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

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.

Some inorganic compounds also contain carbon.

Types of monosaccharides

Glucose General formula: C 6 H 12 O 6 We count the carbons in clockwise direction, starting with the first carbon after the oxygen atom in the ring. 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.

Ribose General formula: C 5 H 10 O 5 We count the carbons in clockwise direction, starting with the first carbon after the oxygen atom in the ring. This is the basic mono-saccharide (single-unit) pentose (5-carbon) sugar molecule. It is found in RNA and a similar version in DNA.

Application: Structure and function of cellulose and starch in plants and glycogen in humans.

Functions of Major Polysaccharides

Skill: Use molecular visualization software to compare cellulose, starch and glycogen.

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

/rasmol/ Go to the below website to pick some software to successfully create cellulose, starch and glycogen. Check out the next slide for what you need to take note of.

Can you… See the monomer is the same for all of them? Explain the bonding and the numbers referring to the carbon numbers that create covalent bonds? See that starch has 2 subcomponents, amylopectin and amylose? See that amylose is the only one of the 3 glucose polysaccharides that is a linear molecule with no side branching? See that all 3 polysaccharides are composed of thousands of glucose monomers?

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

Lactose Breastfeeding logo from: 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.

Glycogen is an insoluble storage molecule in the Liver and in muscle tissue. 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. Liver from: blood glucose too high blood glucose too low

Guidance: The structure of starch should include amylose and amylopectin.

Guidance α Glucose can form long chains with thousands of subunits called an Amylose molecule. Amylose molecules tend to form coiled springs due to the way in which the the glucose units bond, making it quite compact. Large molecules such as amylose differ from glucose in that they are not water soluable. Starch consists of a mixture of Amylose and a branched carbohydrate chain called Amylopectin. The branches are formed when a one end of a chain joins with a glucose in another, forming a (1→4) Glycosidic Bond.

Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.

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

Fatty Acids Not all alike but – They all have a carboxyl group (-COOH) at one end – They all have a methyl group (CH 3 -) at the other end – In between is a chain of hydrocarbons carbons long

Fatty Acids & Glycerol Fatty acid chains can be of many lengths, extended by adding CH 2 units. They are an efficient store of energy and bond with glycerol (a simple sugar alcohol) to make triglycerides – lipids.

SATURATED FATTY ACIDS Carboxyl group Omega end

MONOUNSATURATED FATS One double bond

POLYUNSATURATED At least two double bonds

Hydrogenation Cis Naturally curved fatty acids, called omega-3, 1 st double bond is at the 3 rd carbon atom counting backwards from the omega end trans Hydrogenated, straightened ones

Carbohydrates vs Lipids for energy storage

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

What are some uses of lipids in living things?

ribose glucose amino acid (glycine) glycerol

this one (glycine)

Identify these organic molecules. fatty acid amino acid ribose glucose

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Amino Group (-NH 2 ) Carboxylic Acid Group (-COOH) A generalized amino acid 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. 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.

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.

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