Food & Biomolecules

Question 1

food

Answer 1

is the source of materials required by an organism to provide the energy to live, grow and reproduce.

Question 2

Types of nutrition

Answer 2

Autotrophs = organisms that make their own food

Heterotrophs obtain their food by consuming organic material made by other organisms

Question 3

Chemical Composition ( trace elements )

Answer 3

Iron (Fe), copper (Cu) and zinc (Zn) needed in very small quantity

Question 4

Chemical Composition ( macronutrients)

Answer 4

• Carbon (C), hydrogen (H), nitrogen (N), oxygen (O), Phosphorus (P) and sulfur (S) needed in large quantities

Question 5

Chemical Composition ( micronutrients)

Answer 5

• Sodium (Na), magnesium (Mg), chlorine (Cl), potassium (K) and calcium (Ca) smaller quantities

Question 6

Biomolecules

Answer 6

complex organic molecules

Question 7

Types of autotrophs

Answer 7

photosynthetic

chemosynthetic

Question 8

Carbohydrates ( composition , ratio, groups, sources , functions )

Answer 8

consists of only carbon, hydrogen, and oxygen 2H: 1O
Cx(H2O)y
1. Monosaccharides: These are made up of single sugar units e.g. glucose,
2. Disaccharides: are made up of groups of two sugar units joined together e.g. sucrose
3. Polysaccharides: these are macromolecules made up of many sugar units e.g. starch in plants, glycogen in animals
source = bread, potato, rice
Functions: quickly available energy
fiber to prevent constipation and bowel cancer
Storage Glycogen in animals (stored in the liver) and Starch in plants
Structural e.g. Cellulose in plant cell walls

Question 9

lipids ( fats, oils , composition , phospholipids , sources, functions )

Answer 9

a) Fats are solids at room temperature
b) Oils are liquids at room temperature
C, H and O, but H and O not in 2:1 ratio
Each unit is triglycerides which consists of glycerol and three fatty acids
Phospholipids make up (cell) membranes
Sources in the diet are butter, vegetable oil, cheese Functions: a) Source of energy
b) Storage of energy
c) Structural e.g. Phospholipids make up cell membranes
d) Protection
e) Heat insulation

Question 10

saturated fats

Answer 10

found in animals and are rich in cholesterol which is responsible for clogging arteries

Question 11

Unsaturated fats

Answer 11

found in plants and are less damaging to health

Question 12

Proteins ( composition, sources, functions )

Answer 12

Composition: Consist of C, H, O, and N and many also contain S.
Basic units are amino acids
Long chains of amino acids joined to each other by peptide bonds
they are folded into complex shapes which gives them their properties
Sources meat, fish, egg white
Functions:
a) Structural e.g. myosin in muscle, keratin in hair (Fibrous)
b) Physiological e.g. enzymes are biological catalysts (Globular)

Question 13

vitamins ( fat soluble and water soluble sources, functions and deficiency )

Answer 13

• Vitamin D is fat-soluble and stored in the liver
• Vitamin C is water-soluble

Vitamin D is found in dairy products Formed by skin in sunlight
Vitamin C is found in citrus fruits and green vegetables

Vitamin D is involved in the absorption of Ca in gut
Vitamin C is involved in the formation of skin and blood vessels
Deficiency disease
1. Lack of Vitamin D causes rickets (soft bones and thus bow legs)
2. Lack of Vitamin C causes scurvy (bleeding gums)

Question 14

Deficiency disease

Answer 14

disease caused by the lack of a particular vitamin

Question 15

1) Anabolic

Answer 15

These use energy to build up more complex molecules

e.g. photosynthesis and protein synthesis

Question 16

2) catabolic

Answer 16

These break down complex molecules into simpler molecules and release energy in the process e.g. respiration and digestion.

Question 17

Structural Role of Biomolecules

carbohydrates , protein , lipid

Answer 17

a) Carbohydrates: e.g. cellulose as a component of plant cell walls
b) Protein: e.g. fibrous proteins such as keratin in hair and skin, as well as myosin in muscles
c) Lipid: e.g. phospholipids form cell membranes,

Question 18

Metabolic Role of Biomolecules
( carbohydrates, lipids, proteins, hormones, vitamins )
minerals in plants and animals

Answer 18

Carbohydrates: are primary sources of energy
Lipids: are also primary sources of energy
Proteins ; Enzymes act as biological catalysts.
Hormones act as regulators of metabolic activity.
Vitamins ; required for tissue growth, cell production and health maintenance
Minerals ;
1) Calcium formation of the middle lamella sticks plant cells together
2) Magnesium formation of chlorophyll in photosynthesis
1) Calcium is involved in the formation of teeth and bones
2) Iron is involved in the formation of hemoglobin

Question 19

Hormones

Answer 19

secreted by endocrine [ductless] glands

regulate metabolic activity

Question 20

Importance of Water

Answer 20

1) Component of Cytoplasm
2) Solvent
3) Transport Medium
4) High Heat Capacity
5) Controls Cell Shape

Question 21

Food Tests

Answer 21

qualitative i.e. they tell you if the food type is present or not.
not quantitative i.e. they do not tell you how much of the food type is present

Question 22

1) Starch

Answer 22

potato
drop brown iodine solution
starch is present it will turn blue-black
control for this experiment would be to drop iodine solution onto a white tile.
starch is not present it will remain brown

Question 23

2) Reducing Sugars e.g. glucose in soft drinks

Answer 23

•In this test you mix the soft drink with water in a test tube
•Add Benedict’s solution
• heat the mixture by placing the test tube in a hot water bath.
Do not to boil the solution.
•If reducing sugar is present it will turn from blue to brick red.
control for this experiment add Benedict’s solution to water and heat it in a water bath.
Since reducing sugar is not present it will remain blue.

Question 24

Proteins e.g. egg white

Answer 24

• In this test you mix the egg white with water in a test tube
• You then add some Biuret Solution and mix.
• If protein is present the solution will turn from blue to violet.
• A control for this experiment would be to add Biuret solution to water.
• Since protein is not present it will remain blue.

Question 25

4) Lipids e.g. butter

Answer 25

• In this test you rub the butter onto a piece of brown paper.
• If fat is present it will produce a permanent translucent stain.
• A control would be to rub water onto a piece of brown paper.
• Since fat is not present it will produce a temporary translucent stain which will disappear as it dries.

Question 26

photosynthetic

Answer 26

Photosynthetic organisms make food using light energy

6 CO2 + 6 H2O = C6H12O6 + 6 O2

Question 27

chemosynthetic

Answer 27

2. Chemosynthetic organisms make their food using chemical energy

Question 28

The 5 types of heterotrophs

Answer 28

1. Herbivores eat plant material
2. Carnivores eat other animals
3. Omnivores eat both plants and animals
4. Detritus feeders animals that eat dead and decaying plants and animals
5. Decomposers break down the remains of dead plants and animals