Biol 162 Ch14.2-14.3 DNA structure & replication

Which of these best describes the density of the bacterial DNA after the second round of replication in the Meselson-Stahl experiments?

2 density classes - one intermediate and one 14N DNA

X-ray diffraction was used to determine that the diameter of a DNA molecule is Blank______.

2 nm

How many hydrogen bonds form between cytosine and guanine in the DNA double helix?

3

In the Meselson-Stahl experiment, what was the expected composition of DNA molecules after two rounds of replication, if the dispersive model was correct?

3/4 of each DNA molecule would be light and 1/4 would be heavy, leading to a single density.

A segment of DNA has the sequence 5'-ATGCCC-3'. The complementary sequence would be Blank______.

5'-GGGCAT-3'

Which of these is not required for DNA replication?

NADPH

Of the following list, which 3 items are required for DNA replication?

Polymerase Nucleotides Template

Select all of the following that are components of a nucleotide.

Sugar Phosphate group Nitrogenous base

Features of the Watson and Crick model include Blank______.

a double stranded structure a sugar phosphate backbone a helical structure

The DNA structure proposed by Watson and Crick involves Blank______.

a helical structure a sugar phosphate backbone two grooves (major and minor)

In a DNA double helix, two hydrogen bonds form between Blank______.

adenine and thymine

The density of the bacterial DNA following the first round of DNA replication in the Meselson-Stahl experiment can best be described as Blank______.

an intermediate between 14N and 15N DNA

The term used to describe two DNA strands that run in opposite directions from each other is Blank______.

antiparallel

A heavy isotope of nitrogen was used in the Meselson-Stahl experiment so that Blank______.

different DNA molecules could be separated via ultracentrifugation

This model of DNA replication suggests that newly synthesized strands of DNA have mixtures of parental and newly synthesized portions is called Blank______.

dispersive

The interaction of two strands of DNA via hydrogen bonds results in a structure called the Blank______.

double helix

The level of DNA structure that resembles a spiral staircase is the Blank______.

double helix

The primary purpose of the Meselson and Stahl experiments was to determine Blank______.

how DNA replicates

Regarding Meselson and Stahl's experiment, the primary difference between the proposed models of DNA replication was related to Blank______.

how the parental strands were incorporated into the daughter strands

Which of these are part of the Watson-Crick model of the structure of DNA molecules?

Each DNA molecule is composed of two strands that run antiparallel. Each DNA molecule is composed of 2 phosphodiester strands.

The model organism used by Meselson and Stahl was Blank______.

Escherichia coli

Indicate the 4 nitrogenous bases used in DNA.

Guanine, Cytosine, Adenine, Thymine

Which of the following bonds, while individually weak, are numerous enough to hold the two strands of a double-stranded DNA molecule tightly together?

Hydrogen bonds between basepairs

Consider a double stranded DNA molecule. In complementary base pairing, A pairs with and C pairs with .

Blank 1: T or thymine Blank 2: G or guanine

In the double helix of a native DNA molecule, the two strands always have a(n) configuration, as one strand runs from 3' to 5', while the other runs from 5' to 3'.

Blank 1: antiparallel

DNA's phosphodiester is composed of alternating sugars and phosphates.

Blank 1: backbone, spine, or back-bone

Nucleotides contain a sugar, a phosphate, and a nitrogenous .

Blank 1: base

Franklin used x-ray to suggest that DNA has a helical structure.

Blank 1: diffraction or crystallography

Meselson and Stahl used two isotopes of in their DNA replication experiments so that the daughter strands could be distinguished from the parental strands.

Blank 1: nitrogen or N

In DNA, consecutive nucleotides are linked via bonds, which are made between the 5' phosphate of one nucleotide and the 3' group of another nucleotide.

Blank 1: phosphodiester Blank 2: hydroxyl or OH

Adjacent nucleotides in the same DNA strand are held together by covalent bonds known as bonds.

Blank 1: phosphodiester or phosphoester

The enzyme DNA covalently links nucleotides to synthesize new DNA strands together during DNA replication.

Blank 1: polymerase

Guanine forms hydrogen bonds with cytosine.

Blank 1: three or 3

How many hydrogen bonds are formed between adenine and thymine in the double DNA helix?

Blank 1: two or 2

Which enzyme covalently links nucleotides together?

DNA polymerase

Which of these are used in RNA?

Uracil Cytosine Adenine Guanine

During semiconservative DNA replication, Blank______.

one of the strands in each new double helix comes from the original molecule, and one is newly synthesized

Interpretation of the Meselson-Stahl data supported the Blank______ model of DNA replication.

semiconservative

DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with Blank______.

semiconservative replication

The DNA backbone is composed of Blank______.

sugars phosphate groups