Biology Paper 1 Questions and Answers - Nginda Girls Mock Examination 2023

INSTRUCTIONS

Answer ALL questions in the spaces provided.
Wrong spelling especially of technical terms will be penalized.

QUESTIONS

Name the hormone that is responsible for the development of a deep voice in humans. (1 mark)
1. Name the bacteria found in the root nodules of leguminous plants. (1 mark)
2. What relationship is shown by the bacteria and the leguminous plant. (1 mark)
Study the diagram below and answer the questions that follow
1. On the diagram show the direction of impulse transmission (1mark)
2. State the potential at which parts A and B are: (2marks)
  A…………………………………………………………………………………B……………………………………………………………………………………
Fats produce high amount of energy on oxidation yet they are not the main respiratory substrate. Explain. (2marks)
Distinguish between members of class Monocotyledonae and Dicotyledonae under the following headings
1. Leaf petiole (1mark)
2. Floral parts (1mark)
1. Define continental drift as used in evolution (2marks)
2. What is meant by the term homologous structure (1mark)
Name the gamete cells that are produced by ovaries. (1 mark)
Give the importance of mosaic leaf arrangement. (1 mark)
Identify the genetic disorders in man, characterized by the symptoms described in (a) and (b) below.
1. Inability to distinguish between blue and green colour and various shades of red. (1 mark)
2. Blood takes an abnormally long time to clot (1 mark)
Name the fins that prevent the following movements of fish during swimming. (3marks)
1. Yawing……………………………………………………………………………………
2. Pitching………………………………………………………………………………………
3. Rolling………………………………………………………………………………………
A protein has 100 amino acids. Calculate the number of nitrogenous bases in the gene for this protein (2marks)
An investigation was carried out on a mammalian kidney.
1. Name the structure labeled T. (1mark)
2. What is the function of the structure named in (i) above in the kidney? (1mark)
3. Identify the disease shown in the kidney above. (1mark)
1. Name the part of the eye where image is formed. (1mark)
2. State two characteristics of the image formed on the retina. (2marks)
Name:
1. A cell in the human body that lacks mitochondria……………………………(1mark)
2. A kingdom whose members lack mitochondria………………………………(1mark)
Below is a photograph illustrating a germinating seedling.
1. Identify the type of germination. (1mark)
2. Give two functions of the structure labeled Z? (2marks)
3. What name is given to the part labeled W? (1mark)
Name the cell structures that synthesize the following cell organelles
1. Ribosomes……………………………………………………………………(1mark)
2. Lysosomes……………………………………………………………………… (1mark)
A solution of sugarcane was boiled with hydrochloric acid then cooled. Sodium carbonate was added then Benedict’s solution. The solution was boiled and an orange precipitate was formed.
1. Why was the solution boiled with hydrochloric acid? (1mark)
2. To which class of carbohydrates does sugarcane belong? (1mark)
3. Name the type of reaction that takes place when:
  1. Simple sugars combine to form complex sugars (1mark)
  2. A complex sugar is broken down into simple sugars (1mark)
Name the most appropriate apparatus used to collect the following organisms (2 marks)
1. Mosquitoes………………………………………………………………………
2. Millipede…………………………………………………………………………
1. Name a chemical that can be used to preserve specimens in the laboratory. (1mark)
2. Identify two scientific skill acquired through the study of biology (2mark)
Explain why petals and sepals are referred to as the accessory parts of a flower (1marks)
The diagram below shows the position of an image formed in a defective eye.
1. Name the defect. (1mark)
2. Explain how the defect named in (a) above can be corrected. (2marks)
Describe photolysis (2marks)
Name two instruments used in the laboratory for magnification. (2marks)
Give reasons why microscopic sections require to be: (2marks)
1. Very thin ………………………………………………………………………
2. Kept wet during processing……………………………………………………
State two sites for gaseous exchange in submerged aquatic plants (2marks)
Explain why a person can catch a cold several times in an year but only catches measles once in his/her lifetime. (3marks)
1. Name the structure for gaseous exchange in insects (1mark)
2. Explain the role of chitin ring found in the tracheal system of insects (1mark)
3. Why does the blood of insects lack haemoglobin? (1mark)
Under what conditions do animals use tissue proteins for respiration? (1mark)
Name three processes in the human body in which homeostasis is involved (3marks)
Name two classes of animals that excrete their nitrogenous waste products mainly in the form of uric acid. (2marks)
State three adaptations of the gazelle that prevents them from being preyed upon (3marks)
In rice field, weeds are normally removed by hand when rice plants are still young. One common weed in rice fields is a species of barnyard grass which has a close resemblance to young rice plants. Unlike most other weeds, this species spreads very fast wherever it is newly introduced.
1. What adaptive variation confers a selective advantage to this species of barnyard grass? (1mark)
2. Explain why the weed spreads very fast. (2marks)
The photograph below shows red blood cells that have been put in different solutions. Examine them and answer the questions that follow.
1. 1. Identify the type of solution in which F was placed. (1mark)
  2. State the process which the red blood cells underwent in illustration G. (1mark)
2. Account for the appearance of the red blood cells in illustration E. (3marks)

MARKING SCHEME

Name the hormone that is responsible for the development of a deep voice in humans.
Androgens/Testosterone; (1mark)
1. Name the bacteria found in the root nodules of leguminous plants. (1 mark)
  Rhizobium (bacteria);
2. What relationship is shown by the bacteria and the leguminous plant. (1 mark)
  Symbiosis
Study the diagram below and answer the questions that follow
→Direction of impulse transmission
1. On the diagram show the direction of impulse transmission (1mk)
2. State the potential4 at which parts A and B are: (2mks)
  A: Action Potential;
  B: Resting potential;
Fats produce high amount of energy on oxidation yet they are not the main respiratory substrate. Explain. (2mks)
They require a lot of oxygen for oxidation;
They are insoluble hence not easily transported;
Distinguish between members of class Monocotyledonae and Dicotyledonae under the following headings
1. Leaf petiole (1mk)
  In Monocotyledonae the leaf petiole is modified to a sheath while in Dicotyledonae the leaf petiole is distinct;
2. Floral parts (1mk)
  In Monocotyledonae the floral parts are in threes or multiples of three while in Dicotyledonae the floral parts are in fours or fives or their multiples;
1. Define continental drift as used in evolution (2mks)
  Separation of large land mass; into presence continents (due to internal forces underground);
2. What is meant by the term homologous structure (1mk)
  These are structure that have a common embryonic origin/ basic plan but have become modified to perform different functions;
Name the gamete cells that are produced by ovaries. (1 mark)
0va; Rej ovum
Give the importance of mosaic leaf arrangement. (1 mark)
To increase the surface area /prevent overlapping and shadowing for maximum trapping of light for photosynthesis;
Identify each of the genetic disorders in man, characterized by the symptoms described in (a) and (b) below.
1. Inability to distinguish between blue and green colour and various shades of red.(1 mark)
  Colour blindness;
2. Blood takes an abnormally long time to clot (1 mark)
  Haemophilia; acc bleeder’s disease
Name the fins that prevent the following movements of fish during swimming. (3mks)
1. Yawing: Dorsal/Anal fins;
2. Pitching: Pectoral/Pelvic fin;
3. Rolling: Dorsal/ventral fins/caudal fins;
A protein has 100 amino acids. Calculate the number of nitrogenous bases in the gene for this protein (2mks)
100 amino acids X 3 nitrogen bases ; = 300 nitrogenous bases;
NB: Each amino acid is coded for by 3 nitrogenous bases
An investigation was carried out on a mammalian kidney.
1. Name the structure labeled T. (1mark)
  Adrenal gland;
2. What is the function of the structure named in (i) above in the kidney. (1mark)
  Produce aldosterone hormone (for reabsorption of sodium ion in the kidney tubules);
3. Identify the disease shown in the kidney above. (1mark)
  Kidney stones;
1. Name the part of the eye where image is formed. (1mk)
  Retina acc Fovea/ Yellow spot/fovea centralis;
2. State two characteristics of the image formed on the retina. (2mks)
  Upside down/inverted;
  Back to front/reversed;
  Smaller than object/diminished;
  Real; (Mark 1st two)
Name
1. A cell in the human body that lacks mitochondria
  Red blood cell/ Erythrocyte; rej plural
2. A kingdom whose members lack mitochondria
  Monera; rej monera;
Below is a photograph illustrating a germinating seedling.
1. Identify the type of germination. (1mark)
  Epigeal germination;
2. Give two functions of the structure labeled Z? (2marks)
  Store food for growth;
  Protects plumule during germination;
  For photosynthesis before formation of first foliage leaves; mark 1st two
3. What name is given to the part labeled W? (1mark)
  Epicotyl;
Name the cell structures that synthesize the following cell organelles
1. Ribosomes: Nucleolus; (1mark)
2. Lysosomes: Golgi bodies/apparatus;(1mark)
A solution of sugarcane was boiled with hydrochloric acid then cooled. Sodium carbonate was added then Benedict’s solution. The solution was boiled and an orange precipitate was formed.
1. Why was the solution boiled with hydrochloric acid? (1mark)
  To hydrolyze/break down non-reducing sugars to reducing sugars;
2. To which class of carbohydrates does sugarcane belong? (1mark)
  Disaccharides; rej non-reducing sugar
3. Name the type of reaction that takes place when:
  1. Simple sugars combine to form complex sugars (1mark)
    Condensation;
  2. A complex sugar is broken down into simple sugars (1mark)
    Hydrolysis;
Name the most appropriate apparatus used to collect the following organisms (2 marks)
1. Mosquitoes sweepnet
2. Millipede pitfall trap
1. Name a chemical that can be used to preserve specimens in the lab. (1mark)
  formalin
2. Identify two scientific skill acquired through the study of biology (1mark)
  Analyzing; Identifying; Drawing; Recording; Measuring
  Evaluating; classifying (Any one)
Explain why petals and sepals are referred to as the accessory parts of a flower (1marks)
They are not directly involved in the reproduction process;
The diagram below shows the position of an image formed in a defective eye.
1. Name the defect. (1mk)
  Hypermetropia/long sightedness;
2. Explain how the defect named in (a) above can be corrected. (2mks)
  Use of convex lens; accept converging lens/biconvex lens. To converge the rays so that image is focused on the retina/form a sharp image on the retina;
Describe photolysis (2marks)
Chlorophyll absorbs light energy; which breaks down water into oxygen and hydrogen atoms; some of the light energy is converted to ATP; max 2mks
Name two instruments used in the laboratory for magnification. (2marks)
Microscope;
Hand lens/magnifying lens;
Give reasons why microscopic sections require to be: (2marks)
1. Very thin: To allow light to pass through;
2. Kept wet during processing: To keep the cells turgid/ Prevent them from drying
State two sites for gaseous exchange in submerged aquatic plants. (2marks)
Aerenchyma;
Epidermis;
Explain why a person can catch a cold several times in an year but only catches measles once in his/her lifetime. (3marks)
Antibodies formed against common cold; viruses remain in the body for a while and thus provide immunity for only a few days;
Antibodies formed against the measles virus remain in the body for a life time and provide immunity throughout the person’s life;
1. Name the structure for gaseous exchange in insects (1mark)
  Tracheole;
2. Explain the role of chitin ring found in the tracheal system of insects (1mark)
  Keep the tracheal system open thus preventing it from collapsing;
3. Why does the blood of insects lack haemoglobin? (1mark)
  Oxygen diffuses directly to the body tissues from the tracheoles;
Under what conditions do animals use tissue proteins for respiration? (1mark)
During prolonged starvation (when the carbohydrates and fat reserves are exhausted);
Accept starvation alone
Name three processes in the human body in which homeostasis is involved (3marks)
Temperature regulation;
Osmoregulation;
Blood sugar regulation;
pH regulation; mark 1st three
Name two classes of animals that excrete their nitrogenous waste products mainly in the form of uric acid. (2marks)
Aves;
Reptilia;
Insecta;
State three adaptations of the gazelle that prevents them from being preyed upon (3marks)
Camouflage to conceal from the predator;
Run fast to escape from the predator
Ears senstitve to sound of low pitch;
Eyes on the side to have a wide visual field Mark 1st three
In rice field, weeds are normally removed by hand when rice plants are still young. One common weed in rice fields is a species of barnyard grass which has a close resemblance to young rice plants. Unlike most other weeds, this species spreads very fast wherever it is newly introduced.
1. What adaptive variation confers a selective advantage to this species of barnyard grass?
  Resemblance to rice plants; (1mark)
2. Explain why the weed spreads very fast. (2marks)
  Humans mistake the weed for rice plants and therefore, fail to remove it; This allows it to survive to maturity and reproduce forming seeds which are dispersed to other areas;
The photograph below shows red blood cells that have been put in different solutions.
Examine them and answer the questions that follow.
1. 1. Identify the type of solution in which F was placed. (1mk)
    F – isotonic to cytoplasm of the cells;
  2. State the process which the red blood cells underwent in illustration G. (1mk)
    G – Haemolysis;
2. Account for the appearance the red blood cells in illustration E. (3mks)
  E – The cells were placed in a hypertonic solution (to their cytoplasm); they therefore lost water by osmosis; shrunk and became crenated;