Lesson 3.1.2.2
3.1.2.2 Polysaccharides: glycogen, starch and cellulose Quiz: AQA Biology, Unit 1
20 questions
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Lesson 3.1.2.2, Polysaccharides: glycogen, starch and cellulose: 20 multiple choice questions for the AQA Biology (7402), Unit 1: Biological molecules, written with Revision Ninja.
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The 20 questions
-
Which polysaccharide is the main storage carbohydrate in animal cells?
- Glycogen
- Cellulose
- Starch
- Chitin
-
Which monomer is cellulose made from?
- Alpha-glucose
- Fructose
- Beta-glucose
- Galactose
-
Which monomer is used to build starch and glycogen?
- Fructose
- Galactose
- Alpha-glucose
- Beta-glucose
-
Starch is made from which two polysaccharide components?
- Amylopectin and glycogen
- Amylose and cellulose
- Cellulose and glycogen
- Amylose and amylopectin
-
What is the main function of cellulose in plant cells?
- To store energy as an insoluble granule in the cytoplasm
- To carry genetic information from the nucleus to the ribosomes
- To give strength and support to the cell wall
- To act as a catalyst for reactions in the cytoplasm
-
Which polysaccharide is more highly branched than starch?
- Sucrose
- Maltose
- Cellulose
- Glycogen
-
In which type of organism is starch the main storage polysaccharide?
- Fungi only
- Animals
- Plants
- Bacteria only
-
A cell stores glucose as glycogen rather than as free glucose. Which statement best explains this?
- Glycogen cannot be hydrolysed in the cell, so the glucose it contains is kept permanently for later use
- Glycogen is insoluble and compact, so it has little effect on the water potential of the cell
- Glycogen contains more energy per glucose unit than free glucose, so less material needs to be stored in cells
- Glycogen is soluble, so it can be transported rapidly in the blood to the cells that need glucose most
-
Why does the highly branched structure of glycogen help muscle cells during intense exercise?
- Many terminal ends allow many glucose units to be hydrolysed and released at the same time
- Branches make the molecule heavier, which increases its energy content per gram
- Branches stop enzymes from acting, which keeps the store intact during exercise
- Branches make glycogen dissolve easily so it can move quickly to the blood
-
Humans cannot digest cellulose. What is the most likely reason?
- Cellulose contains no glucose units that can be absorbed through the wall of the small intestine
- Cellulose molecules are always too large to pass through the stomach and enter the small intestine
- Humans lack an enzyme able to hydrolyse the beta-glycosidic bonds in cellulose
- Cellulose is built from fructose units, which humans cannot break down because they lack the enzyme sucrase
-
What is the mass in grams of a single linear polymer made from 1000 glucose units (180 each), formed by condensation?
- 180000
- 162018
- 162000
- 162036
-
How many molecules of water are released when 1000 alpha-glucose units form a single unbranched starch-like chain?
- 998
- 1000
- 1001
- 999
-
Which description matches the structure of cellulose?
- Long unbranched chains of beta-glucose, with hydrogen bonds cross-linking neighbouring chains
- Long branched chains of alpha-glucose, with few hydrogen bonds between chains
- Long branched chains of fructose, linked by peptide bonds
- Short helical chains of alpha-glucose, coiled and stored as granules
-
Why are the alpha-1,4 bonds in starch digested more easily by human enzymes than the beta-1,4 bonds in cellulose?
- Starch contains hydrogen bonds that are weaker than the hydrogen bonds in cellulose
- Human enzymes are specific to alpha-glycosidic bonds, so they can hydrolyse starch but not cellulose
- Cellulose contains more water molecules, which block the digestive enzymes
- Starch contains phosphate groups which act as a substrate for digestion
-
A student says glycogen and cellulose are both polymers of glucose, so they are equally easy to digest. Which evaluation is correct?
- Incorrect, because glycogen uses alpha-glucose linkages that human enzymes hydrolyse, while cellulose uses beta-linkages they cannot
- Correct, because both polymers contain the same monomer and are therefore broken down by the same enzymes
- Correct, because the digestibility of a polymer depends only on its molecular mass and not on its bond types
- Incorrect, because glycogen is a lipid store that cannot be digested by any enzyme found in the human gut
-
Explain why the many branches of glycogen are a more useful structure for liver cells than an unbranched chain would be.
- Branching reduces the number of glycosidic bonds, so less energy is needed to store glucose
- Branching increases the mass of each glucose unit, so more energy is stored per molecule
- Branching makes the molecule soluble in the cytoplasm, so it can be transported around the body
- Branching gives many chain ends for simultaneous enzyme action, so glucose is released faster when blood glucose falls
-
Why do parallel cellulose chains form strong fibres in plant cell walls?
- Their branched structure lets the chains interlock and form tangles that resist stretching under load
- Their straight, unbranched structure lets many hydrogen bonds form between adjacent chains, cross-linking them
- Their coiled structure traps large volumes of water, and the water pressure inside makes the walls rigid with no exceptions
- Their ionic bonds between glucose units form a tight lattice that holds the chains firmly in position
-
A starch granule and a glycogen granule are compared. Which difference is most likely to be seen?
- Glycogen granules are smaller and more branched than starch granules
- Starch granules are made of fructose and glycogen granules of glucose
- Glycogen granules contain beta-glucose, whereas starch granules contain cellulose
- Starch granules are soluble and glycogen granules are insoluble
-
Which property of cellulose is most important for its role in plant cell walls?
- It is a polymer of amino acids joined by peptide bonds
- It is a long unbranched polymer whose chains form rigid, hydrogen-bonded fibres
- It is a branched polymer whose chains easily dissolve in water
- It is a short polymer of two glucose units joined by a glycosidic bond
-
Starch hydrolysis produces maltose and then glucose. What is the effect of hydrolysing a 1000-unit starch-like chain into 1000 separate glucose molecules?
- The number of molecules increases from 1 to 1000, because 999 bonds are broken by hydrolysis
- The number of molecules decreases from 1000 to 1 because water is added
- The number of molecules stays the same because each glucose is simply rearranged
- The number of molecules increases from 1 to 500 because each bond creates two molecules of glucose
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