1.3.1 Function of Food Why do we need food? - PowerPoint Presentation

Slide1

1.3.1 Function of Food

Why do we need food?

Slide2

Need to know

The Function of Food

Three reasons for requiring food

2

Slide3

Food is needed for:

Energy

Growth of new cells and

Repair of existing cells, tissues, organs, etc.

3

Slide4

Food also supplies:

the materials and energy for the processes of:

Metabolism and

Continuity

4

Slide5

Learning check

Why do we need food?

Energy

Growth of new cells and

Repair of existing cells, tissues, organs, etc.

What is metabolism?

Metabolism is the chemical reactions that occur in the cells of living organisms

What is continuity?

Continuity of life is the ability of an organism to exist from generation to the next

5

Slide6

1.3.2 Chemical Elements

Elements in Food

Slide7

Need to know

Chemical elements

Six common elements in food

Five elements in dissolved salts

Three trace elements

7

Slide8

What is Food made up of?

Food is made up of:

Six chemical

elements

C, H, O, N, P, S

Salts

of

Na, Mg, Cl, K, Ca

Three

trace

elements

Fe, Cu, Zn

8

Slide9

Chemical Elements and their Symbols

Calcium

Ca

Nitrogen

N

Carbon

C

Oxygen

O

Chlorine

Cl

Phosphorus

P

Copper

Cu

Potassium

K

Hydrogen

H

Sodium

Na

Iron

Fe

SulphurSMagnesiumMgZincZn

9

Slide10

1.3.3 Biomolecular Structures

Slide11

Need to know

Define Biomolecular Structures

State that simple biomolecular units are composed of a combination of elements in different ratios e.g. carbohydrates C

x

(H

2

O)y

11

Slide12

Types of Food

The elements combine in different ratios to form different food components (biomolecular units)

Food is made up of six different components

Water Proteins

Lipids Carbohydrates

Vitamins Minerals

12

Slide13

Humans are mainly made up of Water!

13

Slide14

Carbohydrates

Carbohydrates contain the elements

Carbon Hydrogen Oxygen

The general formula for a carbohydrate is

C

x

(H

2

O)

y

There are

twice

as many

hydrogen

molecules as oxygen molecules

14

Slide15

Learning check

What are the six different food components?

Water Proteins

Lipids Carbohydrates

Vitamins Minerals

15

Slide16

A common carbohydrate

General formula =

C

x

(H

2

O)y

When x = y = 6

We fet the formula

C

6

H

12O6What is the name of this monosaccharide

carbohydrate?

Glucose

16

Slide17

Another common carbohydrate

General formula =

C

x

(H

2

O)

y

When x = 12 and y = 11

We get the formula

C

12

H22O11

What is the name of this

disaccharide

carbohydrate?

Sucrose

17

Slide18

Learning check

Name the three elements that make up carbohydrates

Carbon Hydrogen Oxygen

What is the general formula for a carbohydrate?

C

x

(H

2

O)

y

18

Slide19

1.3.4 Biomolecular

Sources

and the

Components of Food

Slide20

Need to know

State that simple bio molecular units are composed of a combination of elements in different ratios e.g. carbohydrates C

x

(H

2

O)

y Name the element components, bio molecular components and sources of: carbohydrates, lipids and proteins.

State that carbohydrates are composed of indivisible units and give examples of these e.g.

Monosaccharides – glucose;

Disaccharides – maltose; &

Polysaccharides – starch/cellulose.

20

Slide21

Need to know

What is a vitamin?

Name one water soluble vitamin.

Name one water in-soluble vitamin (fat-soluble)

List the sources of these vitamins

21

Slide22

Carbohydrates

Carbohydrates contain the elements

Carbon

Hydrogen

Oxygen

Usually in the ratio of 1C:2H:1O

They have

twice

as many

hydrogen

molecules as oxygen molecules

22

Slide23

3 Types of Carbohydrate

Monosaccharides

Disaccharides

Polysaccharides

23

Slide24

Monosaccharides

These are

single sugar

molecules

simple

sugars

soluble

in water

sweet

to taste

smallest

carbohydrate unit

Examples: glucose, fructose

Found in: fruit

24

Photo Credit fruit image by

Edvin

selimovic

from Fotolia.com

Slide25

Learning check

What are the elements that make up all carbohydrates?

Carbon Hydrogen Oxygen

Can you remember the general formula for a carbohydrate?

C

x

(H

2

O)

y

25

Slide26

Disaccharides

These are

two monosaccharide sugar units

joined together – known as

double sugar

molecules

soluble

in water

sweet

to taste

Examples: sucrose, lactose, maltose

Found in: table sugar, milk

26

Slide27

Polysaccharides

These are

Many monosaccharide sugar

molecules joined together

Not soluble

in water

Do not

taste sweet

Example: starch, cellulose

Found in: bread, pasta, cereals

27

Slide28

Learning check

Name the three types of carbohydrate

Monosaccharides

Disaccharides

Polysaccharides

28

Slide29

Lipids

Lipids are a diverse group of substances which include

fats

(solid at room temp.)

oils

(liquid at room temp.)

steroids

which include cholesterol and some of the sex hormones

waxes

which cover insect bodies and plant leaves.

29

Slide30

Structure of Lipids

They are made up of the elements

carbon

hydrogen

oxygen

But not have the same ratios as carbohydrates.

They are made up of two main types of molecules

Fatty acids

and

Glycerol

30

Slide31

Learning check

Give examples and sources of:

31

Examples

Sources

Monosaccharides

Disaccharides

Polysaccharides

Glucose

Fructose

fruit

Sucrose

Lactose

Table sugar

Milk

Starch

Cellulose

Bread, Pasta,

Cereals

Slide32

Types of Lipid

Two of the main types of lipids are

Triglycerides

Phospholipids

32

Slide33

Triglyceride

It is made up of

3 fatty acid molecules

and

1 glycerol molecule

33

This is the smallest lipid

Fatty Acid 1

Fatty Acid 2

Fatty Acid 3

Glycerol

Slide34

Phospholipids

If one fatty acid of a lipid molecule is replaced by a phosphate group then a phospholipid is formed

34

Fatty Acid 1

Fatty Acid 2

Glycerol

Phosphate

Slide35

Sources

of Lipids

Fat – in and on meat

Butter (80% fat)

Cooking oils

35

Slide36

Learning check

The

two main types of molecules that make up lipids are:

Fatty acids

and

Glycerol

The two main types of lipids are:

Triglycerides

Phospholipids

36

Slide37

Proteins

Proteins contain the elements

Carbon Hydrogen

Oxygen Nitrogen

Some may also contain

sulphur

,

phosphorous

or

iron

Proteins are found in lean meat, fish, pulses, soya and eggs

37

Slide38

Structure of Proteins

Proteins are made up of long chains of

amino acids

There are 20 common and several rare amino acids found in proteins

More amino acids are found in cells and tissues but are not in proteins

Amino acids are joined together by

peptide bonds

This results in the formation of

polypeptide chains

38

Slide39

Learning check

Proteins contain the elements

Carbon Hydrogen

Oxygen Nitrogen

Sometimes they contain

sulphur

,

phosphorous

or

iron

Proteins are made up of long chains of amino acids

39

Slide40

Vitamins

Vitamins

are essential organic catalysts of metabolism

Needed in small amounts, cannot be produced in the body

Must be supplied continuously and in sufficient quantities

Differ from each other chemically

40

Slide41

Vitamins

We need Vitamins

A, B, C, D, E and K

in our diets to keep us healthy

Vitamins can be

water soluble

or

fat soluble

Vitamins B and C are water soluble

Vitamins A, D, E and K are fat soluble

41

Slide42

Sources of Vitamins

Vitamin

Source

A

Green leafy vegetables, Eggs, Cheese, Carrots

B

Lean Meat, Cereals, Nuts

C

Citrus Fruits, Green vegetables, Turnips

D

Milk and Milk products, Sunlight

E

Vegetable oils, fish, nuts

K

Green leafy vegetables

42

Slide43

Learning check

What is a vitamin?

A

vitamin

is an essential organic catalyst of metabolism

What vitamins dissolve in water?

B &

C

What vitamins are fat-soluble?

A

,

D

, E and K

43

Slide44

1.3.5 Energy Transfer Reactions

Anabolic & Catabolic

Or

Anabolism & Catabolism

Slide45

45

Need to know

Definition of the terms:

Anabolic

Catabolic

Give an example of each

Slide46

46

Anabolic Reactions

This is where

energy is used

to make

large molecules (e.g. C

6

H

12

O

6

) from smaller ones (e.g. CO

2

and H

2

O) using enzymes

e.g.

Photosynthesis

– glucose molecules are formed from carbon dioxide and water using enzymes and the energy from the sun.

This is

anabolism

. Energy is absorbed.

Slide47

47

An Anabolic Reaction

Energy being used to join two small molecules to make a larger molecule

ENERGY

Small molecule

Small molecule

Larger molecule

Slide48

48

Catabolic Reactions

This is where

energy is released

when

large molecules (e.g. C

6

H

12

O

6

) are broken down to form smaller ones (e.g. CO

2

and H

2

O) using enzymes

e.g.

Respiration

– glucose molecules are broken down by enzymes to form carbon dioxide and water and energy is released.

This is

catabolism

. Energy is released.

Slide49

49

Learning check

Explain

Anabolism

Energy absorbed. Small

 large molecules

Give an example of an anabolic reaction

Photosynthesis

Explain

Catabolism

Energy released. Large

 small molecules

Give an example of a catabolic reaction

Respiration

Slide50

CRAP

C

atabolic

Respiration

A

nabolic

Photosynthesis

50

Slide51

51

Is catabolism the opposite of anabolism? – NO

In the examples just given the chemical processes (pathways

*

) involved in each of them are different, therefore catabolism is not the opposite of anabolism.

*

e.g. if you travel from A to B – you followed a certain pathway. On the return journey you may come home through C – you followed a different pathway.

Slide52

52

Energy Transfer Reactions

Respiration – Catabolic reaction

C

6

H

12

O

6

+ Oxygen

 Energy +

CO

2

+ H

2

O

release

Photosynthesis – Anabolic reaction

CO

2

+ H

2

O + Energy

 C6H12O6 + Oxygen absorbed

Slide53

53

Learning check

Is anabolism the opposite of catabolism ?

No

Why?

Different chemical pathways involved in both.