Chapter 3 Lecture 3 - Membrane proteins, signal transductions, extensions of the membrane

Question 1

2nd Messenger System

Answer 1

Binding of a ligand to a receptor protein, leading to a release of molecules within the cell that trigger other changes

Question 2

1st Messenger

Answer 2

Initial ligand, no direct effects on cell

Question 3

2nd Messenger

Answer 3

Intracellular signaling molecules released that lead to effects in the cell

Question 4

Role of hormones in 2nd messenger systems

Answer 4

Act as 1st messengers

Question 5

Examples of hormones in 2nd messenger systems

Answer 5

Adrenaline, glucagon, luteinizing hormone, parathyroid hormone

Question 6

Steps to G-Protein Coupled Receptor function

Answer 6

1. 1st messenger ligand binds to receptor
2. G protein complex binds to receptor
3. Alpha subunit of G-protein complex substitutes GDP (Guanesine Diphosphate) for GTP (Guanesine Triphosphate)
4. Alpha subunit is released from G protein complex
5. Alpha subunit acts as a second messenger, can cause the release of other 2nd messengers, or can directly effect cellular processes

Question 7

Steps of cAMP Signal Pathway function

Answer 7

1. Ligand binds to stimulative hormone receptor
2. G protein complex binds to receptor, GDP->GTP, alpha subunit released
3. Alpha subunit activates Adenylyl Cyclase
4. Adenylyl cyclase converts ATP to cAMP (2nd messenger)
5. cAMP activates protein Kinase A
6. Kinase A phosphorylates (adds P group) proteins to affect cell processes

Question 8

Cilia

Answer 8

Appendages projecting from cell surfaces

Question 9

Functions of cilia

Answer 9

• Capable of movement

- Moves materials over cell surface

Question 10

Where can cilia be found

Answer 10

Respiratory tract and female reproductive tract

Question 11

How do cilia move

Answer 11

Power stroke, slightly pulled back by recovery stroke

Question 12

Flagella

Answer 12

Similar to cilia but longer, and usually only 1 per cell

Question 13

Function of flagella

Answer 13

Moves cell itself

Question 14

Microvilli

Answer 14

Finger like extension of membrane, usually many on each cell

Question 15

Function of microvilli

Answer 15

Increase cell’s surface area, don’t move

Question 16

Where are microvilli found

Answer 16

Intestine, kidneys, ear

Question 17

Pseudopods

Answer 17

Cytoplasm filled extensions, vary in shape, supported by proteins

Question 18

What is a special characteristic of pseudopods

Answer 18

Their shape is dynamic

Question 19

Examples of cells with pseudopods

Answer 19

Amoebas, Neutrophils, Macrophages