carbohydrate and lipids structure function and nutrition Flashcards

1
Q

what is a carbohydrate

A

a hydrated carbon

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2
Q

describe a carbohydrate

A

essential for all living organisms

most abundant class

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3
Q

how are carbohydrates formed primarily

A

by photosynthesis

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4
Q

what are the basic units of carbohydrates

A

monosaccharides

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5
Q

what is the general equation of carbohydrates

A

(CH2O)n

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6
Q

what are carbohydrtes found in

A
bread 
beans
milk
popcorn
spaghetti etc
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7
Q

what are the three classifications of carbohydrates

A

monosaccharides
disaccharides
polysaccharides

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8
Q

what are monosaccharides

A

simple sugars- monomers

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9
Q

what are disaccharides

A

two simple sugars linked together by a covalent bind

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10
Q

what are polysaccharides

A

hundreds or thousands of monosaccharides

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11
Q

give examples of polysaccharides

A

starch
glycogen
cellulose

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12
Q

where are monosaccharides commonly found

A

in humans

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13
Q

how are monosaccharides classified in humans

A

by the number of carbons they contain in their backbone

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14
Q

how many carbons do the major monosaccharides have

A

four to six carbon atoms

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15
Q

how are carbohydrates formed

A

by plants in photosynthesis using C02 and water

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16
Q

how else can glucose be generated in animals

A

glucose is generated by gluconeogenesis

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17
Q

what other molecules can gluconeogenesis occur with

A

starts with lactate which is produced by anaerobic glycolysis or amino acids or glycerol

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18
Q

what is the pathway of AA producing glucose

A

AA—> intermediate of the cytric cycle—-> oxaloacetate—> glucose

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19
Q

what is the pathway of lactate into glucose

A

lactate—> pyruvate—> oxaloacetate —-> glucose

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20
Q

what is the pathway of glycerol into glucose

A

gluconeogenesis

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21
Q

how is glycerol produced

A

from the breakdown of lipids

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22
Q

where is triglycerol sotred

A

in adipose tissue

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23
Q

what is a glucogenic amino acid

A

an amino acid that can be converted into glucose through gluconeogenesis

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24
Q

what are the glucogenic AA in humans

A
alanine 
arginine 
asparagine 
aspartic acid 
cysteine
glutaminc acid 
glutamine 
glycine
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25
Q

where is fructose found

A

fruits
veggies
honey
also the digestion of sucrose

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26
Q

where is glucose found

A

Small amounts are found in some fruits, vegetables and honey
Manufactured foods

Digestion and conversion of other carbohydrates

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27
Q

where is galactose found

A

digestion of lactose

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28
Q

are disaccharides taken uo by cells

A

no as some are too large

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29
Q

where does the covalent bond occur in disaccharides

A

between the anomeric hydroxyl of a cyclic sugar and the hydroxyl second sugar are termed glycosidic bonds

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30
Q

give examples of disaccharides

A

SUCROSE
LACTOSE
MALTOSE

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31
Q

describe lactose

A

found in the milk of mammels

consists of galactose and glucose in a B 1,4 glycosidic bond

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32
Q

what bond is found in lactose

A

b 1-4 glcosidic bond

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33
Q

describe sucrose

A

derived from sugar cane and sugar beet

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34
Q

what bond is found in sucrose

A

a 1,2 glycosidic bond

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35
Q

what is lactose made out of

A

galactose and glucose

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36
Q

what does sucrose made out of

A

glucose and fructose

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37
Q

what is maltose made out of

A

glucose and glucose

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38
Q

what bond is found in maltose

A

a 1,4 glycosidic bond

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39
Q

what are polysaccharides comprised of

A

multiple monosaccharides joined by glycosidic linkages

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40
Q

what is the predominant monosaccharide found in poly saccharides

A

D glucose

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41
Q

what is the major form of stored carbohydrate in animals

A

glycogen

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42
Q

what is glycogen made out of

A

a homopolymer made from glucose in a a 1,4 glycosidic bond and 1,6 glycosidic bond

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43
Q

when does branch linkages occur in glycogen

A

every 8-10 residues

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44
Q

describe glycogen

A

very compact meaning a lot can be stored in a small space

little osmotic effect

45
Q

what is the major form of stored carbs in plants

A

starch

46
Q

when does branching occur in starch

A

every 20-30 residues

47
Q

what is unbranched starch called

A

amylose

48
Q

what is branched starch called

A

amylopectin

49
Q

what enzymes digest starch

A

amylase in the digestive tract

50
Q

what is the full name for cellulose

A

poly(1,4 B D glucopyranoside)

51
Q

can humans digest cellulose

A

no as we have no enzyme to digest it

52
Q

what is roughage

A

fibrous indigestible material in vegetable foodstuffs which aids the passage of food and waste products through the gut.

53
Q

what are monosaccharides and disaccharides used for

A

energy store
glycosylation of proteins (proteoglycans, glycoproteins )
structural components (GAGS and glycolipids
carbon skeletons for biosynthesiss of AA

54
Q

how much glucose entering the body i used for other tissues

A

70%

55
Q

what does the energy from glucose come from

A

the chemical bonds between the carbon atoms

56
Q

what is produced when pyruvate goes through anaerobic respiration

A

fermentation either with lactic acid produced in animals and alcohol and C02 in yeast and bacteria

57
Q

what is the byproduct of fermentation in yeast and bacteria

A

alcohol and C02

58
Q

what is the byproduct of fermentation in animals

A

lactic acid

59
Q

what is cellular respiration

A

the process by which energy is captured from glucose

60
Q

what is the first stage of respiration called

A

glycolysis

61
Q

where does the link reaction take place

A

in the mitochondria

62
Q

how much glycogen is stored in the muscle

A

3/4 of the store

63
Q

how much glycogen is stored in the liver

A

1/4 of the store

64
Q

what is glucose converted to

A

ribose and deoxyribose which are important macromolecules such as and NADPH RNA DNA AND ATP

65
Q

what is NADPH used for

A

important for protection against oxidative stress and can be used for other chemicals

66
Q

what is XS glucose stored as

A

fat

67
Q

what material is obtained from glucose

A

the raw material for amino acids

68
Q

how do we obtain amino acids

A

can only synthesis half of the required amino acids (nonessential amino acids)
the remainder is obtained from dietary sources (essential)

69
Q

What is BMI

A

body mass index relating to height and weight

70
Q

What is the equation for BMI

A

weight in kg divided by height in metres squared

71
Q

What does SACN stand firm

A

The scientific advisory committee on nutrition

72
Q

What did SACN research

A

High levels of sugar consumption are associated with a greater level of tooth decay
Higher sugar higher risk of the high energy intake
Drinking high sugar beverages results in weight gain and increases BMI
Increasing the risk of developing type 2 diabetes

73
Q

What is the energy intake

A

Defined as the total energy content of foods consumed as provided by the major sources of dietary energy

74
Q

What is energy expenditure

A

Amount of energy that a person needs to carry out physical functions such as breathing circulating blood digesting food or exercising

75
Q

What is a positive energy balance

A

Where energy intake exceeds expenditure causing weight gain

76
Q

What is negative energy balance

A

Where energy expenditure exceeds intake resulting in weight loss

77
Q

What is the recommended total carbohydrate contribute to

A

50% of daily energy requirement

78
Q

How much of the 50% should be from free sugars

A

5% of daily energy requirement

79
Q

How much of the 50% of sugars should be from natural sugars

A

45%

80
Q

What should the daily fibre intake be

A

Now 30g a day

81
Q

What is the average fibre intake in the UK

A

12g per day

82
Q

What is the definition of a lipid

A

Biological molecules that are insoluble in aqueous solutions and soluble in organic solvents are classed as lipids

83
Q

Give examples of lipids

A

Fats
Oils
Vitamins such as A,E,D and K
Hormones

84
Q

What are lipids classified into

A

Fatty acids and it’s derivatives
Cholesterol and it’s derivatives
Lipoproteins

85
Q

What are fatty acids comprised of

A

Hydrocarbon chains terminating with carboxylate acids

86
Q

What does the melting point and fluidity depend on in lipids

A

The length and degree of saturation of the hydrocarbon

87
Q

What important roles do fatty acids have

A
Cellular fuel sources 
Energy storage within adipose tissue in the form of triacylglycerols 
Structural functions 
Composition of hormones 
Modification of proteins 
Cell signalling
88
Q

What groups can fatty acids be divided in

A

Saturated and unsaturated

89
Q

Describe saturated fatty acids

A

Solid at room temperate and usually from animal sources

90
Q

Give an example of saturated fatty acids

A

Stearic acid

91
Q

Describe unsaturated fatty acids

A

Usually liquid at room temp comes from veggie sources

They are monounsaturated or polysaturated c-c double bonds

92
Q

What shape can carbon carbon double bonds give

A

Cis or trans isomers

93
Q

What type of fatty acid has lower cholesterol

A

Unsaturated cis fats

94
Q

How many grams of trans fats should we have a day

A

5g

95
Q

Give an example of trans fat

A

Elaidic acid found in partially hydrogenated vegetable oils

96
Q

How many grams of saturated fat should men have

A

30g

97
Q

How many grams of saturated fat should a women have

A

20g

98
Q

What is the basic structure of a triacylglyceride

A

Glycerol backbone to which three fatty acids are esterified

99
Q

Describe triglycerides

A

Fat deposited under skin and throughout body cut heat loss
Protects and cushions organs
Non polar
Long term energy store- high potential energy
More than twice the energy of carbs

100
Q

What’s are steroids

A

Steroids are lipids characterised by carbon skeleton consisting of four fused rings

101
Q

How is cholesterol carried in the blood

A

As low density lipoprotein and high density lipoprotein

102
Q

What can too much LDL lead to

A

Heart disease and stroke

103
Q

Why is HDL beneficial

A

Has a positive effect by taking cholesterol from parts of the body where there is too much to the liver where it is disposed

104
Q

What are hydrogenated fats

A

Are liquid vegetable oils made creamy when manufactures convert some of the unsaturated fats into saturated ones in a process called hydrogenation

105
Q

How much fat should we have in the diet

A

35% of the energy in the diet

106
Q

How much saturated fats should be provided in the energy intake

A

11%

107
Q

How much total fat should women have in their diet

A

70g of total fat a day

108
Q

How much total fat do we have for the average male

A

95g