Proteins (Mid 1)

Question 1

Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of this amino acid.

a
It will be very acidic.

b
It will be very basic.

c
It will be hydrophobic.

d
It will be hydrophilic.

e
None of the above are likely true

Answer 1

c
It will be hydrophobic.

Question 2

In proteins, the _____________ of the protein determines its _____________, which in turn determines its _____________.

a
amino acid sequence, function, three-dimensional shape

b
function, three-dimensional shape, amino acid sequence

c
three-dimensional shape, function, amino acid sequence

d
three-dimensional shape, amino acid sequence, function

e
amino acid sequence, three-dimensional shape, function

Answer 2

e
amino acid sequence, three-dimensional shape, function

Question 3

What might be the effect on protein function if each polypeptide adopted only a single, inflexible shape, based on its primary structure?

a
Prions would be more active and convert more proteins into prions

b
The tertiary structure could not appear, so proteins would not be able to perform their functions.

c
All proteins would perform their functions normally.

d
The ability to regulate protein activity would be impaired. Some proteins would be either permanently active or inactive, depending on how they are folded.

e
None of the above are true

Answer 3

d
The ability to regulate protein activity would be impaired. Some proteins would be either permanently active or inactive, depending on how they are folded.

Question 4

Cells have an internal scaffolding, called the cytoskeleton, that serves a number of purposes. Proteins that form the internal cytoskeleton of individual cells serve a _____ function.

a
Transport

b
Structural

c
Defense

d
Signaling

e
None of the above

Answer 4

b
Structural

Question 5

Someone with a fever of more than 40 degrees C (104 degrees F) must quickly rush to the hospital to receive treatment. Based on the temperature range, why could this potentially cause health problems in the patient?

a
Water and other liquids in the body will boil.

b
Cells will begin moving too quickly and will break apart tissues.

c
Blood vessels in the brain will begin to burn.

d
Enzymes for important reactions will denature.

Answer 5

d
Enzymes for important reactions will denature.

Question 6

Lactase is the enzyme that breaks the disaccharide lactose into two monosaccharides, glucose and galactose. Consider these two scenarios: a change in the amino acid sequence of lactase OR an increase in temperature (to the point of protein denaturation). In both scenarios, lactase is no longer able to break down lactose because: (Choose any/all that apply)

Multiple answers:
Multiple answers are accepted for this question

a
The shape of lactase may be incorrect

b
Lactase may fail to bind to lactose

c
pH has changed

d
Presence of a molecule that inhibits the enzyme

Answer 6

a
The shape of lactase may be incorrect

b
Lactase may fail to bind to lactose