NAME ______DATE ______

Chapter 12: Molecular Genetics – Study Guide

Use the word bank to fill in the blanks below.

threedouble helixnucleotidedeoxyribonucleic acid two adenine sugar nucleus nitrogen thymine phosphates complementary cytosine guanine antiparallel nucleic acid

hydrogen

DNA’s full name is ______. It is an example of a biomolecule called ______. DNA is found in the ______of a cell. It is made up of millions of tiny subunits called ______. In each nucleotide, there is a ______, a phosphate, and a ______base (______, guanine, ______, cytosine). When connected, these nucleotides form the shape of DNA, a ______. This shape is similar to a ladder. The sides, or backbone, of the DNA ladder are made of the sugars and ______. They run ______to each other. The rungs of the ladder are made of pairs of nitrogen bases. These bases are ______, which means they only bond with one other type of base. Adenine always bonds with thymine, and ______always pairs with guanine. The pairs are held together by ______bonds. Adenine and thymine have ______, and ______and cytosine have ______.

Draw and label a nucleotide.

DNA Replication

Where does it take place? ______

When does it take place? ______

Why does it occur? ______

Put the steps of this process in order.

____ Two new molecules of DNA are created.

____ DNA polymerase attach the free-floating nucleotides to the exposed nitrogen bases.

____ Helicase begins to break the hydrogen bonds between nitrogen bases.

____ Cell starts into the mitosis phase of the cell cycle.

____ Free floating nucleotides pair up with exposed nitrogen bases.

Explain the function of the enzymes helicase and polymerase.

Explain the CENTRAL DOGMA:

Use the table to list the differences between DNA and RNA.

DNA / RNA

Type of sugar

# of strands
Nitrogen bases
Base pairs

What is mRNA?

Define transcriptionand translation.

What is a codon?

What do stop and start codons do?

Use the following DNA code to answer the questions: GAT CAC GGT ATC

  1. Replicate it:
  2. Transcribe it:
  3. Translate it:

List and define the two types of mutations and then list and define the specific kinds.

  1. ______:
  2. ______:
  3. ______:
  4. ______:
  5. ______:

Although we are born with our genes, what else can have an impact on them? ______

Mutations that take place in the ______cells will be passed on to offspring in every generation.

Define each of the following

Genetic engineering:

Biotechnology:

Gene therapy:

Cloning:

Breeding:

Selective breeding:

Write a paragraph that explains the relationship between DNA, proteins, cells, chromosomes, traits, and genes. Use each of these words in your paragraph.