BIOLOGY
PAPER 1
TIME: 2 HOURS.
Instructions to candidates
- Answer ALL the questions
- During initial stages of respiration one molecule of glucose is split into two molecules eách a 3 carbon compound. State;
- The name given to this initial stage.(1mk)
- The name of the 3-carbon compound formed.(1mk)
- Where the initial stages occur in cells. (1mk)
- The total number of ATP molecules formed during this initial stage.(1mk)
- Describe the events that lead to inhalation in fish.(4mks)
- What is meant by the following term?
- Crenated cell.(1mk)
- Flaccid cell.(1mk)
- An individual is of blood group A positive.
- Name the antigens in the individual's blood.(2mks)
- Give the reason why the individual cannot receive blood from a blood group B donor.(2mks)
- How is the human stomach adapted to;
- Protein digestion?(2mks)
- Churning?(2mks)
- The diagram below shows one of the nerve cells. Use it to answer the question that follow.
- Identify the cell.(1mk)
- Name the cell that transmit impulse to part A.(1mk)
- State one structural difference between motor and sensory neurone.(1mk)
-
- During germination and early growth, dry weight of endosperm decreases while that of the embryo decreases. Explain.(2mks)
- State three internal conditions with seeds that are necessary for germination.(3mks)
- State three physiological mechanism of controlling the human body temperature during a hot day.(3mks)
- Air is forced into the lungs when the pressure in the thoracic cavity is lowered below the atmosphere pressure. How is the pressure in the thoracic cavity lowered?(3mks)
-
- Name a genetic mutation disorder that illustrates a case of incomplete dominance in human beings. (1mk)
- State the survival advantage associated with the trait named above.(1mk)
- Name two structures in a mammalian body with ciliated epithelial tissue.(2mks)
- The diagrams below represent results of an animal cell that has undergone meiosis I.
- Name the stage of meiosis II represented by the above diagram.(1mk)
- Describe the next stage of meiosis II.(2mks)
- Describe events that occurred in meiosis I that lead to the reduction in the number of chromosomes by half.(3mks)
- The paddles of whales and fins for fish adapt these organisms to aquatic habitat.
- Name the evolutionary process that may have given rise to these structures. (1mk
- What is the name given to such structure?(1mk)
- Give two examples of vestigial organs in man.(2mks)
- The diagram below illustrates germinated pollen grains.
- Name the part labeled B.(1mk)
- Explain the role of part labeled A during fertilization.(2mks)
- State the structural difference between pollen grains produced by insect and wind pollinated flowers.(2mks)
- Using a simple but well labeled diagram illustrate the reflux arch during a knee jerk reflex which occurs when the knee is tapped below the knee. (6 mks)
- State four structural differences between class arachnida and insect. (4 mks)
- The chart is a summary of a certain process in plants. Study it and answer the questions that follow.
- Identify the process and organelle in which it takes place
Process___________________Organelle______________________(2 mks) - Identify the process X and Y
X___________________Y______________________(2 mks) - Identify the gases C and P
C___________________P______________________(2 mks) - What is the role of substance D in the process (1 mk)
- Name the products E and process Z(2 mks)
- Identify the process and organelle in which it takes place
- Name the fins in a bony fish which the following functions
- Changing direction(1 mk)
- Control pitching(1 mk)
- Control yawing.(1 mk)
- State three structural differences between DNA and RNA (3 mks)
- The graph below shows relative levels of hormones during human menstrual cycle.
- By labeling P and Y identify the curve that represents oestrogen and progesterone respectively (2 mks)
- What is the role of the above named hormones during menstrual cycle?
- Progesterone (1mk)
- Oestrogen(2 mks)
- On the graph draw a curve to show relative changes in the level of luteinizing hormone. (1 mk)
MARKING SCHEME
- During initial stages of respiration one molecule of glucose is split into two molecules eách a 3 carbon compound. State;
- The name given to this initial stage.(1mk)
- Glycolysis
- Glycolysis
- The name of the 3-carbon compound formed.(1mk)
- Pyruvic acid, pyruvate
- Pyruvic acid, pyruvate
- Where the initial stages occur in cells. (1mk)
- Cytoplasm
- Cytoplasm
- The total number of ATP molecules formed during this initial stage.(1mk)
- Four
- Four
- The name given to this initial stage.(1mk)
- Describe the events that lead to inhalation in fish.(4mks)
- Muscles during the buccal cavity contract: lowering the floor of the mouth; decreasing pressure but increasing volume; fish opens the mouth; and water flows into the mouth; operculum bulges outwards; while operculum slows pressure against the body, this lowers pressure in gill chambers and water in the mouth flows to the gills.
- Muscles during the buccal cavity contract: lowering the floor of the mouth; decreasing pressure but increasing volume; fish opens the mouth; and water flows into the mouth; operculum bulges outwards; while operculum slows pressure against the body, this lowers pressure in gill chambers and water in the mouth flows to the gills.
- What is meant by the following term?
- Crenated cell.(1mk)
- An animal cell that has shrunk due to loss of water by osmosis.
- An animal cell that has shrunk due to loss of water by osmosis.
- Flaccid cell.(1mk)
- A plant cell that is flabby shrunk due to loss of water by osmosis.
- A plant cell that is flabby shrunk due to loss of water by osmosis.
- Crenated cell.(1mk)
- An individual is of blood group A positive.
- Name the antigens in the individual's blood.(2mks)
- Antigen A - Rhesus antigen/ rhesus factor
- Antigen A - Rhesus antigen/ rhesus factor
- Give the reason why the individual cannot receive blood from a blood group B donor.(2mks)
- He/she have bantibodies that will correspond with B antigen from the donor, causing agglutination.
- He/she have bantibodies that will correspond with B antigen from the donor, causing agglutination.
- Name the antigens in the individual's blood.(2mks)
- How is the human stomach adapted to;
- Protein digestion?(2mks) - Has gastric glands that secret gastric juice/ pepsin/renin.
- Churning?(2mks) - Has thick muscular wall that contract and relax (to mix food with digestive enzymes/ enhance mechanical digestion.
- Protein digestion?(2mks) - Has gastric glands that secret gastric juice/ pepsin/renin.
- The diagram below shows one of the nerve cells. Use it to answer the question that follow.
- Identify the cell.(1mk)
Relay/intermediate interneuron - Name the cell that transmit impulse to part A.(1mk)
Sensory neurone - State one structural difference between motor and sensory neurone.(1mk)
Motor neurone has one nerve fibre while sensory has two.
- Identify the cell.(1mk)
-
- During germination and early growth, dry weight of endosperm decreases while that of the embryo decreases. Explain.(2mks)
- Food stored in the endosperm is hydrolysed andoxidized to provide energy, thus decrease in weight while embryo undergoes mutation cell division leading to growth;
- Food stored in the endosperm is hydrolysed andoxidized to provide energy, thus decrease in weight while embryo undergoes mutation cell division leading to growth;
- State three internal conditions with seeds that are necessary for germination.(3mks)
- Enzymes
- Hormones germination promoters
- Viability of the seed.
- During germination and early growth, dry weight of endosperm decreases while that of the embryo decreases. Explain.(2mks)
- State three physiological mechanism of controlling the human body temperature during a hot day.(3mks)
- Vasodilation of blood capillaries;.
- Increased sweat production
- Erector pilli muscles relax
- Decreased metabolism
- Air is forced into the lungs when the pressure in the thoracic cavity is lowered below the atmosphere pressure. How is the pressure in the thoracic cavity lowered?(3mks)
- Contraction of external intercostal muscles and relaxation of internal intercostal muscles; thus raising rib cage upwards and outwards; while diaphragm muscles relax flattening the diaphragm; thus lowering pressure.
-
- Name a genetic mutation disorder that illustrates a case of incomplete dominance in human beings. (1mk)
- Sickle cell trait
- Sickle cell trait
- State the survival advantage associated with the trait named above.(1mk)
- Individual have increased resistance to malaria
- Individual have increased resistance to malaria
- Name a genetic mutation disorder that illustrates a case of incomplete dominance in human beings. (1mk)
- Name two structures in a mammalian body with ciliated epithelial tissue.(2mks)
- Fallopian tube;
- Trachea -
- The diagrams below represent results of an animal cell that has undergone meiosis I.
- Name the stage of meiosis II represented by the above diagram.(1mk)
- Metaphase II
- Metaphase II
- Describe the next stage of meiosis II.(2mks)
- Chromatids separate at centromere point; and migrate to opposite poles:
- Chromatids separate at centromere point; and migrate to opposite poles:
- Describe events that occurred in meiosis I that lead to the reduction in the number of chromosomes by half.(3mks)
- Synapsis - pairing of homologous chromosomes,
- Arrangement of homologous chromosomncs at the equator o the spindle and during metaphase I.
- Separation of homologous chromosomes and migration of individual homologous chromosomes to opposite poles.
- Name the stage of meiosis II represented by the above diagram.(1mk)
- The paddles of whales and fins for fish adapt these organisms to aquatic habitat.
- Name the evolutionary process that may have given rise to these structures. (1mk)
- Divergent evolution
- Divergent evolution
- What is the name given to such structure?(1mk)
- Homologous structures
- Homologous structures
- Give two examples of vestigial organs in man.(2mks)
- Coccyx Appendix Nictating membrane
- Body hair Muscles that move the car.
- Name the evolutionary process that may have given rise to these structures. (1mk)
- The diagram below illustrates germinated pollen grains.
- Name the part labeled B.(1mk)
- Pollen tube nucleus
- Pollen tube nucleus
- Explain the role of part labeled A during fertilization.(2mks)
- One male nucleus fuse with egg cell to form a zygote while the other with polar nuclei to form tripod nucleus primary endosperm nucleus.
- One male nucleus fuse with egg cell to form a zygote while the other with polar nuclei to form tripod nucleus primary endosperm nucleus.
- State the structural difference between pollen grains produced by insect and wind pollinated flowers.(2mks)
- Pollen grains produced by insect pollinated flowers are large/ heavy and smooth/ stick; polar grains while from wind pollinated flowers are small, smooth and light.
- Pollen grains produced by insect pollinated flowers are large/ heavy and smooth/ stick; polar grains while from wind pollinated flowers are small, smooth and light.
- Name the part labeled B.(1mk)
- Using a simple but well labeled diagram illustrate the reflux arch during a knee jerk reflex which occurs when the knee is tapped below the knee. (6 mks)
- State four structural differences between class arachnida and insect. (4 mks)
Arachnida Insects Has two body parts/ cephalothorax and abdomen Has three body parts, head, thorax and abdomen Have no antennae Has a pair of antennae Have four two pairs of walking legs Has three pairs of walking legs Has eight simple eyes on cephalothorax As a pair of compound and several simple eyes on its head Has two chelicerae on ventral side of cephalothorax Has no chelicerae on its ventral side - The chart is a summary of a certain process in plants. Study it and answer the questions that follow.
- Identify the process and organelle in which it takes place
Process - Photosynthesis Organelle - Chloroplast (2 mks) - Identify the process X and Y
Process X Photolysis Y - Carbon IV Oxide fixation(2 mks) - Identify the gases C and P
Gas C - Oxygen P - Carbon (IV) oxide (2 mks) - What is the role of substance D in the process (1 mk)
- Reacts/ reduces carbon (IV) oxide leading to formation of sugar;
- Reacts/ reduces carbon (IV) oxide leading to formation of sugar;
- Name the products E and process Z(2 mks)
- C-Glucose
- Z-Condensation
- Identify the process and organelle in which it takes place
- Name the fins in a bony fish which the following functions
- Changing direction(1 mk) - Pectoral fins
- Control pitching(1 mk) - Pelvic and pectoral fins
- Control yawing.(1 mk) - Dorsal and anal fins
- State three structural differences between DNA and RNA (3 mks)
DNA RNA Double stranded/ double helix Single stranded Has rhythm Has uracil instead of rhythm Has deoxyribose sugar Has ribose sugar - The graph below shows relative levels of hormones during human menstrual cycle.
- By labeling P and Y identify the curve that represents oestrogen and progesterone respectively (2 mks)
- What is the role of the above named hormones during menstrual cycle?
- Progesterone (1mk) - to promote stimulate thickening of the uterine walis:
- Oestrogen(2 mks) - Stimulate repair of uierine wall endometrium; stimulate pituitary glands to secrete luteinizing hormone
- On the graph draw a curve to show relative changes in the level of luteinizing hormone. (1 mk)
- By labeling P and Y identify the curve that represents oestrogen and progesterone respectively (2 mks)
Join our whatsapp group for latest updates
Tap Here to Download for 50/-
Get on WhatsApp for 50/-
Download Biology Paper 1 Questions and Answers - Mang'u Mock 2020 Exam.
Tap Here to Download for 50/-
Get on WhatsApp for 50/-
Why download?
- ✔ To read offline at any time.
- ✔ To Print at your convenience
- ✔ Share Easily with Friends / Students