Biology Paper 1 Questions and Answers - Wahundura Boys Mock Examination 2023

INSTRUCTIONS

Answer ALL questions

QUESTIONS

Name one factor in nature that increases the process of evolution. (1mk)
What is meant by the term “oxygen debt” (2mks)
Differentiate between characteristics of members of Monera and those of Protoctista (2mks)
Monera Protoctista
Study the diagram below and answer the questions that follow.
1. Name the organelle. (1mk)
2. State function of the structure labeled A (1mk)
State two functions of the substance secreted by sebaceous glands. (2mks)
In an experiment, the pituitary gland of a rat was removed.
1. State the effect that this will have on the quantity of urine produced by the rat. (1mk)
2. Give a reason for your answer in (a) above. (2mks)
The lungs and ileum are adapted for absorption. State three features they have in common which facilitate absorption. (3mks)
State the function of the diaphragm in the light microscope. (1mk)
Explain why food is stored in an insoluble form in the cells of living things. (1mk)
Name two components of blood that are not present in the glomerular filtrate. (2mks)
1. State the importance of the following features in gaseous exchange.
  1. Cartilages in the trachea. (1mk)
  2. Moisture on the surface of alveoli (1mk)
2. Name two sites where gaseous exchange takes place in terrestrial plants. (2mks)
1. Explain how the following adaptations minimize the rate of transpiration.
  1. Sunken stomata (1mk)
  2. Leaf drooping (1mk)
2. State two environmental factors that influence the rate of transpiration. (2mks)
State the role of decomposition in an ecosystem. (2mks)
An animal is found to have large glomeruli and short loop of Henle. Account for the presence of
1. Large glomeruli (1mk)
2. Short loop of Henle. (1mk)
3. State the possible habitat of the above organism (1mk)
The diagram below represents a set up that was used to investigate a certain process in a plant. Both the beaker and funnel are transparent.
1. State the process that was being investigated (1mk)
2. Name the gas collected in the gas jar (1mk)
3. State one factor that would affect the process (1mk)
Name the sites where light and dark reactions of photosynthesis take place. (2mks)
1. Light stage reaction
2. Dark stage reaction
The diagram below represents a reflex arc in human beings
1. Name the parts labeled Q and R. (2mks)
  Q
  R
2. What is the function of part labeled P? (1mk)
3. Using arrows, indicate the direction of impulse transmission on the diagram (1mk)
1. What is the meaning of the following terms as used in ecology. (2mks)
  1. Autecology
  2. Synecology
2. The number and distribution of stomata on three different leaves are shown in the table below.
  
  Leaf
  
  Number of
  
  stomata
  
  Upper epidermis
  
  Lower epidermis
  
  A
  
  B
  
  C
  
  450
  
  185
  
  03
  
  0
  
  270
  
  15
  
  Suggest the possible habitats of the plants from which the leaves were obtained. (3mks)
  A ……………………………………………………………………………………………
  B ……………………………………………………………………………………………
  C ……………………………………………………………………………………………
A bone obtained from a mammal is represented by the diagram below
1. 1. Name the bone shown above? (1mk)
  2. State one reason for your answers in (a) (i) above (1mk)
2. Name a bone articulate with bone shown in the diagram above at the notch . (1mk)
1. Explain why pepsin in stomach of man is secreted in inactive/precursor form. (1mk)
2. Which gland secrets pepsinogen. (1mk)
Name the regions in plants where the following take place (2mks)
1. Primary growth
2. Secondary growth
The figure below illustrates a portion of chromosome with genes E, G, H, P, Q and R

E G H P Q R

Using diagrams similar to the one above, illustrate the changes that the above chromosome would undergo. If the following mutations occurred on gene H and P.
1. Deletion (1mk)
2. Inversion (1mk)
3. Duplication (1mk)
1. Name the type of skeleton that arthropods have. (1mk)
2. What substance is the arthropods skeleton made of? (1mk)
In view of modern genetics, explain why Lamarck’s theory is unacceptable. (2mks)
State two ways in which genetic engineering is applied in the field of medicine. (2mks)
What is the functional difference between a tendon and ligament. (1mk)
1. How is fovea centralis adapted for its function in the human eye. (2mks)
2. A person was not able to see far objects clearly but could view near objects clearly. Name the eye – defect the person had. (1mk)
3. How can the defect be corrected. (1mk)
State two functions of a chloroplast. (2mks)
State three differences between osmosis and active transport. (3mks)

Osmosis

Active transport
1. State two functions of an ovary in a human female. (2mks)
2. State two advantages of internal fertilization in mammals. (2mks)
State two features of petals that enhances insect pollination. (2mks)
How are halophytes adapted for survival in their habitats. (2mks)

MARKING SCHEME

- Natural selection; mutation; cross – breeding.
- The extra Oxygen; required to breakdown accumulated lactic acid in muscles; during a strenuous activity.

Monera

Protoctista

1.Prokaryotic / Nuclear material not enclosed in nucleus membrane.

2.Have few organelles

3.All are unicellular/ single celled.

1.Eukaryotic / Nuclear membrane enclosed by a nuclear membrane.

2.Have many organelles.

3.Some are multicellular. (any 2pts)

1. Rough endoplasmic reticulum
2. Site of protein synthesis.
- Keeps the skin and hair suble / flexible / avoid cracking
- Contain antiseptic substances for protection against bacteria infections through skin.
1. Rat will produce large quantities of dilute urine
2. ADH which regulate the reabsorption of water in nephrons is secreted by pituitary gland; Hence termination of ADH, leads to making nephrons impermeable to water, hence water is lost in urine.
- Thin epithelium i.e one cell thick
- Highly vascularized to maintain steep diffusion gradient
- Ileum has villi are highly folded while lungs have alveolus to increase S.A for absorption.
- Regulate amount of light passing through the condenser to illuminate the specimen.
- To ensure that the osmotic pressure of body fluids is maintained constant.
- Plasma proteins.
- Blood cells eg platelets, RBC, WBC.
1. 1. Keep trachea open
  2. Dissolve the respiratory gases, they dissolve better in solution form.
2. - Moist surface of stomata
  - Moist surface of lenticels
1. Accumulates water in depression thus lowering saturation deficit hence low rate of transpiration.
2. Reduce surface area exposed for transpiration hence lowering transpiration rate.
3. - Temperature changes
  - Changes in humidity
  - Wind
Breakdown of organic materials; into simple substances that are made available for re-use by other organisms.
1. More filtration.
2. Less reabsorption hence water is passed out in urine.
3. Fresh water
1. Photosynthesis
2. Oxygen
3. Temperature changes; light intensity; amount of/dissolved Carbon (IV) oxide;
1. Grana / granum
2. Stroma reg. wrong spellings
1. Q – synapse
  R – Effector muscle / organ.
2. Receive Impulses from the sense organs.
1. 1. Study of a single species within a community / ecosystem / habitat / environment.
  2. Study of natural communities / different species within an ecosystem.
2. Leaf Habitat
  A Aquatic / fresh water
  B Forest terrestrial
  C Arid / semi – arid / desert.
1. 1. Ulna
  2. Has a sigmoid notch;
    Has olecranon process;
2. Radius; Humerus.
1. To avoid digestion of stomach wall / auto digestion.
2. Gastric glands in the stomach wall.
1. Apical meristem.
2. Vascular cambium
1. E G Q R
2. E G P H Q R
3. E G H P H P Q R
1. Exoskeleton
2. Chitin
Acquired phenotypic traits which does not affect genotypic in an organism.
Its lifetime cannot be transmitted to the next generation to the offspring (OWTTE).
- Production of medical proteins in milk.
- Production of vaccines.
- Production of hormones like insulin.
Ligaments holds bones together while tendon attaches bones to muscles.
1. Contain densely packed cones to perceives colours.
2. Myopia / short sightedness
3. Wearing concave / diverging lenses.
Trap sunlight – necessary for photosynthesis|
Offer site for photosynthesis reactions to occur.

Osmosis

Active transport

(i)Does not require energy

(ii)No carrier molecules

(iii)Involve movement of solvent molecules

(iv)Solvent molecules more along a conc-gradient

(i)Require / use energy

(ii)Carrier molecules are involved

(iii)Involve movement of solute particles.

(iv)The solute molecules move against a conc- gradient. (any 3pts)

1. Production of ovum / egg
  Secretion of hormones progesterone / oestrogen.
2. Protection of embryo from mechanical injury.
  Increases chances of fertilization.
  Provides embryo with required warmth / temperature
Brightly colored/conspicuous;
Large size; (to accommodate the insects)
Strongly scented; (any 2pts)
Roots have high salt concentration to increase osmotic pressure and absorb water;
Their tissues are succulent to store water;
Have salt glands to excrete (OWTTE) the excess salts;
Leaves have aerenchyma tissue with large air spaces for gaseous exchange; buoyancy;
Some have pneumatophores for gaseous exchange;
Their tissues are tolerant to dehydration
Chloroplasts are hihghly sensitive to light hence photosynthesize under water for submerged halophytes (Mark any 2 correct points)