X Post-Translational Modification Mfm Dcom Exam2

Front 1

the chemical modification of a protein after it has been translated occurs in ... and ...

Back 1

rough endoplasmic reticulum (RER)
Golgi apparatus

Front 2

post-translational modification does what:
1.
2.
3.
4.

Back 2

1. attaches functional groups
2. change the chemical characteristics of specific amino acids
3. structural changes protein to obtain maximal function
4. a regulatory mechanism

Front 3

signal peptide exists at the amino terminal of a protein and is recognized and bound by ... which in turn binds to an ... receptor within the ER membrane

Back 3

signal-recognition particle
SRP

Front 4

new ... may be added to individual amino acids or added directly to the peptide backbone or ... and ... terminal ends

Back 4

functional groups
C-
N-

Front 5

selenocysteine is sometimes called the 21st amino acid and has its own ...

Back 5

tRNA

Front 6

why are amino acids post-transitionally modified?
1.
2.
3.
4.

Back 6

regulate activity of the protein
target or anchor the protein in membranes
enhance protein’s association with another proteins
target protein for destruction

Front 7

what is glycosylation:

Back 7

addition of sugar to protein forming a glycoprotein

Front 8

the addition of selenium to cysteine forming selenocysteine is an example of ...

Back 8

addition of functional groups

Front 9

why glycosylation?

Back 9

1. glycosylation makes proteins more hydrophilic
2. helps proteins bind to receptors
3. allows recognition of misfolded proteins
4. reduces proteolysis of newly formed proteins by blocking proteases

Front 10

what are the 2 types of glycosylation?
1.
2.

Back 10

O-glycosylation
N-glycosylation

Front 11

in O-glycosylation, where does the sugar attach?

Back 11

to the –OH group of serine, threonine, or tyrosine

Front 12

in N-glycosylation, where does the sugar attach?

Back 12

to the –NH2 group of asparagine

Front 13

what is prenylation?

Back 13

addition of a 15-carbon farnesyl group or a 20-carbon geranylgeranyl group to a Cys residue

Front 14

what do farnesyl groups do?

Back 14

anchor proteins in membranes

Front 15

what are 4 common amino acid modifications?

Back 15

phosphorylation
acetylation
carboxylation
oxidation

Front 16

what is ubiquitination?

Back 16

the adding of ubiquitin to other proteins or peptides

Front 17

why ubiquitination?

Back 17

label old, damaged, or misfolded proteins for destruction in a proteosome

Front 18

describe clinical relevance for ubiquitin:

Back 18

in diagnostics to identify abnormal accumulations of proteins

Front 19

the making of disulfide bridges only occurs in ... where ... enzyme is present

Back 19

only occurs in the RER
protein disulfide isomerase (PDI)

Front 20

pro-proteins are ...

Back 20

inactive precursor proteins that are activated by removal of polypeptides

Front 21

removal of the initiation methionine residue by a specific amino peptidase is an example of

Back 21

proteolytic cleavage ...

Front 22

collagen makes up about ... of the dry weight of human skin

Back 22

75%

Front 23

Type I collagen is the most abundant protein in mammals
consists of (how many...) peptide chains interwoven into a helix, providing great tensile strength to connective tissue

Back 23

three

Front 24

what is the amino acid sequence pattern of collagen I ...

Back 24

Gly-X-Pro

Front 25

collagen synthesis requires hydroxylation of ... and ... by ...

Back 25

proline
lysine
vitamin C

Front 26

... is dietary deficiency in vitamin C that reduces activity of prolyl and lysyl hydroxylase

Back 26

scurvy

Front 27

... is a genetic mutation resulting in substitution of another amino acid for Gly that leads to improper collagen folding

Back 27

osteogenesis imperfecta

Front 28

... are genetic mutations in lysyl oxidase or hydroxylase

Back 28

Ehlers-Danlos Syndrome

Front 29

... is a genetic disorder resulting in poor absorption and distribution of copper that leads to reduced activity of copper-containing enzyme lysyl oxidase

Back 29

Menkes Disease

Front 30

in scurvy you lack the ability to hydroxylate ... and ... for the synthesis of collagen due to ...

Back 30

proline
lysine
lack of vitamin C

Front 31

what are the symptoms of scurvy:
1.
2.
3.
4.
5.

Back 31

1. weakness
2. anemia
3. hemorrhage
4. bleeding gums, gingivitis
5. corkscrew hair growth

abnormal bone growth (in infants)

Front 32

in ... you get common bone fractures, blue-colored sclera, malformed teeth

Back 32

Osteogenesis Imperfecta

Front 33

a symptom of ... is unstable, highly flexible joints, highly elastic, overly stretchable skin and eye problems

Back 33

Ehlers-Danlos Syndrome

Front 34

in ... the hallmarks include: developmental delays or loss of developmental milestones, hypopigmented kinky hair, severe neurodegeneration, arterial weakness, weakened bones, seizures, and low body temperature.

Back 34

Menkes Disease