1. Carbohydrates Lipids Proteins Stephen Taylor
Image: 'Melts In Your Hand' Found on flickrcc.net
Stephen Taylor

2. Assessment Statements Obj.
3.2.1
Distinguish between organic and inorganic compounds. 2
3.2.2
Identify amino acids, glucose, ribose and fatty acids from diagrams showing their structure.
3.2.3
List three examples each of monosaccharides (glucose, galactose, fructose), disaccharides (maltose, lactose, sucrose), and polysaccharides (glycogen, cellulose, starch). 1
3.2.4
State one function of glucose, lactose and glycogen in animals and of fructose, sucrose and cellulose in plants.
3.2.5
Outline the role of condensation and hydrolysis in the relationships between:
monosaccharides, disaccharides and polysaccharides
fatty acids, glycerol and triglycerides
amino acids and polypeptides
3.2.6
State three functions of lipids, including energy storage and thermal insulation (also: protection, membranes, buoyancy, neuron insulation).
3.2.7
Compare the use of carbohydrates and lipids in energy storage
energy storage per gram (kJ/g)
fast/slow release of energy
demand for oxygen & ease of release of energy 3
Command terms:
Assessment statements from: Online IB Biology Subject Guide

3. Organic compounds contain carbon and are found in living things.
They usually contain C-H or C-C bonds.
The organic compounds we study can be used in metabolic reactions.

4. Some inorganic compounds also contain carbon.

5. Carboxylic Acid Group (-COOH)
A generalized amino acid
The basic structure of the amino acids is common. There are 22 different protein-making amino acids, though only 20 are coded for in genetic code. Each has its own unique R-group. Some are polar, others non-polar and their different properties determine their interactions and the shape of the final protein.
Amino Group (-NH2)
Carboxylic Acid Group (-COOH)
The amino group is one of the reasons why nitrogen is an important element in living things.
The carboxylic acid group contains an oxygen double-bonded to the carbon and a hydroxyl group (-OH) that can be lost to form new bonds.

6. Methionine: an amino acid
Methionine is an important amino acid as it is coded by the START codon in mRNA (AUG). This means that is is the first amino acid in all polypeptide chains as it is the first produced in transcription in the ribosomes.
Although methionine (Met) has quite a large R-group, we can still identify the amino group and carboxylic acid group on the amino acid.
Sulphur forms strong bonds (disulphide bridges) with other S-containing amino acids.
The simplest amino acid is glycine, with H in the R-group position.

7. Glucose General formula: C6H12O6
This is the basic mono-saccharide (single-unit) hexose (6-carbon) sugar molecule that is used in respiration. It is a chemical store of energy.
General formula: C6H12O6
We count the carbons in clockwise direction, starting with the first carbon after the oxygen atom in the ring.

8. Ribose General formula: C5H10O5
This is the basic mono-saccharide (single-unit) pentose (5-carbon) sugar molecule. It is found in RNA and a similar version in DNA.
General formula: C5H10O5
We count the carbons in clockwise direction, starting with the first carbon after the oxygen atom in the ring.

9. Fatty Acids & Glycerol
Fatty acid chains can be of many lengths, extended by adding CH2 units. They are an efficient store of energy and bond with glycerol (a simple sugar alcohol) to make triglycerides – lipids.

12. Physical Modeling Which molecule is this? How do you know?
Use the models to make glucose and ribose.

14. amino acid (glycine)
glucose
glycerol
ribose

16. this one
(glycine)

17. Identify these organic molecules.
fatty acid
ribose
glucose
amino acid

20. State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants.
Glucose is used in cell respiration to produce ATP for use in energy processed in cells.
Glucose + Oxygen  Carbon dioxide + water

21. Glycogen is an insoluble storage molecule in the
liver. When blood glucose is high, the
pancreas releases insulin, telling the
liver to capture blood glucose and
combine molecules of glucose to
make the polysaccharide glycogen,
through condensation reactions.
This stores energy for later.
When blood glucose drops,
the hormone glucagon causes
the glycogen to be broken down
(hydrolysis reactions) to glucose and
then released back into the blood.
blood glucose too high
blood glucose too low
Liver from:

22. Lactose Lactose is a disaccharide produced in mammal mothers.
It consists of glucose and galactose and is easily digested by the lactase enzyme in the young animal’s digestive system.
By producing a small disaccharide that can be broken down by lactase, the mother can provide her young with a source of energy that can be quickly digested after feeding and then readily used in respiration.
Breastfeeding logo from:

23. Condensation reactions make bonds. Hydrolysis bonds break these bonds.
Watch these three animations and make a
generalisation about the processes:
function, roles of enzymes, roles of water

26. Animation: http://is.gd/PeptideBond

27. Animation: http://is.gd/PeptideBond

37. Carbohydrates vs Lipids for energy storage

39. Emperor Penguin Masses
Data-based Question
Emperor Penguin Masses
Page 50 in the Course Companion
Image source:

41. What are some uses of lipids in living things?

42. For more resources.
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