Signal Transduction, ECM and Mitochondria

Question 1

What’s the ECM (Extracellular Matrix)

Answer 1

• Insoluble meshwork composed of proteins and polysaccharides
• For structural support and informational cues

Question 2

What is the ECM in plants?

Answer 2

-Cell wall
-Mainly composed of cellulose
- Maintain shape, turgor pressure and prevents pathogens from reaching the cell membrane

Question 3

What are the components of the plant cell wall [3]:

Answer 3

1) Outermost middle lamella
2) Primary cell wall
3) Secondary cell wall

Question 4

What is the middle lamella?

Answer 4

• Synthesized first
• gluelike carbohydrate
• main mechanism by which plant cells adhere to each other

Question 5

What’s the primary cell wall?

Answer 5

-Formed second
- Consists mainly of cellulose
- Thin and flexible

Question 6

What is the secondary cell wall?

Answer 6

-Final thing to be built & not in all plants
- Made of cellulose and lignin
- permits woody plants to grow >300ft

Question 7

Whats the ECM in animals?

Answer 7

-Generally found in connective tissue
- Consists of large fibrous proteins

Question 8

Purposes of connective tissue [2]:

Answer 8

1) Physically connects body parts
2) Physically supports other body parts

Question 9

Role of membrane proteins in signal transduction:

Answer 9

Converting extracellular signals to intracellular signals

Question 10

What is a ligand

Answer 10

Small molecule that binds to a receptor

Question 11

Three stages to signal transduction

Answer 11

1) Binding of ligand to receptor
2) Transduction via second messengers
3) Cellular response

Question 12

Functions of the ECM [4]:

Answer 12

1) Cell adherence
2) Communication between cells
3) Cell shape, support and integrity
4) Barrier, filters out particles

Question 13

Proteoglycans

Answer 13

proteins with chains of polysaccharides

Question 14

What is meant by a membrane’s transition temperature?

Answer 14

is the temperature at which a lipid bilayer transitions from a gel-like solid state (where lipids are tightly packed and less fluid) to a more fluid state (where lipids have greater movement and flexibility)

Question 15

How will the transition temperature of a membrane be affected if the amount of unsaturated lipids is increased?

Answer 15

Increasing the amount of unsaturated lipids will lower the transition temperature.

Question 16

What property of transmembrane domains allows them to remain embedded in a lipid bilayer?

Answer 16

Transmembrane domains typically consist of hydrophobic amino acids, which interact favorably with the hydrophobic core of the lipid bilayer.

Question 17

Thinking about the Na+/K+ pump, how many ATP molecules are required to transport 10 K+ ions into a cell?

Answer 17

The Na+/K+ pump transports 2 K+ ions into the cell for every 1 ATP molecule used. To transport 10 K+ ions, the pump would require 5 ATP molecules.