Identify the laboratory instruments labelled A, B, C, D, and E. State one use for each, and describe how…

Question

Identify the laboratory instruments labelled A, B, C, D, and E. State one use for each, and describe how instrument B is used.

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1. Figure 1 is a set of instrument for carrying out measurement of various physical quantities.

a) Identify the instruments labelled A, B, C, D, and E.

A: Measuring cylinder
B: Pipette
C: Conical flask
D: Dropper
E: Thermometer

b) State one (1) use of each of the following instruments A, B, C, D and E.

A (Measuring cylinder): To measure approximate volumes of liquids.
B (Pipette): To measure and transfer a precise, fixed volume of liquid.
C (Conical flask): To hold and mix liquids, especially during titrations.
D (Dropper): To add small, unmeasured drops of liquid.
E (Thermometer): To measure temperature.

c) Describe how instrument B is used.

Attach a pipette filler (or rubber bulb) to the top of the pipette.
Immerse the tip of the pipette into the liquid to be measured.
Use the pipette filler to draw the liquid up past the calibration mark.
Carefully release the liquid until the bottom of the meniscus aligns precisely with the calibration mark.
Transfer the measured volume of liquid to the desired container by allowing it to drain out, touching the tip to the side of the receiving vessel to ensure complete transfer.
2. Figure 2 below shows an illustration of a half flower.

a) Identify the parts labelled I, II, III, IV, V, VI, and VII.
- I: Anther
- II: Stigma
- III: Ovary
- IV: Ovule
- V: Sepal
- VI: Petal
- VII: Filament
b) State the function of the parts labelled I, II, III, and IV.
- I (Anther): Produces and stores pollen grains.
- II (Stigma): Receives pollen grains during pollination.
- III (Ovary): Contains the ovules and develops into the fruit after fertilization.
- IV (Ovule): Contains the female gamete (egg cell) and develops into a seed after fertilization.
c) With the aid of a diagram, describe how cross-pollination occurs in a flower.
Cross-pollination is the transfer of pollen grains from the anther of one flower to the stigma of another flower on a different plant of the same species.
Pollen grains mature within the anthers of a donor flower.
An external agent, such as an insect, wind, or water, picks up these pollen grains from the anther.
This agent then carries the pollen to a different flower on a separate plant of the same species.
The pollen grains are deposited onto the receptive stigma of the recipient flower, initiating the process that leads to fertilization.
d) State two advantages of cross-pollination.
- • It leads to greater genetic variation in the offspring, which can enhance their adaptability to changing environments.
- • It often results in stronger and healthier offspring with increased vigor and better survival rates.

Identify the laboratory instruments labelled A, B, C, D, and E. State one use for each, and describe how instrument B is used.

Step-by-step solution

Attach a pipette filler (or rubber bulb) to the top of the pipette.

Immerse the tip of the pipette into the liquid to be measured.

Use the pipette filler to draw the liquid up past the calibration mark.

Carefully release the liquid until the bottom of the meniscus aligns precisely with the calibration mark.

Transfer the measured volume of liquid to the desired container by allowing it to drain out, touching the tip to the side of the receiving vessel to ensure complete transfer.

Pollen grains mature within the anthers of a donor flower.

An external agent, such as an insect, wind, or water, picks up these pollen grains from the anther.

This agent then carries the pollen to a different flower on a separate plant of the same species.

The pollen grains are deposited onto the receptive stigma of the recipient flower, initiating the process that leads to fertilization.

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