Carbohydrates, Lipids, Proteins, and Nucleic Acids Macromolecules.
Biological molecules (Carbohydrates and Lipids) water and Proteins Recap-AS Biology [JM]
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Transcript of Biological molecules (Carbohydrates and Lipids) water and Proteins Recap-AS Biology [JM]
BIOLOGICAL MOLECULES 2Carbohydrates and lipids
Jorge Melo
Recap
Water Recap High specific heat capacity.
High latent
heat.
Proteins recap
Recap
Hydrolysis
Condensation
Recap
Recap
Objectives
List the features of carbohydrates. Using diagrams to explain the structure
of a simple carbohydrate. Explain how complex carbohydrates are
formed from simple carbohydrates. List the differences between triglycerides
and phospholipids. Describe the structure of lipids. Explain how the structure of lipids affects
their properties.
Mind map
Carbohydrates Disaccharides Polysaccharides Lipids Triglycerides Phospholipids Cholesterol
Carbohydrates Introduction
Most important source of energy
Store energy
Make structure
Elimination of waste materials and toxins
Sources: dairy products, fruits and sugar (simple) starches are found in grains or cereals such as rice, barley, oat, buckwheat, millet and rye, and in some root vegetables including parsnips and potatoes (more complex).
Carbohydrates Introduction
Carbon Hydrate
Carbon and water
3 atoms
C O H
Carbohydrates Three types of
carbohydrates Monosaccharides
(simple sugars) Disaccharides
(double sugars (form from two monosaccharides)
Polysaccharides (polymer chain – hundreds of monosaccharides)
Carbohydrates
Carbohydrates are made up of sugar molecules, the general formula for sugar is CnH2nOn.
A carbohydrate that is a single sugar molecule is a monosaccharide. Examples include glucose, fructose, and galactose.
As sugars monosaccharides are all sweet.
Glucose is an example of a Hexose, and has two forms alpha and beta.
Carbohydrates
The name of monosaccharides varies with the number of C atoms
Trioses
Pentoses
Hexoses
3 C
5 C
6 C
Glucose Main energy source for
most living organisms
Photosynthesis product
Structural isomers
α 1-4 linkages: starch (amylose and amylopectin) easy to break down by enzymes
β 1-4 linkages: linear microfibrils of cellulose difficult to break down
Other monosaccharides
Fructose Very sweet sugar
Galactose
Galactose Found on milk
Disaccharides Made by joining two
monosaccharides.
Two α glucose molecules form maltose.
condensation reaction.
glycosidic bond (covalent)
Because the link is between carbon 1 and 4, it’s an α 1-4 glycosidic bond.
Disaccharides are also sweet.
Disaccharides
Sucrose: the sugar you put in your tea
lactose: milk sugar
Task1 Using the diagram on the previous slide
work out the formula for maltose.
C12H22O11
What name is given to the carbohydrate in which n is 6 5 3
State 2 different functions of the carbohydrates
Simple carbohydrates are combined to form disaccharides, what else is produced?
Maltose is broken down by the enzyme maltase.
This is a hydrolysis reaction.
Polysaccharides
Polysaccharides
Linking together thousands of α glucose molecules produces amylose found in starch.
Amylose molecules coil to form long spirals held in place by hydrogen bonds, making it compact.
Starch is insoluble and metabolically inactive making it perfect for storing in plant cells.
It is not sweet.
Animals do not store amylose, instead they use glycogen which is similar but contains 1-6 glycosidic bonds forming side branches.
Glycogen is broken down by the enzyme glycogen phosphorylase which is activated by insulin.
Cellulose is similar to amylose but it is made of β-glucose, the β 1-4 bonds do not cause it to coil instead it is straight.
As a result the molecules do not form hydrogen bonds within the same strand but with their neighbours forming bundles called fibrils which in turn for larger bundles called fibres all held by hydrogen bonds.
This makes cellulose extremely strong, and there are very few animals with enzymes to break β 1-4 bonds.
Lipids Fats and oils
Room temp. fats are solids, oils are liquid
Made of: C O H
Higher proportion of H
Insoluble in H2O
Triglyceride Simplest example
of a lipid
3 fatty acids attached to a glycerol molecule
Triglyceride The carboxyl group at the
end of the fatty acid reacts with the hydroxyl group on the glycerol.
Forming an ester bond, (involves covalent bonds).
This is a condensation reaction
Ester bond
Triglycerides
Insoluble in H2O – no charge
Hydrophobic
Saturated (where each of the carbons in the fatty acid are attached to two hydrogen atoms.)
Unsaturated (double bonds)
Unsaturated Lipid
Phospholipids Like a triglyceride but
one of the fatty acid chain replaced by a phosphate group
Different properties
Head hydrophobic Tail hydrophilic
Blue: Fatty acid Pink: Glycerol Yellow phosphate group
Basic form of the cell membrane
Cholesterol
Cholesterol is very different from other lipids, some don’t class it as a lipid at all.
This basic structure is shared with all steroids that are made from it, many of which are hormones.
Task 2
Objectives
List the features of carbohydrates. Using diagrams explain the structure of a
simple carbohydrate. Explain how complex carbohydrates are
formed from simple carbohydrates. List the differences between triglycerides
and phospholipids. Describe the structure of lipids. Explain how the structure of lipids affects
their properties.