26. How many different amino acids are found in proteins?
a) 20
b) 5
c) 10
d) 50
27. Which of the following is an example of a secondary structure in proteins?
a) Alpha helix
b) Amino acid sequence
c) DNA binding
d) Enzymatic activity
28. Which of the following is an example of a polysaccharide?
a) Glucose
b) Sucrose
c) Starch
d) Fructose
29. What is the main difference between DNA and RNA?
a) DNA is double-stranded, while RNA is single-stranded
b) DNA contains uracil, while RNA contains thymine
c) DNA is found only in the nucleus, while RNA is found throughout the cell
d) DNA is involved in protein synthesis, while RNA is involved in energy production
30. Which of the following is an example of a nucleotide base found in DNA?
a) Adenine
b) Guanine
c) Cytosine
d) All of the above
