Section 12.1; DNA: the Genetic Material

1. The discovery of DNA as the genetic material involved many experiments.

2. James Watson and Francis Crick are credited with the “discovery” of DNA.

They used Rosalind Franklin’s Photo 51 to determine the structure of DNA.

3. The subunits or monomers of nucleic acids are called nucleotides.

4. The two different types of nucleic acid are DeoxyriboNucleic Acid; DNA,

and RiboNnucleic Acid; RNA.

Questions 12.1

1. What are the names and one letter abbreviation for the (nitrogenous) bases

found in DNA? RNA?

2. In DNA, the number of A = ______, and the number of C = ______.

3. What is the correct name of the twisted stairway shape of DNA?

4. Are the bases found pointed inward, or pointed outward in the DNA double

helix?

5. How is DNA organized differently in prokaryotes, and eukaryotes?

6. Make a sketch of a DNA molecule. Label the following: complementary

bases, hydrogen bonds, phosphate groups, and. deoxyribose. Sketch it in

“horizontal” form, and double-helix form.

Section 12.2; Replication of DNA

1. DNA replicates (copies) itself by making a strand that is complementary to

each original strand.

2. An original strand, and a new strand are teamed. This is called semi-

conservative replication.

3. The basic three steps in replication (that occurs during interphase) are

DNA unwinds and unzips, complementary bases align, and one new/old

strand join.

4. The enzymes DNA helicase, RNA primase, DNA polymerase, and DNA

ligase are involved in DNA replication.

Question(s) 12.2

Make a sketch of the replication of DNA. Label the following: Leading strand,

DNA polymerase, parental DNA, Lagging strand, Okazaki fragments, DNA polymerase, helicase, and the direction of movement.

Section 12.3; DNA, RNA, and Protein

DNA codes for RNA, which guides

Protein Synthesis.

or…

The Central Dogma of Biology is DNA is transcribed into RNA, and RNA is translated into proteins. The Central Dogma is also called Protein Synthesis, or Gene Expression.

DNA to RNA is called transcription, while RNA to protein is called translation.

The three major types of RNA are

messenger (mRNA), transfer

(tRNA), and ribosomal r(RNA).

The building blocks, subunits, or

monomers of nucleic acids (DNA and RNA) are nucleotides, while the monomers of proteins are amino acids.

5. What is meant by one gene – one expression?

Questions 12.3

1. What is the role of each of the following during protein synthesis?

mRNA, tRNA, rRNA, and the ribosome

2. Where is RNA manufactured in the cell, and why is ist single stranded, and DNA

double-stranded (a double-helix)?

Section 12.4; Gene Expression and Mutation

1. Gene expression is regulated by the cell, and mutations can affect gene expression.

2. Mutations range from point mutations to the deletion, or movement of large

sections of the chromosomes.

3. Mutagens, such as chemicals and radiation, can cause mutations.

Questions 12.4

1. What is a mutation? a point mutation?

2. Point, or gene mutations can be subdivided into substitutions, deletions, and

insertions. Describe each, and give an example of an associated disease.

3. Sometimes a part of a chromosome, or an entire chromosome might be

affected.and an entire chromosome. Give an example of a syndrome that is

caused by this type of mutation (sometimes called a chromosomal mutation).

4. In terms of mutation, what is the difference between a body cell, and a sex

(germ) cell?

Name: ______Number: ______Date: ______

Chapter 12 questions