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CHAPTER
10
The Structure and Function
of DNA
Lecture Outline
I. Biology and Society: Mix-and-Match Viruses
A. DNA: Structure and Replication
1. DNA
2. The discovery of DNA
B. DNA and RNA Structure
1. DNA and RNA are nucleic acids
a. They consist of chemical units called:
b. A nucleotide polymer is a:
c. Nucleotides are joined by covalent bonds between the sugar of one nucleotide and
the phosphate of the next, forming a:
2. The sugar in DNA is deoxyribose. thus, the full name for DNA is deoxyribonucleic acid
3. The four nucleotides found in DNA differ in their nitrogenous bases. These bases are
a. thymine (T),
b. cytosine (C),
c. adenine (A), and
d. guanine (G).
4. RNA has uracil (U) in place of thymine
C. Watson and Crick’s Discovery of the Double Helix
5. DNA bases pair in a complementary fashion:
a. adenine (A) pairs with:
b. cytosine (C) pairs with:
D. DNA Replication
1. When a cell reproduces, a complete copy of the DNA must pass from one generation
to the next
2. DNA can be damaged by:
3. DNA polymerases
a. are enzymes,
b. make the covalent bonds between the nucleotides of a new DNA strand, and
c. are involved in repairing damaged DNA.
4. DNA replication
5. DNA replication in eukaryotes
a. begins at specific sites on a double helix called:
b. proceeds in both directions.
E. The Flow of Genetic Information from DNA to RNA to Protein
F. How an Organism’s Genotype Determines Its Phenotype
1. An organism’s genotype is:
2. The phenotype is:
3. DNA specifies the synthesis of proteins in two stages:
a. transcription:
b. translation:
4. The one gene–one enzyme hypothesis:
5. The function of a gene is to:
6. A protein may consist of two or more different polypeptides
G. From Nucleotides to Amino Acids: An Overview
1. Genetic information in DNA is:
2. A codon is:
H. The Genetic Code
1. The genetic code is:
2. Of the 64 triplets,
a. 61 code for amino acids and
b. 3 are stop codons, instructing the ribosomes to end the polypeptide.
3. Because diverse organisms share a common genetic code, it is possible to program one
species to produce a protein from another species by transplanting DNA
I. Transcription: From DNA to RNA
1. Transcription
a. makes:
2. RNA nucleotides are linked by the transcription enzyme:
J. Initiation of Transcription
1. The “start transcribing” signal is a nucleotide sequence called a promoter, which is:
2. The first phase of transcription is initiation, in which:
K. RNA Elongation
L. Termination of Transcription
1. During the third phase of transcription, called termination
a. a terminator:
M. The Processing of Eukaryotic RNA
1. In messenger RNA (mRNA)
3. RNA processing includes
a. adding a cap and tail
b. removing introns
c. RNA splicing, joining exons
4. RNA splicing is believed to play a significant role in humans
N. Translation: The Players
1. Translation is:
O. Messenger RNA (mRNA)
1. Translation requires
a. mRNA,
b. ATP,
c. enzymes,
d. ribosomes, and
c. transfer RNA (tRNA).
P. Transfer RNA (tRNA)
1. Transfer RNA (tRNA)
Anticodons:
Q. Ribosomes
1. Ribosomes are organelles that:
2. Each subunit is made up of:
R. Translation: The Process
1. Translation is divided into three phases:
a. initiation,
b. elongation, and
c. termination.
S. Initiation
start codon
T. Elongation
1. Elongation occurs in three steps
a. Step 1: Codon recognition.
b. Step 2: Peptide bond formation.
c. Step 3: Translocation.
U. Termination
1. Elongation continues until
a. a stop codon.
V. Review: DNA RNA Protein
1. In a cell, genetic information flows from
a. DNA to RNA in the nucleus and
b. RNA to protein in the cytoplasm.
2. As it is made, a polypeptide
a. coils and folds and
b. assumes a three-dimensional shape, its tertiary structure.
3. Transcription and translation are how genes control the structures and activities of cells
W. Mutations
1. A mutation is any change in the nucleotide sequence of DNA
2. Mutations can involve
3. Mutations within a gene can be divided into two general categories:
a. nucleotide substitutions (the replacement of one base by another) and
b. nucleotide deletions or insertions (the loss or addition of a nucleotide).
4. Insertions and deletions can:
X. Mutagens
1. Mutations may result from
a. errors in DNA replication or recombination or
b. physical or chemical agents called mutagens.
Y. Viruses and Other Noncellular Infectious Agents
1. Viruses share some, but not all, characteristics of living organisms.
Z. Bacteriophages
1. Bacteriophages, or phages, are
2. Phages have two reproductive cycles
a. In the lytic cycle,
b. In the lysogenic cycle,
AA. Plant Viruses
1. Viruses that infect plants can
BB. Animal Viruses
CC. The Process of Science: Do Flu Vaccines Protect the Elderly?
DD. HIV, the AIDS Virus
EE. Viroids and Prions
FF. Evolution Connection: Emerging Viruses
1. Emerging viruses are: