(a)(i) Cut a pieces of specimen A, place it on the... | WAEC SSCE - Biology - 2016 (Practical)

Question 1 Report

(a)(i) Cut a pieces of specimen A, place it on the white tile. Add a few drops of iodine solution. Record the observation and result in a tabular form.

(ii) Squeeze a few drops of specimen E on another clean white tile provided, add a few dre Record the observation and result in a tabular form.

(b)(i) State two observables differences between specimens A and B. (ii) Suggest two factors that are likely to be responsible for the state of specimen B.

(iii) With the aid of hand lens/magnifying lens, observe.specimen B. and name an organism that is likely growing on it. (iv) State the mode of feeding of the organism on specimen B (c) ) Make a drawing 6cm-8 cm long, of specimen C and label fully. one function each of any three parts labeled.

Answer

(a)(i) Iodine test on specimen A (bread)

Test	Observation	Result (inference)
A piece of specimen A is placed on the white tile and a few drops of iodine solution are added	The brown iodine solution turns blue-black	Starch is present in specimen A

(a)(ii) Iodine test on specimen E (orange juice)

Test	Observation	Result (inference)
A few drops of specimen E are squeezed onto a clean white tile and a few drops of iodine solution are added	The iodine solution remains brownish / yellowish (no colour change)	Starch is absent in specimen E

(b)(i) Two observable differences between specimens A and B

Specimen A (fresh bread)	Specimen B (stale bread)
White / cream in colour	Dark brown / black in colour
Soft in texture, fresh, with no mould	Hard in texture, stale / decaying, bearing mould (Rhizopus / Mucor)

(b)(ii) Two factors likely responsible for the state of specimen B

Presence of moisture / humidity.
Presence of warmth (a suitable temperature), together with fungal spores acting over time, which allowed micro-organisms to grow and spoil the bread.

(b)(iii) Organism likely growing on specimen B

A mould (fungus), for example Rhizopus (bread mould) or Mucor.

(b)(iv) Mode of feeding of the organism

Saprophytic: it feeds on the dead organic matter of the bread by secreting enzymes for external (extracellular) digestion and then absorbing the digested nutrients.

(c) Drawing of specimen C (boiled egg)

Below is a labelled drawing, 6 cm to 8 cm long, of the longitudinal section of the boiled egg (specimen C).

Labelled longitudinal section of the boiled egg (specimen C), 6-8 cm long.

(ii) One function of any three labelled parts

Labelled part	Function
Shell	Protects the egg and its contents, gives shape and allows gaseous exchange (aeration)
Albumen (egg white)	Supplies protein and water to, and cushions, the developing embryo
Yolk	Stores food (fat and protein) for the growth and nourishment of the embryo

Other parts labelled include the shell membrane and the air space, both of which aid gaseous exchange for the embryo.

Read lesson note on Modes Of Nutrition (WAEC)

Read lesson note on Spirogyra And Rhizopus (WAEC)

Answer Details

(a)(i) Iodine test on specimen A (bread)

Test	Observation	Result (inference)
A piece of specimen A is placed on the white tile and a few drops of iodine solution are added	The brown iodine solution turns blue-black	Starch is present in specimen A

(a)(ii) Iodine test on specimen E (orange juice)

Test	Observation	Result (inference)
A few drops of specimen E are squeezed onto a clean white tile and a few drops of iodine solution are added	The iodine solution remains brownish / yellowish (no colour change)	Starch is absent in specimen E

(b)(i) Two observable differences between specimens A and B

Specimen A (fresh bread)	Specimen B (stale bread)
White / cream in colour	Dark brown / black in colour
Soft in texture, fresh, with no mould	Hard in texture, stale / decaying, bearing mould (Rhizopus / Mucor)

(b)(ii) Two factors likely responsible for the state of specimen B

Presence of moisture / humidity.
Presence of warmth (a suitable temperature), together with fungal spores acting over time, which allowed micro-organisms to grow and spoil the bread.

(b)(iii) Organism likely growing on specimen B

A mould (fungus), for example Rhizopus (bread mould) or Mucor.

(b)(iv) Mode of feeding of the organism

Saprophytic: it feeds on the dead organic matter of the bread by secreting enzymes for external (extracellular) digestion and then absorbing the digested nutrients.

(c) Drawing of specimen C (boiled egg)

Below is a labelled drawing, 6 cm to 8 cm long, of the longitudinal section of the boiled egg (specimen C).

(ii) One function of any three labelled parts

Labelled part	Function
Shell	Protects the egg and its contents, gives shape and allows gaseous exchange (aeration)
Albumen (egg white)	Supplies protein and water to, and cushions, the developing embryo
Yolk	Stores food (fat and protein) for the growth and nourishment of the embryo

Other parts labelled include the shell membrane and the air space, both of which aid gaseous exchange for the embryo.

Read lesson note on Modes Of Nutrition (WAEC)

Read lesson note on Spirogyra And Rhizopus (WAEC)

Modes Of Nutrition

Spirogyra And Rhizopus

View Answer

(a)(i) Cut a pieces of specimen A, place it on the white tile. Add a few drops of iodine solution. Record the observation and result in a tabular form. (ii)...

(a)(i) Iodine test on specimen A (bread)

(a)(ii) Iodine test on specimen E (orange juice)

(b)(i) Two observable differences between specimens A and B

(b)(ii) Two factors likely responsible for the state of specimen B

(b)(iii) Organism likely growing on specimen B

(b)(iv) Mode of feeding of the organism

(c) Drawing of specimen C (boiled egg)

(ii) One function of any three labelled parts

(a)(i) Iodine test on specimen A (bread)

(a)(ii) Iodine test on specimen E (orange juice)

(b)(i) Two observable differences between specimens A and B

(b)(ii) Two factors likely responsible for the state of specimen B

(b)(iii) Organism likely growing on specimen B

(b)(iv) Mode of feeding of the organism

(c) Drawing of specimen C (boiled egg)

(ii) One function of any three labelled parts

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(a)(i) Cut a pieces of specimen A, place it on the white tile. Add a few drops of iodine solution. Record the observation and result in a tabular form. (ii)...

(a)(i) Iodine test on specimen A (bread)

(a)(ii) Iodine test on specimen E (orange juice)

(b)(i) Two observable differences between specimens A and B

(b)(ii) Two factors likely responsible for the state of specimen B

(b)(iii) Organism likely growing on specimen B

(b)(iv) Mode of feeding of the organism

(c) Drawing of specimen C (boiled egg)

(ii) One function of any three labelled parts

(a)(i) Iodine test on specimen A (bread)

(a)(ii) Iodine test on specimen E (orange juice)

(b)(i) Two observable differences between specimens A and B

(b)(ii) Two factors likely responsible for the state of specimen B

(b)(iii) Organism likely growing on specimen B

(b)(iv) Mode of feeding of the organism

(c) Drawing of specimen C (boiled egg)

(ii) One function of any three labelled parts

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