Identifying Biochemical Molecules

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Biochemistry › Identifying Biochemical Molecules

Questions 1 - 10
1

Which of the following describes amino acids with aromatic R-roups?

All other answers

Hydrophobic

Nonpolar

Phenylalanine, tyrosine, and tryptophan

Can absorb ultraviolet light

Explanation

Phenylalanine, tyrosine, and tryptophan are amino acids with an aromatic (benzene) ring that are relatively nonpolar aand participate in hydrophobic interactions.

2

Which of the following describes amino acids with aromatic R-roups?

All other answers

Hydrophobic

Nonpolar

Phenylalanine, tyrosine, and tryptophan

Can absorb ultraviolet light

Explanation

Phenylalanine, tyrosine, and tryptophan are amino acids with an aromatic (benzene) ring that are relatively nonpolar aand participate in hydrophobic interactions.

3

Which of the following describes amino acids with aromatic R-roups?

All other answers

Hydrophobic

Nonpolar

Phenylalanine, tyrosine, and tryptophan

Can absorb ultraviolet light

Explanation

Phenylalanine, tyrosine, and tryptophan are amino acids with an aromatic (benzene) ring that are relatively nonpolar aand participate in hydrophobic interactions.

4

Cytosine

What is the name of the molecule shown?

Cytosine

Cytidine

Uracil

Thymine

Pyrimidine

Explanation

A nucleoside is the nitrogenous base bound to a sugar via glycosidic bond. A nucleotide is a nitrogenous base bonded to a sugar bonded to the phosphate. This nitrogenous base is cytosine. If it were bound to ribose, it would be called cytidine. Although cytosine is a pyrimidine like uracil and thymine, pyrimidine is a class of ring structure, not the specific name of a base.

5

Which of the following statements best describes high-density lipoproteins as compared to other lipoproteins?

They have the highest protein content

They have more triglycerides than very low-density lipoproteins

They have the most triglycerides and least protein

They have the highest content of cholesterol and cholesterol esters

Explanation

High-density lipoproteins have the highest proportion of protein of the five classes of blood lipoproteins: chylomicrons, very-low-density lipoproteins, intermediate-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Chylomicrons have the lowest density of the five classes of lipoproteins. This is because the have the highest proportion of triglycerides and the least lowest proportion of protein. Very-low-density lipoproteins are a bit more dense than chylomicrons; however, the relative amount of triglycerides is still high. Intermediate-density lipoproteins which are formed from the very-low-density lipoproteins have a higher density than very-low-density lipoproteins due to the fact that they have less than half of the amount of triglycerides as very-low-density lipoproteins. Low-density lipoproteins have the highest amount of cholesterol and an even lesser amount of triglycerides than intermediate-density lipoproteins. Lastly, high-density lipoproteins are the densest of the lipoproteins due to the fact that they have the highest amount of protein in relation to the amount of triglycerides they contain.

6

Which of the following are pyrimidines?

Cytosine (C), uracil (U), and thymine (T)

Adenine (A) and guanine (G)

Cytosine (C) and uracil (U)

Adenine (A), guanine (G), and uracil (U)

Explanation

Think of it as this. CUT the PY (pie) PYrimidines. PURe As Gold. PURines. A will pair with T (and U in RNA). G will pair with C. The deamination of cytosine makes uracil, which is in RNA.

7

Cytosine

What is the name of the molecule shown?

Cytosine

Cytidine

Uracil

Thymine

Pyrimidine

Explanation

A nucleoside is the nitrogenous base bound to a sugar via glycosidic bond. A nucleotide is a nitrogenous base bonded to a sugar bonded to the phosphate. This nitrogenous base is cytosine. If it were bound to ribose, it would be called cytidine. Although cytosine is a pyrimidine like uracil and thymine, pyrimidine is a class of ring structure, not the specific name of a base.

8

Cytosine

What is the name of the molecule shown?

Cytosine

Cytidine

Uracil

Thymine

Pyrimidine

Explanation

A nucleoside is the nitrogenous base bound to a sugar via glycosidic bond. A nucleotide is a nitrogenous base bonded to a sugar bonded to the phosphate. This nitrogenous base is cytosine. If it were bound to ribose, it would be called cytidine. Although cytosine is a pyrimidine like uracil and thymine, pyrimidine is a class of ring structure, not the specific name of a base.

9

Which of the following are pyrimidines?

Cytosine (C), uracil (U), and thymine (T)

Adenine (A) and guanine (G)

Cytosine (C) and uracil (U)

Adenine (A), guanine (G), and uracil (U)

Explanation

Think of it as this. CUT the PY (pie) PYrimidines. PURe As Gold. PURines. A will pair with T (and U in RNA). G will pair with C. The deamination of cytosine makes uracil, which is in RNA.

10

Which of the following statements best describes high-density lipoproteins as compared to other lipoproteins?

They have the highest protein content

They have more triglycerides than very low-density lipoproteins

They have the most triglycerides and least protein

They have the highest content of cholesterol and cholesterol esters

Explanation

High-density lipoproteins have the highest proportion of protein of the five classes of blood lipoproteins: chylomicrons, very-low-density lipoproteins, intermediate-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Chylomicrons have the lowest density of the five classes of lipoproteins. This is because the have the highest proportion of triglycerides and the least lowest proportion of protein. Very-low-density lipoproteins are a bit more dense than chylomicrons; however, the relative amount of triglycerides is still high. Intermediate-density lipoproteins which are formed from the very-low-density lipoproteins have a higher density than very-low-density lipoproteins due to the fact that they have less than half of the amount of triglycerides as very-low-density lipoproteins. Low-density lipoproteins have the highest amount of cholesterol and an even lesser amount of triglycerides than intermediate-density lipoproteins. Lastly, high-density lipoproteins are the densest of the lipoproteins due to the fact that they have the highest amount of protein in relation to the amount of triglycerides they contain.

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