cell lab quiz 3

Give 4 examples of pairs of polar amino acids that might be substituted for each other with little effect on protein function due to the amino acids having the same functional group. Name the common functional group for each pair.

1. aspartic acid, glutamic acid - carboxylic acids 2. lysine, arginine- ammonia 3. glutamine, asparagine - amide 4. serine, tyrosine- hydroxyl

For each substance, what is it and what color is it? 1. Blue Dextran 2. BSA 3. Myoglobin 4. Yellow food coloring

1. polymer of anhydroglucose coupled to radioactive Blue 2 dye - blue 2. protein - colorless 3. protein - red 4. small molecule dye- yellow

A. What is void volume? B. how do you measure it?

A. (Vo)- volume eluted that contains very large molecules that cant fit in pores and can only occupy space between the beads B. measure volume eluted from the time the sample is loaded until all blue dextran is eluted

A. Which proteins could the fraction contain? B. What will we do next week to find out the content of each fraction?

A. BSA and myoglobin B. assay our fractions by electrophoresis to find the BSA

A. on the basis of which property are molecules separated by gel filtration? B. What kind of molecules move fastest? C. Do molecules bind to the column?

A. Size B. large molecules C. No

A. What substance allows us to measure the column's void volume? B. Is it a protein? C. How big is it?

A. blue dextran B. glucose polymer C. very large. ( 2 MDAa)

A. What is the definition of the inert volume? B. How do you determine the inert volume?

A. the volume of the beads which are unaccessible to any molecules. B. subtract the accessible volume from the space occupied by the beads (πr^2h) - (Vo + Vi)

A. What is the definition of the included volume? B. How do you determine the included volume?

A. volume eluted containing very small molecules that can fill in bead pores. B. measure the volume of the yellow food coloring eluted

A. What substance enables us to measure the entire accessible volume of the column? B. Is it a protein? C. How big is it?

A. yellow food coloring B. No C. small molecule (50 DAa)

Which amino acid can form a disulfide bond?

Cysteine

Name 5 nonpolar amino acids.

alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan

Which amino acids are basic? When fully ionized, what is their charge?

arginine, lysine, histadine positive

Which amino acids are acidic? When fully ionized, what is their charge?

aspartic acid, glutamic acid negative

A. Which amino acid has an R group of -H? B. Does it prefer hydrophobic or hydrophilic environments?

glycine either

Briefly describe how we will determine which fractions contain protein this week.

immobilizing proteins on nitrocellulose filter, stain, rinse, and estimate relative amounts of proteins by eye using the fact that the amount of dye present is proportional to the protein present.

which amino acids are aromatic?

phenylalanine, tyrosine, tryptophan

Which amino acid puts a kink in a polypeptide chain?

proline

Which amino acids are polar, but uncharged?

serine, threonine, glutamine, asparagine, tyrosine

Describe the matrix used in gel filtration. What is it made of? What are its features?

the column matrix consists of bio gel, P-60beads with pores of various sizes, and water.