Question

13.

Which of the following are not features commonly observed in α-helices and β-sheets?

	A.	amino acid side R groups that point outward, parallel regions
	B.	left-handedness, coiled-coil patterns
	C.	cylindrical shape, extended polypeptide backbone
	D.	one helical turn every 3.6 amino acids, antiparallel regions

14.

1. Fill in the blanks: The α-helices and β-sheets are examples of protein ____________ structure. A protein such as hemoglobin, which is composed of more than one protein ____________, has ____________ structure. A molecule such an enzymatic substrate, a hormone, or a growth factor, is called a ____________.

   	A.	secondary, subunit, quaternary, ligand
   	B.	tertiary, domain, secondary, substrate
   	C.	primary, subunit, secondary, transmitter
   	D.	quaternary, active site, secondary, ligand

17.

1. Find the mismatched pair:

   	A.	ΔG < 0 – Energetically favorable (spontaneous) reaction
   	B.	First Law of Thermodynamics — Energy in a system is not created nor destroyed, only transformed
   	C.	Second Law of Thermodynamics —The entropy of a perfect crystal at 0 K is exactly equal to zero.
   	D.	Entropy (TΔS) – Measurement of disorder in a thermodynamic system

18.

A cell exchanges matter and energy with the environment. From a thermodynamic perspective, a cell is

	A.	capable of absorbing electromagnetic (e.g. light) or chemical energy from the environment and release heat and waste products to its surroundings.
	B.	an open system.
	C.	subject to the laws of thermodynamics: First, energy is neither created nor destroyed; and second, every energy transfer increases the entropy (disorder) of the universe.
	D.	All of the above

20.

Which one is not an example of a protein with quaternary structure?

	A.	The plant enzyme Rubisco is composed of 8 L subunits and 8 S subunits.
	B.	South American rattlesnake toxin (crotoxin) is actually a phospholipase A enzyme with two different subunits.
	C.	Hemoglobin in adult humans has the composition α2β2.
	D.	Myoglobin, an oxygen-binding protein in muscle, consists of a single subunit.

21

1. Chemical reactions carried out by living systems depend upon the ability of some organisms to capture and use matter (atoms, ions, molecules) from non-living sources in the environment. The specific subset of these reactions that break down nutrients in food is called _________, whereas biosynthetic pathways form the subset called _______ and some biochemical pathways that include both types are called _______.

   	A.	catabolism, anabolism, amphibolic
   	B.	catabolism, anabolism, oxidation reactions
   	C.	hydrolysis, reducing reactions, biosynthesis
   	D.	anabolic, amphibolic, anaplerotic

22.

1. Find the mismatched pair function–protein:

   	A.	Insulin – Primary messenger in hormonal signaling
   	B.	Ferritin – Prokaryotic transcription factor
   	C.	Cloned green fluorescent protein – Artificial intracellular marker
   	D.	Rhodopsin – Light receptor

24.

1. Find the incorrect statement:

   	A.	Enzymes may be active inside and outside the cell.
   	B.	Substrate binding and catalysis depend on specific amino acids present in the active site.
   	C.	Enzymes possess certain specific domains called active sites, where catalysis take place.
   	D.	All enzymes are proteins.

Answer 1

13.

The features not commonly observed in α-helices and β-sheets are:l

Left-handedness, coiled-coil patterns.

Mostly alpha helix are right handed helical and no coiled- coil pattern. Coiled - coil pattern of packing occurs in DNA.

14

The α-helices and β-sheets are examples of protein Secondary structure. A protein such as hemoglobin, which is composed of more than one protein Subunit, has Quaternary structure. A molecule such an enzymatic substrate, a hormone, or a growth factor, is called a Ligand.

17.

Find the mismatched pair is:

C. Second Law of Thermodynamics —The entropy of a perfect crystal at 0 K is exactly equal to zero.

This is Third Law of Thermodynamics.

18.

The correct option is:

E. All of the above.

20.

The correct option is:

D.Myoglobin, an oxygen-binding protein in muscle, consists of a single subunit.

To have quaternary structure the protein must have more than one subunit.

21,

1.

Chemical reactions carried out by living systems depend upon the ability of some organisms to capture and use matter (atoms, ions, molecules) from non-living sources in the environment. The specific subset of these reactions that break down nutrients in food is called Catabolism, whereas biosynthetic pathways form the subset called Anabolism and some biochemical pathways that include both types are called Amphibolic.

22.

The mismatched pair function-protein is:

Ferritin : Prokaryotic transcription factor.

Ferritin is the iron storing protein in the cells.

24.

The incorrect statement is:

D. All enzymes are proteins.

some RNA molecules act as enzymes called Ribozymes.