Exam 2 Cell Bio

Question 1

The plasma membrane is involved in many vital functions including:

Answer 1

cell communication

import and export of molecules

cell growth and motility

Question 2

A cell membrane is composed of what:

Answer 2

a lipid bilayer in which proteins are embedded

Question 3

The properties of fats depend on what?

Answer 3

the length and saturation of the fatty acid chains they carry

Question 4

Effects of Fatty Acid Composition on Membrane Fluidity (number of carbon atoms and heat)

Answer 4

More fluid with fewer carbon atoms (more heat required with more carbons)

Question 5

Effects of Fatty Acid Composition on Membrane Fluidity (number of double bonds and heat)

Answer 5

More fluid with more saturated double bonds (more heat required for no double bonds)

Question 6

Cholesterol

Answer 6

a type of sterol (lipid) found in lipid bilayers that stiffens cell membranes

Has a polar head, ring structure head and nonpolar tail)

Question 7

Four types of membrane protein functions:

Answer 7

1. Transporters and channels
2. Anchors
3. Receptors
4. Enzymes

Question 8

Types of integral membrane proteins

Answer 8

1. Transmembrane
2. Monolayer associated
3. Lipid linked

Question 9

Types of peripheral proteins

Answer 9

Protein attached proteins

Question 10

Why are a-helices proteins the most common to cross the bilayer?

Answer 10

They easily form hydrophilic interiors and hydrophobic exteriors that reside in the hydrophobic portions of a membrane

Question 11

What types of channels are formed with porins?

Answer 11

B-barrels made with B-sheets

Question 12

Two common detergents

Answer 12

SDS and Triton X-100

Question 13

What are three protein filaments found in cytoskeletons?

Answer 13

1. Actin filaments
2. Microtubules
3. Intermediate filaments

Question 14

Actin filaments

Answer 14

AKA Microfilaments - flexible structures and linear networks found in the cortex and other locations in a cell

Question 15

Microtubules

Answer 15

Hollow cylinder proteins of tubulin that are straight and long conjoined at a centromere

Assists in meiosis and mitosis to separate cells

Question 16

Intermediate filaments

Answer 16

Provides strength to cells and tissues

Question 17

Rates at which different molecules can pass through a membrane through simple diffusion?

Answer 17

Quickly (Small, nonpolar)
Semi-quick (small, uncharged polar)
Slow (larger, uncharged polar)
Impossible (ions)

Question 18

Passive transport examples

Answer 18

Channel mediated and transporter mediated (from high to low concentration)

Question 19

Active transport example

Answer 19

pump (low to high concentration)

Question 20

An electrochemical gradient has two components: it is the sum of a force of the ___ ____ of the solute and a force from the ___ ___.

Answer 20

concentration gradient ; membrane potential

Question 21

What happens if there are unequal concentrations of an ion across a membrane?

Answer 21

The ion will move from an area of high to low concentration until the charges are balanced. Otherwise, energy is required to go from low to high

Question 22

aquaporin

Answer 22

Water channels for fast diffusion

Question 23

Example of a passive transporter

Answer 23

Glucose comes in through a glucose transporter, binds at binding site and releases into cell

Randomly opens and closes with movement from high to low concentration