WAEC SSCE - Biology - 2020 (Practical)
Frage 1 Bericht
Study Specimens E(Paw paw), F(Tomato), and H(Legume) and answer questions 2(a) to 2(f).
(a) What types of fruits are specimens E, F, and H?
E: _________ F:_________ H: ___________
(b) Name the types of placentation possessed by each of specimens E, F and H:
(c) Name one agent of dispersal each of specimens E, F and H? E: H: F: F:
(d)(i) Explain briefly how specimen E is dispersed. (ii) State two types of nutrients present in specimen E.
(e)(i) What is the color of specimen H? (ii) What does the color of specimen H signify?
(f) Using the scalpel/blunt knife provided, cut open specimen H along the line of split from one side only.
(i) Name the type of placentation found in specimen H.
(ii) Make a drawing, 6 cm to 8 cm long of the two split halves of specimen H while still joined at one length and label fully.
Study of Specimens E (pawpaw fruit), F (tomato fruit) and H (pod of Pride of Barbados)
(a) Types of fruit
E: berry F: berry H: legume (pod)
(b) Types of placentation
E: parietal F: axile H: marginal
(c) One agent of dispersal each
E: man / animal F: man / animal H: explosive (self / mechanical) mechanism
(d)(i) How specimen E is dispersed
The epicarp of the pawpaw is brightly coloured and the mesocarp is sweet, fleshy and succulent. This attracts man and animals, who pluck and eat the juicy edible parts and then throw away, drop or deliberately plant the seeds some distance from the parent plant. In this way the seeds are carried far from the parent and dispersed.
(d)(ii) Two nutrients present in specimen E
Vitamins (e.g. vitamin A and vitamin C) and carbohydrates (sugars such as fructose and sucrose). It also contains mineral salts and water.
(e)(i) Colour of specimen H: green.
(e)(ii) Significance of the colour: the green colour shows that the pod is unripe (immature) and still contains chlorophyll, so it is still photosynthesising and has not yet dried and turned brown ready to split and shed its seeds.
(f)(i) Type of placentation found in specimen H: marginal placentation - the ovules/seeds are borne in a single row along the fused ventral margin (suture) of the single carpel.
(f)(ii) Drawing of the two split halves of specimen H, still joined at one end, fully labelled
The pod splits along the two sutures into two boat-shaped valves of the pericarp (fruit wall) that remain joined at the stalk (base) end. The seeds are seen attached by short stalks (funicles) in a single row along the margin of each valve, confirming marginal placentation.
Antwortdetails
Study of Specimens E (pawpaw fruit), F (tomato fruit) and H (pod of Pride of Barbados)
(a) Types of fruit
E: berry F: berry H: legume (pod)
(b) Types of placentation
E: parietal F: axile H: marginal
(c) One agent of dispersal each
E: man / animal F: man / animal H: explosive (self / mechanical) mechanism
(d)(i) How specimen E is dispersed
The epicarp of the pawpaw is brightly coloured and the mesocarp is sweet, fleshy and succulent. This attracts man and animals, who pluck and eat the juicy edible parts and then throw away, drop or deliberately plant the seeds some distance from the parent plant. In this way the seeds are carried far from the parent and dispersed.
(d)(ii) Two nutrients present in specimen E
Vitamins (e.g. vitamin A and vitamin C) and carbohydrates (sugars such as fructose and sucrose). It also contains mineral salts and water.
(e)(i) Colour of specimen H: green.
(e)(ii) Significance of the colour: the green colour shows that the pod is unripe (immature) and still contains chlorophyll, so it is still photosynthesising and has not yet dried and turned brown ready to split and shed its seeds.
(f)(i) Type of placentation found in specimen H: marginal placentation - the ovules/seeds are borne in a single row along the fused ventral margin (suture) of the single carpel.
(f)(ii) Drawing of the two split halves of specimen H, still joined at one end, fully labelled
The pod splits along the two sutures into two boat-shaped valves of the pericarp (fruit wall) that remain joined at the stalk (base) end. The seeds are seen attached by short stalks (funicles) in a single row along the margin of each valve, confirming marginal placentation.
Frage 2 Bericht
Study Specimens P, Q and R and answer questions 4(a) to 4(d).
(a) Use the information below to complete the following table. (i) Add two drops of specimen P into a beaker containing water, leave it undisturbed and note the time it completely disperses in water. (ii) Add a leveled teaspoonful of specimen Q into another beaker containing water, stir for one second and note the time it takes to completely dissolve. (iii) Cut open specimen R and note the time the odor was perceived. (iv) Give the medium of spread for each of the tests in 4(a)(i) to 4(a) i).
(v) Name the sense organ in humans involved in each of the observations in 4(a)(i) to 4(a)(iii).
| specimen | Test | Observation time(sec) | Medium of spread | sense organ |
(b) Name the biological phenomenon that occurred in 4(a)(iii).
(c) State two factors each that will increase the rate of the phenomenon named in 4(b) for each of the activities in 4(a)(i). (ii) and (iii)
(i) _____________ (ii) _____________ (iii) _____________
(d) Gently place your thumb on the inked stamp pad provided. (i) Neatly thumbprint clearly showing the pattern in the box below.
(ii) Name the type of pattern in the fingerprint in 4(e)(i).
(iii) List three other types of fingerprints. (iv) State three advantages of fingerprints.
(v) What type of variation is fingerprint?
Specimen P is a coloured drop (ink/dye) that spreads in water, Q is a soluble solid (sugar or salt) that dissolves in water, and R is a cut object (such as an onion) whose odour spreads through air. The completed table reflects this.
(a) Completed table
| Specimen | Test | Observation time (sec) | Medium of spread | Sense organ |
|---|---|---|---|---|
| P | Two drops added to water and left undisturbed until it disperses | About 120 | Liquid (water) | Eye (sight) |
| Q | A level teaspoon added to water, stirred once, timed until dissolved | About 40 | Liquid (water) | Eye (sight) |
| R | Cut open and timed until the odour is perceived | About 5 | Gas (air) | Nose (smell) |
(The exact times depend on the actual observation; the values above are typical.)
(b) Biological phenomenon in 4(a)(iii): Diffusion (the spreading of the odour molecules from a region of higher concentration to a region of lower concentration through the air).
(c) Two factors that increase the rate of the phenomenon in each activity
- (i) P (dispersal in water): increase in temperature; steeper concentration difference (more coloured drops); smaller particle size.
- (ii) Q (dissolving in water): increase in temperature; stirring/agitation; smaller particle size (finer powder).
- (iii) R (odour spreading in air): increase in temperature; movement of air (wind/draught); higher concentration of the odour.
(d) Fingerprints
- (ii) Type of pattern: a loop (typical thumbprint pattern).
- (iii) Three other types of fingerprints: whorl, arch and composite (mixed) patterns.
- (iv) Three advantages of fingerprints: they are unique to each individual and so are used for identification; they are useful in crime detection (forensic evidence); they are used for security and access (biometric verification) and do not change throughout life.
- (v) Type of variation: discontinuous variation (fingerprints fall into distinct pattern classes).
Antwortdetails
Specimen P is a coloured drop (ink/dye) that spreads in water, Q is a soluble solid (sugar or salt) that dissolves in water, and R is a cut object (such as an onion) whose odour spreads through air. The completed table reflects this.
(a) Completed table
| Specimen | Test | Observation time (sec) | Medium of spread | Sense organ |
|---|---|---|---|---|
| P | Two drops added to water and left undisturbed until it disperses | About 120 | Liquid (water) | Eye (sight) |
| Q | A level teaspoon added to water, stirred once, timed until dissolved | About 40 | Liquid (water) | Eye (sight) |
| R | Cut open and timed until the odour is perceived | About 5 | Gas (air) | Nose (smell) |
(The exact times depend on the actual observation; the values above are typical.)
(b) Biological phenomenon in 4(a)(iii): Diffusion (the spreading of the odour molecules from a region of higher concentration to a region of lower concentration through the air).
(c) Two factors that increase the rate of the phenomenon in each activity
- (i) P (dispersal in water): increase in temperature; steeper concentration difference (more coloured drops); smaller particle size.
- (ii) Q (dissolving in water): increase in temperature; stirring/agitation; smaller particle size (finer powder).
- (iii) R (odour spreading in air): increase in temperature; movement of air (wind/draught); higher concentration of the odour.
(d) Fingerprints
- (ii) Type of pattern: a loop (typical thumbprint pattern).
- (iii) Three other types of fingerprints: whorl, arch and composite (mixed) patterns.
- (iv) Three advantages of fingerprints: they are unique to each individual and so are used for identification; they are useful in crime detection (forensic evidence); they are used for security and access (biometric verification) and do not change throughout life.
- (v) Type of variation: discontinuous variation (fingerprints fall into distinct pattern classes).
Frage 3 Bericht
1. Study Specimens B, C and D and answer questions 1(a) To 1(f).
(a) i) Place two drops of specimen B on a white tile and add two drops of iodine solution.
Complete the table below with the test, observation and inference:
| test | observation | inference |
(aii) Put 5 ml of specimen B into a test tube and add 2 ml of sodium hydroxide solution followed by three drops of copper (ii) tetraoxosulphate (VI) solution and shake Complete the table below with the test, observation and inference.
| test | observation | inference |
(b) Give the name of each of the tests in 1(a)i) and 1(a)(ii). (i) ____________ (ii) _____________
(c) State two ways by which specimen C is of economic importance.
(d)(i) Name the Kingdom to (1) (ii) which specimen C belongs. (ii) State three reasons for the. answer in 1(d)(i). (iii) Name four other organisms that belong to the same Kingdom as specimen C.
(ei) Name the Phylum to which specimen D belongs. (ii) State three reasons for the answer in 1(d)(i).
(f)(i) Explain briefly the role of specimen C in nutrient cycling. (ii) What is the mode of nutrition of specimen C.
(a)(i) Iodine test on specimen B (milk)
| Test | Observation | Inference |
|---|---|---|
| Two drops of specimen B on a white tile + two drops of iodine solution | The brown/yellow colour of the iodine remains unchanged | Starch is absent in specimen B |
(a)(ii) Sodium hydroxide + copper (II) tetraoxosulphate (VI) test on specimen B
| Test | Observation | Inference |
|---|---|---|
| 5 ml of B + 2 ml sodium hydroxide + three drops of copper (II) tetraoxosulphate (VI), shaken | A violet/purple colour forms | Protein is present in specimen B |
(b) Names of the tests
- (i) Iodine test (test for starch)
- (ii) Biuret test (test for protein)
(c) Two ways specimen C (mushroom) is of economic importance
- It is edible and serves as food, being a source of protein and vitamins.
- It is used in the manufacture of drugs (antibiotics) and provides a source of income and employment.
(d)(i) Kingdom to which specimen C belongs: Kingdom Fungi (Mycota).
(d)(ii) Three reasons:
- It lacks chlorophyll and so cannot photosynthesise.
- Its body is filamentous, made of hyphae forming a mycelium.
- It reproduces asexually by spores and has a chitin cell wall.
(d)(iii) Four other organisms in the same kingdom: Mucor, Rhizopus, yeast and Penicillium.
(e)(i) Phylum to which specimen D (giant land snail) belongs: Phylum Mollusca.
(e)(ii) Three reasons:
- It has a hard external shell.
- Its head bears tentacles and it has a muscular foot for locomotion.
- Its body is divided into a head, a visceral hump and a muscular foot, and it has a mantle.
(f)(i) Role of specimen C in nutrient cycling
Specimen C (mushroom) is a decomposer. Acting saprophytically on dead plant and animal matter, it breaks the material down and releases mineral nutrients back into the soil. Green plants absorb these nutrients for growth, and herbivores in turn feed on the plants, so the fungus keeps nutrients cycling through the ecosystem.
(f)(ii) Mode of nutrition of specimen C: Saprophytic (heterotrophic) nutrition.
Antwortdetails
(a)(i) Iodine test on specimen B (milk)
| Test | Observation | Inference |
|---|---|---|
| Two drops of specimen B on a white tile + two drops of iodine solution | The brown/yellow colour of the iodine remains unchanged | Starch is absent in specimen B |
(a)(ii) Sodium hydroxide + copper (II) tetraoxosulphate (VI) test on specimen B
| Test | Observation | Inference |
|---|---|---|
| 5 ml of B + 2 ml sodium hydroxide + three drops of copper (II) tetraoxosulphate (VI), shaken | A violet/purple colour forms | Protein is present in specimen B |
(b) Names of the tests
- (i) Iodine test (test for starch)
- (ii) Biuret test (test for protein)
(c) Two ways specimen C (mushroom) is of economic importance
- It is edible and serves as food, being a source of protein and vitamins.
- It is used in the manufacture of drugs (antibiotics) and provides a source of income and employment.
(d)(i) Kingdom to which specimen C belongs: Kingdom Fungi (Mycota).
(d)(ii) Three reasons:
- It lacks chlorophyll and so cannot photosynthesise.
- Its body is filamentous, made of hyphae forming a mycelium.
- It reproduces asexually by spores and has a chitin cell wall.
(d)(iii) Four other organisms in the same kingdom: Mucor, Rhizopus, yeast and Penicillium.
(e)(i) Phylum to which specimen D (giant land snail) belongs: Phylum Mollusca.
(e)(ii) Three reasons:
- It has a hard external shell.
- Its head bears tentacles and it has a muscular foot for locomotion.
- Its body is divided into a head, a visceral hump and a muscular foot, and it has a mantle.
(f)(i) Role of specimen C in nutrient cycling
Specimen C (mushroom) is a decomposer. Acting saprophytically on dead plant and animal matter, it breaks the material down and releases mineral nutrients back into the soil. Green plants absorb these nutrients for growth, and herbivores in turn feed on the plants, so the fungus keeps nutrients cycling through the ecosystem.
(f)(ii) Mode of nutrition of specimen C: Saprophytic (heterotrophic) nutrition.
