Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Home Ec > Protein > Flashcards

Protein Flashcards

1
Q

Elemental Composition of Proteins

A

C (Carbon)
H (Hydrogen)
O (Oxygen
N (Nitrogen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Chemical Structure of Protein

A

Each protein molecule contains a number of amino acids
The amino acids are joined together by peptide links or bonds
A number of linked amino acids are called a polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Essential Amino Acids

A

Cannot be manufactured in the body. Must be obtained from food.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Examples of essential amino acids

A

Valine
Lysine
Leucine
Isoleucine

arginine
histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Children’s extra essential amino acids

A

arginine
histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Non-Essential amino acids

A

Glycine
Cysteine
Alanine
Asparagine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Protein Structure - Primary Structure

A

Primary structure is the sequence/order of the number of amino acids in a chain.
For example, insulin is made up of 51 amino acids arranged in a definite order.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Protein Structure - Secondary Structure

A

In a protein molecule, a polypeptide chain (or two different polypeptide chains) can be interlinked.
This creates a coiled or spiral shape.
These are known as cross-links or bridges and give proteins their properties - for example, the protein gluten is elastic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Examples of Cross-Links
Disulphide links

A

This link occurs when two sulphurs join together.
The amino acid cysteine contains sulphur.
When two cysteine units, either in the same chain or two different polypeptide chains, are adjacent, a disulphide link may be formed.
Insulin has disulphide links.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Examples of Cross-Links
Hydrogen Bonds

A

Polypeptide chains can also be linked by hydrogen bonds.
The hydrogen in one chain joins with the oxygen in another chain.
Collagen has hydrogen bonds.
Define and tyrosine are capable of forming hydrogen bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Protein Structure - Tertiary Structure

A

Tertiary structure relates to the pattern of folding of the polypeptide chains.
The coiled or spiral shape of the secondary structure may then be folded over to form a globule: a three dimensional organisation of the polypeptide chain held firmly by links.
Tertiary structures may be either fibrous or globular.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fibrous

A

The polypeptide chain, composed of long, narrow strands of amino acids, is arranged in a straight, spiral or zigzag shape.
Example: Gluten and collagen, which are insoluble (not easily denatured) in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Globular

A

The polypeptide chain is arranged in a globe shape.
Example: Ovalbumin (egg white) and myoglobin, which are soluble in water (easily denatured)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Classification of Protein
Simple Proteins

A

Animal:
Fibrous (eg: collagen in skin, myosin in muscle)
Globular (eg: albumin in egg, myoglobin in meat)

Plant:
Glutelins (insoluble in water, soluble in acids and alkalis eg: gluten in wheat)

Prolamins (insoluble in water, soluble in alcohol eg: gliadin in wheat)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Classification of Protein
Conjugated Proteins

A

these proteins consist of amino acids and a non-protein molecule:

Lipoproteins (lipid + protein) eg: lecithin in egg yolks
Phosphoprotein (phosphate + protein) eg: caseinogen in milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Sources of Protein - Animal

A

Cheese
Chicken
Meat
Fish
Eggs
Milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sources of Protein - Plant

A

Soya beans
TVP good
Nuts
Lentils
Leas
Beans
Cereals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Cheese

A

casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Meat connective tissue

A

collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Meat fibres

A

myosin/albumin/actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Meat bones

A

gelatine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Fish

A

myosin/collagen/actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Eggs

A

albumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Milk

A

lactalbumin/caseinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Wheat

A

gluten

26
Q

Properties of protein

A

Denaturation
Solubility
Maillard Reaction
Elasticity
Gel forming/Gelling
Foam Formation

27
Q

The effects of dry and moist heat on protein

A

Coagulation
Colour Change
Maillard Reaction
Tenderising
Overcooking causes proteins to become indigestible

28
Q

The effects of dry and moist heat on protein
Coagulation

A

Proteins set or harden when subjected to dry or moist heat.
Eg: Egg proteins solidify upon cooking (boiling/frying)

29
Q

The effects of dry and moist heat on protein
Colour Change

A

Dry and moist heat make proteins change colour.
Eg: Myoglobin in meat turns brown (haematin)

30
Q

The effects of dry and moist heat on protein
Maillard Reactions

A

Dry heat causes a browning of food when amino acids and carbohydrates react together
Eg: Roast potatoes

31
Q

The effects of dry and moist heat on protein
Tenderising

A

Collagen in meat changes to gelatine, causing the fibres to fall apart and meat to become more digestible
Eg: lamb casserole

32
Q

The effects of dry and moist heat on protein
Overcooking causes proteins to become indigestible

A

Prolonged cooking causes proteins to become indigestible.
Eg: overcooking meat will make it tough and difficult to digest

33
Q

Biological Functions of Proteins
Structural Protein

A

Production of: Cell membrane, Muscle and skin (and growth and repair)

34
Q

Biological Functions of Proteins
Physiologically active proteins

A

Production of:
Hormones
Enzymes
Antibodies
Blood proteins and nucleoproteins

35
Q

Biological Functions of Proteins
Nutrient Proteins

A

Supply the body with essential amino acids
Excess protein can be used for energy

36
Q

Deamination

A

Is using protein as a source of energy
Excess protein not required for growth and repair is deaminated in the liver

The NH2 group is removed, converted to ammonia and then urea, and is excreted by the kidneys.
The COOH group is oxidised to produce heat and energy.

37
Q

Biological value of proteins
HBV

A

HBV proteins contain all essential amino acids
They’re known as complete proteins
HBV generally comes from animal sources but also from soya beans

Eg:
Eggs
Milk
Meat/Fish
Soya Beans

38
Q

Biological value of proteins
LBV

A

LBV proteins contain only some of the essential amino acids
They’re known as incomplete proteins
LBV proteins generally come from plant sources but also from gelatine

Eg:
Rice
Wheat
Maize
Gelatine

39
Q

Supplementary/Complementary value of protein

A

Eating two LBV protein foods together can ensure that all the essential amino acids are obtained.
This is very important in vegan diets, where no animal protein is eaten.
Beans on toast is an example of proteins supplementing or complementing each other.
Beans are high in lysine but low in methionine.
Bread (wheat) is low in lysine but high in methionine.

40
Q

Energy value of protein

A

Protein should make up 15% of total energy value of the average diet

RDA is based on:
Body weight
Rate of growth

1g per kg of body weight

41
Q

Protein digestion
Organ/Gland: Stomach

A

Secretion: Gastric juice
Enzyme: Rennin, Pepsin
Substrate: Caseinogen, Proteins
Proteins: Casein, Peptones

42
Q

Protein digestion
Organ/Gland: Pancreas

A

Secretion: Pancreatic juice
Enzyme: Trypsin
Substrate: Peptones
Product: Peptides

43
Q

Protein digestion
Organ/Gland: Lleum

A

Secretion: Intestinal juice
Enzyme: Peptidase
Substrate: Peptides
Product: Amino acids

44
Q

Absorption and Utilisation of amino acids

A

Amino acids are absorbed through the villi of the small intestine into the bloodstream. The portal vein carries them to the liver.

In the liver:
They’re used to maintain and repair liver cells
They’re sent into the bloodstream to form new cells, repair damaged cells and manufacture hormones, enzymes, antibodies, blood proteins and nucleoproteins.
The excess is deaminated to produce heat and energy

45
Q

Formation of peptide bonds

A

Peptide bonds form when a “H” from the NH2 group of one amino acid and the “OH” from the carboxyl group of another amino acid joins together to form a water molecule forming a peptide link in a condensation reaction

46
Q

Hydrolysis

A

a reaction that involves the addition of water and enzyme action

47
Q

Condensation reaction

A

a reaction that results in the loss of a water molecule

48
Q

Draw the structure with a key

A

H
|
R——C——COOH
|
NH2

C- carbon
H- hydrogen
NH2 - amino group**
COOH - carboxyl group**
R - variable

49
Q

Properties of protein - Denaturation

A

Heat causes coagulation. For example upon heating, the albumin in egg hardens/coagulates
Culinary application: protein coagulates when eggs are cooked

Acids lower the pH. For example, milk souring bacteria changes lactose to lactic acid which causes the caseinogen in milk to coagulate
Culinary application: Lactic acid bacteria is added to milk in cheese making

Enzymes denature protein. For example, rennin coagulates milk during cheese-making
Culinary application: Tenderising salts contain enzymes, which tenderise meats, proteolytic enzymes (papain) tenderise meat by converting collagen to gelatine

Mechanical action: Heat produced by friction slightly coagulates egg protein. For example, whisking egg whites causes them to foam.
Culinary application: Aeration of sponge cakes, soufflés and meringues

50
Q

Properties of protein - Solubility

A

Most proteins are insoluble in water, except egg whites in cold water and collagen in hot water
Culinary application: Collagen is converted to gelatine in moist heat, which tenderises meat.

51
Q

Properties of protein - Maillard Reaction

A

The maillard reaction is the browning of food caused by dry heat when amino acids and carbohydrates react together. It’d non-enzymes browning.
Culinary application: Browning of fried potatoes

amino acid + sugar + dry heat = attractive brown colour and flavour (eg:) roast potato

52
Q

Properties of protein - Elasticity

A

Elasticity is a property of some proteins — for example gluten

Culinary application: gluten in wheat flour allows baked goods to rise

53
Q

Properties of protein - Gell formation

A

Gelatine is a setting agent that is extracted from the bones of animals.
Gelatine can absorb large amounts of water forming a gel.
Culinary application: Gelatine is used as a setting agent in soufflés and mousses

54
Q

Denaturation definition

A

Denaturation id the unfolding of the protein chain, resulting in an irreversible change in shape.
Coagulation of protein is an example of denaturation.
Denaturation is caused by:
Heat
Acids
Enzymes
Mechanical action

55
Q

Causes of Denaturation: Heat

A

Heat causes coagulation. For example upon heating, the albumin in egg hardens/coagulates
Culinary application: protein coagulates when eggs are cooked

56
Q

Causes of Denaturation: Acids

A

Acids lower the pH. For example, milk souring bacteria changes lactose to lactic acid which causes the caseinogen in milk to coagulate

Culinary application: Lactic acid bacteria is added to milk in cheese making

57
Q

Causes of Denaturation: Enzymes

A

Enzymes denature protein. For example, rennin coagulates milk during cheese-making

Culinary application: Tenderising salts contain enzymes, which tenderise meats, proteolytic enzymes (papain) tenderise meat by converting collagen to gelatine

58
Q

Causes of Denaturation: Mechanical Action

A

Mechanical action: Heat produced by friction slightly coagulates egg protein. For example, whisking egg whites causes them to foam.

Culinary application: Aeration of sponge cakes, soufflés and meringues

59
Q

Properties of Protein - Foam Formation

A

When egg white is whisked, protein chains unfold and air bubbles form.
The protein chains entrap air, creating a foam.
Whisking also creates heat that begins to set the egg albumin.
This is known as a temporary foam.
It will collapse after a while unless heated to coagulate and set a permanent foam.

Culinary application: Meringues/Sponges

60
Q

Biological Functions of Proteins - Deficiency of Structural Proteins

A

Delayed growth and healing

61
Q

Biological Functions of Proteins - Deficiency of Physiologically active proteins

A

Body organs and systems malfunction
Easily infected

62
Q

Biological Functions of Proteins - Deficiency in Nutrient Proteins

A

Lack of energy
Kwashiorkor Marasmus

Home Ec (39 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions