Biology Paper 3, Aug-Sept 2018

Question 1

Diagrams A, B, C and D below are illustrations of the parts of a flower. Diagram C is a section of diagram B. Study them and answer questions 1(a) to 1(c).

(a)        (i)         Name the parts labelled I to VI                                                          [3 marks]
(ii)        Name the type of section on diagram C.                                            [1 mark]
(b)        (i)         List two of the labelled parts which can be grouped as the stamen. [2 marks]
(ii)        List three of the labelled parts which can be grouped as the carpel. [3 marks]
(c)        State one function each of the parts labelled I, II, V and VI.                       [4 marks]
(d)       The diagrams below are illustrations of types of placentation in fruits. Study them and answer the questions that follow.

(i)         Name the types of placentation illustrated in diagrams E to H.         [4 marks]
(ii)        Give one reason each for the answers in 1(d)(i).                               [4 marks]
(iii)       Name one example each of a fruit that has each of the placentation illustrated
in diagrams E to H.                                                                             [4 marks]

Observation

Candidates who performed well were able to identify the diagrams as parts of a flower, while those who performed poorly could not recognize what the structures were despite the preamble, hence, they missed the identification of the parts and other related questions.

Some candidates could not even identify the labelled parts and those that could identify them were using plural terms instead of singular e.g. ovules, when the label is clearly pointing to one ovule.

Some candidates were poor in stating the function of the labelled parts.

Many candidates were unable to name the types of placentation illustrated in diagrams E to H. the candidates that scored good arks here were able to give examples of the types of placentation.

The expected answers are:

1. 1. Names of labelled parts
    1. Petal;
    2. Filament
    3. Ovule;
    4. Anther
    5. Ovary;
    6. Stigma
  2. Type of section
    Longitudinal/Vertical
2. 1. Parts grouped as the stamen
    IV/filament; V/anther
  2. Parts grouped as the carpel
    II/ovule; III/ovary; VI/stigma
3. Function of parts labelled I, II, V and VI
  I/Petal: attracts insects for pollination;
  II/Ovule: becomes the seed after fertilization;
  V/Anther; male part contains/produces the pollen grains;
  VI/Stigma; receives the pollen grains (for fertilization).
4. 1. Types of placentation
    E: Marginal
    F: Axile
    G: Parietal
    H: Free central
  2. Reason for the answers
    E/Marginal: seeds are attached to the placenta along one margin of the fruit.
    F/Axile: seeds are attached to the placenta at the centre..
    G/Parietal: seeds are attached to the sides/ periphery of the inner wall of the fruit.
    H/Free central: seeds are attached to the knob at the base of the fruit.
  3. Examples of fruits with placentation
    E/Marginal: Pride of Barbados/Bean/cowpea/any correctly named
    F/Axile: Tomato/Garden egg/orange any correctly named
    G/Parietal: Pawpaw/any correctly named
    H/Free central: Waterleaf/any correctly named

Biology Paper 3 (Practical), WASSCE (PC 2ND), 2018

Question 1

Observation