Ch 7-Membrane Structure and Function

Question 1

Cell Membrane Fluid Mosaic Model

Answer 1

The Fluid Mosaic Model States That a Membrane is Fluid Structure with a “Mosaic” of Various Proteins Randomly Distributed in it.

Question 2

Describe Phospholipid, Protein, and Carbohydrate Functions in Membrane

Answer 2

• Phospholipid
  
  • The Lipid Bilayer Acts as a Barrier to the Passage of Molecules and Ions into and Out of the Cell.
• Protein
  
  • Receiving Signals from Outside the Cell, Translating Chemical Signals into Intracellular Action, and Sometimes Anchoring the Cell in a Particular Location.
• Carbohydrate
  
  • Participate in Cell Recogntion and Adhesion, Either Cell-Cell Signaling or Cell-Pathogen Interactions, and they Have a Structural Role as a Physical Barrier.

Question 3

Membrane Fluidity

Answer 3

• Membranes Held Together by Weak Hydrophobic Interactions
• Most Lipids and Some Proteins Move Sideways Within the Membrane

Question 4

Why and How Passive Transport Occurs

Answer 4

• Is a Naturally-occurring Phenomenon and Does not Require the Cell to Exert any of its Energy to Accomplish the Movement. Substances move From an Area of Higher Concentration to an Area of Lower Concentration.
• Type
  
  • Diffusion and Osmosis

Question 5

Osmosis and Diffusion

Answer 5

• Diffusion
  
  • Substance Move from an Area of High Concentration to an Area of Low Concentration
    
    • Diffusion of Oxygen and Carbon Dioxide
• Osmosis
  
  • Diffusion of Water Across a Selectively Permeable Membrane
    
    • From Lower Solute Concentration to the Higher Solute Concentration

Question 6

Define Tonicity and its Relevance to Passive Transport

Answer 6

• Ability of a Surrounding Solution to Cause a Cell to Gain or Lose water
• Depends on the Concentration of Solutes that Cross the Membrane
• This is Relevant to Passive Transport Because Passive Transport is the Ability to Move a Solution Through a Membrane Without Energy, This Involves Osmosis as Well.

Question 7

Explain Active Transport

Answer 7

Is the Energy-Requiring Process of Pumping Molecules and Ions Across Membranes “Uphill”-Against a Concentration Gradient.

Question 8

Difference Between Passive Transport and Active Transport

Answer 8

• Active
  
  • Energy is Required Which is in the Form of ATP
  • Against the Concentration Gradient
  • Upwards
• Passive
  
  • No Energy is Required
  • Along the Concentration Gradient
  • Downwards

Question 9

The Process of Exocytosis

Answer 9

• Transport Vesicles Fuse with Cell Membrane
• Release their Contents

Question 10

Describe Endocytosis

Answer 10

• Takes in Vesicles Containing Macromolecules from the Plasma Membrane
• Types
  
  • Phagocytosis
    
    • Cellular Eating
  • Pinocytosis
    
    • Cellular Drinking
  • Receptor
    
    • Mediated Endocytosis