Exam 2 (Ch. 14- proteins)

Question 1

inborn errors of metabolism
- alkaptonuria
- phenylketonuria

Answer 1

archibald garrod’s work

Question 2

Garrod provided the 1st published account of a case of recessive inheritance in humans: called ___

Answer 2

Alkaptonuria

Question 3

worked on mutants of the fungus Neurospora crassa (a mold) leading to their groundbreaking discovery that genes provide the instructions for making proteins

Answer 3

Beadle and Tatum (1941)

Question 4

Beadle and Tatum’s Experiment –> one gene:

later updated to:
- one gene:

Answer 4

one enzyme hypothesis (genes are responsible for encoding an enzyme);

one polypeptide hypothesis

Question 5

when phenylalanine is blocked by an enzyme called phenylalanine hydroxylase, results in excess phenylalanine converting into __

Answer 5

phenylpyruvic acid

Question 6

if there is no phenylketonuria block then phenylalanine can convert to

Answer 6

tyrosine

Question 7

the 1st case of recessive inheritance that would connect the genes and proteins (and the function of proteins)

Answer 7

Alkaptonuria block (homogentisic acid oxidase)

Question 8

Garrod contribution to errors in metabolic pathways were caused by 2 main blocks

Answer 8

• Phenylketonuria block (newborn PKU test)
• Alkaptonuria block (recessive inheritance)

Question 9

• A physician that studied alkaptonuria & phenylketonuria and how they were inherited in families. He concluded that hereditary information controls chemical reactions in the body. “unit factors” aka genes –> “ferments” aka enzymes. (1902)
• Provided the first published account of a case of recessive inheritance in humans & attributed a biochemical role to genes

Answer 9

Archilbald Garrod

Question 10

Cannot metabolize the alkapton 2,5 dihydroxyphenylacetic acid known as homagentistic acid. This acid accumulates in cells an tissues and is excreted in urine.
- Arthritis and urine turns black when exposed to air, dark skin in ears and nose.

Answer 10

Alkaptonuria

Question 11

a disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of phenylalanine (UUU)

Answer 11

Phenylketonuria (PKU)

Question 12

protein synthesis requires the translation of

Answer 12

mRNA

Question 13

each polypeptide is properly folded and placed at the correct cellular or extracellular location/ and assume higher order structures, and they may interact with other polypeptides.

Answer 13

What happens after translation?

Question 14

4 levels of structure in proteins

Answer 14

1. Primary
2. Secondary
3. Tertiary
4. Quaternary

Question 15

amino acid sequence of a protein

Answer 15

primary structure

Question 16

Alpha-helix and beta-pleated sheets, stabilized by the formation of hydrogen bonds between atoms located in the polypeptide backbone

Answer 16

secondary structure of protein

Question 17

A coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone (not the side chains).

Answer 17

alpha helix

Question 18

secondary structure found in proteins in which “pleats” are formed by hydrogen bonding between atoms on the backbone of the polypeptide chain

Answer 18

beta-pleated sheet (β-pleated)

Question 19

protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure
- final folding
- structure determined by hydrophobic & ionic interactions; also hydrogen bonds & Van der Waals interactions

Answer 19

tertiary structure of protein

Question 20

protein structure that is a protein consisting of more than one folded amino acid chain
- This is formed when the various polypeptides associate with one another to make a functional protein

Answer 20

quaternary structure of a protein

Question 21

• isolated from diseased and normal individuals differ in their rates of electrophoretic migration.
• This was the result of a single amino acid change
• Studies established that one gene encodes one polypeptide

Answer 21

hemoglobin

Question 22

iron-containing structures on hemoglobin, the sites of oxygen binding

Answer 22

heme group

Question 23

a genetic disorder that causes abnormal hemoglobin, resulting in some red blood cells assuming an abnormal sickle shape, transport of hemoglobin is blocked

Answer 23

sickle cell anemia

Question 24

one single amino acid change causes sickle cell anemia: substitution from __ –> __ in position 6 of the beta-chain

Answer 24

Valine (hydrophobic) for glutamic acid (hydrophilic)

Question 25

What can modify polypeptide structure?

Answer 25

posttranslational processing

Question 26

DNA Charge

Answer 26

DNA has a negative charge because of its negatively charged P group (important for gel electrophoresis).

Question 27

Types of posttranscriptional processing
(3)

Answer 27

1) Cleavage may remove an amino acid
2) Cleavage may split a polyprotein (example: Insulin)
3) Chemical constituent addition may modify a protein (phosphorylation)

Question 28

an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule.

Answer 28

Kinase

Question 29

removes phosphate group

Answer 29

phosphatease

Question 30

The metabolic process of introducing a phosphate group into an organic molecule

Answer 30

Phosphorylation (If phosphorylated goes to nucleus if not goes to cytoplasm)