biochem ch 5 lipids

Question 1

Ratio of C:H:O for most carbohydrates ?

Answer 1

1:2:1

Question 2

what are the distinct functional groups of an amino acid

Answer 2

amine and carboxyl functional groups

Question 3

What is the basic structure for lipids ?

Answer 3

A long hydrophobic alkyl chain sometimes with functional groups like

-COOH carboxyl ( fatty acids)
-PO₄³⁻ in phospholipids
–OH (hydroxyl) in sterols.

Question 4

Are lipids nonpolar or polar?
Hydrophobic or hydrophilic?

Answer 4

Lipids are nonpolar hydrophobic

Question 5

What is wax and its function

Answer 5

wax is a pretective secretion made of lipids that serves as waterproofing compound for many plants and animals.

Question 6

What is a signaling lipid

Answer 6

A specialized lipid involved in signal transduction pathways.

Question 7

What is a steroid

Answer 7

A lipid characterized by a 4 ring structure and make up many hormones.

Question 8

what is cholesterol

Answer 8

A common steroid that plays a role in cell membranes and is a precursor for steroid hormones and other molecules.

Question 9

What is a steroid hormone?

Answer 9

lipid hormones specifically secreted by endocrine glands

Question 10

What are prostaglandins

Answer 10

Lipids derived from arachidonic acid rather than cholesterol and play a role in paracrine and autocrine signaling.

Question 11

What are vitamins and which ones are fat soluble and which ones are water soluble

Answer 11

Vitamins are cofactors for enzymes acquired via diet.

Vitamin B and C are water soluble
A,D,E and K are fat soluble

Question 12

What is an amphipathic molecule?

Answer 12

a molecule with hydrophobic and hydrophilic regions.

Question 13

what is a phospholipid?

Answer 13

the primary component of the phospholipid bilayer of the cell membrane.

Question 14

What part of a phospholipid is hydrophobic and hydrophilic

Answer 14

head hydrophilic
tail hydrophobic

think of a dog tucking their TAIL in when in fear (phobia) of something

Question 15

What is fatty acid saturation

Answer 15

fatty acid saturation refers to the presence of single or double bonds in a fatty acid

Question 16

What is the structural difference between Saturated and Unsaturated fatty acids as well as their properties at room temparature?

Answer 16

Saturated Fatty acids - only contain single bonds
-Tend to be solid and cohesive at room temp

Unsaturated fatty acids- contains at least one or more double bonds in alkyl chain which introduces kinks in the structure
-Less likely to solidify at room temp

Question 17

What are triglycerides aka triacylglycerides

Answer 17

Group of lipids used for energy storage

Question 18

micelles vs bicelles

Answer 18

Micelles are spherical structures formed when amphipathic phospholipids are in an aqueous environment.

Bicelles are disk-like structures mimicking membranes with a bilayer center formed from lipids

Question 19

what is a bilayer

Answer 19

2 layers of phospholipids with the hydrophillics heads pointing out on either side and the hydrophobic tails both facing inward towards each other.

Question 20

What do the enzymes flippase and floppase do respectively

Answer 20

Flippase enzyme- moves phospholipids from the outer leaflet to the inner leaflet of the bilayer

Floppase enzyme- moves phospholipids from the inner leaflet to the outer leaflet of a bilayer

Question 21

What is the fluid mosaic model

Answer 21

the fluid mosaic model describes the cell membrane as a fluid, flexible structure composed of a phospholipid bilayer with a mosaic of proteins that can move laterally.

Question 22

What is the role of carbohydrates as they relate to cell membranes?

Answer 22

Carbohydrates can attach to proteins on the cell membrane and act as signaling molecules as well as immune recognition.

Question 23

What does cholesterol do in the cell membrane

Answer 23

plays critical role in stability and fluidity of cell membrane. At low temps cholesterol increases fluidity by creating more space in between phospholipids to prevent breaking. At high temps cholesterol helps to reduce the fluidity of phospholipids preventing it from becoming too fluid or leaky

Question 24

What are transmembrane proteins?

Answer 24

Transmembrane proteins are proteins which are embedded in the cell membrane and span the entire membrane as they are amphipathic

Question 25

What are Ligand-gated and voltage-gated ion channels

Answer 25

ligand-gated and voltage-gated ion channels are both transmembrane proteins that allow the passage of ions into or out of the cell.

Ligand-gated ion channels work when the appropriate ligand is bound to it’s receptor

Voltage-gated ion channels work when the membrane has the proper charge or voltage.

Question 26

difference between passive and active transport

Answer 26

passive- high to low conentration without the use of energy

active- low to high concentration using energy

Question 27

difference between simple and facilitated diffusion

Answer 27

both types of passive transport

Simple- does not require any transporter molecule

Facilitated- requires the use of a transporter molecule

Question 28

what is osmosis

Answer 28

type of simple diffusion specifically referring to the movement of water from an area of high to low concentration.

Question 29

What are aquaporins

Answer 29

Transmembrane proteins with a polar environment allowing for the movement of water past a cell membrane

Question 30

Primary active vs secondary active transport

Answer 30

Primary active transport- transport using energy from ATP hydrolysis

Secondary active transport - transport using energy acquired from the movement of a separate solute going favorably down it’s gradient (high to low concentration)

Question 31

Symport vs Antiport

Answer 31

types of secondary active transport

Symport- Both solutes go in the same direction (one is going from high to low and the other is going from low to high concentration)

Antiport - Solutes going in opposite directions( one from high to low concentration and the other from low to high)