Midterm Topics: Cell Membrane

Question 1

What are amphipathic molecules?

Answer 1

• Molecules with both hydrophobic and hydrophilic parts
• Ex: Phospholipids

Question 2

How does the chemistry of the cell membrane allow for life?

Answer 2

• Necessary for cell structure and function
• Cells are aqueous (water ballon; water is in different then the water out)
• Lets compartmentalization in cells occur (mitochondria= has own membrane)

Question 3

What makes up the cell membrane? How to get in and out?

Answer 3

• Made up of phospholipids (bilayer)
• Proteins and lipids
• Protein channels are embedded and their chemistry determines what comes in and out of the membrane

Question 4

Describe the inner and outer leaflets of the membrane

Answer 4

• The inner leaflets are hydrophobic
• The outer leaflets are hydrophilic
• The inner heads are typically negative

Question 5

What is a heterokaryon? What did we learn from the 1970 experiment?

Answer 5

• Heterokaryons= 2 cells
• Large mega cell made by fusing 2 cells together
• Wanting to learn if membranes are fluid–> They were since they ended up mixing together versus staying seperate

Question 6

What are the monomers of proteins? Polymer?

Answer 6

• Monomer is amino acids –> There are 20 kinds; can be polar, non-polar, charged
• Polymer= Peptide; Polypeptide

Question 7

What are the 3 overarching categories of R-group? What kind of chemistry do they make?

Answer 7

• The different side chains have different chemical properties
  
  • Non-polar: Hydrophobic, do not mix well with water
  • Polar: Hydrophilic, forms hydrogen bonds
  • Charged: forms ionic bonds

Question 8

How/why would a single Amino Acid substitute create a disease phenotype?

Answer 8

• Since the codons code for specific amino acids and that is wrong it will cause the amino acid to be different with causes a mutation

Question 9

How/why would a single amino acid substitution result in no change to the organism?

Answer 9

The change could be synomomous, since many codons code the same amino acid or if it changes the amino acid then it may be a change that doesn’t code for mutations

Question 10

How could environmental changes change protein funtion?

Answer 10

• Temp:
  
  • Slows the protein function down
    when cold
• pH;
  
  • Changes shape which changes
    functions
  • Charged things react which
    interferes with folding/shape
• Salinity:
  
  • When salts are in the water they
    break into ions
  • Charged things in water react