food Flashcards
Nutrition
Nutrition is the way an organism gains and
uses food
Food (nutrition) is needed for:
Energy
Growth of new cells and repair of existing
cells, tissues, organs, etc.
To make the chemicals needed for
metabolic reactions
how many common elements in food
six
How many trace elements in food
three
how many dissolved salts
five
chemical elements
C, H, O, N, P, S
Dissolved Salts
Na, Mg, Cl, K, Ca
trace elements
Fe, Cu, Zn
There are 4 main types of biomolecules
found in food;
Carbohydrates
Lipids (fats & oils)
Proteins
Vitamins
Carbohydrates contain the elements
Carbon
Hydrogen
Oxygen
The general formula for a carbohydrate is
Cx(H2O)y
There are 3 types of carbohydrate;
Monosaccharides
Disaccharides
Polysaccharides
monosaccharides
single sugar molecules
simple sugars
soluble in water
sweet to taste
smallest carbohydrate unit
example of monosachhrides
glucose, fructose
where are monosaccharides found
fruit
Disaccharides
Made of two sugar units joined together –
known as double sugar molecules
soluble in water
sweet to taste
example of Disaccharides
sucrose, lactose, maltose
Disaccharides are Found in:
table sugar, milk
Polysaccharides
Many sugar molecules joined together
Not soluble in water
Do not taste sweet
Example of Polysaccharides
starch, cellulose
Polysaccharides are found in
bread, pasta, cereals
Sources of Carbohydrates
Bread
Pasta
Rice
Potatoes
Fruits
Sweets
Baked goods
structural role of carbohydrates
Cellulose forms
plant cell walls
metabolic role of carbohydrates
Glucose is broken
down during
respiration to
release energy
Glucose is made
during
photosynthesis
Lipids include
fats, oils, steroids, waxes
lipids are made up of the elements
carbon
hydrogen
oxygen
Difference between carbohydrates and lipids in their chemical structure
lipids have very little oxygen compared to carbohydrates
Types of Lipid
Triglycerides
Phospholipids
Triglyceride
this is the smallest lipid made out of 3 fatty acids and one glycerol molecul
Phospholipids
If one fatty acid of a lipid molecule is
replaced by a phosphate group then a
phospholipid is formed
Sources of Lipids
Fat – in and on meat
Butter (80% fat)
Cooking oils
structural role of lipids
Lipids form energy stores in plants and animals
Lipids combine with phosphorus to form phospholipids and with proteins to
form lipoproteins which are important in cell membrane
metabolic role of lipids
Broken down during
respiration to
release energy
Proteins contain the elements
Carbon
Hydrogen
Oxygen
Nitrogen
Some proteins may also contain
sulphur,
phosphorous or iron
Proteins are found in
lean meat, fish, pulses, soya and eggs
what are proteins made up of
long chains of amino acids
how many common proteins are there
20
Amino acids are joined together by
peptide bonds
amino acids joined together by peptide bonds result in the formation of
polypeptide chains
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
Fibrous proteins
show little or no folding.
They form long fibres and are strong
example of fibrous protein
keratin
Globular proteins
show lots of folding. They
form rounded shapes
example of Globular proteins
enzymes
structural role of proteins
Fibrous protein
such as keratin is
found in the hair
and nails
metabolic role of protein
Enzymes (proteins)
are used to control
cellular reactions
Form antibodies to
fight infections
Some hormones
are protein based
and are used to
regulate body
reactions
what vitamins do we need
A, B, C, D, E and K
there are two types of vitamins
water soluble or fat soluble
water solube vitamins
B and C
fat solube vitamins
A, D, E and K
Vit. C is also called
ascorbic acid
Role of Vitamin
Helps to form connective tissue such as
skin, gums etc.
Used for the growth and maintenance of
bones and teeth
Helps to heal wounds
Helps the immune system to properly
function
Vitamin C Deficiency Disease:
scurvy
symptomes of lack of vitamin C deficiency
bruising, bleeding gums
Role of Vitamin D
Helps calcium be absorbed from the
intestine
Needed for healthy tooth and bone
development
Deficiency of Vitamin D Disease
Rickets (in children) and
osteomalacia (in adults)
Symptoms of dificiency of vitamin d
weak, deformed bones that tend
to break easily
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
Role of minerals
Form rigid body structures such as bone
and the cement between plant cell walls
Make soft body parts e.g. muscle
Form salts in cell and body fluids e.g.
tears/saliva
Form biomolecules e.g. haemoglobin
Plants absorb minerals through their roots.
They use:
Calcium (Ca) to help cell walls attach to
each other
Magnesium (Mg) to make the pigment
chlorophyll
Minerals and Animals
Calcium (Ca) to help form bones and
teeth. Found in milk, cheese etc.
Iron (Fe) to make the pigment
haemoglobin. Found in meat, green leafy
vegetables
Water is essential for 3 main reasons;
It is the liquid in which all metabolic
reactions take place
It provides the basis for transport systems
in organisms
It is the environment in which many
organisms live
Importance of Water
Component of cytoplasm and body fluids
Good Solvent (i.e. it can dissolve a large
variety of solutes)
Participates in chemical reactions (e.g.
photosynthesis, respiration and digestion)
Movement through membranes
Good absorber of heat (helps to keep
temperatures stable)
