1. 1.3.6 + 7 Structural & Metabolic Roles of Biomolecules

2. Need to know Structural Role of Biomolecules
State carbohydrates role as cellulose in cell walls
State proteins role as fibrous protein e.g. keratin or as myosin
State the role of lipids as Phospholipids in cell membranes

3. What does the ‘Structural Role of Biomolecules’ mean?
Structure = the way in which something is built e.g. timber structure, steel structure Role = function/job or position Biomolecules = carbohydrates, fats, proteins Structural Role of Biomolecules = the function/job of carbohydrates, fats, proteins in making various parts of living things

4. Structural role of Carbohydrate
Cell Structure
Cellulose found in plant cell walls
Cotton fibres represent the purest natural form of cellulose, containing more than 90% of this fibre
Chitin found in fungal cell walls and insect exoskeletons

5. Structural role of Proteins
Cell structure
Proteins are fibrous (threadlike) in nature.
They combine with phospholipids to from cell membranes (lipoproteins)
Keratin is the structural protein in skin, hair and nails
Myosin is the structural protein in muscle

6. Learning check
What does the ‘Structural Role of Biomolecules’ mean? Structural Role of Biomolecules = the function / job of carbohydrates, fats, proteins in making various parts of living things

7. Structural role of Lipids
Cell Structure
Important storage molecules in organisms
Heat insulation – e.g. under the skin
Waterproof the body
Protection around body organs e.g. kidney, heart
Phospholipids and lipoproteins are major components in cell membranes
Myelin helps transmit messages in nerve cells

8. Learning check What is the structural role of proteins?
Proteins are fibrous (threadlike) in nature.
They combine with phospholipids to from cell membranes (lipoproteins)
Keratin is the structural protein in skin, hair and nails
Myosin is the structural protein in muscle

9. 1.3.7 Metabolic Role of Biomolecules

10. Need to know
State that carbohydrates & lipids act as a primary source of energy
State that proteins act as enzymes and are made of amino acids
State that hormones (protein) act as regulators of metabolic activity
State that vitamin C & D are used for tissue growth, cell production and health maintenance
Name disorders associated with deficiency of a water soluble and a fat-soluble vitamin

11. What does the ‘Metabolic Role of Biomolecules’ mean?
Metabolic = metabolism = all the chemical reactions in a cell
Role = function/job or position/involvement
Biomolecules = carbohydrates, fats, proteins
Metabolic Role of Biomolecules = the function / job / involvement of carbohydrates, fats, proteins in the chemical reactions in cells making various substances for living things

12. Metabolic Role of Carbohydrates and Lipids
These are the primary sources of energy for metabolism – e.g.
glucose (carbohydrate) is an immediate source of energy
lipids are a long-term energy storage

13. Metabolic Role of Carbohydrates and Lipids
They are important in the following processes:
Respiration – energy is released when glucose is broken down to form carbon dioxide and water – catabolism
Photosynthesis – glucose molecules are made from carbon dioxide and water using the sun’s energy – anabolism

14. Metabolic Role of Proteins
All enzymes are proteins and have a folded shape. Enzymes control the chemical reactions in cells.
e.g. enzymes control the processes of photosynthesis and respiration
Chlorophyll is a protein that traps the sun’s energy during photosynthesis

15. Learning check
Give examples of the primary sources of energy for metabolism
Glucose & Lipids
Name two important metabolic pathways and state whether they are anabolic or catabolic
Photosynthesis – anabolic
Respiration – catabolic

16. Metabolic Role of Hormones
Hormones regulate body functions
e.g. the hormone insulin controls the amount of glucose in the blood
Oestrogen, progesterone and testosterone are other hormones controlling human sexual development

17. Learning check What is the metabolic role of protein?
Enzymes are proteins.
Enzymes control the processes of photosynthesis and respiration
Chlorophyll is a protein that traps the sun’s energy during photosynthesis

18. Metabolic Role of Vitamins
Definition: can you remember it
Vitamins are essential organic catalysts of metabolism
They are needed in small amounts for the correct functioning of the body
They cannot be made by the body
They must be in the diet

19. Vitamin C Chemical name: ascorbic acid Solubility: water soluble
Function: for building connective tissue i.e. tissue used for attaching organs together or for protection, e.g. skin, blood vessels, bone, tendons, cartilage, ligaments
Source: Citrus Fruits, Green vegetables

20. Vitamin D Chemical name: calciferol Solubility: fat soluble
Function: needed to absorb calcium from food. Calcium needed for healthy teeth and bone formation and their maintenance
Source: Dairy products, fish liver oils, egg yolk, made by skin in sunlight

21. Learning check For the vitamins C & D give the following
The chemical name -
Solubility -
Function -
Source in the diet -
Vit C
Vit D
Ascorbic acid
Calciferol
Water soluble
Fat soluble
Connective tissue formation
Absorb calcium
One source
One source

22. Vitamin deficiency disorders
Lack of Vitamin C causes
scurvy
Symptoms: soft bleeding gums, bad and loose teeth
Lack of Vitamin D causes
rickets in young children
Symptoms: softening of the bones of the spinal column and bowlegs
osteomalacia in adults
Symptoms: the bones lose calcium and become weak – common in vegans

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