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Biomolecular Structures:
Chemicals that are made inside living things
Need to know
• Define Biomolecular Structures
• State that simple biomolecular units are composed
of a combination of elements in different ratios
e.g. carbohydrates Cx(H2O)y
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What are they?
Bio-molecular Structures:
Chemicals that are made inside living
things
(food components)
4 major types of Biomolecules:
- Carbohydrates
- Proteins
- Lipids
- Vitamins
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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
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Humans are mainly made up of Water!
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Carbohydrates
Carbohydrates contain the elements
Carbon
Hydrogen
Oxygen
The general formula for a carbohydrate is
Cx(H2O)y
Usually in the ratio of 1C:2H:1O
There are twice as many hydrogen molecules as oxygen
molecules
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Learning check
What are the four major biomolecules?
Name the three elements that make up carbohydrates.
What is the general formula for a carbohydrate?
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3 Types of Carbohydrate
Monosaccharides
Disaccharides
Polysaccharides
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Monosaccharides
These are
single sugar molecules
simple sugars
soluble in water
sweet to taste
smallest carbohydrate unit
Examples:
Found in:
glucose, fructose
fruit
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Learning check
What are the elements that make up all
carbohydrates?
Can you remember the general formula for a
carbohydrate?
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Disaccharides
These are
• two monosaccharide sugar units joined together –
known as double sugar molecules
• soluble in water
• sweet to taste
Examples:
Found in:
sucrose, lactose, maltose
table sugar, milk
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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
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Learning check
Name the three types of carbohydrate
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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
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leaves.
Structure of Lipids
They are made up of the elements
carbon
hydrogen
oxygen
But don’t have the same ratios as carbohydrates.
They are made up of two main types of molecules
Fatty acids
and
Glycerol
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Learning check
Give examples and sources of:
Examples
Sources
Monosaccharides
Disaccharides
Polysaccharides
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Types of Lipid
Two of the main types of lipids are
Triglycerides
Phospholipids
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Triglyceride
This is the smallest lipid
It is made up of
3 fatty acid molecules
and
1 glycerol molecule
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Phospholipids
If one fatty acid of a lipid molecule is
replaced by a phosphate group then a
phospholipid is formed
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Sources of Lipids
• Fat – in and on meat
• Butter (80% fat)
• Cooking oils
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Learning check
The two main types of molecules that make
up lipids are:
The two main types of lipids are:
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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
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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
• Amino acids are joined together by
peptide bonds
• This results in the formation of polypeptide
chains
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Amino Acids
All amino acids contain four distinct chemical
groups connected to a central carbon atom:
• a single hydrogen atom
• an amino group
• a carboxyl group
• a side chain
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Learning check
Proteins contain the elements
Sometimes they contain
Proteins are made up of long chains of
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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
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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
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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
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Learning check
What is a vitamin?
A vitamin is an essential organic catalyst of
metabolism
What vitamins dissolve in water?
What vitamins are fat-soluble?
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Need to know
• State that simple bio molecular units are composed of a
combination of elements in different ratios e.g.
carbohydrates Cx(H2O)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.
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Need to know
• What is a vitamin?
• Name one water soluble vitamin.
• Name one water in-soluble vitamin (fatsoluble)
• List the sources of these vitamins
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1.3.8 Minerals
Minerals
Minerals are salts formed from the earth’s rocks.
These mineral salts then dissolve in water and are
absorbed by plants.
Animals get their minerals by eating plants or
other animals that contain them.
* Minerals are required by organisms in very
small amounts.
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Minerals and Plants
Plants absorb minerals through their roots.
They use:
• *Calcium (Ca) to make cell walls
• *Magnesium (Mg) to make the pigment
chlorophyll
• Nitrates (N) to make proteins
• Phosphates (P) to make ATP, DNA
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Minerals and Animals
Animals get their minerals in the food they eat.
They use
• *Calcium (Ca) to make bones and teeth
• *Iron (Fe) to make the pigment haemoglobin
• Sodium (Na) for the regulation of the osmotic
balance (water content) of cells and the
blood.
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Learning check
How do plants get their minerals?
_________________________________
Plants absorb minerals through their roots
Plants use:
• Calcium (Ca) to make ________
pigment
• Magnesium (Mg) to make the
_________
_________
• Nitrates (N) to make ______
• Phosphates (P) to make _________
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Learning check
How do animals get their minerals?
________________
In the food they eat
Animals use:
• Calcium (Ca) to make ____________
• Iron (Fe) to make the pigment __________
• Sodium (Na) for the regulation of the
_____________
osmotic balance (___________) of cells and
the blood.
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Minerals Summary
They are required to:
• Form part of rigid body tissues
Calcium in bones and cell walls
• Form certain pigments
Iron is needed to make haemoglobin – the
red pigment of blood
Magnesium is needed to make chlorophyll
– the green pigment in plants
• Regulate body fluids
Sodium balances water content in cells
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Need to know
• Minerals required in small amounts
• Minerals used in three ways
– **Form part of rigid body structures
– **Form soft body tissues
– **Function in cellular and body fluids
• State the requirements & use of any 2
minerals in plants.
• State the requirements & use of any 2
minerals in animals.
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1.3.5 Energy Transfer Reactions
Anabolic & Catabolic
Or
Anabolism & Catabolism
Anabolic Reactions
This is where energy is used to make large
molecules (e.g. C6H12O6) from smaller ones (e.g.
CO2 and H2O) using enzymes
e.g. Photosynthesis – glucose molecules (large) are
formed from carbon dioxide and water (small)
using enzymes and the energy from the sun.
This is anabolism. Energy is absorbed.
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An Anabolic Reaction
Energy being used to join two small molecules to
make a larger molecule
Small molecule
Small molecule
ENERGY
Larger molecule
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Catabolic Reactions
This is where energy is released when large
molecules (e.g. C6H12O6) are broken down to
form smaller ones (e.g. CO2 and H2O) using
enzymes
e.g. Respiration – glucose molecules (large) are
broken down by enzymes to form carbon dioxide
and water (small) and energy is released.
This is catabolism. Energy is released.
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Remember….
• Catabolic
• Respiration
• Anabolic
• Photosynthesis
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Learning check
Explain Anabolism
Give an example of an anabolic reaction
Explain Catabolism
Give an example of a catabolic reaction
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Is catabolism the opposite of
anabolism?
No, there are different chemical pathways in both
* 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.
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Energy Transfer Reactions
Respiration – Catabolic reaction
C6H12O6 + Oxygen  Energy + CO2 + H2O
release
Photosynthesis – Anabolic reaction
CO2 + H2O + Energy  C6H12O6 + Oxygen
absorbed
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Learning check
Is anabolism the opposite of catabolism ?
Why?
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Need to know
Definition of the terms:
Anabolic
Catabolic
Give an example of each
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Water
Importance of water in Living Things
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Water is Essential for Life
1. Liquid in which all metabolic reactions
take place.
2. Basis for transport systems in organisms.
3. Environment in which many organisms
live.
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Importance of water in Living Things
• Makes up the bulk of the cytoplasm and is also
found in tissue fluid and blood
• Is a good solvent which allows
– a)cell reactions and b) transport
• Participates in chemical reactions
• Moves in and out of cells, giving them the correct
shape
• Is a good absorber of heat which provides stable
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temperatures for living things and their reactions
Need to know
Five good reasons why water is important for
organisms.
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END
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