Carbohydrates Flashcards

1
Q

What forms the bulk of our nutrition

A

Carbohydrates

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2
Q

What type of foods are carbohydrates found in

A
  • Almost every type
  • Particularly bread, pasta and rice
  • Also soluble form in soft drinks and juices
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3
Q

What is glucose the major fuel in and is it commonly found as such in food?

A

Blood plasma

- Rarely found as a major fuel source in food

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4
Q

What is the most commonly occurring sugar?

A

Disaccharide sucrose.

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5
Q

Where is disaccharide sucrose derived from?

A

Variety of plants

E.g. sugar beet and sugar cane

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6
Q

What is the main carbohydrate found in milk?

A

Lactose

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7
Q

What is the main carbohydrate found in mushrooms?

A

Trehalose

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8
Q

How does Glucose occur?

A

In two forms that are in equilibrium with each other, in ring form and linear form

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9
Q

(Glucose) In solution how much is found in linear form

A

Less than 0.1%

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10
Q

What are the conformations of the ring form (Glucose)

A

α - D - glucopyranose conformation

β- D - glucopyranose

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11
Q

(Glucose) In solution of the ring form what percent is found in the different conformations?

A

α - D - glucopyranose conformation (36%)

β- D - glucopyranose (63%)

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12
Q

How are (α - D - glucopyranose conformation) and (β- D - glucopyranose conformation) convertible?

A

Via the linear form

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13
Q

Which form shows that glucose is an aldehyde?

A

Linear form (aldehyde is fairly reactive functional group)

  • This can cause problems when blood glucose levels are too high (diabetes)
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14
Q

What forms the majority of our nutrients

A

Carbohydrates

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15
Q

Can we digest all types of carbohydrates?

A

No

- Most notably Cellulose

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16
Q

Where is cellulose found?

A

Plant cell walls

17
Q

Describe cellulose (structure)

A

Polysaccharide based on repetitive units of β (1-4) glucose

18
Q

What do ruminants do?

A

Digest cellulose with the help of bacteria

19
Q

Describe starch (structure)

A

Repetitions of α (1-4) glucose

20
Q

Is α (1-4) glucose easily digestible

A

Yes

21
Q

What is Agarose used for

A

In the food industry and bacteriology

- can not be digested by man or bacteria

22
Q

What is pectin and what is it used for?

A

Used in food industry to solidify liquid products (e.g. custard, icecream)

  • They are modified polysaccharides based on galacturonic acid
23
Q

What explains polysaccharides used as solidifiers

A

They bind large amounts of water