1.3 Lipids Flashcards
Why do fats form good waterproofing layers?
lipid tail is hydrophobic so they are insoluble in water
What is a structure of a triglyceride?
1 glycerol and 3 fatty acid tails
What chemical group does glycerol belong to?
alcohol
What are the two different types of fatty acids?
saturated or unsaturated
What bond forms between a fatty acid and glycerol in a triglyceride?
esther bond
What type of reaction happens when esther bonds form?
condensation
What test is used to idenify lipids?
the emulsion test
How is the emulsion test carried out?
take equal vol of water and ethanol with food sample
shake
a cloudy white emulsion will form if lipid present
What part of the phosphlipid is non-polar?
fatty acid tails
What is a respiratory substrate?
any molecule that can be released as energy to create ATP
How do animals get energy from a resp substrate?
energy is released by breaking the C-C bonds and C-H bonds
Why do lipids store more chemical potential energy than carbs?
lipids have more C-C and C-H bonds due to the hydrocarbon tail
What elements are present in lipids?
carbon, hydrogen, oxygen
Are lipids soluble in water? if no what are they soluble in?
no, soluble in organic solutes like ethanol
What are some examples of lipids?
triglycerides - fats and oils
waxes
steroids
cholesterol
What are all the functions of lipids?
thermal insulation
cell membrane structure
energy store
waterproof
source of metabolic water
buoyancy
protection
How are lipids good for insulation?
fats are slow conductors of heat
stored underneath the body surface to help retain body heat
eg: adipose tissue
What is adipose tissue?
a connective tissue that extends throughout your body - body fat
found under the skin
What properties of lipids make is a good energy store?
compact - can store more in small space
insoluble - osmotically inert
high energy yeild - x2 the energy released than carbs when oxidised
What property of lipids make them waterproof? and where would it be found?
insoluble to water
eg: waxy cuticles on insects and plants
skin, fur, feathers
animals produce oily secretion on the skin
What propery of lipids makes them buoyant?
have a lower density than water
What are the two types of lipids?
simple lipids
compound lipids
What are simple lipids made of? and an example?
glycerol and fatty acids only
eg: triglycerides
What are compound lipids made of and an example?
glycerol, fatty acids and another group/molecule/compound
eg: Phospholipids
What is the chemical formula of glycerol?
C3H8O3
What is the general formula for fatty acids?
CH3(CH2)nCOOH
What does a dotted line in the displayed ans skeletal formula of a fatty acid represent?
the variable group
How is a monoglyceride formed?
condensation reaction of a glycerol and fatty acid
an OH from the glycerol and the H from the Carboxyl group on fatty acid
forms an esther bond
What does saturated mean?
full compliment of hydrogens, no double carbon bonds
What does unstaturated mean?
double bond in the hydrocarbon tail, not completely saturated with hydrogens
What does polyunsaturated mean?
more than 1 c=c double bond
What is the difference between unsaturated and saturated fatty acids melting points?
saturated has a higher boiling point
unsaturated has a lower boiling point
What state is a saturated fatty acids at room temp?
solid
What state is a unsaturated fatty acid at room temp?
liquid
Which fatty acid (saturated/unsaturated) is worse for your diet?
saturated is worst for your diet as high intake can increase the risk of coronary heart diseases
What group does a phospholipid contain?
phosphate group
How many tails does a triglyceride have?
3
How many tails does a phospholipid have?
2
What makes up the phospholipids head?
glycerol and phosphate
why are unsaturated fatty acids liquid at room temp?
the double bonds cause the molecule to bend so they cannot pack together so closely
Why are triglycerides a good source of energy?
they have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms
Why are tryglycerides good storage molecules?
have low mass to energy ratio - lots of energy can be stored inn a small vol
How are tryglycerides insoluble?
large and non-polar
How do tryglycerides provide a good source of water?
have a high ratio of hydrogen to oxygen atoms
Are fatty acid molecules hydrophyllic or hydrophobic?
hydrophobic
Are phospholipids polar or non-polar?
polar - hydrophyllic head and hydrophobic tail
What happens when a phospholipid combines with carbohydrates?
forms a glycolipid which are important in cell recognition
How is a triglyceride formed?
1 glycerol and 3 fatty acids
condensation reaction to join them and the removal of 3 water molcules
an esther bond forms
