In: Biology
1. You have a mixture of three proteins X, Y, and Z.
X is positively charged, has a mass of 100 kDa, it binds sugars.
Y is positively charged, has a mass of 200 kDa, it does not bind sugars.
Z is negatively charged, has a mass of 100 kDa, it does not bind sugars.
What will be the most efficient method to purify protein X from the mixture of X, Y, and Z?
A. washing
B. drying
C. ion-exchange chromatography
D. gel filtration chromatography
E. affinity chromatography
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2. What is the function of molecular chaperones?
A. They increase the rate of correct protein folding and prevent the formation of incorrectly folded intermediates
B. They transport ions across biological membranes
C. They catalyze chemical reactions in cells
D. They denature other proteins
E. They heat shock other proteins
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3. Arrangement of two or more polypeptide chains into a multi-subunit protein is referred to as:
A. Quaternary structure
B. Conformation
C. Tertiary structure
D. Primary structure
E. Secondary structure
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4. Research scientists are trying to clone a gene. In order to accomplish this task they join two pieces of DNA. Which class of the enzymes below might accomplish this task?
A. ligases
B. lyases
C. hydrolases
D. oxidoreductases
E. isomerases
Answer 1: Option (E) is correct
Explanation: Separation of individual component from a mixture is called as Chromatography. Here according to the question we have sample X,Y and Z which have difference based on their interaction towards attaching molecule. So we if separate mixture(DNA,RNA,Protein or other compound) on the basis of molecular interaction so we call it Affinity Chromatography.
Answer 2: Option (A) is correct
Explanation: Chaperones are used for the correct folding of protein.It is generally used to correct the denatured protein whose structure is destabilized by any means. So we can say that molecular chaperon are used to unfold the protein which is denatured in order to recorrect or renature it properly.
Answer 3: Option(A) is correct
Explanation:As we know that in the primary secondary and tertiory structure of protein it is generally formed by a single polypeptide chain. Single polypeptide chain undergoes coiling and folding to form the primary secondary and tertiary structure. But in case of Quaternary structure as it is formed by two or more then two polypeptide chains which is linked by non covalent interaction (hydrogen bond, electrostatic etc.)
Answer 4: Option (A) is correct
Explanation: Ligase is very important enzyme which is used in molecular cloning for the process of rejoining of two distant DNA segments. This enzyme is generally required during the process of replication to reseal gap(Nicks) which is generated in single stranded DNA during replication.