Chapter 3 Wk 2

Question 1

Are the hydrophilic heads of the phospholipid bilayer polar or non polar?

Answer 1

Polar.

They are able to interact with the polar molecules of the water inside and out of the cell.

Question 2

Are the hydrophobic tails of the phospholipid bilayer polar?

Answer 2

No

Question 3

What is DIFFUSION?

Answer 3

The movement of chemicals from higher solute concentration to lower solute concentration.

It is a product of the constant random motion of all atoms.

Question 4

What is a measure of a fluid’s resistance to flow?

Answer 4

VISCOSITY

More viscosity = slower flow rate
Less viscosity = faster flow rate

Question 5

The diffusion of water across a semi permeable membrane is called?

Answer 5

OSMOSIS

Selectively (or semi) permeable membrane means that the membrane allows water but not all the solutes dissolved in the water to diffuse through it.

Question 6

What are the characteristic functions of a cell?

Answer 6

1. Cell metabolism and energy use
2. Synthesis of molecules
3. Communication

Question 7

What does “cell metabolism and energy use” mean?

Answer 7

CELL METABOLISM is the metabolic reactions (or chemical reactions) that occur within cells. These reactions are collectively known as cell metabolism.

The ENERGY released by some metabolic reactions fuels cellular activities, such as the synthesis of molecules and muscle contraction. During some metabolic reactions energy is released as heat, helping regulate body temps.

Question 8

What does “synthesis of molecules” involve in relation to the characteristic function of a cell?

Answer 8

The different cells of the body synthesize various types of molecules, including proteins, nucleic acids, and lipids.

The structural and functional characteristics of cells are determined by the types of molecules they produce.

Question 9

What does “communication” mean in respect to the characteristic functions of a cell?

Answer 9

Cells produce and respond to chemical and electrical signals that allow them to communicate with one another.

Ex: Nerve cells produce chemical signals by which they communicate with muscle cells, and muscle cells respond by contracting or relaxing.

Question 10

What is the fluid-mosaic model?

Answer 10

It suggests that the plasma membrane is neither rigid nor static in structure but is highly flexible and can change its shape and composition through time.

The lipid bilayer functions as a dense liquid in which other molecules, such as proteins, are suspended.

Question 11

What are some functions of MARKER PROTEINS within a cell?

Answer 11

They can function as marker molecules, attachment proteins, transport proteins, receptor proteins, or enzymes.

Question 12

What are MARKER MOLECULES?

Answer 12

Cell surface molecules allow cells to identify other cells or other molecules.

They are either GLYCOPROTEINS or GLYCOLIPIDS.

Question 13

What is a glycoprotein?

Answer 13

A protein with attached carbohydrates.

Question 14

What is a glycolipid?

Answer 14

A lipid with attached carbohydrates.

Question 15

What is an INTEGRAL membrane protein?

Answer 15

A protein molecule that penetrates deeply into the lipid bilayer.

Question 16

What is a PERIPHERAL membrane protein?

Answer 16

Proteins that are attached to either the inner or the outer surfaces of the lipid bilayer.

Question 17

What is an ATTACHMENT protein?

Answer 17

An integral protein that allow cells to attach to other cells or to extracellular molecules.

Many attach to intracellular molecules as well.

Question 18

What is a TRANSPORT protein?

Answer 18

Integral proteins that allow ions or molecules to move from one side of the plasma membrane to the other.

These proteins have 3 characteristics:

1. SPECIFICITY
2. COMPETITION
3. SATURATION

Ex: ATP powered pumps, Carrier proteins, Channel proteins

Question 19

SPECIFICITY

Answer 19

/

Question 20

COMPETITION

Answer 20

;

Question 21

SATURATION

Answer 21

L

Question 22

What is a LEAK ION CHANNEL?

Answer 22

AKA Nongated ion channel.

They are always open and are responsible for the plasma membrane’s permeability to ions when the plasma membrane is at rest.

Question 23

What is a GATED ION CHANNEL?

Answer 23

They can be opened or closed.

Question 24

What is a LIGAND-GATED ION CHANNEL?

Answer 24

A gated ion channel that opens or closes in response to chemical signals (called LIGANDS).

The ligands, or small molecules, bind to the proteins or glycoproteins.

Question 25

What is a VOLTAGE-GATED ION CHANNEL?

Answer 25

An ion channel that opens or closes when there is a change in the membrane potential.

Question 26

Functions of MEMBRANE PROTEINS:

Answer 26

Marker molecules
Attachment proteins
Transport proteins
Enzymes
Receptors

Question 27

A complex of DNA and protein, which consists of many different genes is called a:

Answer 27

Chromosome.

Question 28

What do we call the system of microfilaments, actin (intermediate filaments), and microtubles that give the cell shape, allow movement, and the routing of molecules and organelles within the cell?

Answer 28

CYTOSKELETON

Question 29

Functions of CYTOPLASMIC membrane proteins:

Answer 29

Allows cells to identify other cells or molecules

Catalyze chemical reactions

Serve as a binding site for chemical signals

Anchor one cell to another

Allow for molecules and ions to pass through the cell membrane.

Question 30

CENTROSOME

Answer 30

.

Question 31

CENTRIOLES

Answer 31

S