ch 3 Food Flashcards

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1
Q

what are the elements present in food ?

A

c, h, o, n, (p, s)

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1
Q

why is food necessary?

A

as a source of energy
growth and repair etc.

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2
Q

what are the elements present in dissolved salts?

A

sodium, magnesium, chlorine, potassium, calcium.

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3
Q

what are the three trace elements?

A

iron, copper, zinc
only required in tiny amounts

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4
Q

what are biomolecules?

A

chemicals that are made inside a living thing.

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5
Q

carbohydrates - elements
what is the ratio?
formula?
example?

A

c, h, o
2:1
Cx(H2O)y
glucose C6H12O6

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6
Q

what are the three types of carbs?

A

monosaccharides
disaccharides
polysaccharides

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7
Q

what are monosaccharides?

A

single sugar unit, simplest carb, water soluble

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8
Q

what is a disaccharide?

A

composed of two sugar units joined together, water soluble e.g. maltose

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9
Q

what is a polysaccharide?

A

composed of many sugar units, insoluble in water, very large molecules, e.g. starch

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10
Q

structural role of carbs

A

cellulose is used to form plant cell walls.

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11
Q

metabolic role of carbs

A

glucose is broken down in respiration to produce energy.

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12
Q

lipids - elements
ratio?
temp?
structure?

A

c, h, o
no simple ratio, very little oxygen
fats = SOLID at room temp
oils = LIQUID at room temp
triglyceride - glycerol linked to three fatty acids

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13
Q

what is a phospholipid?

A

fat like substance in which one of the fatty acids is replaced by a phosphate group.

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14
Q

what is the structural role of lipids?

A

lipids are important food stores in plants and animals.

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15
Q

what is the metabolic role of lipids?

A

lipids can be broken down in respiration to release energy.

16
Q

Protein- elements
ratio?
structure?
sources?

A

c, h, o, n
no ratio but they are very large and complex
composed of amino acids, held together by peptide bonds
meat, eggs etc.

17
Q

how many common amino acids is there ?

A

20

18
Q

what is a polypeptide?

A

has more than 20 amino acids
a protein is a long polypeptide (at least 200 amino acids)

19
Q

what are the two types of proteins? explain

A

fibrous- show little to no folding. they form long fibres, strong and tough e.g. keratin in hair and nails

globular- show lots of folding, form rounded shapes, e.g. enzymes.

20
Q

what is the structural role of proteins?

A

fibrous proteins such as keratin are found in skin and hair.

21
Q

what is the metabolic role of protein?

A

they form antibodies to fight infection.

22
Q

vitamins- types, explain

A

water soluble- B,C soluble in water.
fat soluble- A,D,E,K

23
Q

what is the metabolic role of vitamin c?
deficiency?

A

the formation of connective tissue, such as the gums, skin
causes scurvy

24
Q

what is the metabolic role of vitamin d?
deficiency?

A

helps to absorb calcium, healthy bones and teeth
rickets, osteomalacia

25
Q

minerals- why are they needed?

A

to form rigid bone structures such as bone, to form biomolecules such as haemoglobin.

26
Q

water- why is it needed?

A

it is a liquid in which all metabolic reactions take place,
it provides the basis of transport systems in organisms

27
Q

where id water mainly found?

A

the cytoplasm

28
Q

why is water a good solvent?

A

it is able to dissolve a wide range of molecules.

29
Q

energy transfer reactions- types?

A

anabolic reactions- use energy to convert smaller molecules into larger ones. e.g. protein synthesis

catabolic reactions- release energy when a complex molecule is broken down to a simpler form. e.g. respiration.

30
Q

what is the test for reducing sugar?
colour change?

A

benedict’s solution
negative result = blue
positive result = red

31
Q

what is the test for starch?

A

iodine test
if starch is present- blue/black/purple
if starch is absent- red/yellow

32
Q

what is the test for lipids?

A

brown paper

33
Q

what is the test for protein?
results?

A

biuret test
a negative result= blue
a positive result= purple