BIOLOGY
PAPER 3
TIME: 2¼ HOURS.
Instructions to candidates
- Answer all the questions
- You are required to spend the first 15 minutes of the 1/4 hours allowed for this paper reading the whole paper carefully before commencing your work
- You are provided with 20% glucose solution about 2.0grams of substance labeled J and solution labeled K place 20cm3 of glucose solution in a boiling tube. To the boiling tube add 2.0g of substance. Tightly fit a rubber stopper carrying a delivery tube to the boiling tube. Place the boiling tube in a water bath maintained at 350 to 40°C. Place the delivery tube into a test tube containing 1.0cm of solution K. Allow the set up to stand for twenty minutes.
- Record your observations (2mks)
- What conclusion would you draw for your observations in (a) above? (2mks)
-
- Name the biological process that took place in the boiling tube(2mks)
- Explain the process you have named in c(i)(2mks)
- Suggest the identity of J (1 mk)
-
- Suggest a reason why the temperature range in this experiment was maintained between 35° and 40° (2mks)
- With reasons, suggest the expected results if the experiment was performed at (4mks)
0°C
Reason
100°C
Reasons
- Examine the seedling below and use them to answer the questions that follow
- Name the parts labeled C, D, E and state their importance for the seedling.
C(1mk)
Importance
D:(1mk)
Importance
E: (1mk)
Importance - The R series of seedlings form swellings on the roots later in its life.
- What is the name of the swellings our ten (1mk)
- Name the organisms that would be found in the swellings (1mnk)
- Explain the relationship that exists between the named organisms and the plant. (2mks)
-
- State the types of germination exhibited by R series of the seedlings (1mk)
- Give a reason for your answer in c) (i) above. (1mk)
- State any two external factors necessary for germination (2mks)
- Name the parts labeled C, D, E and state their importance for the seedling.
- Below is a photograph obtained from the pelvic region of a human being, and showing some bone of the vertebral column. Examine it
- Name the bones labeled 1, 2 and 3 on the photograph (3mks)
-
- Name the type of joint formed at the proximal end bone 3 as it articulates with the adjacent bone (1mk)
- Give an observable feature on bone 3 for your answer in (b) (i) above (1mk)
-
- Name the part labeled Q:(1mk)
- Give TWO functions of the part named in c (i) above (2mks)
- Indicate on the above diagram the position of pubis symphysis (1mk)
- Using observable features only, state how bone l as adapted to its functions (4mks)
MARKING SCHEME
-
- Record your observations.
- Bubbling/effervescence/ fizzing gas formed
- White precipitate in solution K.
- What conclusion would you draw for your observation in (a) above?
- Gas produced is carbon (IV) oxide;
- Solution K is lime water/ calcium hydroxide
-
- Name the biological process that took place in the boiling tube
- Anaerobic respiration/ fermentation
- Anaerobic respiration/ fermentation
- Explain the process you have named in c (i)
- Glucose is broken down by enzymes (in yeast);
- Giving out Carbon (TV) oxide/ ethanol and energy.
- Suggest the identity of J.
- Yeast:
- Yeast:
- Name the biological process that took place in the boiling tube
-
- Suggest a reason why the temperature range in this experiment was maintained between 35° and40°.
- It's the optimum temperature range for enzymatic reactions.
- It's the optimum temperature range for enzymatic reactions.
- With reasons, suggest the expected results if the experiment was performed at
- 0ºC.
- No reaction/ slow reaction
- No. CO, produced
- less CO
- Reason
- at this temperature, enzymes are inactive
- at this temperature, enzymes are inactive
- 100°C
- No reaction/ reaction stopped/
- no CO, produced
- rej. no change;
- Reason
- Enzymes are denatured/ yeast cells killed
- rej. Yeast cells denatured.
- 0ºC.
- Suggest a reason why the temperature range in this experiment was maintained between 35° and40°.
- Record your observations.
-
- Name the parts labeled C, D, E and state their importance for the seedling
- C:
- Hypocotyl - protects the plumule/ shoot vip/ opens path for cotyledons to pass through the soil -
- D-Cotyledons/ Seed leaves -
- Photosynthesis; storage of food
- E-Coleoptile/ plumule Sheath-Protects delicate tip/first leaves/ foliage leaves
-
- What is the name of the swellings .
- Root nodules
- Root nodules
- Name the organisms that would be found in the swellings -
- Rhizobium bacteria;
- Rhizobium bacteria;
- Explain the relationship that exists between the named organisms and the plant
- Symbic tic relationships were the bacteria get protection and nutrient while the points get nitrates fixed by bacteria.
- Symbic tic relationships were the bacteria get protection and nutrient while the points get nitrates fixed by bacteria.
- What is the name of the swellings .
-
- State the types of germination exhibited by R series of the seedlings
- Epigeal
- Epigeal
- Give a reason for your answer in c (1) above
- Cotyledons are brought out of the ground
- Cotyledons are brought out of the ground
- State the types of germination exhibited by R series of the seedlings
- State any two external factors necessary for germination
- Water
- Oxygen
- Optimum temperature
- Name the parts labeled C, D, E and state their importance for the seedling
-
- Name the bones labeled 1, 2, and 3 on the photograph
- -Tlium -
- Pubis -
- Femur
- .
- Name type of joint found at the proximal end bone 3 as it articulates with the adjacent bone
- Ball and socket
- Ball and socket
- Give an observable feature on bone 3 for your answer in (b) (i) above
- Ball like head/Rounded head;
- Name type of joint found at the proximal end bone 3 as it articulates with the adjacent bone
-
- Name the part labeled Q.
- Lumbar vertebra;
- rej. vertebrae
- Give two functions of the part named above
- Attachment of abdominal muscles
- Supports the animals weight
- Name the part labeled Q.
- Indicate on the above diagram the position of pub symphysis
- Pubis Bynphysis
- Pubis Bynphysis
- Using observable features only, state how bone I is adapted to its functions
- Broad/ wide to provide large surface area for muscle attachment Has broad sacral facet; that attaches it to the terrace process of first sacral vertebrae;
- Name the bones labeled 1, 2, and 3 on the photograph
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