Concept 5.3: lipids are a diverse group of hydrophobic molecules

what is a lipid

a large biological molecule that does not include true polymers

how do lipids mix with water

lipids mix poorly if at all with water

are lipids polar or nonpolar

they are nonpolar because they contain mostly hydrocarbon regions

what molecules make up fats

glycerol and fatty acids

why do fats separate from water

because water molecule hydrogen bond to one another and exclude the fats

what makes up a fat

3 fatty acids are joined to glycerol by dehydration to form an ester linkage

what is an ester linkage

3 fatty acids and a glycerol joined together through a dehydration reaction

what are triglycerol/triaclyglycerol/triglyceride

what forms when a 3 fatty acids are joined by a glycerol

why are triglycerides important

they are important cell energy storage molecules

what is the simplest type of lipid

a fatty acid

describe a saturated fatty acid

a saturated fatty acid has the maximum number of hydrogen atoms possible and no double bonds

describe an unsaturated fatty acid

an unsaturated fatty acid has one or more double bonds

describe a fat made from saturated fatty acids

saturated fat are made from saturated fatty acids and are solid at room temperature and make up most animal fats (like butter)

describe fats made from unsaturated fatty acids

a fat made from unsaturated fatty acids is an unsaturated fat or an oil and it is liquid at room temperature and make up mostly plant fats and fish fats

what could happen to a person if they consumed too many saturated fats

it could result in cardiovascular disease

what is hydrogenation

the process of converting unsaturated fats to saturated fats by adding hydrogen

what is a trans fat

when you hydrogenate vegetable oils, it can create unsaturated fats with trans double bonds that contribute significantly to cardiovascular disease

where can you find omega- 3 fatty acids and why do you need them

fatty fish, certain nuts and vegetable oils, you need them because they are not synthesized in the human body

what is the major function of fats in the human body

to store energy long term

what is a phospholipid

consists of two fatty acids and a phosphate group attached to a glycerol

define amphipathic

a molecule that has both hydrophilic and hydrophobic regions in the structure

describe the attraction of water related to phospholipids

the two fatty acid tails are hydrophobic but the head it hydrophilic due to the phosphate group and its attachments

what doe phospholipids from when they are put in water

they self assemble into double layered sheets called bilayers

what is the most important purpose of a phospholipid

it makes up the cell membrane

in a cell what direction does the hydrophobic tail of a phospholipid point towards

the hydrophobic tail points inward towards the interior

what are steroids

lipids characterized by a carbon skeleton consisting of four fused rings

what is cholesterol

a type of steroid that is a component in animal and cell membranes and a precursor from which other steroids are synthesized

how can steroids function

steroids can function as hormones or chemical messengers that pass through the cardiovascular system

what are the two sex hormones called

estradiol and testosterone

what is the most important steroid

vitamin D

how does vitamin d work

it is synthesized in the skin when exposed to UV light and important for calcium absorption and bone formation

functions of monosaccharides

fuel, and a carbon source that can be converted to other molecules or combined into polymers

what is the function of disaccharides

fuel, and a carbon source that can be converted to other molecules or combined into polymers

what is the function of the four polysaccharides

cellulose strengthens plant cell walls

starch stores glucose for energy in plants

glycogen stores glucose for energy in animals

chitin strengthens animal exoskeletons and fungal cell walls

what is the function of trioclyglycerols (fats or oils)

important energy source

what is the function of phospholipids

lipid bilayers of membrane

what is the function of steroids

component of cell membrane (for cholesterol) and signaling molecules that travel through the body (hormones)