1/19: Cell Membrane, Membrane Transport, & Membrane Potential I

Question 1

What are the functions of the plasma membrane?

Answer 1

1. Separate cytoplasm from ECF
2. Regulate exchange between ECF and cytoplasm
3. Communicate with other cells
4. Provide structural attachments between cells or between cell and extracellular matrix

Question 2

What is the plasma membrane described by?

Answer 2

The fluid mosaic model

Question 3

What 4 different types of organic molecules make up the plasma membrane?

Answer 3

1. Phospholipids
2. Steroids
3. Protiens
4. Carbohydrates

Question 4

What is the consistency of the plasma membrane at body temperature?

Answer 4

Thick oil

Question 5

What kind of substances are phospholipids?

Answer 5

Amphipathic

Question 6

What are phospholipids organized into?

Answer 6

A bilayer
Hydrophilic heads
Hydrophobic tails

Question 7

What are the functions of phospholipids?

Answer 7

Creates a barrier

Question 8

What substances are permeable?

Answer 8

Hydrophobic substances

Question 9

What are examples of hydrophobic substances?

Answer 9

Small, nonpolar molecules
ex: Gases (O2, CO2), fatty acids, steroids
Lipophilic substances
ex: ethanol
Water

Question 10

What substances are non-permeable substances?

Answer 10

Larger molecules
Polar molecules
Charged substances
ex: glucose, ions, amino acids, proteins

Question 11

What are two functions of cholesterol?

Answer 11

1. Help keep membrane fluid over a wide range of temperatures
2. Help make membrane water tight

Question 12

A proteins shape determines ________

Answer 12

Function

Question 13

What are factors that alter protein shape?

Answer 13

1. Mutations
2. pH, temp, Osm
3. Covalent/Allosteric modulation

Question 14

What structures do mutations change?

Answer 14

1⁰ structure

Question 15

What structures does pH, T, osm change?

Answer 15

Loss of 2⁰, 3⁰, and 4⁰ structure - denaturation (causes the structure to unfold)

Question 16

What structures does covalent/allosteric modulation change?

Answer 16

2⁰, 3⁰, and 4⁰ structure and how cells regulate proteins

Question 17

What are types of structural classifications?

Answer 17

Transmembrane proteins
Integral proteins
Peripheral proteins

Question 18

What are receptor proteins?

Answer 18

Bind to specific chemical signals (ligands) and transmit that information to the cytoplasm

Question 19

What are properties of receptor proteins?

Answer 19

1. Specificity
2. Saturation
3. competition

Question 20

What does specificity mean?

Answer 20

Shape of the binding site determines what will bind

Question 21

Each type of protein will interact with only ______ type of substance or class of substances

Answer 21

one
ex: Insulin receptor only binds to insulin, enzyme maltase will only interact with substrate maltose, glucose transporter will only bind to and transport glucose

Question 22

Within the solution of the body there are a ______ number of proteins and therefore a _____ number of binding sites

Answer 22

Set; set

Question 23

What does saturation refer to?

Answer 23

The fraction of total binding sites that are occupied at any given time

Question 24

What is saturation dependent on

Answer 24

Protein and the substance

Question 25

What is transport rate proportional to?

Answer 25

Substrate concentration until the carriers are saturated

Question 26

What is a competitive inhibitor?

Answer 26

A chemical substance (exogenous ligand) that binds to the active site of the protein and blocks the endogenous ligand from binding

Question 27

When bound, what kind of effect to competitors have?

Answer 27

Do not produce an effect

Question 28

What is the level of inhibition dependent on?

Answer 28

The concentration of the protein, endogenous ligand, and competitive inhibitor

Question 29

What are examples of competitive inhibitors?

Answer 29

Penicillin
ACE inhibitors
Beta blockers

Question 30

What do primary ligands do?

Answer 30

Activate the receptor resulting in a response

Question 31

What do agonists do?

Answer 31

Activate the receptor resulting in a response

Question 32

What do antagonists do?

Answer 32

Block receptor activity resulting in no response

Question 33

Response of a cell to a chemical signal is mediated by what?

Answer 33

Receptor mediated NOT signal mediated

Question 34

No receptor =

Answer 34

No response

Question 35

Two different ligands binding to same receptor =

Answer 35

Same response

Question 36

One ligand binding to two different receptors =

Answer 36

Two different responses

Question 37

What is affinity directly proportional to?

Answer 37

1. Number of ligands bound to receptors at any given [ligand]
2. 1/Kd (Kd=[ligand] where 1/2 receptor occupied)

Question 38

Which drug has a higher affinity for this receptor?

Answer 38

Drug 2
Because drug 1 requires more drug to get 1/2 the receptors occupied than drug 2 which means that drug 1 has a lower affinity

Question 39

Which receptor would have the largest Kd value?

Answer 39

Protein 3
Because the higher the Kd value = the lower the affinity

Question 40

The higher the Kd =

Answer 40

The lower the affinity

Question 41

What is a transmembrane protein?

Answer 41

Span entire membrane all the way through

Question 42

What is an integral protein?

Answer 42

Embedded in membrane, doesn’t go whole way through

Question 43

What is a peripheral protein?

Answer 43

Outside of membrane

Question 44

What is signal transduction?

Answer 44

Steps that occur from the time the ligand binds to receptor til you have a change in cell function

Question 45

For saturation to occur, what does the saturation of transporters need to be like?

Answer 45

Constant