Structure And Properties Of Starch Flashcards

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1
Q

Where is glucose produced?

A

In plant cells.

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2
Q

How is glucose produced?

A

Using light energy.

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3
Q

When is glucose produced?

A

During photosynthesis.

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4
Q

What is glucose?

A

A store of chemical energy which can be released during respiration.

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5
Q

Why is glucose extremely hydrophilic and soluble in water?

A

It contains a large number of hydroxyl groups.

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6
Q

Why are hydroxyl groups polar?

A

Due to the negative charge on the oxygen atom and positive charge on the hydrogen atom.

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7
Q

What can hydroxyl groups form?

A

Hydrogen bonds with water molecules.

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8
Q

What is a problem with glucose’s solubility?

A

If a cell contains a large amount of dissolved glucose then it can cause water to move into the cell by osmosis.

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9
Q

How do plants solve glucose’s solubility problem?

A

They store glucose as starch.

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10
Q

Where do we find starch?

A

In starch grains.

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11
Q

What two molecules does starch consist of?

A

Amylose and amylopectin.

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12
Q

What are amylose molecules?

A

Polymers of alpha glucose molecules.

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13
Q

What do amylose molecules/chains form?

A

A compact helix.

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14
Q

What forms between the molecules/chains of glucose in amylose?

A

Hydrogen bonds.

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15
Q

What happens when the cell needs glucose?

A

Water is used to break the glycosidic bonds in starch (starch is hydrolysed).

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16
Q

What does the helical shape in amylose help with?

A

To make starch a compact molecule.

17
Q

What are amylopectin molecules?

A

Chains of alpha glucose molecules with a branch of another alpha glucose chain every 25-30 glucoses.

18
Q

What is the difference between the polysaccharide amylose and amylopectin?

A

Amylose is unbranched whereas amylopectin is heavily branched.

19
Q

Why does starch have to be insoluble?

A

So it doesn’t cause water to enter the cell by osmosis.

20
Q

Why can’t amylose and amylopectin diffuse out of starch?

A

They are very large polymers.

21
Q

What are used to hydrolyse starch and break the glycosidic bonds?

A

Enzymes.

22
Q

Why can enzymes break down starch easily?

A

Since enzymes act at the ends of molecules and amylopectin in starch has a lot of branches and ends.