Water and Its Importance in Plants and Animals | OCR A-Level Biology B (Advancing Biology) (H422)
Water and Its Importance in Plants and Animals
- 86 questions
- 5 subtopics
- Biology content, examined on all three papers
- Component 01, Component 02 and Component 03
Water and Its Importance in Plants and Animals is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper.
It covers the properties of water, water as a transport medium and the composition of body fluids, Detecting and measuring sugars and proteins, monomers, polymers and the carbohydrates and osmosis and water potential.
Sample questions from Water and Its Importance in Plants and Animals
Answer each one closed book first, then open the answer.
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The properties of water
Why does water have a high latent heat of vaporisation?
Show the answer
A great deal of energy is needed to break all the hydrogen bonds holding a molecule to its neighbours before it can escape as vapour. -
The properties of water
Explain why ice floats on water and state the biological importance of this.
Show the answer
In ice the hydrogen bonds hold the molecules in a rigid open lattice that is less dense than liquid water, so ice forms an insulating layer on the surface of a pond and the water beneath stays liquid and habitable. -
Water as a transport medium and the composition of body fluids
How does water maintain turgor in a plant cell?
Show the answer
Water enters the vacuole by osmosis and pushes the cytoplasm against the cellulose cell wall; because water is incompressible the wall resists and a pressure builds up that makes the cell rigid and supports the tissue. -
Water as a transport medium and the composition of body fluids
State the approximate concentrations of sodium and potassium ions in human blood plasma.
Show the answer
Sodium ions are about 135 to 145 mmol dm⁻³ and potassium ions about 3.5 to 5.0 mmol dm⁻³. -
Detecting and measuring sugars and proteins
Describe how the Biuret test for protein is carried out and the result of a positive test.
Show the answer
Sodium hydroxide solution is added to the sample followed by a few drops of dilute copper(II) sulfate solution, with no heating; the mixture turns purple or lilac if protein is present and stays blue if it is not. -
Detecting and measuring sugars and proteins
How does a reagent test strip detect glucose in urine?
Show the answer
The pad carries immobilised glucose oxidase and peroxidase with a colourless chromogen; glucose oxidase oxidises glucose and produces hydrogen peroxide, and peroxidase then uses that to oxidise the chromogen to a coloured product whose intensity is matched against a chart. -
Monomers, polymers and the carbohydrates
Which elements are present in a carbohydrate, and which additional elements are found in proteins and in nucleotides?
Show the answer
Carbohydrates contain carbon, hydrogen and oxygen; proteins also contain nitrogen and often sulfur, and nucleotides also contain nitrogen and phosphorus. -
Monomers, polymers and the carbohydrates
How does glycogen compare with amylopectin?
Show the answer
Glycogen is built the same way from α-glucose with 1,4- and 1,6-glycosidic bonds, but it is much more highly branched, and it is the storage carbohydrate of animals rather than of plants.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| The properties of water | Recall questions on the polarity of water and hydrogen bonding, its high specific heat capacity and latent heat of vaporisation, cohesion, water as a solvent and reactant, why ice floats, incompressibility, transparency and surface tension. | 15 |
| Water as a transport medium and the composition of body fluids | Recall questions on intracellular and extracellular fluid, the transpiration stream, cell sap and turgor, plasma, serum, tissue fluid and lymph, urine, the main electrolytes H⁺, K⁺, Na⁺, Cl⁻, HCO₃⁻ and Mg²⁺, and what glucose or protein in urine suggests. | 18 |
| Detecting and measuring sugars and proteins | Recall questions on the Benedict's test for reducing sugars and making it quantitative, the Biuret test for protein, choosing a colorimeter filter, blanks and calibration curves, glucose test strips with glucose oxidase, and how a glucose biosensor works. | 17 |
| Monomers, polymers and the carbohydrates | Recall questions on monomers and polymers, condensation and hydrolysis, the elements in organic molecules, α-glucose and lactose, the structures of amylose, amylopectin and glycogen, why branching and insolubility suit storage, and the iodine test for starch. | 18 |
| Osmosis and water potential | Recall questions on water potential and its units, why solutes lower it, the solute and pressure equation, plant cells and erythrocytes in strong solutions, and percentage change in potato mass. | 18 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
OCR A-Level Biology B (Advancing Biology) Active Recall Guide
Every topic, not just this one. 2,895 questions with their answers.