Home BIOLOGY Respiration Biology​​ Practical Questions And Answers

Respiration Biology​​ Practical Questions And Answers

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Respiration Biology​​ Practical Questions And Answers

Respiration Biology​​ Practical Questions And Answers

BIOLOGY PRACTICAL O’LEVEL Respiration | Respiration Biology​​ Practical | Respiration Biology​​ Practical | Respiration Questions With Answers | Respiration

Format

Until 2008, NECTA biology practicals contained three questions. Question 1 was required, and was a food test. Students then chose to answer either question 2 or question 3.

One of these questions was usually classification. The format changed in 2008. Now, the practical contains two questions, and both are required.

Food test and classification remain the most common questions, but sometimes only one of these two topics is on a given exam.

The second question may cover one of a variety of topics, including respiration, transport, coordination, photosynthesis, and movement.

Each question is worth 25 marks.

Common Practicals

<> Food test:​​ students must test a solution for starch, sugars, fats, and protein

<> Classification:​​ students must name and classify specimens, then answer questions about their characteristics

<> Respiration:​​ students use lime water to test air from the lungs for carbon dioxide

<> Transport:​​ students investigate osmosis by placing leaf petioles or pieces of raw potato in solutions of different solute concentrations

<> Photosynthesis:​​ students test a variegated leaf for starch to prove that chlorophyll is necessary for photosynthesis

<>Coordination:​​ students look at themselves in the mirror and answer questions about the sense organs they see

Note:​​ These are the most common practicals, but they are not necessarily the only practicals that can occur on the national exam. Biology practicals frequently change, and it is possible that a given exam will contain a new kind of question. Look through past NECTA practicals yourself to get an idea of the kind of questions that can occur

Respiration

The purpose of this practical is to investigate the properties of air exhaled from the lungs. This section contains the following:

  • Limewater
  • Apparatus
  • Sample respiration practical with solutions

Limewater

Limewater is a saturated solution of calcium hydroxide. It is used to test for carbon dioxide.

When carbon dioxide is bubbled through limewater, the solution becomes cloudy. This is due to the precipitation of calcium carbonate by the reaction:

CO2(g) + Ca(OH)2(aq)​​ →​​ CaCO3(s)

Limewater can be prepared from either calcium hydroxide or calcium oxide.

Calcium oxide reacts with water to form calcium hydroxide, so either way you end up with a calcium hydroxide solution. Calcium oxide is the primary component in cement. Calcium hydroxide is available from building supply shops as chokaa.

Apparatus

Many books call for delivery tubes, test tubes, and stoppers. These are totally unnecessary. Add the limewater to any small clear container and blow into it with a straw.

Sample practical with solutions

Practical 01

You are given limewater in a test tube and Rubber tube Blow some air through a rubber tube and at the same times observe the changes that take place. Then answer questions that follows

Solution
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