Biology 3.4

Glycerol

3-carbon molecule with one hydroxyl group (-OH) bonded to each carbon

Fatty acid

A chain of carbon and hydrogen atoms with a carboxyl group (-COOH) at one end

more a higher portion of C-H bonds

A gram of fat stores _ energy than a gram of starch due to _ within fat molecules relative to starch molecules (C-H bonds, more energy a molecule can yield)

Testosterone

A steroid hormone found largely in males

Hydrocarbons Long structures that resemble a fatty acid attached by its carboxyl group to another long hydrocarbon chain

All waxes contain

Phospholipids

Another class of lipids, are similar in structure to triglycerides, but 3rd hydroxyl group of glycerol is linked to a phosphate group instead of a fatty acid; a small polar/ charged nitrogen-containing molecule is attached to a phosphate

Essential fatty acids

Certain fatty acids are necessary for good health but cannot be synthesized by the body (they must be obtained in the diet)

Waxes

Complex lipids that help prevent water loss from organisms

Unsaturated fatty acids

Contains 1 or more C=C double bonds and consequently fewer C-H bonds

Fatty acid

During the synthesis of a triglyceride, what is attached to glycerol in each dehydration reaction?

Ester bond

Each of hydroxyl groups in glycerol is linked to the carboxyl group of a fatty acid by the removal of a molecule of water by a dehydration reaction (example)

Triglycerides

Energy storage

Fat

Energy storage for mobile organisms in which excess body mass may be a disadvantage; structure support for organs; provides insulation under the skin that helps protect many terrestrial animals during cold weather and marine mammals in cold water

Stearic acid

Example of saturates

Linoleic acid

Example of unsaturated

Nonpolar hydrophobic region

Fatty acid chains provide _ at the opposite end

Monounsaturated fatty acid

Fatty acid with one C=C

Polyunsaturated fatty acid

Fatty acid with two C=C bonds

Steroids

Form hormones important in reproduction

Triglycerides (fat)

Formed by bonding glycerol to three fatty acids

Cholesterol

Found in the blood and cellular membranes of animals (contribute to the formation of blockages in major blood vessels)

Steroids

Four fused rings of carbon atoms form the skeleton; 1 or more polar hydroxyl groups are attached to this ring structure

Polar hydrophilic region

Glycerol backbone, phosphate group, and constitute a _ at one end of phospholipid

Steroid Ring structure

Hormone production

ATP

Hydrolysis of triglycerides releases the fatty acids from glycerol, and these products can then be metabolized to provide energy to make_

Lipids

Hydrophobic molecules composed mainly of hydrogen and carbon atoms, and some oxygen (nonpolar & insoluble in water)

Bilayers

In an aqueous environment, phospholipids form lipid _ with hydrophobic ends facing the interior because this is energetically most favorable for these molecules

Fats Phospholipids Steroids Waxes

Lipids account for 40% of the organic matter in the avg human body and includes:

Nonpolar molecules

Lipids are insoluble to water. Why?

carbon Hydrogen

Lipids are molecules that are composed of primarily what two elements

Unsaturated fatty acid

Liquid at room temperature Oil Found primarily in plants and plant products Double bonds within carbon backbone Trans fat are a synthetic form that has a higher melting point

Phospholipid

Membrane formation

Saturated fatty acids

No double bonds within carbon backbone Solid at room temperature Comes primarily from animals and animal products

Saturated

No double-bonded carbons

low melting point of unsaturated fats is due to double bounds forming structures that stop tightly bound formations

Olive oil and butter both contain fats; however, one is liquid at room temperature and the other is solid. Why?

unsaturated

Olive oil is a liquid and is therefore expected to have a high proportion of _ fatty acids

Unsaturated

One or more double bonds

Amphipathic

Phospholipids are:

Phospholipids

Plasma membrane structure

High melting point tend to be solid at room temperature

Saturated fats have

Estrogen

Steroid hormone found in high amounts in female vertebrates

Ring structures

Steroids contain:

carbon hydrogen

The amount of energy a fat contains is determined by how many bonds it has between _ atoms and _ atoms

four fused rings of carbon atoms

The distinct chemical structure of steroids includes

hydrophilic heads sticking out toward the interior and exterior of the cell

The plasma membrane is made up of a phospholipid bilayer, with the _ of the phospholipids _

Pack together as tightly

Unsaturated fats are not able to _ as saturated fats

Low melting point Tens to be liquids at room temperature

Unsaturated fats have

Linoleic acid

Unsaturated fatty acids form in the shape of

lipids

Waxes are a class of what?

Saturated fatty acid

When all carbons in a fatty acid are linked by single covalent bonds (bc all carbons are saturated with covalently bound hydrogen)

Bilayer is the most energetically favorable arrangement in aqueous solution The hydrophilic ends attract water while the hydrophobic ends exclude water

Why do phospholipids arrange into bilayers?

Wax

water storage