Question

Which of the following amino acids has a positive charge that helps to hold the DNA in contact with the histones?

a) Aspartic acid
b) Lysine
c) Glutamine
d) Serine

Answer 1

Lysine is the amino acid that has a positive charge and helps to hold the DNA in contact with the histones.

Step-by-step explanation:

The amino acid that has a positive charge and helps to hold the DNA in contact with the histones is Lysine. Histones are basic proteins that contain many lysine and arginine amino acids. The positively charged side chains of these amino acids enable them to bind to the acidic, negatively charged phosphodiester backbone of double helical DNA.

Answer 2

Lysine is the amino acid that has a positive charge, facilitating its interaction with DNA and histones. Option B is answer.

Step-by-step explanation:

DNA-Histone Interaction: In eukaryotic cells, DNA is tightly packed with histone proteins to form chromatin. Positively charged amino acids, such as lysine, play a crucial role in binding to the negatively charged phosphate groups of DNA, maintaining the structure.

Lysine's Positive Charge: Lysine contains a positively charged amino group in its side chain, making it basic. This positive charge enables lysine to form electrostatic interactions with the negatively charged DNA, aiding in the stabilization of nucleosomes.

Role in Histone Proteins: Histones are rich in basic amino acids, including lysine, contributing to their positive charge. This positive charge helps histones bind to and neutralize the negatively charged DNA.

Therefore, option B (Lysine) is the correct answer as the amino acid with a positive charge that assists in holding DNA in contact with histones.