Interaction of the Cell With its Environment

Question 1

Where do cells receive messages

Answer 1

Messages being to be processed

1. at the cell membrane
2. need to pass through the cell membrane to be interpreted

Question 2

What are proteins

Answer 2

Molecules formed by amino acids

Question 3

What are the functions of proteins

Answer 3

Hemoglobin (O2 transporting via blood)
Hormones (cell communication)
Antibodies (body protection)
DNA replication
Metabolism (enzymes)

Question 4

What are the 4 membrane proteins

Answer 4

ion channels
enzymes
receptors
membrane carriers

Question 5

What are the role of membrane proteins

Answer 5

To bring nutrients in, waste out, and communicate with other cells

Question 6

What are the 5 mechanisms of membrane transport

Answer 6

1. Endo/exocytosis
2. Diffusion through the lipid bilayer
3. Diffusion through protein channels
4. Facilitated diffusion
5. Active transport

Question 7

What is the definition of simple diffusion

Answer 7

The movement of molecules from an area of high [ ] to an area of low [ ] due to a molecules random thermal motion

Question 8

What are the 6 factors that affect the rate of diffusion for lipid soluble molecules?

Answer 8

1. Composition of the lipid bilayer
2. Membrane surface area
3. Lipid solubility
4. Molecular size of molecule
5. Membrane thickness
6. [ ] gradient

Question 9

What are the 4 factors that affect the diffusion of water-soluble molecules?

Answer 9

1. [ ] Gradient
2. Molecule Size
3. Charge
4. Number of channels

Question 10

What does glucose and amino acids need in order to pass the lipid bilayer?

Answer 10

Carrier proteins

Question 11

What are the 2 main differences between transport mechanisms for water soluble molecules and facilitated diffusion?

Answer 11

Differentiated by either channels or proteins

1. ion channel moves molecules quicker
2. channels are continuous

Question 12

What is the definition of active transport?

Answer 12

A process that moves molecules against their [ ] gradient

-requires ATP

Question 13

What is a common example of active transport?

Answer 13

Na+/K+ pump

-helps maintain the Na and K [ ] gradient across the membrane

Question 14

What kind of signals can cells use to maintain homeostasis

Answer 14

Cells can send electrical or chemical signals to communicate to other cells.

Question 15

What is long distance communication

Answer 15

When cells have the ability to send messages that travel long distances

Question 16

What is local communication

Answer 16

When cells send signals only to their neighbours

Question 17

How is most long distance cell communication mediated

Answer 17

Endocrine (hormones) and Nervous (chemical) Systems

Question 18

How is most local cell communication mediated

Answer 18

If cells are not of the endocrine or nervous system, they can communicate with one another through chemical and physical means

Question 19

What is an autocrine signal

Answer 19

Used in cell communication when one cell releases a signal and it is self stimulating

Question 20

What is a paracrine signal

Answer 20

Used in cell communication when one cell releases a signal and it stimulates neighbouring cells

Question 21

What is a contact dependent signal

Answer 21

Used in cell communication when one cell membrane binds to a membrane protein of another cell

Question 22

What are gap junctions

Answer 22

Protein channels make bridges between to cells made from connexins
-direct transfer of chemical and electrical signals

Question 23

What is the ratio of the Na+/K+ pump?

Answer 23

For 1 molecule of ATP, you get 3 Na+ OUT and 2K+ IN