MACROMOLECULES NOTES - Mr. Adamosky's Biology

MACROMOLECULES NOTES

I. Chemistry of Carbon A. Carbon has four electrons available for bonding. B. Carbon forms strong covalent bonds with hydrogen, oxygen, sulfur, nitrogen, and phosphorus.

C. Carbon atoms can form bonds with each other.

Ethane

Ethene

Ethyne

Benzene

D. Bonding between carbon atoms gives carbon the ability to form chains that can be unlimited in length and shape.

II. Macromolecules

-Macromolecules are giant molecules that can be made up of thousands of smaller molecules.

-Macromolecules are polymers. Polymers are made up of smaller units called monomers.

A. Carbohydrates (saccharides)

1. Monosaccharides (simple sugars): General formula = (CH2O)n, where n 3.

a. Glucose

-known as blood sugar

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-formula = C6H12O6

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4

#1 Carbon

b. Galactose -known as brain sugar

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2

Simple version

-formula = C6H12O6

-found in gums, mucilage, pectin, and milk

c. Fructose -known as fruit or honey sugar -formula = C6H12O6

2. Dissacharides (double sugars) a. Sucrose -known as cane sugar -is made of glucose and fructose -formula = C12H22O11 H2O

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MACROMOLECULES NOTES

14 glycosidic bond

b. Lactose

-known as milk sugar

-is made of glucose and galactose

-formula = C12H22O11 H2O

c. Maltose

-known as malt sugar

-is made of glucose + glucose

-formula = C12H22O11

H2O 3. Polysaccharides (Complex carbohydrates)

a. Glycogen

-used by animals to store extra sugar

-sometimes called `animal starch'

-made entirely of -glucose with

(14) glycosidic bonds

-is highly branched molecule in the

form of granules

-branching occurs every 8 to 12 glucose

Highly

Glycogen

units via (16) bonds

branched

granule

-insoluble in water

-primary storage is in adipose tissue (body fat)

-primarily made in liver and skeletal muscle

-the liver will remove or add glucose to the blood in response to insulin levels:

-after a meal, pancreas releases insulin into blood stream

-when insulin levels are high, liver removes glucose and makes glycogen.

-when insulin levels are low, liver breaks down glycogen and releases glucose.

b. Starches -used by plants to store extra sugar -the enzyme amylase breaks down starches into maltose -stored in amyloplasts in the form of starch granules.

Amyloplasts in a potato cell

Starch granules

-found in high concentrations in wheat, corn, rice, roots and tubers (potatoes)

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MACROMOLECULES NOTES

b. Starches continued i. Amylose -can be linear or helical in shape -insoluble in water -made entirely of -glucose with (14) glycosidic bonds

ii. Amylopectin -moderately branched -branching occurs every 24 to 30 glucose units via (16) bonds -soluble in water -made entirely of -glucose with (14) glycosidic bonds

c. Cellulose (C6H10O5)n -structural component of plant cell walls -90% of cotton and 40% of wood is cellulose -used to make cardboard and paper -insoluble in water -most abundant substance in nature -ruminants and termites can digest cellulose with help of symbiotic microbes -made entirely of -glucose with (14) bonds (every other glucose is inverted)

d. Chitin (C8H13O5N)n -main component of the cells walls of fungi -main component of arthropod (crabs, shrimps, insects) exoskeletons -main component in the beaks of squid and octopuses -made entirely of N-acetylglucosamine with (14) bonds.

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MACROMOLECULES NOTES

B. Lipids 1. Examples: Oils, fats, waxes, steroids, cholesterol 2. Non-polar and insoluble in water 3. Fats provide about 9 kilocalories/gram (compared to carbohydrates at 4 kilocalories/gram) 4. Triglycerides (a common lipid) a. Main constituent of vegetable oil and animal fats b. Formed by combining glycerol with three molecules of fatty acid.

c. An ester bond forms when glycerol links to a fatty-acid chain releasing a molecule of water.

Before bonding

During bonding After bonding

d. These are two simple ways of drawing a triglyceride

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MACROMOLECULES NOTES

e. Triglycerides are stored in adipose tissue (body fat) consisting of adipocytes (fat cells).

f. Mammals use triglycerides for - Bouyancy (lipids are less dense than water so it helps animals float)

g. Insulation (a layer of fat beneath the skin cuts down on heat loss)

h. Production of water (fatty acids produce a lot of metabolic water when they are oxidized during cellular respiration). Camels' humps are made of fat and supply water when needed.

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