22. Are all enzymes proteins? A) Yes, of course! What kind of question is that?
ID: 151454 • Letter: 2
Question
22. Are all enzymes proteins?
A) Yes, of course! What kind of question is that?
B) No. Actually, the coenzymes and cofactors are the molecules that catalyze biological reactions. C)
depend on RNA for their catalytic activity.
D) No. DNA can repair itself due to intrinsic catalytic activity. E) None of the above.
23. The cell membrane can be described most accurately as
A) permeable to most small molecules but impermeable to larger ones.
B) permeable to only larger molecules.
C) permeable to all molecules.
D) permeable to some molecules and impermeable to others.
E) impermeable to all polar molecules.
No. Ribozymes
24. The structure and general chemical composition of the cell membrane is similar to the membranes of organelles. True or false?
25. Find the incorrect statement regarding the dalton (Da) unit:
A) 1 u (unified atomic mass unit) = 1 dalton (Da)
B) 1Da=1.66X10–24 g
C) 1Da=1/12themassof12C
D) A molecule of human insulin has a mass of 5,808 Da. This can be represented as 5.8 kilodaltons (kDa).
E) None of the above
26. Briefly describe what is an ultracentrifuge. Compare and contrast an ultracentrifuge with a clinical centrifuge in terms of capabilities and applications.
27. Why do polar substances such as NaCl dissolve so readily in water?
A) NaCl is a very dry powder, and the water is able to soak into the salt.
B) The sodium ions repel the negative end of the water molecule.
C) Spheres of hydration form between the water and the ions.
D) The charged ends of the water molecules are able to surround the oppositely charged salt ion.
E) bothCandD
28. When bound to certain atoms, hydrogen can form a special type of bond. The following is correct regarding hydrogen bonds:
A) In order to form a hydrogen bond, H must be bound to a more electronegative element such as O or N.
B) Hydrogen bonds are non-covalent.
C) Hydrogen bonds are weaker but numerous so they contribute to stabilize the structure of molecules such as proteins.
D) All of the above.
E) None of the above.
29. Using two terms from the list below, fill in the blanks: The synthesis of a protein by condensation of a-L-amino acids occurs by a \ eaction in which a molecule of water is eliminated; in contrast, the of a polypeptide requires a molecule of water and produces free amino acids.
ligation deamination reduction oxidation dehydration
30. Which one of the following biological polymers is mismatched with its monomer?
A) DNA — nucleotide
B) protein — fatty acid
C) starch — a-(D)-glucose
D) fatty acid — Acetyl-S-coenzyme A
E) isoprenoid — isopentenyl
31. One of these organic groups is not properly identified. Which one is it?
A) R-OH — hydroxyl
B) R1–O–R2 — aldehyde
C) R–NH2 — amino
D) R–SH2 — sulfhydryl
O
||
E) R1–C–R2 — ketone
hydrolysis
Explanation / Answer
Q22
Answer: option C
Reason: depend on RNA for their catalytic activity. All enzymes are proteins except for ribosomes or Catalytic RNA which are the RNA-based catalyst. They are also considered as a catalyst which is the role of enzymes.
Q23
Answer: option D
Reason: permeable to some molecules and impermeable to others The plasma membrane's function is o protect the cell from the outside condition, this is the reason why it is selectively permeable. It only allows some molecules that can maintain the cell's internal composition and integrity to pass by while inhibiting those the other
Q24
Answer: false
Reason: False. The two varies in molecular composition and because with organelle membrane, they are well suited for the functions of organelle that they perform
Q25
Answer: option B
Reason: As the real representation of DA is 1,660538921 (73) × 10-27
Q26
Answer: The ultracentrifuge is a centrifuge optimized with a rotor to get higher speeds. It is commonly used in sedimentation experiments.
In terms of use a clinical centrifuge also applies this use with biological fluids, measuring the sedimentation speed, separating blood elements to be studied in the lab as red components and serum
Q27
Answer: option E
Reason: Spheres of hydration form between the water and the ions and The charged ends of the water molecules are able to surround the oppositely charged salt ion.
Q28
Answer: option A
Reason: these bounds are characteristic because of a partially electrostatic attraction between H and another more electronegative ions.
Q29
Answer: dehydration and reduction.
Q30,
Answer: Option B
Reason: B) protein — fatty acid
Q31
Answer: option D
Reason: D) R–SH2 — sulfhydrylO||
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