lipids
TRANSCRIPT
![Page 1: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/1.jpg)
![Page 2: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/2.jpg)
Lipids are:water-insoluble organic substances but
readily soluble in organic solutions e.g. ether
![Page 3: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/3.jpg)
The term ‘lipid’ defines compounds:
not on the basis of structural similarity
BUT in terms of their
solubility
![Page 4: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/4.jpg)
‘’;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Water is so attracted to other water molecules that anything between them
is squeezed out of the way.
![Page 5: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/5.jpg)
Lipids do not form polymers. Why?
Not made of monomers.
Lipids are:structurally functionally
DIVERSE
![Page 6: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/6.jpg)
Types of Lipid
1. Triglycerides [Fats & Oils]2. Waxes3. Phospholipids4. Steroids5. Glycolipids6. Lipoproteins7. Terpenes
![Page 7: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/7.jpg)
Types of Lipid
1. Triglycerides [Fats & Oils]
2. Waxes3. Phospholipids4. Steroids5. Glycolipids6. Lipoproteins7. Terpenes
![Page 8: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/8.jpg)
1. Fats & Oils [Triglycerides]
•the commonest lipids in nature
•the constituents of triglycerides are:-
fatty acids (alkanoic acids)
glycerol (propane 1-2-3 triol)
![Page 9: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/9.jpg)
1) Fatty acids- general formula: R.COOH
- most have an even number of C: most commonly 16-18
C16H32O2
R
- fatty acids may be: saturated or unsaturated
![Page 10: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/10.jpg)
Saturated fatty acid[Single bonds only]
Unsaturated fatty acid[Double bonds]
![Page 11: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/11.jpg)
Saturated fatty acids
Unsaturated fatty acid
![Page 12: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/12.jpg)
The more double bonds present, the more bent the molecule is
![Page 13: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/13.jpg)
Difference between a fat and an oil:
fats - solid at 20C oils - liquid at 20C
![Page 14: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/14.jpg)
Why are fats solid and oils liquid at room temperature?
Molecule has kinks, keeping the fatty acids apart and as a result, oil is liquid at room
temperature.
![Page 15: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/15.jpg)
A glyceride forms when an –OH in glycerol is replaced by an organic acid
Fatty acid
glycerol
![Page 16: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/16.jpg)
Types of glycerides:Monoglyceride
Diglyceride
Triglyceride
![Page 17: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/17.jpg)
Why are fats and oils classified as triglycerides?
![Page 18: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/18.jpg)
Triglycerides:- are non-polar - float on water
Polar head - Hydrophilic
Non-polar tail - Hydrophobic
![Page 19: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/19.jpg)
Animal fat solidifies at a low temperature
![Page 20: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/20.jpg)
Why do plants and poikilotherms tend to have a high proportion of
unsaturated fatty acids?
To prevent their triglycerides from solidifying.
![Page 21: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/21.jpg)
Fatty acids link to glycerol as a water molecule is lost
![Page 22: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/22.jpg)
Fats & oils are made of one glycerol and three fatty acids
![Page 23: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/23.jpg)
Formation of a triglyceride
formed by esterification / condensation
![Page 24: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/24.jpg)
![Page 25: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/25.jpg)
Fatty acids may be
different in a
triglyceride
![Page 26: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/26.jpg)
Functions of Triglycerides1. Store energy in animals +
Yield energy
![Page 27: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/27.jpg)
Comparison of energy yield from:
Triglycerides: 37 kJ g-1
Carbohydrates: 17 kJ g-1
MORE energy from triglycerides:
Due to more hydrogen.
![Page 28: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/28.jpg)
2. Animals store extra fat when hibernating: acts as an insulator.
Subcutaneous fat
![Page 29: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/29.jpg)
2. Fat around organs: protect against bumps keeps them warm
Kidney surrounded by fat
![Page 30: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/30.jpg)
3. Brown adipose tissue (brown fat) - releases heat but no ATP- heat maintains core temperature in:
small mammals in newborn humans, particularly during cold
exposure without shivering
![Page 31: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/31.jpg)
![Page 32: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/32.jpg)
4. In aquatic mammals blubber contributes to buoyancy.
![Page 33: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/33.jpg)
What is present in the hump? Why?
When fat is metabolised, it yields: 1. energy 2. more than 1 g of water for each 1 g of
fat by respiration.
FAT
![Page 34: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/34.jpg)
5. Water is produced when fats are oxidised - this metabolic water is important in desert animals.
A kangaroo rat never drinks. Mention TWO ways
how it can get water.1. Eating2. Metabolism
![Page 35: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/35.jpg)
6. Nerves are covered with a myelin sheath for insulation of the fibre and for fast conduction of impulses.
![Page 36: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/36.jpg)
Test for Triglycerides
Paper becomes translucent.
![Page 38: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/38.jpg)
Test for Triglycerides
Emulsion Test
![Page 39: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/39.jpg)
Types of Lipid
1. Triglycerides [Fats & Oils]
2.Waxes3. Phospholipids4. Steroids5. Glycolipids6. Lipoproteins7. Terpenes
![Page 40: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/40.jpg)
Waxes: not a food source no enzymes to break them down
![Page 41: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/41.jpg)
Structure of Waxes
one fatty acid an alcohol of high molecular weight instead of glycerol
![Page 42: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/42.jpg)
Feathers do not get wet.
WHY?
Raindrops on feathers.
![Page 43: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/43.jpg)
![Page 44: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/44.jpg)
Waxes are mainly for e.g.
cutin makes up the waxy cuticle of leaves
fruits produce a waxy coating to
keep from drying out
![Page 45: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/45.jpg)
Sebum in mammalian skin
![Page 46: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/46.jpg)
Wax in ears traps:dustsandother foreign
particles
do not go deeper into the ear and cause no damage
![Page 47: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/47.jpg)
Suberin in Casparian strips,
![Page 48: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/48.jpg)
Exoskeleton in
insects
[contains wax]
![Page 49: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/49.jpg)
Waxes build elaborate structures such as beehives
![Page 50: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/50.jpg)
Types of Lipid1. Triglycerides [Fats & Oils]2. Waxes
3.Phospholipids4. Steroids5. Glycolipids6. Lipoproteins7. Terpenes
![Page 51: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/51.jpg)
Phospholipidslipids with a
phosphate group condensationH2O
![Page 52: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/52.jpg)
Phospholipids are made of one phosphate group and 2 fatty acids
Phospholipids are amphipathic – have both polar & nonpolar portions
![Page 53: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/53.jpg)
Phospholipids are constituents of membranes
![Page 54: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/54.jpg)
Two structures formed by self-assembly of phospholipids in aqueous environments
![Page 55: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/55.jpg)
Types of Lipid1. Triglycerides [Fats & Oils]2. Waxes3. Phospholipids
4.Steroids5. Glycolipids6. Lipoproteins7. Terpenes
![Page 56: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/56.jpg)
Steroids are structurally different from all other
lipids
consist of a complex carbon ring structure
Cholesterol is a steroid.
![Page 57: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/57.jpg)
Cholesterol:• is the steroid present in the
largest amount in humans
• a key intermediate in the synthesis of related steroids
• an important constituent of animal plasma membranes
made in the liver
![Page 58: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/58.jpg)
![Page 59: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/59.jpg)
Sex hormones are Steroids
![Page 60: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/60.jpg)
Types of Lipid
1. Triglycerides [Fats & Oils]2. Waxes3. Phospholipids4. Steroids
5.Glycolipids6. Lipoproteins7. Terpenes
![Page 61: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/61.jpg)
Glycolipids• carbohydrate + lipid • components of cell membranes
![Page 62: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/62.jpg)
Types of Lipid1. Triglycerides [Fats & Oils]2. Waxes3. Phospholipids4. Steroids5. Glycolipids
6.Lipoproteins7. Terpenes
![Page 63: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/63.jpg)
Lipoproteins• occur in membranes • are the form in which
lipids are transported in the blood e.g. fatty acids are bound to albumin
protein
triglyceride &
cholesterol
phospholipid
Lipoproteins vary in size and composition
![Page 64: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/64.jpg)
Types of Lipid
1. Triglycerides [Fats & Oils]2. Waxes3. Phospholipids4. Steroids5. Glycolipids6. Lipoproteins
7.Terpenes
![Page 65: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/65.jpg)
Terpenes may be:volatile : attract pollinators
less volatile:strongly bitter-tasting to prevent plants being eaten by herbivores
![Page 66: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/66.jpg)
Examples of terpenes:
light-absorbing pigments in animals & plants
carotenoidsrubber
![Page 67: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/67.jpg)
β carotene:- traps light in plants and in humans- is broken down into two vitamin A
molecules from which we make rhodopsin
![Page 68: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/68.jpg)
Carotenoids also act as antioxidants:
trap free radicals and
inhibit oxidation
![Page 69: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/69.jpg)
What are free radicals?
free radicals attack healthy cells through a damaging chain reaction of
oxidation [free radicals steal electrons]
An atom or group of atoms that has at least one unpaired electron and is therefore unstable and
highly reactive
![Page 70: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/70.jpg)
Antioxidants neutralise the free radicals
Antioxidants: prevent cancer improve the
immune system
electron
Antioxidant
Free radical
![Page 71: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/71.jpg)
Question: [MAY, 2007]
Suggest explanations for the following statement.Fats are used as storage molecules rather than as an immediate energy source. (2)Fats are ideal for storing energy as they release large quantities of energy. This means that small quantities of stored fat carried by the organism provide sufficient energy without having to carry a heavy load. Fat molecules are large and would take a long time to release energy, making them unsuitable for immediate sources of energy.
![Page 72: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/72.jpg)
Question: [SEP, 2007]
Use your knowledge of biology to explain the following. (5 marks)
Most animals use fats, rather than starch, as energy-storage molecules.
![Page 73: Lipids](https://reader035.vdocument.in/reader035/viewer/2022062515/55c30ec4bb61ebde738b4733/html5/thumbnails/73.jpg)
No life as we know it can exist without lipids. Comment on the importance of lipids to life.
[1994]
Give an account of the important roles played by lipids in living organisms. [SEP, 1998]
Give an overview of the importance of lipids for living organisms. [SEP, 2009]
Essay Titles