BIOLOGICAL MOLECULES: carbohydrates

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  • Created by: Davina1st
  • Created on: 30-10-20 15:02
What are carbohydrates? What elements do they contain?l
Molecules that only contain the elements carbon, hydrogen and oxygen
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What is the formula for carbohydrates?
Cx(H2O)y
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What is a single sugar molecule called? Example?
A monosaccharide, Glucose, fructose and ribose
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Give an example of a disaccharide?
Lactose and sucrose
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Give an example of a polysaccharide?
Glycogen, cellulose and starch
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What is the chemical formulae of glucose?
C6 H12 O6
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What is a hexose monosaccharide? Give three examples
A monosaccharide composed of 6 carbons. Glucose, fructose and galactose
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What is the difference between alpha and beta glucose?
alpha = H on top Oh below Beta= OH on top H below
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What is the importance of glucose being polar and soluble in water? How does it become this?
Hydrogen bonds that form between hydroxyl groups on the alpha glucose and water molecules. Solubility means it can be transported via water to the cytosol of the cell which is mainly made of water
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What is a condensation reaction?
A reaction in which two molecules combine to form a larger molecule, producing a small molecule such as H2O as a by-product.
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What is a glycosidic bond?
A covalent bond formed as a result of a condensation reaction, two glucose molecules join together. Their carbon 1 and carbon 4 bond together = 1-4 glycosidic bond
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What is fructose?
A naturally occurring sugar in fruit, often in combination with glucose to form to make the disaccharide sucrose.
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What is sucrose?
Cane sugar, made from fructose and glucose
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What is lactose and how is it formed?
Galactose and glucose forms lactose. Commonly found in milk and milk products
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What are pentose monosaccharides? Why are they important?
Sugars that contain 5 carbon atoms, Two pentose sugars= important components of biological molecules. Ribose is a sugar presnt in RNA nucleotides and DNA
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What is starch? How is it made?
Many alpha glucose particles joined by glycosidic bonds to form starch. Glucose made by photosynthesis is stored as starch, it is a chemical energy stores.
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What is amylose? How is it formed?
Amylose is a polysaccharide of starch. Formed by alpha glucose particles joined by 1-4 glycosidic bonds, the angle of these bonds causes amylose to twist into a helix. It is stabilised by hydrogen bonds= compact and much less soluble than glucose.
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What are the two polysaccharides of starch?
Amylose and Amylopectin
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What is amylopectin? How is it made?
Starch polysaccharide. Made of 1-4 glycosidic bonds and also 1-6 glycosidic bonds on every 25th glucose subunit = branched structure
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What is glycogen? What is its use?
Storage molecule equivalent to starch, but for animals and fungi. Glycogen forms more branches than amylopectin = more compact and less psace needed for it to be stored.
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Why is the compactness of glycogen good for storage?
More branches than amylopectin=compact and less space needed for storing it. Animals are mobile unlike plants, so this is useful. Branching =free ends where glucose molecules can be add/remove=sped up process of adding/removing glucose.
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What are the three key properties of amylopectin and glycogen?
Compact, insoluble and branched
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What is a hydrolysis reaction? Why is it performed?
To release glycogen in animals or starch in plants, they undergo hydrolysis reactions. This reaction needs the addition of water molecules, the reaction is catalysed by enzymes. This is the revers of a condensation reaction.
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How do beta glucose molecules join together?
One of them is flipped so that the hydroxyl groups are close enough to join. This makes a 1-6 glycosidic bond.
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Can a polysaccharide of beta glucose coil/ form branches?
No, because one of the beta glucose molecules are flipped
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What is an example of a polysaccharide of beta glucose?
Cellulose (no branches/ coils)
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What is cellulose used for?
Cellulose forms hydrogen bonds with each other=microfibrils, these then join together to form macrofibrils. these are strong and insoluble so make cell walls. Difficult to break down in dgsytem= great fibre
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Other cards in this set

Card 2

Front

What is the formula for carbohydrates?

Back

Cx(H2O)y

Card 3

Front

What is a single sugar molecule called? Example?

Back

Preview of the front of card 3

Card 4

Front

Give an example of a disaccharide?

Back

Preview of the front of card 4

Card 5

Front

Give an example of a polysaccharide?

Back

Preview of the front of card 5
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