Lecture 2 Old Notes

Question 1

What are the three components of plasma membranes?

Answer 1

Lipids, proteins and sugars

Question 2

What is the bulk of the membrane made of? (hint: 2 of something)

Answer 2

Lipid bilayer

Question 3

How do you make hydrophobic proteins stay in the lipid bilayer?

Answer 3

Using nonpolar amino acids

Question 4

Why would small, charged ions be unable to cross the phospholipid bilayer?

Answer 4

If there is a gradient

Question 5

What two things make sodium move?

Answer 5

Electric gradient and concentration gradient (electrochemical gradient)

Question 6

What objects use passive diffusion to cross a membrane?

Answer 6

Small, uncharged molecules and gases

Question 7

Passive diffusion is inversely proportional to what? Directly proportional to what?

Answer 7

Inversely proportion to the radius of the molecule and the viscosity of the membrane; directly proportional to the area of the membrane, temperature and electrochemical

Question 8

What is a flux?

Answer 8

The amount an item moves per unit of time

Question 9

What type of molecule is needed to help sodium move down an electrochemical gradient?

Answer 9

A protein

Question 10

What are the two ion channel examples for facilitated diffusion?

Answer 10

Voltage-gated sodium channels and ligand-gated channels

Question 11

What is meant by a sodium gradient is indirectly couple to the hydrolysis of ATP as a form of active transport?

Answer 11

The sodium ion is let in and they energy released is used to do work for some other purpose

Question 12

What forms of transportation can be saturated?

Answer 12

Active transport and facilitated diffusion, due to not enough transport proteins being available for transport

Question 13

Endocytosis and exocytosis are examples of what kind of transport?

Answer 13

Across (bulk) transport

Question 14

What type of particles are brought into the cell by cell invagination (i.e. endocytosis)?

Answer 14

Large particles, such as the invagination of osteoclasts

Question 15

Pinocytosis is not necessarily about moving liquid into the cell, but rather what?

Answer 15

Trying to remove part of the membrane

Question 16

By what process are most neurotransmitters and polypeptide hormones released from cells?

Answer 16

Exocytosis

Question 17

All cells have 3 functions they have to perform; what are they?

Answer 17

Survive, detect what is in the environment, response to what is detected in said environment

Question 18

Cell membranes are stabilized by what two types of bonding?

Answer 18

Hydrophobic interactions and Van der Waals interactions

Question 19

How does increasing the membrane fluidity influence the survival of the cell?

Answer 19

It increases the survivability of the cell

Question 20

What three factors contribute to increasing membrane fluidity?

Answer 20

Shorter fatty acid chains, more unsaturated fatty acids, and less cholesterol

Question 21

What are the three primary types of lipids?

Answer 21

Phospholipids, glycolipids and cholesterol

Question 22

What is the most abundant type of lipid?

Answer 22

Phospholipids

Question 23

What two functions do glycolipids have, which are related to “recognition”?

Answer 23

Cell to cell recognition and signal recogition

Question 24

Where are sulfatides (a subclass of glycolipids) commonly found in?

Answer 24

Neuronal cell membranes

Question 25

Where are gangliosides (a type of glycolipids) abundant?

Answer 25

Nerve endings

Question 26

Where is cholesterol found in a cell?

Answer 26

In the central core of the lipid bilayer

Question 27

Where are sugars mostly located in a cell membrane?

Answer 27

The outer leaflet

Question 28

What is a glycocalyx?

Answer 28

It is a polysaccharide layer on the cell membrane (made from sugars)

Question 29

What is the function of sugars for the cell?

Answer 29

They are used to recognize signals outside the cell, such as from a nearby cell; think “recognition”

Question 30

What constitutes a glycoprotein? Where is it found?

Answer 30

It is made of an oligosaccharide attached to a protein, and is found on the outer leaflet.

Question 31

What are three functions of glycoproteins?

Answer 31

Receptors, hormones, and used as a structural molecule (i.e. collagen)