PreviousNucleic Acids: Score: 0 / 0Next

Nucleic Acids - MCAT Practice Questions

Nucleic acids, such as DNA and RNA, are polymers made up of what monomers?
Nucleotides






A molecule consisting of a 5-carbon sugar and a nitrogenous base, but lacking a phosphate group, is called a:
Nucleoside






What component of the DNA structure is responsible for giving the molecule a negative charge?
The phosphate backbone






According to the Watson-Crick model, the two strands of the DNA double helix run in which orientation relative to each other?
Antiparallel






What is the specific type of bond that holds the sugar and phosphate groups together to form the backbone of a DNA strand?
Phosphodiester bonds






Which nitrogenous base is found in RNA but is substituted by Thymine in DNA?
Uracil






Which bases are classified as Purines and are structurally characterized by having two rings?
Adenine and Guanine






Adenine (A) and Thymine (T) base pairs are held together by how many hydrogen bonds?
2






Guanine (G) and Cytosine (C) base pairs are held together by how many hydrogen bonds?
3






Chargaff's rules state that in DNA, the total number of Purines must equal the total number of:
Pyrimidines






The uniform diameter of the DNA double helix is cited as approximately:
20 angstroms






The Primary structure of nucleic acids is defined as the:
Linear sequence of nucleotides






The Secondary structure of RNA is made up of interactions between bases within the same molecule and is responsible for its shape, featuring elements like:
Loops, helices, bulges, and junctions






The Quaternary structure of nucleic acids involves their interactions with other molecules, such as chromatin interacting with:
Histones






DNA replication occurs during which phase of the cell cycle?
S (Synthesis) phase






Which enzyme is responsible for unwinding the DNA double helix, relieving the torsional strain ahead of the replication fork?
Topoisomerase






Which enzyme is responsible for breaking the hydrogen bonds between the nitrogenous bases to separate the two DNA strands?
Helicase






What molecules bind to single-stranded DNA to prevent the separate strands from immediately reannealing back into double-stranded DNA?
Single strand binding protein






Which enzyme is critical because it catalyzes the synthesis of the RNA primer, which provides the starting point for DNA synthesis?
DNA Primase






What are the short RNA nucleotide sequences that are complementary to the ssDNA and must be synthesized before DNA replication can begin?
RNA primers






The enzyme that adds nucleotides to the growing DNA strand and also functions to remove the RNA primer is:
DNA Polymerase






Okazaki fragments are the short, newly synthesized DNA fragments formed specifically on which DNA strand during replication?
The lagging template strand






Which enzyme joins DNA strands together by catalyzing the formation of phosphodiester bonds, particularly connecting Okazaki fragments?
DNA Ligase






DNA replication is the process of producing an identical replica of a DNA molecule, which is defined as:
DNA replication






The overall goal of DNA replication is for the DNA strands to be used as a template for the synthesis of new, complementary strands, leading to two complete DNA molecules. This is what type of replication?
Semiconservative