Lipids & Cell Membranes

Selectively permeable

some things can move in, but not other things

Phospholipid

Type of lipid that makes up the bilayer structure of cell membranes

Hydrophilic v.s. Hydrophobic

philic - likes/dissolves in water

phobic - does not like/dissolve in water “water fearing”

Selectively permeable/semipermeable

characteristics of allowing some things to pass through the cell membrane easily and other substances need help

What is the function of the cell membrane?

Regulates what goes in and what comes out of a cell

What are the function of each part of the cell membrane (Phospholipids, proteins, cholesterol, carbohydrate chains)

Phospholipids: creates the boundary between the inside and outside of the cell

Protein: form channels and pumps to allow things to move in and out

Cholesterol: Regulates membrane fluidity over wide range of temperatures

carbohydrate chains: Allow individual cells to identify one another

Know the structure of a phospholipid-What structure(phosphate head and lipid tails) is hydrophilic vs. hydrophobic?

Phosphate head- hydrophilic

Lipid tails- hydrophobic

be able to label a cell membrane diagram**

monomer

a molecule that can be bonded with another molecule to create a polymer, building blocks

polymer

when smaller molecules aka monomers join together to form larger molecules, another name is macromolecules

Hydrolysis

this reaction breaks apart polymers due to the addition of water 

hydro = adding water lysis = to break 

*occurs during digestion of food

Dehydration synthesis

this reaction joins monomers to build polymers by removing water

dehydration = lack of water synthesis = to build/to make 

Lipid

aka fats, oils, steroids, and waxes, long-term energy storage 

*non polar; does not dissolve in water

Triglyceride

formed by glycerol and 3 fatty acids, large lipid (fat)

*tri = 3

Saturated fats

becomes solid at room temp. ; ex - butter, mayo, lard 

*bad :(

Unsaturated fats

becomes a liquid at room temp. ; ex - oil

*good :)

Steroid

they are hydrophobic; ex - estrogen (female sex hormone), testosterone (male sex hormone). Cholesterol

*4 rings 

*some steroids circulate in your body as chemical signals - can be good or bad

Transfat

it is bad b/c our body does not recognize them, type of fat that is manmade by hydrogenation (adding Hydrogens to an oil to make it solid)

hydrogenating = adding hydrogen

• made by hydrogenating oils to make them solids; adding hydrogen to unsaturated fats to make them saturated fats

What makes a compound organic?

Contains carbon & hydrogen

Why is Carbon the backbone of the macromolecules and so important in living things?

carbon is able to bond w/ numerous other elements

*has 4 valence electrons; can create 4 covalent bond

What is the relationship between monomers and polymers? 

monomers are the building blocks and what makes up a polymer

What reaction builds polymers (macromolecules)? Is water added or removed in this reaction/process?

dehydration synthesis; the removal of water to build polymers

What reaction breaks polymers (macromolecules) into its individual monomers?  Is water added or removed in this reaction/process?

hydrolysis; the addition of water that ends up breaking apart polymers

What are the main functions of Lipids?

Long-term energy storage & insulation (Tri-glycerides), major part of cell membranes (phospholipids), circulate the body sending chemical signals (steroids)

Identify the elements that make up Lipids.

CHO - carbon, hydrogen, oxygen (no ratio)

What is the monomer and polymer of Lipids?

monomer - glycerol & fatty acid

polymer - lipid (Tri-glyercide)

What is the difference in structures & characteristics of saturated & unsaturated fats?

saturated - single bonds between the carbons, solid at room temperature ex: butter

unsaturated - double bond between a carbon; can bend, liquid at room temperature ex:  oils

Why are steroids considered Lipids and identify their structure and how it’s different from regular Lipids?

steroids are hydrophobic just like other lipids,has 4 rings unlike a normal lipid which is a chain

Give an example of steroids

ex - estrogen (female sex hormone), testostrone (male sex hormone), cholesterol

What process produces transfats? 

The process of hydrogenation (adding Hydrogens to an unsaturated fat) creates transfats

Why are transfats bad for us?

the body does not recognize transfat, and therefore cannot break them down through hydrolysis