DNA Replication

Which of the following units are repeatedly joined together to form a strand of DNA?

• amino acids

• fatty acids

• nucleotides

• monosaccharides

Answer explanation

DNA strands are formed by linking nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. Amino acids, fatty acids, and monosaccharides are not involved in DNA structure.

In what phase of the cell cycle does DNA replication take place?

• G1

• S

• G2

• M

Answer explanation

DNA replication occurs during the S phase of the cell cycle. This is the stage where the cell synthesizes a complete copy of its DNA, preparing for cell division.

Match each nitrogenous base with its match

• Guanine

• Guanine

• Adenine

• Adenine

• Thymine

• Thymine

• Cytosine

• Cytosine

A process in which DNA has the unique ability to make an exact copy of itself.

• Replication

• Translation

• Transcription

Answer explanation

Replication is the process by which DNA makes an exact copy of itself, ensuring genetic information is passed on during cell division. Translation and transcription are processes related to protein synthesis and RNA production, respectively.

Tags

NGSS.HS-LS3-2

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

A nucleotide consists of three components: a sugar molecule, a phosphate group, and a nitrogen base. The correct answer is 'sugar, phosphate, nitrogen base', as the other options incorrectly include hydrogen, oxygen, or protein.

What determines the code, or information, of a DNA molecule?

• the shape (structure) of the nitrogen bases

• the order (sequence) of the nitrogen bases

• the color of the nitrogen bases

• the frequency (number) of nitrogen bases

Answer explanation

The code of a DNA molecule is determined by the order (sequence) of the nitrogen bases. This sequence encodes the genetic information, while the shape, color, and frequency of the bases do not define the genetic code.

Tags

NGSS.HS-LS1-1

Which sequence of DNA bases would pair with this template strand
ATG TGA CAG

• ATG TGA CAG

• TAC ACT GTC

• GTA AGT GAC

• CAT TCA CTG

Answer explanation

The template strand ATG TGA CAG pairs with TAC ACT GTC, as adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Thus, the correct complementary sequence is TAC ACT GTC.

In the diagram strand I and II represent portions of DNA molecule. Strand II would normally include...

• AGC

• TCG

• TAC

• GAT

Answer explanation

Strand II would normally include the complementary base pairs to strand I. If strand I has 'CTA', the complementary sequence would be 'GAT', making 'GAT' the correct choice.

Tags

NGSS.HS-LS1-1

Which sequence of DNA bases would pair with this partial strand
CAT TCA CTG

• ATG TGA CAG

• TAC ACT GTC

• GTA AGT GAC

• CAT TCA CTG

Answer explanation

The DNA base pairing follows the rule A-T and C-G. The given strand CAT TCA CTG pairs with GTA AGT GAC, as G pairs with C, T with A, and A with T, making it the correct complementary sequence.

Replicate the following strand of DNA: 
AATCATGGA

• AATCATGGA

• TTAGTACCT

• UUAGUACCU

• GGATAUCUA

Answer explanation

To replicate the DNA strand AATCATGGA, we replace each base with its complementary base: A with T, T with A, C with G, and G with C. Thus, AATCATGGA becomes TTAGTACCT.