1.3.7 Metabolic Role of
Biomolecules
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
Meetabolic Role of Biomolecules = the
function / job / involvement of
carbohydrates, fats, proteins in the chemical
reactions in cells making various substances
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for living things
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
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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
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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
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Learning check
1. Give examples of the primary sources of
energy for metabolism
Glucose & Lipids
2. Name two important metabolic pathways
and state whether they are anabolic or
catabolic
Photosynthesis – anabolic
Respiration – catabolic
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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
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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
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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
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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
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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
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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 Absorb
tissue
calcium
formation
- One source
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One source
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
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weak – common in vegans
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 vitamin14
END
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