1. LON-CAPA Logo
  2. Help
  3. Log In
 

Biology Quiz/Test #1 - Multiple Choice Key

  1. B
  2. D
  3. E
  4. D
  5. A
  6. C
  7. ANY
  8. E
  9. C
  10. D
  11. A
  12. D
  13. C
  14. C
  15. B
  16. C
  17. B
  18. D
  19. D
  20. D

Grader's Key for Quiz/Test 1, Biol 201

Page 6 - Part II, #1

  1. Isoprene
  2. Choline
  3. Cholesterol (Steroid, 1 pt)
  4. Amylose (2 pts), starch (1pt), glycogen (1pt)
  5. Cellulose (polysaccharide, 1pt)
  6. Chitin (n-acetyl glucosamine, 2pts)

NOTE: spelling not critical, as long as you can identify the molecule

Page 7, #2

  1. Adenine

    2. Give 1 pt for the 2 rings

    2 pts for the N's in the 2 rings

    3 pts for the double bonds correct

    4 pts for the #6 NH2

  2. Cytosine

    3. Give 1 pt for the ring

    2 pts for the 2 N's in the ring

    3 pts for correct double bonds

    4 pts for #2 double bonded O, #4 NH2 group

     

    Page 7, C. Tripeptide question.

    Acidic aa's: Asp, Glu

    Basic aa's: Lys, Arg, His

    Polar aa's: Gly, Ser, Thr, Cys, Tyr, Asn, Gln

    Give 5 pts for the NCCNCCNCC backbone, preceded with amine, ending with carboxyl…any ionized or protonated form, if all else wrong.

    Deduct 1 pt for each wrong R group (should have one acidic, one basic, one polar in any order); accept any R group that is recognizable as long as they're close.

    Give 1 pt for correct single letter code sequence

    Give 1 pt for correct triplet letter code sequence

    Give 3 pts for a correct aa by itself

    If student didn't link aa's, deduct 2 pts

    This is a 15 pt question - other than above, grade it holistically.

     

  3. Palmitoleic acid, a 16 Carbon delta 9 mono-unsaturated fatty acid

Give 2 pts for carboxyl group

Give 2 pts for double bond between 9th and 10th C (count begins at carboxyl group)

Give 1 pt for cis H's at the double bond

Deduct 1 pt if they can't count to 16.

 

 

Essays: A. What is meant by"Fluid Mosaic"? 5 pts total

Major Points include:

2pts @ Membrane is a 2 dimensional fluid (a p'lipid bilayer)

P'lipids and proteins can diffuse laterally in the plane of the membrane - move freely

1pt @ No covalent bonds among constituent molecules

There are proteins embedded in the p'lipid layer

Cholesterol improves fluidity of animal membranes

a"mosaic" of particles (proteins) embedded in the fluid yet free to move

 

 

B) Informational Macromolecules (15 pts total)

1. Proteins 6 pts total; 2 pts each (1 pt if weakly stated):

Monomers are asymmetrical

Polymers are inherently asymmetrical, have a sense (direction)

Varying sequence of monomers creates information

Primary structure determines secondary, tertiary structure

Any residue can be one of 20 aa's (20 to the nth power possibilities)

Different R groups can interact with substrate, DNA

Contains information from the DNA

Contains information for self-assembly

Signal sequences…repressor/enhancer/start/stop

 

2. Nucleic Acids 6 pts total; 2 pts each (1 pt if weakly stated):

Strand(s) have a sense (direction)

Structures are inherently asymmetrical

4 possible bases per nucleotide, but structurally identical

Only 4"letters", but extreme length allows information

Complementary base pairing defines antiparallel strand

 

3. Carbohydrates 3 pts total

2 pts each (1 pt if weakly stated):

Many are monomeric chains, thus non-informational

Branched glycoproteins, glycolipids on exterior of cell membrane are identifiers = informational

Proteins for export tagged with carbohydrates in Golgi body