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Chapter 12
DNA , the Chromosome and
Protein Synthesis
Comparative Scale of a Gene Map
Section 11-5
Mapping of Earth’s
Features
Mapping of Cells,
Chromosomes, and Genes
Cell
Earth
Country
Chromosome
State
Chromosome
fragment
City
People
Go to
Section:
Gene
Nucleotide
base pairs
Figure 12–5 DNA Nucleotides
Purines
Adenine
Guanine
Phosphate
group
Go to
Section:
Pyrimidines
Cytosine
Thymine
Deoxyribose
Figure 12–7 Structure of DNA
Nucleotide
Hydrogen
bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Go to
Section:
Percentage of Bases in
Four Organisms
Go to
Section:
Source of DNA
A
T
G
C
Streptococcus
29.8
31.6
20.5
18.0
Yeast
31.3
32.9
18.7
17.1
Herring
27.8
27.5
22.2
22.6
Human
30.9
29.4
19.9
19.8
The Structure of DNA
1.
Chargaff’s Rules
2.
X-Ray Evidence
3.
The Double Helix Watson and Crick
What do you know about DNA?
Figure 12-10 Chromosome
Structure of Eukaryotes
____________
Nucleosome
_____
_____
_____
Coils
Supercoils
----------------
Go to
Section:
2/02 hmwk:
• Read pgs 39-43 in review book
• complete the Odd questions #s 1-21
12–2
Section 12-2
A.
Eukaryotic Chromosomes
and DNA Replication
DNA and Chromosomes
1. DNA Length
30 million base pairs
2. Chromosome Structure
B. DNA Replication
Steps:
1. Helicase: unwinds the helix
2. Binding proteins help to stabilize the DNA strands at
replication fork.
3. Primase primes the DNA strand for synthesis.
4. DNA Polymerase adds on many nucleotide monomers for
Go to
Section: elongation.
Figure 12–11 DNA Replication
New strand
Original
strand
DNA
polymerase
Growth
DNA
polymerase
Growth
Replication
fork
Replication
fork
New strand
Go to
Section:
Original
strand
Nitrogenous
bases
DNA Replication Review
replicationdna\16_14LeadingStrand_A.html
Prokaryotic Chromosome
Structure
Section 12-2
Chromosome
E. coli bacterium
Bases on the chromosome
Go to
Section:
Types of Replication
1. Asexual Reproduction: production of
offspring from one parent
a. forms identical information
1.
2.
3.
4.
5.
6.
Binary fission: ex. bacterial cells
Budding: ex. Hydras
Spore formation: ex. Molds
Vegetative propagation: strawberries
cloning
mitosis
Binary Fission:
Prokaryote Reproduction
• Formation of
two identical
organisms involving
an equal division of
the organism’s
cytoplasm and
Genetic material
Budding
• Hydra:
Kingdom Animalia
Phylum Cnidaria
Class Hydrozoa
Order Capitata
Family Hydridae
Genus Hydra
involves division of
the nucleus from one parent’s
(genetic material) equally,
but cytoplasm unequally
•
Sporulation
• Spore Formation
is the reproduction
involving one parent
Forming specialized
single cells
Mitosis: Eukaryote cell division
• The division
of the nucleus
and the even
distribution of
the cytoplasm
in Eukaryotic
cells
Cloning
Figure 13-13 Cloning of the First
Mammal
Section 13-4
A donor cell is taken from
a sheep’s udder.
Donor
Nucleus
These two cells are fused
using an electric shock.
Fused Cell
Egg Cell
The nucleus of the
egg cell is removed.
An egg cell is taken
from an adult
female sheep.
Embryo
Cloned Lamb
The embryo
develops normally
into a lamb—Dolly
Go to
Section:
The fused cell
begins dividing
normally.
Foster
Mother
The embryo is placed
in the uterus of a foster
mother.
polyermerase.exe
• Dolan DNA Learning Center's Gene
Almanac
12–3 RNA and Protein Synthesis
Section 12-3
Define the following Steps
1. Transcription:
The synthesis of a mRNA from a DNA
template.
2. Translation:
Ribosomes read the mRNA helps to
bond a sequence of amino acids that
correspond to the nitrogenous base
sequence of mRNA.
3. Protein Synthesis:
The production of a protein from the
sequence of mRNA and the ribosome
which translates the code.
Figure 12–14 Transcription
Adenine
Cystosine
Guanine
Thymine
Uracil
RNA
polymerase
DNA
RNA
Go to
Section:
Figure 12–18 Translation
• What is the role of tRNA?
Messenger RNA
Nucleus
Messenger RNA is transcribed in the nucleus.
Phenylalanine
tRNA
Methionine
Ribosome
mRNA
Go to
Section:
Start codon
Lysine
mRNA
Transfer RNA
Figure 12–18 Translation
The Polypeptide “Assembly Line”
Growing polypeptide chain
Ribosome
tRNA
Lysine
tRNA
mRNA
Completing the Polypeptide
mRNA
Go to
Section:
Translation direction
Ribosome
translatio
n.transcri
ption\17_
18Transla
tionIntro_
A.html
TRANSCRIPTION
DNA
3
5
RNA
polymerase
RNA
transcript
RNA PROCESSING
Exon
RNA transcript
(pre-mRNA)
Intron
Aminoacyl-tRNA
synthetase
Dolan DNA
Learning
Center's
NUCLEUS
CYTOPLASM
FORMATION OF
INITIATION COMPLEX
Amino
acid
mRNA
translation
.transcripti
on\17_07T
ranscriptio
nIntro_A.h
tml
AMINO ACID ACTIVATION
tRNA
Growing
polypeptide
Activated
amino acid
3
A
P
E
Ribosomal
subunits
5
TRANSLATION
E
A
Codon
Ribosome
Anticodon