Module 5.1 Cell Membranes

Question 1

Every cell has a

Answer 1

cell membrane

Question 2

What is the difference between cell membrane and plasma membrane?

Answer 2

Plasma membrane is the membrane surrounding a cell; cell membrane includes the plasma membrane and internal membranes.

Question 3

Plasma membrane

Answer 3

is the membrane surrounding a cell

Question 4

Cell membrane

Answer 4

the plasma membrane and the internal membranes as well

Question 5

All cells (bacteria, plant, animal, ancient cells) have a

Answer 5

plasma membrane

Question 6

Human/animal cells typically only have a cell membrane and not a

Answer 6

cell wall

Question 7

What is the major function of the plasma membrane?

Answer 7

To separate outside from inside the cell.

Question 8

The plasma membrane is a protective

Answer 8

wall or fence that goes around the entire cell

Question 9

Plasma membranes regulate

Answer 9

Plasma membranes regulate

Question 10

Plasma membranes are an important part of the definition of the

Answer 10

Cell Theory

Question 11

What is the plasma membrane’s permeability?

Answer 11

Semi-permeable/selectively permeable.

Question 12

What types of molecules can enter the cell through the plasma membrane?

Answer 12

• Glucose (needs active transport)
• Water
• Oxygen

Question 13

What types of waste molecules leave the cell?

Answer 13

• Carbon dioxide

Question 14

What is the Fluid Mosaic Model?

Answer 14

The structure of a cell membranes as a mosaic (art) of compounds. A combination of phospholipids and proteins (and others) arranged in a bilayer that gives it a fluid character.

Question 15

All membranes are a combination of

Answer 15

phospholipids arranged in the bilayer

Question 16

What components are found in the phospholipid bilayer?

Answer 16

• Hydrophilic heads
• Hydrophobic tails

Question 17

What are phospholipid heads made of?

Answer 17

The hydrophilic heads are made of glycerol and phosphate

Question 18

What are phospholipid tails made of?

Answer 18

2 hydrophobic fatty acids that may be saturated or unsaturated

Question 19

How do phospholipids arrange in the bilayer?

Answer 19

Hydrophilic heads face the water outside and inside the cell; hydrophobic tails form an oily middle.

Question 20

What is the fluid part of the Fluid Mosaic Model?

Answer 20

Phospholipids can move laterally in their own half of the bilayer. They can go side to side

Question 21

True or False: Phospholipids can flip flop from one half of the bilayer to another.

Answer 21

False.

Question 22

What is the permeability of the phospholipid bilayer?

Answer 22

Impermeable to most molecules. They are semipermeable

Question 23

What types of molecules can pass through the phospholipid bilayer? ***** slide 15

Answer 23

• Small uncharged polar molecules (O2, CO2, n2, h20, glycerol, ethanol, urea)
• Small hydrophobic molecules (O2, CO2, N2, triglycerides)

Question 24

What needs help passing through the bilayer? What needs active transport?

Answer 24

• Large polar molecules (glucose, sucrose)
• Hydrophilic ions
• Ions (charged molecules)

Question 25

Animal cells also have what in the bilayer of the plasma membrane?

Answer 25

Cholesterol.

Question 26

Cholesterol helps with what

Answer 26

It helps with the cell rigidity, flexibility, stiffness and strength of that cell membrane.

Question 27

Human cells also have what associated with the outside of the plasma membranes​?

Answer 27

Carbohydrates

Question 28

What role does cholesterol play in animal cell membranes?

Answer 28

Cholesterol stiffens animal membranes (especially at temperature extremes) and provides strength and flexibility.

Question 29

Cholesterol is about the size of the

Answer 29

fatty acid tail. (remember 4 fused rings)

Question 30

Being a lipid, cholesterol will insert into the what?

Answer 30

Middle of the membrane

Question 31

Why do plants not require cholesterol in their membranes?

Answer 31

Plants have a rigid cell wall surrounding their plasma membranes and so they don't need the strengthening of cholesterol

Question 32

If a package is labeled “No cholesterol”, it is less likely to contain

Answer 32

Animal matter

Question 33

Carbohydrates stick out of the

Answer 33

phospholipid bilayer

Question 34

What function do carbohydrates serve on the surface of cells?

Answer 34

Act as cell 'nametags' for immune system recognition.

Question 35

True or false: Every cell in your body has a name tag

Answer 35

True

Question 36

Carbohydrates recognize whether a cell is

Answer 36

friendly or foe

Question 37

If the cell is “friendly”, the immune system will

Answer 37

leave alone

Question 38

How does the immune system respond to 'unfriendly' cells?

Answer 38

The immune system usually attacks them.

Question 39

If you cut your finger and introduce bacteria, the body will recognize the bacteria

Answer 39

unfriendly. It will attack and destroy

Question 40

Sometimes the body gets too vigilant and will think the pollen we breathe in is

Answer 40

unfriendly and vigorously attacks it

Question 41

What are the 4 blood groups

Answer 41

Group A, Group B, Group AB, Group O

Question 42

Our red blood cells have

Answer 42

Antigens and antibodies in plasma

Question 43

Antigens are

Answer 43

carbohydrate markers

Question 44

Group A has which antigen

Answer 44

A antigen

Question 45

Group A has which antibodies in plasma?

Answer 45

Anti-B

Question 46

Group O has which antibodies in plasma?

Answer 46

Anti-A and Anti-B

Question 47

Which blood group has no antigens

Answer 47

Group O

Question 48

Which blood group does no have antibodies in plasma?

Answer 48

Group AB

Question 49

What are blood groups an example of?

Answer 49

Carbohydrate nametags.

Question 50

Where are proteins found on a membrane?

Answer 50

In the membrane or attached to them

Question 51

What is the role of proteins in membranes?

Answer 51

Proteins serve various functions, including transportation and signaling.

Question 52

What are transport proteins?

Answer 52

Proteins that allow molecules to enter or exit the cell. They are like the doorway to the building

Question 53

What is the function of channel proteins?

Answer 53

Form a channel for specific molecules to enter the cell.

Question 54

Channel proteins have

Answer 54

They have gates that open only at a signal.

Question 55

Channel proteins will only accept molecules of a given

Answer 55

size/proper fit/shape

Question 56

The channel is protected by

Answer 56

a gate that will open only at a signal​

Question 57

What are carrier proteins?

Answer 57

Proteins that transport specific molecules across the membrane.

Question 58

What happens to carrier proteins when a specific molecule enters?

Answer 58

They change shape to release the molecule on the other side.

Question 59

Some carrier proteins require what to transport?

Answer 59

ATP

Question 60

What is the role of receptor proteins?

Answer 60

Receive chemical signals that cause changes inside the cell.

Question 61

Receptor proteins receive a

Answer 61

chemical signal from outside that will cause a shape-change in the membrane protein

Question 62

A shape change in the membrane protein causes

Answer 62

other changes inside the cell

Question 63

9 times out of 10 receptor based transport is mostely

Answer 63

hormones coming in or out

Question 64

Many hormones work by binding to

Answer 64

receptor proteins on target cells