2. Carbs, Lipids & Proteins
3.2.1 Distinguish between organic and inorganic compounds.
Compounds containing carbon that are found in living organisms
(except hydrogencarbonates, carbonates and oxides of carbon)
are regarded as organic.
3.2.2 Identify amino acids, glucose, ribose and fatty acids from
diagrams showing their structure.
Specific names of amino acids and fatty acids are not expected.
3. Carbs, Lipids & Proteins
3.2.3 List three examples each of monosaccharides,
disaccharides and polysaccharides.
The examples used should be:
glucose, galactose and fructose
maltose, lactose and sucrose
starch, glycogen and cellulose.
3.2.4 State one function of glucose, lactose and glycogen in
animals, and of fructose, sucrose and cellulose in plants.
4. Carbs, Lipids & Proteins
3.2.5 Outline the role of condensation and hydrolysis in the
relationships between monosaccharides, disaccharides and
polysaccharides; between fatty acids, glycerol and triglycerides;
and between amino acids and polypeptides. (This can be dealt
with using equations with words or chemical formulas).
3.2.6 State three functions of lipids. (Include energy storage and
thermal insulation).
3.2.7 Compare the use of carbohydrates and lipids in energy
storage.
5. Organic and Inorganic
Recall that Organic compounds are substances that contain
carbon and are found in living systems.
There are a few exceptions:
– Carbon dioxide, carbonates
All other substances are considered Inorganic Compounds.
Organic compounds often have covalent bonds
Inorganic compounds can have either covalent or ionic bonding
– Covalent - Bonds where electrons are shared between the atoms
• Formed between two non-metals
– Ionic - bonds where electrons are transferred between atoms
• Formed between a metal and a non metal
6. Amino Acids
There are 20 amino acids.
Amino acids are the building blocks of proteins.
All amino acids have:
– An amine group. –NH2
– A carboxyl group. -COOH
– A central carbon atom and hydrogen atom.
– An R group – side chain.
The generalised structure of an amino acid is:
Amine
group
Carboxyl
group
7. Carbohydrates
These are Organic Compounds Containing:
– Carbon, Hydrogen, Oxygen (CH20’s)
Carbohydrates can be divided into 3 main groups:
– Monosaccharides
• Single, simple sugars eg: glucose, fructose, ribose
• Soluble in water.
– Disaccharides
• Pairs of monosaccharides
– Sucrose – Glucose + Fructose
– maltose – Glucose + Glucose
• Soluble in water.
– Polysaccharides
• Large chains of monosaccharides eg: starch, glycogen, cellulose
• Insoluble in water.
9. Carbohydrates
Carbohydrates have different functions in living
things:
Glucose – energy source for cell respiration
Lactose – sugar/source of energy in milk
Glycogen – stores glucose in liver & muscles
Fructose – sweetens most succulent fruits
Sucrose – transport sugar in plants (phloem)
Cellulose - primary component of plant cell wall
10. Lipids
Lipids release about twice as much energy per gram as
carbohydrates.
Lipids have many different functions in living things:
– Energy storage:
• Layers of fat in animals.
• Oil in plants.
– Heat insulation:
• Layer of fat under skin reduced heat loss.
– Buoyancy:
• Lipids are less dense than water and so help animals float.
– Waterproofing:
• Waxy cuticle on leaves reduce water loss
– Cell membranes.
11. Lipids
Lipids can be classified into different groups:
– Fats
• Usually solid at room temperature.
• Contain saturated fatty acids.
• Usually made in animals.
– Oils
• Usually liquids at room temperature.
• Contain unsaturated fatty acids.
• Usually made in plants.
– Waxes
– Steriods
• Different structure to other lipids
• Examples include some hormones.
12. Lipids
A common group of lipids are neutral fats:
They consist of a glycerol molecule and fatty acids.
– glycerol + 1 fatty acid monoglyceride
– glycerol + 2 fatty acids diglyceride
– glycerol + 3 fatty acids triglyceride
13. Condensation Reactions
In condensation reactions two units are joined together to create
larger molecules and water.
– Carbohydrates
• glucose + glucose maltose + water
– Amino Acids
• amino acid + amino acid dipeptide + water
– Lipids
• glycerol + fatty acid monglyceride + water
14. Hydrolysis Reactions
In Hydrolysis reactions, two units are separated using water.
– Remember hydro means water and lysis means to split.
– Carbohydrates
• polysaccharides + water disaccharides or monosaccharides
– Amino Acids
• polypeptide + water dipeptides or amino acids
– Lipids
• Glycerides + water glycerol + fatty acid
21. IBO guide:
3.2.1 Distinguish between organic and inorganic compounds.
Compounds containing carbon that are found in living organisms
(except hydrogencarbonates, carbonates and oxides of carbon)
are regarded as organic.
3.2.2 Identify amino acids, glucose, ribose and fatty acids from
diagrams showing their structure.
Specific names of amino acids and fatty acids are not expected.
22. IBO guide:
3.2.3 List three examples each of monosaccharides,
disaccharides and polysaccharides.
The examples used should be:
glucose, galactose and fructose
maltose, lactose and sucrose
starch, glycogen and cellulose.
3.2.4 State one function of glucose, lactose and glycogen in
animals, and of fructose, sucrose and cellulose in plants.
23. IBO guide:
3.2.5 Outline the role of condensation and hydrolysis in the
relationships between monosaccharides, disaccharides and
polysaccharides; between fatty acids, glycerol and triglycerides;
and between amino acids and polypeptides. (This can be dealt
with using equations with words or chemical formulas).
3.2.6 State three functions of lipids. (Include energy storage and
thermal insulation).
3.2.7 Compare the use of carbohydrates and lipids in energy
storage.
