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Ch 5 reading guide – Biology in Focus- Membrane Transport and Cell Signaling

(Adapted from Fred and Theresa Holtzclaw’s reading guides)

Overview - Life at the Edge

  1. What is selective permeability?

Concept 5.1 Cellular membranes are Fluid Mosaics of Lipids and Proteins

  1. Explain how the plasma membrane a “fluid mosaic model”?
  1. How do the hydrophobic tails of the phospholipids affect the plasma membrane?
  1. Complete the table of membrane proteins.

Type of membrane protein / Function/description
Transport Protein
Enzymatic Protein
Attachment Protein
Recognition Protein
Joining Protein
Signal Protein
  1. Explain the difference between a transmembrane protein, peripheral protein and an integral protein.
  1. What is the role of carbohydrates in the plasma membrane? Give examples.
  1. What organelles build the plasma membrane?

Concept 5.2 – Membrane Structure Results in Selective Permeability

  1. What types of molecules can cross easily through the membrane? Why can they?
  1. How does water get through the membrane? Why does it need to get through this way?
  1. How do carrier proteins work in the membrane? Give an example.

Concept 5.3 Passive transport is diffusion of a substance across a membrane with no energy investment.

  1. What is a concentration gradient?
  1. Define tonicity.
  1. Define osmoregulation. Give an example of how this is used.
  1. Using figure 5.11 as a guide, if I was a patient that was severely dehydrated, what type of a solution would I want to have in my IV? Why?
  1. Define the following terms
  2. Turgid
  1. Flaccid
  1. Plasmolysis
  1. Why is facilitated diffusion not a form of active transport?

Concept 5.4 Active transport uses energy to move solutes against their gradients.

  1. Answer question #3 in the Scientific Skills Exercise
  1. Explain membrane potential.
  1. Explain how a proton pump works.
  1. Explain how cotransport works. Give an example.

Concept 5.5 Bulk transport across the plasma membrane occurs by exocytosis and endocytosis.

  1. What is the difference among phagocytosis, pinocytosis and receptor-mediated endocytosis.
  1. Explain, from a transport view, why cholesterol is a problem in people.

Concept 5.6 – The plasma membrane plays a key role in most cell signaling

  1. Explain these three different types of local and long distance signaling. Give an example for each
  2. Local signaling - paracrine
  1. Local signaling – synaptic
  1. Long-distance signaling - endocrine
  1. What are the three stages of cell signaling? And briefly describe what is happening in each.
  1. Define ligand.
  1. Where are the two types of receptors located in the cell? What types of ligands would bind to each type of receptor?
  1. Label and explain this G-protein receptor

  1. Label and explain this ion channel receptor.

  1. Label and explain this steroid hormone intracellular receptor.

  1. Transduction: Draw Figure 5.24 and explain it.
  1. What are second messengers?
  1. What role does cyclic AMP (cAMP) play in cell communication?
  1. What is/are the end result(s) of a signal pathway (response)?