carbohydrate and lipids structure function and nutrition Flashcards
(108 cards)
1
Q
what is a carbohydrate
A
a hydrated carbon
2
Q
describe a carbohydrate
A
essential for all living organisms
most abundant class
3
Q
how are carbohydrates formed primarily
A
by photosynthesis
4
Q
what are the basic units of carbohydrates
A
monosaccharides
5
Q
what is the general equation of carbohydrates
A
(CH2O)n
6
Q
what are carbohydrtes found in
A
bread beans milk popcorn spaghetti etc
7
Q
what are the three classifications of carbohydrates
A
monosaccharides
disaccharides
polysaccharides
8
Q
what are monosaccharides
A
simple sugars- monomers
9
Q
what are disaccharides
A
two simple sugars linked together by a covalent bind
10
Q
what are polysaccharides
A
hundreds or thousands of monosaccharides
11
Q
give examples of polysaccharides
A
starch
glycogen
cellulose
12
Q
where are monosaccharides commonly found
A
in humans
13
Q
how are monosaccharides classified in humans
A
by the number of carbons they contain in their backbone
14
Q
how many carbons do the major monosaccharides have
A
four to six carbon atoms
15
Q
how are carbohydrates formed
A
by plants in photosynthesis using C02 and water
16
Q
how else can glucose be generated in animals
A
glucose is generated by gluconeogenesis
17
Q
what other molecules can gluconeogenesis occur with
A
starts with lactate which is produced by anaerobic glycolysis or amino acids or glycerol
18
Q
what is the pathway of AA producing glucose
A
AA—> intermediate of the cytric cycle—-> oxaloacetate—> glucose
19
Q
what is the pathway of lactate into glucose
A
lactate—> pyruvate—> oxaloacetate —-> glucose
20
Q
what is the pathway of glycerol into glucose
A
gluconeogenesis
21
Q
how is glycerol produced
A
from the breakdown of lipids
22
Q
where is triglycerol sotred
A
in adipose tissue
23
Q
what is a glucogenic amino acid
A
an amino acid that can be converted into glucose through gluconeogenesis
24
Q
what are the glucogenic AA in humans
A
alanine arginine asparagine aspartic acid cysteine glutaminc acid glutamine glycine
25
where is fructose found
fruits
veggies
honey
also the digestion of sucrose
26
where is glucose found
Small amounts are found in some fruits, vegetables and honey
Manufactured foods
Digestion and conversion of other carbohydrates
27
where is galactose found
digestion of lactose
28
are disaccharides taken uo by cells
no as some are too large
29
where does the covalent bond occur in disaccharides
between the anomeric hydroxyl of a cyclic sugar and the hydroxyl second sugar are termed glycosidic bonds
30
give examples of disaccharides
SUCROSE
LACTOSE
MALTOSE
31
describe lactose
found in the milk of mammels
| consists of galactose and glucose in a B 1,4 glycosidic bond
32
what bond is found in lactose
b 1-4 glcosidic bond
33
describe sucrose
derived from sugar cane and sugar beet
34
what bond is found in sucrose
a 1,2 glycosidic bond
35
what is lactose made out of
galactose and glucose
36
what does sucrose made out of
glucose and fructose
37
what is maltose made out of
glucose and glucose
38
what bond is found in maltose
a 1,4 glycosidic bond
39
what are polysaccharides comprised of
multiple monosaccharides joined by glycosidic linkages
40
what is the predominant monosaccharide found in poly saccharides
D glucose
41
what is the major form of stored carbohydrate in animals
glycogen
42
what is glycogen made out of
a homopolymer made from glucose in a a 1,4 glycosidic bond and 1,6 glycosidic bond
43
when does branch linkages occur in glycogen
every 8-10 residues
44
describe glycogen
very compact meaning a lot can be stored in a small space
| little osmotic effect
45
what is the major form of stored carbs in plants
starch
46
when does branching occur in starch
every 20-30 residues
47
what is unbranched starch called
amylose
48
what is branched starch called
amylopectin
49
what enzymes digest starch
amylase in the digestive tract
50
what is the full name for cellulose
poly(1,4 B D glucopyranoside)
51
can humans digest cellulose
no as we have no enzyme to digest it
52
what is roughage
fibrous indigestible material in vegetable foodstuffs which aids the passage of food and waste products through the gut.
53
what are monosaccharides and disaccharides used for
energy store
glycosylation of proteins (proteoglycans, glycoproteins )
structural components (GAGS and glycolipids
carbon skeletons for biosynthesiss of AA
54
how much glucose entering the body i used for other tissues
70%
55
what does the energy from glucose come from
the chemical bonds between the carbon atoms
56
what is produced when pyruvate goes through anaerobic respiration
fermentation either with lactic acid produced in animals and alcohol and C02 in yeast and bacteria
57
what is the byproduct of fermentation in yeast and bacteria
alcohol and C02
58
what is the byproduct of fermentation in animals
lactic acid
59
what is cellular respiration
the process by which energy is captured from glucose
60
what is the first stage of respiration called
glycolysis
61
where does the link reaction take place
in the mitochondria
62
how much glycogen is stored in the muscle
3/4 of the store
63
how much glycogen is stored in the liver
1/4 of the store
64
what is glucose converted to
ribose and deoxyribose which are important macromolecules such as and NADPH RNA DNA AND ATP
65
what is NADPH used for
important for protection against oxidative stress and can be used for other chemicals
66
what is XS glucose stored as
fat
67
what material is obtained from glucose
the raw material for amino acids
68
how do we obtain amino acids
can only synthesis half of the required amino acids (nonessential amino acids)
the remainder is obtained from dietary sources (essential)
69
What is BMI
body mass index relating to height and weight
70
What is the equation for BMI
weight in kg divided by height in metres squared
71
What does SACN stand firm
The scientific advisory committee on nutrition
72
What did SACN research
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
What is the energy intake
Defined as the total energy content of foods consumed as provided by the major sources of dietary energy
74
What is energy expenditure
Amount of energy that a person needs to carry out physical functions such as breathing circulating blood digesting food or exercising
75
What is a positive energy balance
Where energy intake exceeds expenditure causing weight gain
76
What is negative energy balance
Where energy expenditure exceeds intake resulting in weight loss
77
What is the recommended total carbohydrate contribute to
50% of daily energy requirement
78
How much of the 50% should be from free sugars
5% of daily energy requirement
79
How much of the 50% of sugars should be from natural sugars
45%
80
What should the daily fibre intake be
Now 30g a day
81
What is the average fibre intake in the UK
12g per day
82
What is the definition of a lipid
Biological molecules that are insoluble in aqueous solutions and soluble in organic solvents are classed as lipids
83
Give examples of lipids
Fats
Oils
Vitamins such as A,E,D and K
Hormones
84
What are lipids classified into
Fatty acids and it’s derivatives
Cholesterol and it’s derivatives
Lipoproteins
85
What are fatty acids comprised of
Hydrocarbon chains terminating with carboxylate acids
86
What does the melting point and fluidity depend on in lipids
The length and degree of saturation of the hydrocarbon
87
What important roles do fatty acids have
```
Cellular fuel sources
Energy storage within adipose tissue in the form of triacylglycerols
Structural functions
Composition of hormones
Modification of proteins
Cell signalling
```
88
What groups can fatty acids be divided in
Saturated and unsaturated
89
Describe saturated fatty acids
Solid at room temperate and usually from animal sources
90
Give an example of saturated fatty acids
Stearic acid
91
Describe unsaturated fatty acids
Usually liquid at room temp comes from veggie sources
| They are monounsaturated or polysaturated c-c double bonds
92
What shape can carbon carbon double bonds give
Cis or trans isomers
93
What type of fatty acid has lower cholesterol
Unsaturated cis fats
94
How many grams of trans fats should we have a day
5g
95
Give an example of trans fat
Elaidic acid found in partially hydrogenated vegetable oils
96
How many grams of saturated fat should men have
30g
97
How many grams of saturated fat should a women have
20g
98
What is the basic structure of a triacylglyceride
Glycerol backbone to which three fatty acids are esterified
99
Describe triglycerides
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
What’s are steroids
Steroids are lipids characterised by carbon skeleton consisting of four fused rings
101
How is cholesterol carried in the blood
As low density lipoprotein and high density lipoprotein
102
What can too much LDL lead to
Heart disease and stroke
103
Why is HDL beneficial
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
What are hydrogenated fats
Are liquid vegetable oils made creamy when manufactures convert some of the unsaturated fats into saturated ones in a process called hydrogenation
105
How much fat should we have in the diet
35% of the energy in the diet
106
How much saturated fats should be provided in the energy intake
11%
107
How much total fat should women have in their diet
70g of total fat a day
108
How much total fat do we have for the average male
95g
