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Leaving Cert Home Ec - > Protein > Flashcards

Protein Flashcards

1
Q

Elements in protein

A

Carbon
Hydrogen
Oxygen
Nitrogen

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2
Q

What element in protein is not in others? Why?

A

Nitrogen for growth

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3
Q

How are amnino acids joined?

A

Peptide links

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4
Q

What’s a chain of amino acids called

A

Peptide chain

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5
Q

What are essential amino acids

A

Amnino Acids which must be obtained from food as they cannot be produced in the body

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6
Q

What are non essential amino acids

A

Amino acids that can be produced in the body

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7
Q

What is condensation reaction

A

When peptide bonds form as amino acids join together

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8
Q

What’s the reverse of condensation reaction?

A

Hydrolysis

Occurs during digestion

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9
Q

What’s the primary structure of protein

A

Primary structure of protein is the sequence and number of amino acids in the chain
Eg insulin is 51 amino acids in a definite order

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10
Q

What’s the secondary structure of protein

A

Folding of a polypeptide chain onto another chain or itself causing a spiral shape
Spiralled proteins are called cross links
2 types disulfide and hydrogen bonds

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11
Q

Examples of cross links

A

Disulphide: two sulphurs join from the same or different polypeptide chains eg in cysteine

Hydrogen bonds: hydrogen from one chain joins with oxygen in a neighboring or same chain eg serine

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12
Q

Functions of cross links

A

Give protein their unique properties eg gluten in elasticy

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13
Q

Name all Essential Amino acids (10)

A 
Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Leucine
Lysine 
Histidine
Arginine
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14
Q

Amino acids that are just for kids

A

Histidine

Arginine

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15
Q

Explain hydrolysis

A

During digestion a water molecule is added to peptide links causing a reverse to occur: broken into smaller, single amino acids which are more digestible and can be used in the body

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16
Q

Important protein in meat connective tissues

A

Collagen

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17
Q

Important protein in eggs

A

Albumin

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18
Q

Import at protein in wheat

A

Gluten

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19
Q

Animal Sources of protein

A 
Cheese
Chicken
Meat
Fish
Eggs
Milk
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20
Q

Plant source of protein

A 
Soya beans
TVP foods
Nuts
Lentils
Peas
Beans
Cereals
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21
Q

Difference between HBV and LBV proteins

A

HBV contain all essential amino acids where as LBV only contain some

HBV are also known as complete proteins but LBV are known as incomplete

HBV come form animal sources and soya beans and LBV come from ponga sources and gelatine

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22
Q

RDA of protein

A

1 g for KG of body weight

Or

Extra during periods of radios growth eg kids and teenagers, pregnant women, Sick people

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23
Q

Digestion of protein

A

Mouth; food is chewed

Stomach; hydronic acid denatures protein
Enzyme rennin converts caseinogen to casein
Enzyme Pepsin converts proteins to peptones

Small intestine: enzyme trypsin from pancreas converts peptones into peptides
Enzyme peptidase from small intestine converts peptides to amino acids which are ready for absorption in the intestine

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24
Q

Where is protein absorbed?

A

Amino acids are absorbed Through the villi of the small intestine into blodstream to the liver

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25
Q

What is protein used for in the liver

A

Maintain and repair liver cells

Sent to bloodstream to form new cells, repair damaged cells, make hormones, enzymes, antibodies and blood proteins

Excess used for heat and energy

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26
Q

Chemical structures of amino acids

A 
1 Hydrogen 
1 carbon in middle
1 COOH (acidic carboxyl group)
1 NH2 (alkaline group)
1 R (variable)
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27
Q

How are peptide links formed

A

Acidic carboxyl group (COOH) of one amino acid reacts with an alkaline group (NH2) of another amino acid

This eliminates a water molecule in a process Called condensation

A CONH bond is formed with the remaining elements and a dipeptide link is formed

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28
Q

Tertiary structure of proteins

A

Secondary structure is condensed and compressed to make shapes, cross links form between proteins

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29
Q

Shapes in 3rd structure

A

Fibrous; straight, spiral,zigzag

Globular; spherical

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30
Q

Properties of fibrous structures

A

Elastic or non elastic
Insoluble in water
Polypeptide chains in straight, zigzag or spiral shape

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31
Q

Example of fibrous protein

A

Gluten

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32
Q

Properties of globular proteins

A

Easily denatured
Soluble in water
Polypeptide chains in sphere 3D shape

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33
Q

Example of globular structures

34
Q

Classification of proteins

A

Simple and conjugated

Simple - animal and plant
Animal - fibrous and globular
Plant - glutenins and prolamines

Conjugated - lipoproteins and phosphoproteins

35
Q

What’s an example of a fibrous protein

A

Collagen in meat connective tissue

36
Q

What’s an example of globular protein

A

Ovalbumin in egg white

36
Q

What’s an example of a glutenin

A

Glutenin in wheat

37
Q

What’s an example of a prolamine

A

Zein in maize

37
Q

What’s a conjugated Protein

A

A protein that forms when a protein combines with another non protein molecule

37
Q

What’s a lipoprotein made of and an example of a lipoprotein

A

Lipid and protein

Eg lecithin in eggs

37
Q

What’s a phosphoprotein made of and an example of a phosphoprotein

A

Phosphate and protein

Eg caseinogen in milk

38
Q

What is the biological value of protein

A

Measure of quality of protein in food by %

Determined by number of amino acids eg 100% protein foods will contain;all essential amino acids

39
Q

Sources of HBV

A

Eggs
Milk
Meat
Soya beans

40
Q

Sources of LBV

A

Rice
Wheat
Maize

41
Q

% biological value in:

Eggs
Milk
Soya bean

A

100%
95%
74%

(Respectively)

42
Q

Proteins present in eggs

A

Livetin
Ovalbumin
Vitelin

43
Q

Proteins present in milk

A

Caseinognen
Lactalbumin
Lactoglobulin

44
Q

Proteins present in soya beans

45
Q

% of biological value in :

Wheat
Maize

46
Q

Proteins present in wheat

47
Q

Proteins present in maize

48
Q

What’s complementary/ supplementary role of protein

A

Consuming two LBV protein foods together ( each containing different amino acids) to ensure all essential amino acids are obtained eg beans and toast

49
Q

Examples of supplementary value of protein

A

Hummus and pitta
Beans on toast
Lentil Dahl and Naan

50
Q

List the Properties of protein

A 
Desaturation
Elasticity
Maillard reaction
Solubility
Gel formation 
Foam formation
51
Q

What’s denaturation

A

Irreversible change in shape of protein by physical or chemical means resulting in coagulation

52
Q

Causes of denaturation

A

Heat - protein chains unfold and bond eg egg whites change from liquid translucent to solid opaque when fried

Chemicals - acids or alkalines changes proteins shape eg vinegar based marinate (acidic) tenderises meat

Mechanical action - eg whipping causing protein chains to unfold and partial coagulation eg in meringues

Enzymes - they change proteins structure eg rennet causes caseinogen in milk to coagulate in cheese making forming curd and whey

53
Q

How is elasticity a property of protein

A

Fibrous proteins can be elasticy eg gluten

Gluten makes dough elastic enough to trap CO2 gas produced by yeast helping it to rise eg bread

54
Q

How is maillard reaction a property of protein

A

It’s a non enzymic browning caused by a reaction between amino acids and sugar under dry heat creating a brown crust

Eg shortbread and roast potatoes

55
Q

How is solubility a property of protein

A

Most proteins are insoluble in water except collagen in meat (soluble in hot water) and albumin in eggs (soluble in cold water)

Used for tenderising meat eg stew

56
Q

How is gel formation a property of protein

A

Collagen (in bones and skin of meat) is heated and converted into gelatine which can absorb large amounts of heated water.

Proteins chains uncoil and water becomes trapped forming a sol ( a semi viscous solution that has trapped water molecules called a gel)

Eg for cheesecakes and jelly sweets

57
Q

What’s a sol ?

A

A solution that contains undissolved particles evenly dispersed throughout liquid

58
Q

How is foam formation a property of protein

A

When egg white sure whisked protein chains unfold and air bubbles are trapped forming a foam. Heat from whisking begins to coagulate eggs. If not heated to permanently coagulate, foam will collapse

Eg meringues

59
Q

Effect of 1.dry, 2.moist and 3.dry and moist heat on protein

A
  1. Maillard reaction
  2. Tenderise meat as collagen changes to gelatine
  3. Coagulation, colour change and indigestible of over cooked
60
Q

3 types of protein functions

A

Structural (build body)
For growth and repair of cells, muscle and skin

Physiologically active proteins (normal functioning)
Produce hormones, enzymes, antibodies, blood proteins, nucleoproteins

Nutrient proteins (nutritional role)
Excess for energy
Provide all essential amino acids

61
Q

Deficiency diseases of proteins

A 
Restarted growth
Delayed healing
Malfunctioning body organs and systems
Increase risk of illness and infection 
Lack of energy
62
Q

Short function of hormones

A

Coordinate normal body activities

63
Q

Function of enzymes

A

Speed up chemical reactions

64
Q

Function of antibodies

A

Defend bodies from harmful substances

65
Q

Function of blood proteins

A

Move molecules around body eg plasma

66
Q

Function of nucleoproteins

A

DNA for genes in chromosomes

67
Q

RDA protein

A

Depend on body weight

0.75g per kg of body weight

68
Q

Energy value of protein

A

1g has 4kcal of energy

69
Q

Mouth during digestion of proteins

A

Breaks food

70
Q

Stomach in digestion of protein

A

Produces gastric acid which contain rennin, pepsin and hydrochloric acid

Rennin breaks down caseinogen into casein
Pepsin breaks proteins into peptones
Hydrochloric acid denatures

71
Q

Pancreas in digestion of protein

A

Releases pancreatic juice which contains Trypsin

Trypsin breaks peptones into peptides

72
Q

Small intestine function during digestion of protein

A

In the ileum, intestinal juice is released containing peptidase

Peptidase breaks peptides into amino acids to be absorbed by intestine and brought to blood stream

73
Q

Absorption of protein

A

Amino acids pass through villi into bloodstream

Hepatic vein transports amino acids to liver where they’re used to maintain and repair liver cells and passed into body

Excess amino acids are deaminated to provide heat and energy

74
Q

Explain deamination

A

Excess Procyon brought to liver

Split in 2

NH2 is changed into ammonia, then urea and excreted by kidneys

COOH is oxidised to produce heat and energy

75
Q

Example of disulphide

76
Q

Example of hydrogen bond

Leaving Cert Home Ec - (41 decks)

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