Basics from Cell Bio

Question 1

What are the three essential lipids in biology?

Answer 1

fats, phospholipids, and steroids

Question 2

How are fats constructed?

Answer 2

dehydration reaction between glycerol and fatty acids

Question 3

What is glycerol?

Answer 3

3 carbons with hydroxyl groups attached to each carbon (an alcohol)

Question 4

What is a fatty acid?

Answer 4

long hydrocarbon with a carboxyl group at one end

Question 5

Definition of hydrophobic

Answer 5

does not like water, includes nonpolar molecules

Question 6

definition of hydrophilic

Answer 6

likes water, includes polar molecules

Question 7

What is an ester linkage

Answer 7

a covalent bond between a hydroxyl group and a carboxyl group, which joins the fatty acid tails to the glycerol

Question 8

What is a saturated fatty acid?

Answer 8

A carbon chain with no double bonds, completely filled with hydrogens; no “kinks”; solid at room temperature; more viscous

Question 9

What is an unsaturated fatty acid?

Answer 9

Carbon chain with one or more double bonds, forming “kinks”, resulting in a more fluid substance; liquid at room temperature.

Question 10

What is the main function of fats?

Answer 10

energy storage; stores twice as much energy per gram as a polysaccharide

Question 11

What is the primary molecule that forms membranes?

Answer 11

Phospholipids

Question 12

What is a phopholipid?

Answer 12

2 fatty acid tails attached to a glycerol backbone

Question 13

What gives the phospholipid head a negative charge?

Answer 13

The phosphate group

Question 14

What is a steroid?

Answer 14

Lipids that have a 4 ring carbon skeleton with a hydrophobic tail and a small hydrophilic head.

Question 15

What does amphipathic mean?

Answer 15

It has both a hydrophilic and hydrophobic region

Question 16

In the term “fluid mosaic model”, what does “fluid” mean?

Answer 16

The membrane undulates and moves, changing constantly

Question 17

In the term “fluid mosaic model”, what does “mosaic” mean?

Answer 17

The membrane is made up of a myriad of molecules, including phospholipids, proteins, cholesterol, and glycoproteins.

Question 18

What significant quality of a membrane, other than fluidity, changes when a membrane freezes?

Answer 18

its permeability

Question 19

What interactions hold the bilayer together?

Answer 19

hydrophobic, or Van der Waals interactions

Question 20

“Like remains with like”. What does this mean in the context of membranes in the cell.

Answer 20

Compounds that are polar and hydrophilic tend to be near or facing other polar and hydrophilic compounds all the time. The opposite is true with nonpolar and hydrophobic compounds.

Question 21

What compound hinders the close packing of phospholipids, lowering the freezing temperature of the membrane?

Answer 21

Cholesterol

Question 22

What determines a membranes function?

Answer 22

The proteins embedded within it.

Question 23

What are the two types of membrane proteins?

Answer 23

Integral and peripheral proteins.

Question 24

What kind of protein extends all the way through the lipid bilayer?

Answer 24

A transmembrane protein

Question 25

Where are membrane proteins and phospholipids synthesized and organized?

Answer 25

endoplasmic reticulum

Question 26

Where do glycoproteins undergo further carbohydrate modification, and lipids acquire carbohydrates to form glycolipids?

Answer 26

Golgi apparatus