(a) (i) List three characteristics of living organisms. [3 marks] (ii) Explain briefly the characteristics listed in 1(a) (i) above [6 marks] (b) In a tabular form, state four differences between plants and animals [4 marks]
(c) (i) Name one organism that exhibits both plant and animal features [1 mark]
(ii) State four animal features and two plant features possessed by the
organism named in 1(c)(i) [6 marks]
Explanation of characteristics of living Organisms (ii) Movement Living things change the position of the whole body/parts of the body; from one place to another; in search of food/shelter/mates, etc.
Excretion This involves the removal/getting rid of waste products of cell metabolism; metabolic wastes are poisonous if allowed to accumulate. Respiration This is the breakdown/burning of food substances; by aerobic/anaerobic respiration; to release energy needed for all processes of life.
Reproduction This is the ability of living organisms to produce new individuals of their own kind; this ensures the continuity of the species of an organism.
Irritability Response/reaction of organisms; towards changes in the environment; to ensure survival.
Nutrition The process involved in obtaining/manufacturing food; can be autotrophic/ heterotrophic; and utilizing it for growth and maintenance/life processes.
Growth This is the irreversible increase; in size and weight of an organism; which leads to complexity and maturation.
Competition Ability of organisms to struggle; for all necessity of life; to survive in their environment.
Adaptation Ability of organisms to adjust; to changes in environment; for survival. Life span/Death All living organisms have definite period of existence; all organisms die. (b) Differences between plants and animals
– Move from place to place/locomotion; move with the whole body
Are fixed/do not move from place to place; and move only parts of the body, root/stem/leaves;
Heterotrophic mode of nutrition that depend on already-made food
Autotrophic mode of nutrition/manufacture their own food using the energy from the sun;
Sense organs present
Sense organs absent;
No cell wall
Has a cell wall made of cellulose;
Growth is limited/definite; growth in all parts of the body
Growth is unlimited/indefinite; growth is apical or terminal;
Store carbohydrate as glycogen
Store carbohydrate as starch;
Has special excretory organs
No special excretory organs;
Response is fast/ short termed
Response very slow/long termed;
Respiratory organs present
No respiratory organs;
Note: Points must correspond to score. No tabulation minus (-) 1 mark.
(c)(i) Name of organism Euglena/Chlamydomonas Note: Spelling must be correct to score. (ii) Animal Features For Euglena For Chlamydomonas – Gullet for feeding; – Flagella; – Has flagellum for locomotion in water; – eye spot; – Myonemes for movement; – contractile vacuole – Has pellicle that gives it a definite shape; – Has eye spot to detect light intensity; – Has contractile vacuole for osmoregulation and excretion.
Plant features – definite shape; – has chloroplasts containing chlorophyll used to absorb light; – Paramylum granules; – Pyrenoid.
1.(a) Define the following terms: (a)elimination; (b) excretion; (c) secretion. [6 marks] (b) Describe the digestion of boiled fish in the gut of humans. [6 marks] (c) Make a diagram 8 cm – 10 cm long of a longitudinal section of a villus and label fully. [8 marks]
(a) Definition of terms
Elimination: Removal of undigested food; from the body of living organisms.
Excretion: Removal of waste products of metabolism; from the cells/tissues of an organism; may be toxic if retained in the body.
Secretion: Production and release of substances; useful to the body; by
specialised glands of living organisms. (b) Digestion of Boiled Fish in the Gut of Humans
Boiled fish is a source of protein; chewed and swallowed into the stomach; digestion of protein starts from the stomach; stomach secretes gastric juice; containing pepsin, rennin and hydrochloric acid; pepsin in acidic medium acts on the boiled fish and convert it to peptides; peptides move into the duodenum / small intestine; into which pancreatic juice is secreted; undigested protein is acted upon by trypsin in alkaline medium; into peptides/peptones; erepsin finally acts on peptides/peptones in alkaline medium; and converts it into amino acids.
(c) Diagram of Villus
Title (TL) – Longitudinal section of villus Size (Sz)(8 – 10cm long)
Quality (Q) Clarity of lines (CL) Neatness of Labels (NL)
venule, arteriole, Crypt of Lieberkuhn, cells of Paneth, Muscularis mucosa.
A survey to determine blood groups was carried out on 250 people living a community. The results are represented in the Table below.
(a) (i) Explain the term co-dominance . [2 marks] (ii) Calculate the number of individuals with co-dominant blood group. [3 marks] (iii) What is the total number of individuals in the Table that are able to donate blood to an accident victim with blood group B? [6 marks]
(b) A man whose blood group is heterozygous A is married to a woman whose blood group is AB. With the aid of a genetic diagram, suggest the possible blood groups of their children. [9 marks]
(a)(i) Codominance Codominance occurs when both the alleles in an heterozygous individual are fully expressed; that is both alleles exert their effects so that the hybrid has a phenotype; that is different from what the parents exhibit.
(ii) Calculation of Individuals with Co dominant blood group Mention of codominant blood group is AB
Evidence of Calculation
32 .8% of 250 OR 32.8 x 250 100 = 82 individuals/people
(iii) Total number of individuals that can donate blood to blood group B The total number of individuals will be from groups B and O
14% of the population is Blood group B
14% of 250 OR 14 x 250 100 = 35 individuals/people
45.2% of the population is blood group O
45.2% of 250
45.2 x 250 = 113 individuals/people 100
Total number of people = 113 of group O
35 of group B 148 individuals/people can donate blood to the accident victim in B OR
The Total number of individuals from (B and O) blood group B and O
14% + 45.2% = 59.2%
59.2% of 250
= 148 people/individuals
OR Punnet Square – scoring/ (Punnet Square)
(a) State five reasons way animals move from place to place. [5 marks] (b) State one function each of the following structures found in plants.
(i) epidermis: (ii) phloem; (iii) sclernchyma. [3 marks]
(c) Give two examples each of the following types of organisms:
(i) parasitic plants;
(ii) saprophytes. [4 marks] (d) State two adaptive feature of plants which inhabit salt water swamp. [4 marks] (e) State two factors each which result in:
(ii) decrease, in population density. [4 marks]
(f) Mention four ways in which modern agricultural activities may threaten the survival of species. [4 marks] (g) State three reasons why mitosis is important to living organisms. [3 marks]
(h) State three causes of food spoilage. [3 marks]
6(a), (b) and (c) satisfactorily. Majority could not completely express themselves in other questions
The expected answers are:
(c) Examples of Organisms
(i) Parasitic plants Viscum/Mistletoe; dodder plant/Cassytha; Cuscuta; Phytophthor; Peronospora (any correctly named example) Note: Spelling must be correct to score
(ii) Saprophytes Bacteria; fungi/Rhizopus, Mucor, Aspergillus; Mushroom/ Agaricus (any correctly named example) Note: Spelling must be correct to score
(d) Adaptive features of plants in salt water swamps – succulent stem/root/store water; to dilute the salt; – presence of pneumatophores/breathing roots; for breathing atmospheric – air/oxygen; – presence of stilt roots; for anchorage; – viviparous seedling; to ensure their survival/continuity; – some secrete excess salt into swamps; to maintain balance of body salt. (e) Ways modern agricultural activities may threaten the survival of species – Deforestation/commercial farming destroys habitats of species; – Destruction/loss of natural vegetation/habitat; – Over hunting of games reduces population of species; – Improper/Indiscriminate application of chemical/ salanization/eutrophication/pesticides destroys species; – Lack of afforestation practices; – Inappropriate fishing methods threaten the population of fish.
(f) Reasons why mitosis is important to living organisms – It ensures growth; – Involved asexual reproduction e.g fission, budding, spore formation; – Ensures retention of diploid condition; – Repair of tissues within organisms; – Transfer of exact genetic code from parents to offspring. (g) Causes of food Spoilage – Microbial attacks by bacteria or fungi/or saprophytic action; – Pest attack by beetles, weevils that destroy stored grains; – Improper storage which results in deterioration and spoilage of stored foods. – Destruction of stored fruits and meat by some worms, usually larva of flies; – Delay in transportation due to bad roads; – Lack of market facilities for the commodity; – Poor harvesting method/damage to fruits/vegetables/tubers during harvesting; – Poor unhygienic handling/processing/exposure to dust; – Storage in contaminated containers;