Biology 212 Mastering Biology: Test 2 Review

-The sugar in this molecule contains four carbons. -The nitrogenous base is cytosine. -This is a monomer of RNA. -This is an amino acid.

-False -True -True -False

-the arrowheads represent the 3' ends of the strands. -this is a double stranded DNA -the nitrogenous bases are paired correctly -Hydrogen bonds are not shown but are suggested by the base pairing in the model -The arrowhead represent the phosphate group at the end of the strand -the vertical lines represent sugar-phosphate backbone s

-True -True -True -True -False -True

Single strands of nucleic acids are directional, meaning that there are two different ends. What functional groups define the two different ends of a strand?

-a free phosphate group on the 5' carbon -a free hydroxyl group on the 3' carbon

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of _____.

120 Thymine and 120 adenine molecules

What do the red arrows in this student-drawn model represent?

A sugar-phosphate backbone

Compare proteins to nucleic acids. Which of the following is TRUE?

Both have primary and secondary structure.

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

The phosphodiester linkages of the polynucleotide backbone would be broken.

Four students were asked to draw a simple model of a nucleotide using the following color code. Sugar = red Phosphate group = yellow Nitrogenous base = blue Which model is correct?

Yellow phosphate group- Red sugar group- Blue Nitrogenous base

In a nucleic acid polymer, the bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers?

nitrogenous bases

What do the arrowheads in this student-drawn model represent?

the 3' end of the DNA strand