Cell membrane

Question 1

What is the cell membrane?

Answer 1

The cell membrane is a selectively permeable membrane that separates the cell from its outside environment.

Question 2

List the roles of the cell membrane

Answer 2

• Osmoregulation, allows the cell to maintain homeostasis.
• Secrete waste materials
• To gain nutrients
• communicate with other cells

Question 3

What does selectively permeable means?

Answer 3

This mean that it allows the passage of some molecules and inhibits the passage of others

Question 4

What does phospholipid bilayer of the cell consists of ?

Answer 4

A phosphate head which is hydrophilic and a lipid tail that is hydrophobic. (Two layer)

Question 5

What are the two kinds of proteins found in the cell membrane?

Answer 5

• Integral embedded protein

- peripheral proteins

Question 6

What are the functions of the following
1. Glycolipids

2. glycoproteins
3. cholesterol

Answer 6

1. Maintain stability of cell membrane and facilitate cellular recognition.
2. Responsible for the immune response
3. Keeps membrane at the right fluidity making membrane less soluble molecules by reducing the fatty acid chain.

Question 7

Name the protein being described

“ Do not go through the membrane found on the exterior area of the membrane, acts an enzyme”

Answer 7

Peripheral protein

Question 8

Integral proteins are the entrance routes and exit routes for many ions, nutrients etc.

True or False ?

Answer 8

True

Question 9

Draw fluid mosaic cell membrane

Question 10

What kind of molecules can pass through the cell membrane polar or non polar molecules?

Answer 10

Non polar molecules such as oxygen and CO2

Question 11

What are the two types of cell transport ?

Answer 11

Passive and Active transport

Question 12

What’s the difference between active and passive transport ?

Answer 12

Passive transport is an automatic process that require no energy while active transport moves in opposition of the concentration gradient there it requires energy.

Question 13

Facilitated diffusion is when particles move from an area where they are found in high concentrations to an area of low concentration without the use of protein channels/ carriers.

True or False

Answer 13

False , this is simple diffusion

Question 14

Simple diffusion only works for __________ molecules and _________ ions.

Answer 14

Small molecules

Uncharged ions

Question 15

Why does facilitated diffusion require the use of protein channels?

Answer 15

This is as large molecules/ charged ions such as Glucose and Na+ have a hard time passing through the membrane so they need special proteins channels to help them cross it.

Question 16

What are two kinds of transport proteins that are used in facilitated diffusion?

Answer 16

Channel proteins and carrier proteins that contains water filled hydrophobic channels or pores whose shape is specific to a particular ion or molecules.

Question 17

What are some factors that affect the rate of diffusion?

Answer 17

Concentration gradient -

Distance - If the diffusion distance is small diffusion happens faster because the particles do not have as far to travel.

Temperature- when temperature increase the kinetic energy of the particles has increased causing them to diffuse faster.

Question 18

What is osmosis ?

Answer 18

The movement of water molecules from an area of higher water potential to an area of lower water potential through a selectively permeable membrane.

Question 19

What is water potential ?

Answer 19

Water potential is the tendency of water to move from one place to another.

Question 20

0 is the highest water potential this is the water potential of _______.

Answer 20

Pure water

Question 21

Solute potential lower water potential as it has a negative value.

True or False

Answer 21

True the water molecules are attracted to solute molecules so it pull in the water molecules.

Question 22

If the extra cellular solution has higher water concentration than what is found inside the cell. This solution can be described as what kind of solution? And the cell would be describe as?

Answer 22

A hypotonic solution

A hyperosomtic cell

Question 23

What is pressure potential ?

Answer 23

The pressure exerted by the protoplasts due to entry of water against the rigid walls is called pressure potential

Question 24

Where is the energy supplied from for active transport?

Answer 24

The energy used in Active transport and is directly or indirectly supplied by hydrolysis of ATP

Question 25

What is Bulk transport ?

Answer 25

The transport of larger amount of substances.

Question 26

What is exocytosis ?

Answer 26

Exocytosis is the fusion of secretory vesicles with the plasma membrane and results in the discharge of vesicle content into the extracellular space.

Question 27

Describe the process of exocytosis

Answer 27

Vacuoles with secretory cellular products migrate from the interior cytoplasm to the cell surface where they fuse with the plasma membrane and discharge the products to the exterior.

Question 28

What is Endocytosis ?

Answer 28

Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with th e cell membr ane. The membrane folds over the substance and it becomes completely enclosed by the membrane. At this point a membrane-bound sac, or vesicle, pinches off and moves the substance into the cytosol.

Question 29

Identify and describe the two types of exocytosis ?

Answer 29

Pinocytosis - ingestion of fluids

Phagocytosis - ingestion of solid material