Lipids (Biochemistry) Flashcards
What are lipids?
fats, oils and waxes
What elements do they contain?
CArbon, Hydrogen and oxygen
Compare oxygen count in carbs to lipids
oxygen content is much lower than in carbohydrates
What is the polarity of lipids?
non-polar
What is the solubility of lipids?
insoluble in water, soluble in organic solvents (acetone and ether (also non polar)
What are the roles of lipids?
Thermal insulation
Energy Store
Buoyancy
Protection
Waterproofing
reducing water loss
source of metabolic water
Why do lipids provide thermal insulation?
fat tissue has fewer capillaries
How much energy per 1g is stored by lipids?
34KJ energy per 1g
Why does fat provide buoyancy?
it is less dense than either muscle or bone
how does fat provide protection?
fat can absorb shocks/impacts, protects organs against physical damage
Why is lipids good for waterproofing?
lipid is hydrophobic so repels water
How does lipid reduce water loss?
prevents desiccation/ drying out
Why are lipids a source of metabolic water?
3 water molecules given off per one triglyceride formed
How does an elephant seal use lipids?
as thermal insulation, buoyancy and a food store
How does a dormouse use lipids?
energy store for hibernation
how do seeds use lipids?
energy sore for germination/growth
how do kidneys use lipids?
protection against physical damage
How do leaves use lipids?
wax, reduces water loss
How do ducks use lipids?
waterproofing
What is the structure of triglycerides?
consists of one glycerol molecule and 3 fatty acids
What is the structure of Glycerol?
Small
3 central carbon atoms
3 hydroxyl groups (OH)
What is the structure of a fatty acid?
carboxyl group COOH
hydrocarbon tail/chain
What is the difference in structure between saturated and unsaturated fatty acids?
Unsaturated have double carbon bonds, consist of less hydrogen atoms
Where is Stearic acid found what is its melting point?
mammalian adipose tissue
69.6 deg. C
Where is oleic acid found what is its melting point?
olive oil
13.4 deg. C
What is the general formula for a Saturated fatty acid?
CH3(CH2)nCOOH
What bond forms between a glycerol and a fatty acid?
ester bond
How does an ester bond form?
by a condensation reaction
What are the components of phopholipids?
1 glycerol
2 fatty acids
1 phosphate group
What do phospholipids form? in which organelles?
cell surface membrane and membrane of other organelles
such as endoplasmic reticulum, golgi apparatus, nuclear envelope of nucleus
What is coronary heart disease?
condition in which proper circulation of blood and oxygen are not provided to the heart and surrounding tissue. Due to narrowing of blood vessels which normally supply the heart with blood and oxygen
What contributes to heart disease?
a high intake of fats, especially saturated fats
What is atherosclerosis?
formation of plaque and fatty build up on the artery walls, narrowing the vessels
How are lipids transported in the body?
Low Density Lipoproteins (LDP) and High Density Lipoproteins transport triglycerides and cholesterol in the blood
What are HDLs composed of?
mainly of proteins, only small amounts of cholesterol
Why are HDLs often referred to as ‘good’ cholesterol?
help remove cholesterol from artery walls and transport it to the liver for removal from the body.
What do higher HDL levels protect against?
coronary heart disease
What are LDLs composed of?
mainly cholesterol, very little protein
Why are LDLs often referred to as ‘bad’ cholesterol?
mostly responsible for depositing cholesterol inside arteries
What are high levels of LDLs associated with?
increased risk of coronary heart disease
How can an artheromatous plaque form?
early damage of protective lining of the artery means white blood cells move to the damaged area. muscle cells divide in the artery wall and there is a build-up of lipids.
What can happen to an atheromatous plaque during exercise or stress?
the plaque can break. Blood enters the crack. Platelets in the blood are activated and a clot forms. Part of the clot may break off, travel to smaller vessels like arterioles and block them. Blood flow can be restricted by plaque or blocked by clot
What is Angina?
affects the heart muscle, blocking of oxygen rich blood to the heart, leads to less oxygen in heart.
What conditions put someone at greater risk of coronary heart disease?
Age (particularly 40+)
Diabetes
Gender
Genetics (heredity)
High blood pressure
high bad cholesterol (LDL)
Lack of sufficient physical activity
Low good cholesterol (HDL)
Menopause
Obesity
smoking
