Questions
INSTRUCTIONS
- All Questions are Compulsory
- Wrong Spelling of Technical Terms shall be Penalized
- State TWO ways in which the study of Biology has helped the world in the accelerated fight against the recent Covid-19 pandemic. (2mks
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- Give ONE function of centrioles (1mk
- Name a Kingdom in which all members lack centrioles in their cells (1mk)
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- Name the skin pigment formed by cells in the mammalian skin
- Which genetic disorder is associated with the absence of the pigment named in 2a)?
- How does the skin pigment help protect human beings against skin cancer?(1mk)
- Explain the following observations
- More water hyacinth plants are found growing along the shore of Lake Victoria than in the deep waters (1mk)
- Green plants grow faster in lower altitudes areas than in higher altitude areas (2mks)
- State TWO functions of a cover slip in light microscope work (2mks)
- Use the diagram of the heart shown below to answer the questions that follow
- From the diagram, give a reason to show that X is the left ventricle (1mk)
- Name a class of organisms where all members have the heart structure above(1mk)
- Why are the muscles found in the heart above said to be myogenic? (1mk)
- Account for the following
- Red blood cells lack mitochondria (1mk)
- The testes are found hanging outside the body in male human beings (1mk)
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- Why is pancreas said to be a dual gland? (1mk)
- Name the endocrine tissue in the pancreas (1mk)
- A student made a set up shown below to study a physiological process
- In which beaker did the dialysis tubing reduce in size? (1mk)
- Account for your answer in a) above (2mks)
- The diagram below shows a graph of body temperature of two different organisms against changing environmental temperature
- State the name used to refer to animal A in terms of thermoregulation (1mk)
- State TWO advantages animal B has over animal A (2mks)
- The diagram shown below is of a flower
- Name the agent of pollination for this flower (1mk)
- Give TWO adaptive features from the diagram to support your answer in a) above (2mks)
- The process of gamete formation is represented below|
- State a reason why the process above represents gamete formation in female mammals (1mk)
- Name the chromosomal mutation represented above (1mk)
- Identify the genetic disorder that arise when the following gametes are fertilized
- P (1mk)
- Q .(1mk)
- A sample of air was passed through pyrogallic acid and its volume reduced from 8 cm3 to 7 cm3. When it was later passed through lime water, the volume reduced to 6.8cm3.
- What was the role of pyrogallic acid in this experiment? (1mk
- Determine the percentage of Carbon (IV) oxide in the sample of air (2mks
- Is this sample of air exhaled air or inhaled air? (1mk
- The stage-wise process of germination of a seed is shown below
- Give a reason why the diagram above represents hypogeal germination(1mk
- Account for the change in dry weight of the cotyledon at stage X and Y(2mks
- Barbra observed animal cells in a field of view of a light microscope as shown below. If she used a total magnification of X1000 determine the actual diameter of one cell(3mks)
- Explain the importance of the following features
- Acrosome in the spermatozoa(2mks)
- Hair-like structures in the fallopian tube(1mk)
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- What are vestigial structures?(1mk)
- Explain why divergent evolution is advantageous to living organisms?(2mks)
- The various stages of mitosis are represented below
- Identify the stages represented by the letters:
- D .(1mk)
- E (1mk)
- What shows that the process represented above is taking place in a plant cell?(1mk
- Identify the stages represented by the letters:
- The diagram shown below represents the various nerve cells
- Use arrows to show direction of impulse in a reflex arc in the diagram above (1mk
- Outline expected TWO structural differences between nerve cell R and X(2mks
- State the function of the following muscles in the body
- Cardiac sphincter muscles(1mk
- Erector pili muscles(1mk
- The diagrams below are of seedlings before and after an experiment.
- Under which light condition was the experiment carried out.(1mk
- Which term describes the appearance of the seedlings at the end of the experiment(1mk
- What is the importance of the above experiment in crop production?(1mk
- State the function of the following cells in the body of organisms
- Palisade.(1mk
- Schwann(1mk
- Sertoli(1mk
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- Mary suspects that she has diabetes mellitus. Using a sample of her urine describe a school laboratory procedure she can follow to confirm it is true(3mks
- Why is insulin not administered orally?(1mk
- The following is an illustration of a bone
- Give the name of the bone.(1mk
- State an advantage of the joint formed at the part labelled M(1mk
- State the function of the part labelled N.(1mk
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- Distinguish between population and community as used in ecological studies(2mks
- State the formula for population estimation using capture recapture method(1mk
- The diagram below shows the structure of germinating pollen grain
- Name the type of cell division that formed the parts labelled A(1mk)
- State the role of part labelled B(1mk)
- The picture of a common animal is represented below
- Name the class to which the organism shown above belongs.(1mk)
- Give TWO reasons for your answer in a) above(2mks)
- The following experimental set up was placed in sunshine to investigate a biological process
- Account for the expected result in the level of water in the beaker labelled B.(2mks)
- Why were the set up C and D included in the experiment?.(1mk)
Marking Scheme
- Knowledge on its cause; Knowledge on how the virus spreads; Increased knowledge on how to control the spread/containment measures; development of vaccines; global cooperation in research/fight against the virus; Mark 1st 2
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- Formation of Spindle fibers; Formation of flagella/cilia;
- Plantae; Monera;
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- Melanin
- Albinism;
- Absorbs UV/Ultraviolet rays;
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- Eutrophication/Enrichment of water by pollutants;
- Higher concentration of Carbon (IV) Oxide; thus higher rate of photosynthesis;
Conducive/Optimum temperatures; thus faster rate of metabolism\Activated enzymes;
- Exclude dust/contaminants; Prevent dehydration; Hold specimen in position; OWTTE
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- Thicker muscular wall;
- Mammalia; Aves;
- Contract without nervous stimulation/Initiate contraction on their own;
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- To prevent oxygen utillisation for efficient transport;
- To Create conducive/optimum temperature for sperm formation/ spermatogenesis;
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- Has endocrine and exocrine function/Forms both/ hormones and enzymes;
- Islet of Langerhans;
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- A;
- Sucrose solution is hypertonic; thus it gains water molecules by osmosis;
Accept: Water is hypotonic; thus water molecules move into the dialysis tubing by osmosis;
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- Poikilotherm; Accept Ectotherm/Ectothermic/Poikilothermic Rej cold blooded
- Can live in any habitat; Is More active both day and night;
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- Wind
- Long filament; Anthers hanging outside; Feather/Net-like stigma; Smaller bracts to allow the stigma/anthers to be exposed to wind;
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- Only X chromosomes are involved;
- Non-disjunction;
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- Turner’s Syndrome;
- Klinefelter’s Syndrome;
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- Remove Oxygen;
- % of CO2 =[(7cm3 – 6.8cm3) X 100] ÷ 8cm3; Deny if Units Omitted
= [0.2 cm3 X 100] ÷ 8cm3
= 2.5%; Deny if % symbol missing - Exhaled air;
- Cotyledon is found below the ground surface; elongated epicotyl;
- Decreases; since stored nutrients are hydrolyzed to facilitate growth/germination/cell division;
- 3cells measure 1.5mm
Therefore 1 cell will measure?
= (1cell X 1.5mm)/3cells; =0.5mm Deny if Units Omitted
Magnification = image length/actual length
Thus Actual length =image length/magnification
=05mm/1000; Deny if Units Omitted
=0.0005mm; Deny if Units Omitted -
- Release lytic enzymes; that Neutralize secretions/destroy/digest vitelline and cell membrane for entry of sperm head into the ovum;
- Waft/push the ovum/zygote/blastula towards the uterus;
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- Structures that have lost function thus become smaller;
- Development of necessary adaptations; to survive a give habitat/conquer different habitats;
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- D-Telophase;
- E-Anaphase
- Laying of a Cell plate/Cellulose deposits to separate the daughter cells; Centrioles/Spindle fibers are not involved/seen;
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- Differences
R X Unipolar Multipolar/Bipolar; Has Myelin Sheath Lacks Myelin Sheath; Has Nodes of Ranvier Lacks Nodes of Ranvier; Has Schwann cells Lacks Schwann cells; Long Axon Shorter axon;
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- Cardiac sphincter muscles: Relaxes to allow entry of food/food bolus into the stomach/Prevent exit of food from stomach to oesophagus/gullet;
- Erector Pili Muscles: Contracts and relaxes to make the body hairs straighten or lie flat on the body;
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- Low/dim; Accept darkness;
- Etiolation;
- Increase productivity of Dwarf plants;
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- Photosynthesis;
- Secretion of myelin sheath;
- Nourish young sperm cells; point of attachment of sperm cells as they develop;
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- Place 2ml of her urine in a boiling tube
Add Equal amount/2ml of Benedict’ solution;
Boil;
Green/Yellow/Orange/Brown colour change would show a positive test/result; - It may be digested (since it is protein in nature);
- Place 2ml of her urine in a boiling tube
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- Innominate bone/Half pelvic girdle; REJ Pelvic girdle alone
- Achieves movement in all planes; Achieves a 3600 rotation thus greater flexibility;
- Passage of blood vessels/nerve fibers to lower regions of the hind limbs; Reduces weight/density at the hip region;
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- Population is a group of organisms of same species found in the same place at the same time; while Community is different populations/group of animals and plants living in the same habitat; Award 0, 1 or 2 mrks
- Population = [First Marked X Second Capture] ÷ Marked Recaptured
REJ Abbreviations
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- Mitosis;
- Regulate Growth of pollen tube;
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- Mammalia; REJ Mammals/mammmalia/Mammmalian
- Body fur/hair; Heterodont dentition/Different types of teeth; Presence of Ear pinna; 1st 2
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- Remained the same; all the stomata blocked by jelly thus no water uptake/loss/transpiration;
- Act as a Control experiment;
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