Cytology - Cell Membrane

Question 1

CYTOLOGY DEFINITION

Answer 1

The study of cells

Question 2

3 MOST COMMON CELL SHAPES

Answer 2

Squamous
Cuboidal
Columnar

Question 3

PRIMARY CELL COMPONENTS

Answer 3

Cell membrane - encapsulates the cell
Cytoskeleton - Network of proteins that provides internal support for the cell
Cytoplasm - contents of the cell (cytosol & organelles)

Question 4

CELL MEMBRANE
3 functions

Answer 4

Defines boundaries and protects the cell
Controls interactions with other cells
Controls movement of materials into and out of the cell

Question 5

CELL MEMBRANE STRUCTURE
What type of membrane
Made of what components

Answer 5

Bilayer membrane - two layers of phospholipids
Amphiphilic - heads are in contact with the water that exists inside and outside the cell
Fatty acid tails face the inside of the bilayer. Phospholipids do not bond to eachother.
Selectively permeable

Question 6

What kinds of substances can pass through cell membrane?

Answer 6

Small, neutral, and lipid-soluable substances

Question 7

What types of substances cannot pass through a cell membrane?

Answer 7

Large, charged substances (ions) like water

Question 8

What is found between the phospholipids and provides rigidity for the membrane?

Answer 8

Cholesterol

Question 9

Glycolipids

Answer 9

Attached to the exterior surface of the cell
Combination of carbohydrates and lipids

Question 10

TRANSMEMBRANE PROTEINS

Answer 10

Pass through the membrane and are exposed on both sides

Question 11

PERIPHERAL PROTEINS

Answer 11

Only exposed on one side of the membrane - either to the ICF (intercellular fluid) or the ECF (extracellular fluid)

Question 12

RECEPTOR PROTEIN FUNCTIONS

Answer 12

Receive and identify neurotransmitters and hormones from other cells and tissues
2nd messengers relay signals from outside to inside of cell to cause further changes

Question 13

ENZYME PROTEIN FUNCTION

Answer 13

Break down chemical messengers and neutrients

Question 14

ION CHANNEL PROTEINS FUNCTION

Answer 14

Allow water and hydrophilic solutes to pass through.
Some always open
Some open and close with electrical charge - require ATP to function

Question 15

CELL IDENTITY MARKER
FUNCTION

Answer 15

Glycoproteins that identify the cells as self cells and not foreign cells

Question 16

CELL ADHESION MOLECULES

Answer 16

Physically connect adjacent cells and their tissues

Question 17

3 TYPES OF CELL SURFACE EXTENSIONS AND THEIR FUNCTIONS

Answer 17

Microvilli: numerous small projections that increase the surface area of a cell (digestion)
Cilia: Small hairlike extensions - some motile (help move fluid like mucous in resp. System) some non-motile (like in ears to help with hearing)
Flagella: Help propel cell in fluid (sperm is the only example of this.)

Question 18

What part of phospholipids form the internal and external surfaces of the membrane and are in contact with ICF and ECF?

Answer 18

Phosphate heads

Question 19

What are the properties of substances that pass easily through the membrane?

Answer 19

Small and non-polar (hydrophobic, meaning made from lipids)

Question 20

What are properties of substances that have a difficult time passing through the membrane, requiring the assistance of channels or carriers?

Answer 20

Large, and charged

Question 21

Two categories for transport mechanisms?

Answer 21

Passive: requiring no ATP
Active: requires ATP

Question 22

4 TYPES OF PASSIVE TRANSPORT MECHANISMS
And their definitions

Answer 22

Filtration - movement of substances through membrane due to fluid pressure (hydrostatic pressure)
Simple Diffusion - movement of particles through a concentration gradient from areas of high concentration to areas of low concentration.
Osmosis - diffusion of water. Areas of high water concentration to areas of low water concentration
Facilitated Diffusion (form of Carrier-Mediated transport) - Movement through a transmembrane protein without the use of energy

Question 23

Carrier-Mediated Active Transport

Answer 23

Movement through a transmembrane protein with the use of ATP

Question 24

VESICULAR TRANSPORT
Definition
2 types

Answer 24

Transportation of substances across a membrane in small packages called vesicles. Requires ATP
Endocytosis: Moves substances into the cell
Exocytosis: Moves substances out of the cell