Compare carbohydrate and lipid structures, then connect condensation, hydrolysis, solubility and molecular organisation to energy storage, membranes and recognition.
97 questions in this syllabus scope, with question parts counted together.
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Carbon is an essential element for life on Earth and must be distributed and recycled within ecosystems.
Outline the chemical properties of carbon that allow it to form diverse compounds.
The equation shows a reaction that leaf cells perform.
What are features of this reaction?
Sugar X is alpha-D-glucose, Sugar Z is maltose, and the reaction is catabolic.
Sugar Y is beta-D-glucose, Sugar Z is sucrose, and the reaction is anabolic.
A disaccharide is produced by a condensation reaction.
Two monosaccharides are combined in a hydrolysis reaction.
The image shows the molecular structure of sucrose, which the body digests in order to absorb the monosaccharides glucose and fructose.
State the type of reaction that produces monosaccharides from disaccharides.
Monosaccharides, disaccharides and polysaccharides are three categories of carbohydrate.
The structural formula for a polysaccharide is shown.
Identify the monomer that makes up this polysaccharide.
All living organisms require energy to survive.
Outline three characteristics of polysaccharides that make them efficient compounds to store energy in organisms.
What describes the structure of cellulose?
Branched with bonds between alpha-glucose and beta-glucose molecules
Branched with bonds between alpha-glucose molecules
Linear with bonds between alpha-glucose molecules
Linear with bonds between beta-glucose molecules
Animal cells often secrete glycoproteins as extracellular components. What is a role of these glycoproteins?
Adhesion
Additional energy reserve
Membrane fluidity
Water uptake
Fats are used by mammals and oils are used by plants for energy storage. Both of these types of lipid are triglycerides.
Explain the reasons for oils being insoluble and sugars such as glucose being soluble in water.
Which molecular diagram shows a phospholipid molecule?
The diagram shows a fatty acid molecule.
What type of fatty acid is this?
Saturated
Monounsaturated
Cis unsaturated
Trans unsaturated
The table shows the approximate energy stores in a man with an average mass.
| Available energy / kJ | |||
|---|---|---|---|
| Organ or tissue | Carbohydrates | Lipids | Proteins |
| Brain | 30 | 0 | 0 |
| Liver | 1700 | 2000 | 1700 |
| Adipose tissue | 330 | 560000 | 170 |
What can be concluded from the data?
The brain contains no short-term stored energy.
The liver contains less long-term than short-term stored energy.
The adipose tissue provides for most of the long-term energy storage.
Carbohydrates provide more energy per gram than lipids or proteins.
Cell membranes have a fluid mosaic structure.
Phospholipids are the most common molecules in cell membranes. Draw a diagram of the simplified structure of a phospholipid and label its amphipathic properties.
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