BIOCHEM Chapter 12 Flashcards
10 Questions
100 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

An antiporter and a symporter are examples of:

  • Primary active transporters
  • Passive diffusion
  • A secondary transporter (correct)
  • Entropy-driven pores
  • An ABC transporter
  • What force(s) stabilize(s) the lipid bilayers?

  • Covalent bonds between the lipid tails
  • Covalent bonds between the lipids and membrane proteins
  • Van der Waals interactions
  • Electrostatic and hydrogen bonding between the polar heads and surrounding water
  • A and B (correct)
  • Why do phospholipids and glycolipids form bimolecular sheets?

    Due to the presence of two fatty acyl chains.

    In the movement of small molecules across a lipid bilayer, what is most correlated with the permeability coefficient?

    <p>The solubility of the molecule in a nonpolar solvent.</p> Signup and view all the answers

    What is the most common way integral membrane proteins span the membrane?

    <p>α-helical segments.</p> Signup and view all the answers

    What would be expected to lower the Tm for a phospholipid bilayer?

    <p>Replacing a lipid containing 18-C fatty acids with one containing 16-C fatty acids.</p> Signup and view all the answers

    In passive transport, what provides the energy for movement across a membrane?

    <p>The concentration gradient across the membrane.</p> Signup and view all the answers

    What does the Na+-K+ pump do?

    <p>Pumps sodium ions out of the cell and potassium ions into the cell.</p> Signup and view all the answers

    What distinguishes symporters from antiporters in secondary transporters?

    <p>Symporters use energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the same direction against its concentration gradient while antiporters drive the movement in the opposite direction.</p> Signup and view all the answers

    Which of the following is NOT true of ion channels?

    <p>Ion channels are continually open while pumps or secondary transporters depend on an energy source to open.</p> Signup and view all the answers

    Study Notes

    Transport Mechanisms

    • Antiporters and symporters are types of secondary transporters involved in moving substances across membranes.
    • Passive transport relies on the concentration gradient for energy, without the need for ATP.

    Lipid Bilayers

    • Lipid bilayers are stabilized by van der Waals interactions and hydrogen bonding between polar head groups and surrounding water.
    • Salts of fatty acids form micelles, while phospholipids and glycolipids form bimolecular sheets due to the presence of two fatty acyl chains.

    Permeability and Solubility

    • The permeability of small molecules across lipid bilayers is most closely correlated with their solubility in nonpolar solvents.
    • Integral membrane proteins commonly span the membrane in α-helical segments, which contribute to stability and function.

    Membrane Fluidity and Composition

    • Transition temperature (Tm) for phospholipid bilayers can be lowered by replacing longer-chain fatty acids with shorter ones, impacting membrane fluidity.
    • Ion channels allow rapid ion movement and are highly specific, but they are gated and not always open. This contrasts with pumps and secondary transporters which require energy to operate.

    Sodium-Potassium Pump

    • The Na+-K+ pump is crucial for maintaining cellular ion balance by pumping sodium out of the cell and potassium into the cell, utilizing active transport.

    Secondary Transporters

    • Secondary transporters, like symporters and antiporters, differ in their movement direction: symporters transport two molecules in the same direction while antiporters move them in opposite directions.

    Ion Channels vs. Pumps

    • Ion channels enable faster ion transport compared to pumps or secondary transporters which depend on energy sources. Ion channels can be gated and are designed for specific substrates.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your knowledge on Chapter 12 of biochemistry with these flashcards. This quiz covers essential concepts such as transport mechanisms and the forces that stabilize lipid bilayers. Perfect for revision or as a quick study tool.

    More Like This

    Use Quizgecko on...
    Browser
    Browser