DNA & RNA

DNA replication occurs during ​ (a)   .

• interphase

• metaphase

• telophase

• anaphase

• prophase

Answer explanation

DNA replication occurs during interphase, the phase of the cell cycle where the cell grows and DNA is replicated before cell division.

Reorder the following

• Ligase bonds DNA fragments

• Primase marks region to begin replication

• DNA is unzipped

• Polymerase builds complimentary DNA strand

After replication, each strand has ​ (a)   new strand(s) and ​ (b)   old strand(s).

• one

• two

• zero

Answer explanation

After replication, each strand has one new strand and one old strand, as the DNA molecule is composed of one original strand and one newly synthesized strand.

Why is DNA important?

• it is very small and very complicated

• it's in everything

• it serves as the blueprint for traits of all living things

• because we eat it every day for energy

Answer explanation

DNA is important because it serves as the blueprint for traits of all living things.

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-1

What are the three components of a nucleotide?

• sugar, hydrogen, nitrogen base

• sugar, oxygen, nitrogen base

• sugar, phosphate, nitrogen base

• sugar, phosphate, protein

Answer explanation

The three components of a nucleotide are sugar, phosphate, and nitrogen base. These components make up the basic structure of DNA and RNA molecules.

Which shows the correct complementary base pairing for DNA?

• C-A, T-G

• A-G, C-T

• C-G, U-A

• T-A, G-C

Answer explanation

The correct complementary base pairing for DNA is T-A and G-C. Adenine pairs with Thymine (A-T) and Cytosine pairs with Guanine (C-G).

All organisms contain DNA and RNA. What are the subunits of DNA and RNA?

• simple sugars

• amino acids

• carbohydrates

• nucleotides

Answer explanation

DNA and RNA are composed of nucleotides, which are the subunits that make up the genetic material in all organisms.

Which biomolecules are found in all organisms?

• glucose, maltose, fructose, sucrose

• adenine, cytosine, thymine, guanine

• chlorophyll, cytosine, thymine, guanine

• cholesterol, phospholipid, cellulose, gibberellin

Answer explanation

The correct choice is adenine, cytosine, thymine, guanine as they are the four nucleotide bases found in DNA, which are essential biomolecules present in all organisms.

Dr. Tanaka discovered a new virus. The virus has a single strand of a nucleic acid, but she does not know if it is DNA or RNA. After running tests, she concludes that it is DNA. Which of the following would lead her to that conclusion?

• It contains uracil.

• It contains adenine.

• It contains thymine.

• It contains cytosine.

Answer explanation

The correct choice to conclude that the virus is DNA is that it contains thymine, which is a characteristic of DNA and not RNA.

Nitrogenous bases are joined by which type of bond?

• polar bonds

• ionic bonds

• covalent bonds

• hydrogen bonds

Answer explanation

Nitrogenous bases are joined by hydrogen bonds, which are weak attractions between a hydrogen atom and an electronegative atom like nitrogen or oxygen.

Tags

NGSS.HS-LS1-1