tick feeding on the leopard.
(c) The two pyramids shown were obtained in the park.
Identify each type of pyramid.
Date posted:
May 27, 2019
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Answers (1)
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Study the diagram shown below of the anterior view of a lumbar vertebra of a mammal.
(a) Name the parts labelled: A,B,C
(b) State the function...
(Solved)
Study the diagram shown below of the anterior view of a lumbar vertebra of a mammal.
(a) Name the parts labelled: A,B,C
(b) State the function of the part labelled D.
(c) State three roles of skeletons in organisms.
(d) State how the part labelled D in adapted for the function stated in (b) above.
Date posted:
May 27, 2019
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Answers (1)
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The graph below shows rates of photosynthesis in a plant at different temperatures.
(a) Account for the decrease in the rate of product formation at 410C...
(Solved)
The graph below shows rates of photosynthesis in a plant at different temperatures.
(a) Account for the decrease in the rate of product formation at 410C from 5 to 20 minutes.
(b) Explain the results obtained at
(i) 250C.
(ii) 360C.
(c) (i) Other than temperature, state one external factor that affect the rate of photosynthesis.
(ii) Suggest the product which could have been used in the experiment.
Date posted:
May 27, 2019
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Answers (1)
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The diagram below shows a model of the nephron of a mammalian kidney.
(a) Which parts of the nephron are represented by the:
(i) Syringe?
(ii) Perforated rubber...
(Solved)
The diagram below shows a model of the nephron of a mammalian kidney.
(a) Which parts of the nephron are represented by the:
(i) Syringe?
(ii) Perforated rubber tubing?
(iii) Free rubber tubing?
(b) Name the type of filtration taking place within the perforated rubber tubing.
(c) What would happen to the contents of the syringe if its handle was slowly pushed forward? Explain.
Date posted:
May 27, 2019
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Answers (1)
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The picture below shows series of beaks in birds.
a) State the type of evolution that may have led to the emergence of the different beaks...
(Solved)
The picture below shows series of beaks in birds.
a) State the type of evolution that may have led to the emergence of the different beaks shown on the pictures above.
(b) Name the type of evolution structure represented by the beaks shown on the pictures above.
(c) Observe the pictures carefully. From your observations, what features are responsible for the different types of beaks?
(d) Suggest the type of food likely eaten by birds whose beaks are shown in pictures A, B, C and D.
(e) Briefly state how beak shown in picture A is adapted to feeding.
Date posted:
May 27, 2019
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Answers (1)
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You have been provided with photographs of specimens labelled Q1, Q2 and Q3. Examine them.
a) By using observable features only, state the phylum and class...
(Solved)
You have been provided with photographs of specimens labelled Q1, Q2 and Q3. Examine them.
a) By using observable features only, state the phylum and class to which the specimens belong. By using the three specimens, give reasons for each case.
(a) Phylum
Reasons
(b) Class
Reasons
(c) Using observable features only, give three differences between specimen Q1 and Q3.
(d) (i) Apart from locomotion, state the other role of the hind limbs of specimen Q1.
(ii) How are the hind limbs of specimen Q1 adapted to perform role named in d (i) above.
Date posted:
May 27, 2019
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Answers (1)
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Study the photographs below and answer the questions below.
(i) To which phylum does organisms x,y and z belong to.
(ii) Name the classes to which...
(Solved)
Study the photographs below and answer the questions below.
(i) To which phylum does organisms x,y and z belong to.
(ii) Name the classes to which X, Y and Z belongs to.
(iii) Give two important economic roles of specimen Y.
(iv) Give three harmful effects of specimen X to animals.
(v) With reasons identify two modes of locomotion of specimen Y .
Date posted:
May 27, 2019
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Answers (1)
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Describe the effects of the various abiotic factors in a terrestrial ecosystem to plants.
(Solved)
Describe the effects of the various abiotic factors in a terrestrial ecosystem to plants.
Date posted:
May 27, 2019
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Answers (1)
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Describe the role of the mammalian liver in carbohydrate metabolism.
(Solved)
Describe the role of the mammalian liver in carbohydrate metabolism.
Date posted:
May 27, 2019
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Answers (1)
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In an experiment, lactic acid concentration was measured before, during and after exercise to determine the effect of exercise on the concentration of lactic acid...
(Solved)
In an experiment, lactic acid concentration was measured before, during and after exercise to determine the effect of exercise on the concentration of lactic acid in blood. Study the data obtained and use it to answer the questions that follow.
a) Plot a graph of the concentration of lactic acid against time using a suitable scale. (6 marks)
b) From the graph:
i) Determine the period of exercise.
ii) Explain
c) i) Determine the time when oxygen debt incurred.
ii) Explain
d) i) The duration it took to pay back the oxygen debt
ii) Explain
e) Plot a hypothetical curve for oxygen intake during the experimental period on the same axes.
f) Why does lactic acid level usually continue to rise in the blood after the exercise ceases?
g) State two of effects of lactic acid on tissues.
Date posted:
May 27, 2019
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Answers (1)
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Name the gland associated with the secretion of aldosterone hormone.
(Solved)
Name the gland associated with the secretion of aldosterone hormone.
Date posted:
May 27, 2019
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Answers (1)
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The diagram below is a longitudinal section of an organ in mammals.
a) Name the organ.
b) Identify the parts R and S.
c) i) State three...
(Solved)
The diagram below is a longitudinal section of an organ in mammals.
a) Name the organ.
b) Identify the parts R and S.
c) i) State three differences in the structure above found in the desert rat and fish.
ii) Account for the differences stated above.
(d) Name the gland associated with the secretion of aldosterone hormone.
Date posted:
May 27, 2019
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Answers (1)
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The diagram below is a cross section of a portion of alimentary canal.
a) i) Which part of the alimentary canal is represented by the portion...
(Solved)
The diagram below is a cross section of a portion of alimentary canal.
a) i) Which part of the alimentary canal is represented by the portion above.
ii) Give a reason for your answer in (a) (i) above.
b) i) State two functions of the part of alimentary canal represented above.
ii) Explain two structural adaptations of the part of alimentary canal represented above.
Date posted:
May 27, 2019
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Answers (1)
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The colour of tips of hair in Shepherd dog is controlled by a gene with three alleles B for Black, R for red and C...
(Solved)
The colour of tips of hair in Shepherd dog is controlled by a gene with three alleles B for Black, R for red and C for copper.
A cross between pure breeding red and copper hair tips produce offsprings with scarlet hair tips. Crossing pure breeding
red and black hair tips yields all red offsprings. A cross between pure breeds of copper and black produce offsprings that
are all copper.
a) Comment on the inheritance of the three alleles B, R and C.
b) A dog breeder wishes to know the genotype of a dog with red hair tips. State and explain the cross needed to determine
the dog’s genotype.
c) A mother of blood group AB was married to a man of blood group B heterozygous. What is the probability that one of
their sons would be blood group A? Show your working.
Date posted:
May 27, 2019
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Answers (1)
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Give three types of movable joints found in mammalian skeleton.
(Solved)
Give three types of movable joints found in mammalian skeleton.
Date posted:
May 27, 2019
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Answers (1)
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Distinguish between exocrine and endocrine glands.
(Solved)
Distinguish between exocrine and endocrine glands.
Date posted:
May 27, 2019
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Answers (1)
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What is the significance of the high tail power in fish locomotion.
(Solved)
What is the significance of the high tail power in fish locomotion.
Date posted:
May 27, 2019
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Answers (1)
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The length from tail tip to the anus in a fish is 8cm whereas that from tail tip is 24cm. Calculate the tail power of...
(Solved)
The length from tail tip to the anus in a fish is 8cm whereas that from tail tip is 24cm. Calculate the tail power of the fish.
Date posted:
May 27, 2019
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Answers (1)