Organelles, Membrane Transport

Question 1

What type of organelle is Actin? What is its purpose?

Answer 1

Microfilament

Involved in muscle contraction and cell cleavage

Question 2

What composes the plasma membrane? How does it gain fluidity?

Answer 2

Phospholipids

Gains fluidity from unsaturated fatty acids

Question 3

Purpose of Microtubules

Answer 3

transport railroad system of cell

attach to kinetochores during mitosis

anti-cancer drug, Taxol, prevents microtubules from binding to kinetochores

Question 4

2 Examples of Microtubules

Answer 4

Kinesin and Dyenine

-motor proteins that travel along system carrying proteins, vesicles, and organelles

Question 5

Purpose of Intermediate Filaments

Answer 5

support and anchoring

Question 6

Glycocalyx

Answer 6

• outer gelatinous membrane of cell
• anchored to cell via intermediate filaments
• where many enzymes function
• where receptors are located

Question 7

Which organelle controls the half-life of proteins?

Answer 7

lysosomes

Question 8

What happens to an old protein?

Answer 8

gets Ubiquitone attached to it which sends it to lysosome for digestion

Question 9

Which organelle digests foreign antigens?

Answer 9

lysosome

Question 10

pH of lysosome

Answer 10

4-5.5

Question 11

Purpose and Function of Rough ER

Answer 11

extension of nuclear membrane where ribosomes sit and translation occurs

Question 12

Purpose and Function of Rough ER

Answer 12

extension of rough ER

where proteins go to get distributed everywhere except cytosol

all organelles, plasma membrane, exocytosis

Question 13

Describe Mitochondria

Answer 13

-thought to be prokaryotes at one time

(aerobic prokaryote that was ingested by anaerobic eukaryote)

• self-replicate
• own double stranded DNA that is circular
• own ribosomes
• makes 20% of its own proteins

Question 14

What is the pH of the intermembrane space of the mitochondria?

Answer 14

Low pH of 4-6 (involved in metabolism)

Question 15

What are endothelial cells?

Answer 15

modified epithelial cells that line blood vessels and organs

Question 16

Active Transport

Answer 16

• requires ATP
• works via carrier protein that uses ATP to carry a molecule across the plasma membrane
• moves hydrophilic molecules against concentration gradient

Question 17

Simple Passive Diffusion

Answer 17

small, hydrophobic molecules go right through membrane

O2 and CO2

Question 18

Channel Passive Diffusion

Answer 18

small, hydrophilic ions

Water, Cl-, Na+, Ca+

Question 19

Primary Active Transport

Answer 19

non-polar transporter uses ATP

Question 20

Secondary Active Transport

Answer 20

• uses active transport and facilitated carrier
• facilitated carrier moves 2 ions either symport or antiport
• 1 ion has large [] gradient set up by pump in order to drive another molecule into the cell
• carrier protein either on apical or basolateral side of cell

Question 21

Example of Secondary Active Transport

Answer 21

Enterocyte of Intestinal Tract:

• apical has facilitated carrier that brings glucose and sodium into enterocyte via symport
• carrier doesn’t use ATP, but can move glucose against its [] gradient provided that there is a large enough sodium gradient to drive glucose into the cell
• large sodium gradient is set up by Na/K pump on basolateral side

Question 22

Sodium-Potassium Pump

Answer 22

• uses ATP
• 3 Na+ out
• 2 K+ in

Question 23

Carriers transport which type of molecule?

Answer 23

large, hydrophilic molecules like glucose

Question 24

Channels transport which type of molecule?

Answer 24

small, hydrophilic molecules like ions, water, and electrolytes

Question 25

What drives channels?

Answer 25

electro-chemical gradient

Question 26

Which obeys saturation kinetics: channels or carriers?

Answer 26

carriers

Question 27

What is the difference between channels and carriers?

Answer 27

Channels are just pores that can be crossed with no limitation.