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a) i) Kill microorganisms;
ii) Flame heating ; use of disinfectant;
b) I - enzyme diastase in germinating seed hydrolysed / digested starch in nutrient agar; forming simple sugars;
II- Salivary amylase converted starch in nutrient agar into maltose;
III-Enzyme maltase is inactivated; by pH / acidic medium ;
sharon kalunda answered the question on May 24, 2019 at 07:48
- 50cm³ of 10% glucose solution was boiled and allowed to cool. The solution was then poured into a vacuum flask and about
5cm³ of groundnut oil...(Solved)
50cm³ of 10% glucose solution was boiled and allowed to cool. The solution was then poured into a vacuum flask and about
5cm³ of groundnut oil added to it. 10% yeast solution was introduced into the glucose solution using a pipette. A
thermometer was placed in the flask and supported with a cotton wool plug. A second flask was set up as above, but
containing cooled boiled water instead of 10% glucose solution. The temperature of each flask was recorded at the
beginning and thereafter at hourly intervals for several hours.
a) Why was a vacuum flask used in this experiment?
b) What was the purpose of the second flask?
c) Write a word equation to summarize the reaction that took place in the first flask.
d) Why was groundnut oil added to the flask?
e) Why was it necessary to boil the glucose and the water before they were poured into the flask?
Date posted: May 24, 2019. Answers (1)
- Distinguish between obligate and facultative anaerobes.(Solved)
Distinguish between obligate and facultative anaerobes.
Date posted: May 24, 2019. Answers (1)
- Haemophilia is a bleeders disease. The disease is caused by a recessive gene which is carried in the X chromosome. XH
stands for normal gene whereas...(Solved)
Haemophilia is a bleeders disease. The disease is caused by a recessive gene which is carried in the X chromosome. XH
stands for normal gene whereas Xh stands for haemophilia gene. The figure below shows a family tree.
a) What is the genotype of
i) Mother
ii) Son marked 2
iii) Daughter marked 1
b) If the haemophilia son marries a girl who has no history of haemophilia in her family, what will be the genotype of the
offspring ? (Show your working)
Date posted: May 24, 2019. Answers (1)
- The diagram below represents recycling of nutrients in a certain ecosystem.
a) Name the trophic level represented by M.
b) Name the processes represented by. I,II,III...(Solved)
The diagram below represents recycling of nutrients in a certain ecosystem.
a) Name the trophic level represented by M.
b) Name the processes represented by. I,II,III
c) Name the organisms involved in process II.
d) What would happen within the ecosystem if all secondary consumers were eliminated?
Date posted: May 24, 2019. Answers (1)
- State ONE cause of variations in organisms that take place during gametogenesis.(Solved)
State ONE cause of variations in organisms that take place during gametogenesis.
Date posted: May 24, 2019. Answers (1)
- What is the meaning of the following terms?
i) Fermentation.
ii) Oxygen debt.(Solved)
What is the meaning of the following terms?
i) Fermentation.
ii) Oxygen debt.
Date posted: May 24, 2019. Answers (1)
- Name the cell organelles that are responsible for the formation of the following organelles.
i) Lysosomes
ii) Ribosomes(Solved)
Name the cell organelles that are responsible for the formation of the following organelles.
i) Lysosomes
ii) Ribosomes
Date posted: May 24, 2019. Answers (1)
- State one disadvantage of using quadrat method in population estimation.(Solved)
State one disadvantage of using quadrat method in population estimation.
Date posted: May 24, 2019. Answers (1)
- The following diagram shows a feeding relationship in an ecosystem.
From the diagram, write down a food chain with crocodile as the tertiary consumer.
(Solved)
The following diagram shows a feeding relationship in an ecosystem.
From the diagram, write down a food chain with crocodile as the tertiary consumer.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents the internal structure of a bean seed.
a) Name the parts the seed embryo represented by letter X and Y.
b) What...(Solved)
The diagram below represents the internal structure of a bean seed.
a) Name the parts the seed embryo represented by letter X and Y.
b) What type of germination would result if the hypocotyl elongates faster.
c) What is the significance of the part labelled Y emerging first during germination.
Date posted: May 24, 2019. Answers (1)
- Plants of a particular species growing in certain habitat flower at the same time. What is the importance of this adaptation.(Solved)
Plants of a particular species growing in certain habitat flower at the same time. What is the importance of this adaptation.
Date posted: May 24, 2019. Answers (1)
- Describe how osmotic pressure develops.(Solved)
Describe how osmotic pressure develops.
Date posted: May 24, 2019. Answers (1)
- What is carapace?(Solved)
What is carapace?
Date posted: May 24, 2019. Answers (1)
- An investigation was carried to show the effect of antidiuretic hormone (ADH) on urine production in a mammal. The rate of urine production was measured...(Solved)
An investigation was carried to show the effect of antidiuretic hormone (ADH) on urine production in a mammal. The rate of urine production was measured over a period of 30 minutes. Five minutes after measurements began; ADH was injected into a vein of the mammal. The results are shown in table below.
a) Plot a graph of rate of urine production against time.
b) Name the gland that releases ADH.
c) Describe the effect of injection of ADH on the rate of urine production in the mammal in this investigation.
d) Describe the mechanism by which ADH produces the effect seen in this investigation.
e) In a similar investigation, an injection of sodium chloride (salt) solution was given after five minutes instead of ADH. This injection was observed to affect urine production in a similar way to ADH. Suggest how the sodium chloride brought about this effect.
Date posted: May 24, 2019. Answers (1)
- State any two differences between an ovum and a sperm.(Solved)
State any two differences between an ovum and a sperm.
Date posted: May 24, 2019. Answers (1)
- Differentiate between Monoecious and Dioecious plant.(Solved)
Differentiate between Monoecious and Dioecious plant.
Date posted: May 24, 2019. Answers (1)
- State two ways in which male parts of a wind pollinated flower are adapted to their mode of pollination.(Solved)
State two ways in which male parts of a wind pollinated flower are adapted to their mode of pollination.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents a mature fruit from a dicotyledonous plant. Observe it and answer questions that follow.
i) To what group of fruits does the...(Solved)
The diagram below represents a mature fruit from a dicotyledonous plant. Observe it and answer questions that follow.
i) To what group of fruits does the specimen belong? .
ii) Suggest the possible agent of dispersed of the fruit.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents the nitrogen cycle.
a) State the process labelled.
A
D
b) Name the compound represented by B.
c) Name the group of organisms labelled...(Solved)
The diagram below represents the nitrogen cycle.
a) State the process labelled.
A
D
b) Name the compound represented by B.
c) Name the group of organisms labelled C.
d) i) Name the group of plants which promote process A.
ii) State the part of the plant where process A takes place.
e) How would excess pesticides in the soil interfere with process A.
Date posted: May 24, 2019. Answers (1)
- The diagram below shows a certain cell. Use it to answer questions that follow.
a) Identify the structures labelled A, B, C and D.
b) With a...(Solved)
The diagram below shows a certain cell. Use it to answer questions that follow.
a) Identify the structures labelled A, B, C and D.
b) With a reason identify the kingdom from which the cell was obtained.
Kingdom.
Reason.
Date posted: May 24, 2019. Answers (1)