DNA and Genes
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Transcript DNA and Genes
Chapter 11
Chapter 11, Section 1
Determines
an organism’s traits
Produces proteins
Long
Polymer
of repeating subunits (nucleotides)
3
Parts:
Simple Sugar
Phosphate Group
Deoxyribose
Phosphate with 4 oxygen
Nitrogenous Base
Carbon ring with 1 or more nitrogen
Four types:
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Nucleotides
form chains
Phosphate group of one nucleotide bonds to
sugar of another nucleotide
Complementary
base pairs held with weak
hydrogen bonds
Adenine and Thymine
Guanine and Cytosine
Discovered
DNA structure
Double Helix
Also involved: Maurice Wilkins and the other
by Rosalind Franklin
Use
white board
Use
white board
Use
laminated pieces
Use
Play-Doh
Circles for Phosphate
Squares for Sugar
Triangles for Nitrogen Bases
Results
from the differing sequences of the
four different nucleotides
Determine
relatedness
evolutionary relationships
What would be closely related to the chimp?
During
interphase – before meiosis or mitosis
Four Steps
DNA
double helix unzips
Hydrogen bonds between nitrogenous bases
split
Result: 2 nucleotide strands with their
nitrogenous bases exposed
Base
Pairing – free nucleotides
base pair with exposed
nucleotides
Adenine with Thymine
Guanine with Cytosine
Result:
each strand builds its
complement
Sugar
and phosphate parts of
adjacent nucleotides bond
Result: new backbone for each
strand
Two
molecules of DNA are
formed
Semi-Conservative
Replication – each new
molecule has one strand from
the original molecule and
one strand that has been
newly synthesized from free
nucleotides
Chapter 11, Section 2
Polymer
made of amino acids (monomer)
Control bodily functions
DNA is responsible for constructing
Use amino acids
Deoxyribonucleic
Acid
Composed of nucleotides
Gives instructions on how to make protein
Ribonucleic
acid
Composed of nucleotides
Single stranded
Sugar = ribose
Replaces thymine (nitrogenous base) with
uracil
Base pairs with adenine
Messenger
Brings info from DNA in the nucleus to cytoplasm
Ribosomal
RNA (rRNA)
Ribosomes clamp onto the mRNA and use its info
to assemble the amino acids in the correct order
Transfer
RNA (mRNA)
RNA (tRNA)
Transports amino acids to the
ribosome to assemble the protein
On
mRNA
Each set of three nitrogen bases
Codes for a specific amino acid
On
tRNA
Each set of three nitrogen bases
Carries a specific amino acid
Page
297
Answer all questions
Everyone needs to write answers
Answer can be written in notes
Universal
ie:
UAC codes for the amino acid tyrosine
ALWAYS
In bacteria, birch trees, bison and every other
living thing on the planet
Evidence
that all life on Earth evolved from a
common origin
Four
nucleotides
20 Amino Acids
Proteins are built from long chains of DNA
DNA lined-up end-to-end in all the human cells of
an adult would stretch to about 60 billion miles
(about 60 times the distance from the sun to
Pluto, the outer most fake planet)
Double
stranded DNA to single stranded RNA
mRNA
Sugar
is now ribose
Uracil is used (instead of thymine)
Occurs in nucleus
DNA
RNA
polymerase
Codon
1
Codon
2
Triplet 1
1
Triplet 2
2
Triplet 3
3
Gene
Complementary
triplets
Promoter
Triplet 4
mRNA
strand
Codon
1
2
4
Codon
3
Codon 4
(stop signal)
RNA
nucleotide
KEY
Adenine
Guanine
Cytosine
Uracil (RNA)
Thymine
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-18
1 of 5
DNA
Gene
KEY
Adenine
Guanine
Cytosine
Uracil (RNA)
Thymine
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-18
2 of 5
DNA
RNA
polymerase
Triplet 1
1
Triplet 2
2
Triplet 3
3
Gene
Triplet 4
Complementary
triplets
Promoter
2
4
KEY
Adenine
Guanine
Cytosine
Uracil (RNA)
Thymine
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-18
3 of 5
DNA
RNA
polymerase
Triplet 1
1
Triplet 2
2
Triplet 3
3
Gene
Triplet 4
Complementary
triplets
Promoter
Codon
1
2
4
RNA
nucleotide
KEY
Adenine
Guanine
Cytosine
Uracil (RNA)
Thymine
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-18
4 of 5
DNA
RNA
polymerase
Codon
1
Codon
2
Triplet 1
1
Triplet 2
2
Triplet 3
3
Gene
Complementary
triplets
Promoter
Triplet 4
mRNA
strand
Codon
1
2
4
Codon
3
Codon 4
(stop signal)
RNA
nucleotide
KEY
Adenine
Guanine
Cytosine
Uracil (RNA)
Thymine
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-18
5 of 5
From
mRNA to protein
Takes place at the ribosomes
Uses tRNA
Carry
Anticodon
Opposite nitrogenous bases from codon
Used to attach to codon on mRNA
Carry
1 specific amino acid
Happen
on ribosome (made of rRNA and protein)
tRNA bring in first amino acid by attaching it’s
anticodon to mRNA’s codon
Ribosome moves down
Next tRNA brings in next amino acid by
attaching it’s anticodon to mRNA’s codon
2 amino acids bond
First tRNA detaches
Repeats until protein is constructed
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
The small and large ribosomal subunits
interlock around the mRNA strand.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Large
ribosomal
subunit
Thymine
Start codon
A second tRNA arrives at the
adjacent binding site of the
ribosome. The anticodon of the
second tRNA binds to the next mRNA
codon.
mRNA strand
The first amino acid is detached from
its tRNA and is joined to the second
amino acid by a peptide bond. The
ribosome moves one codon farther
along the mRNA strand; the first tRNA
detaches as another tRNA arrives.
The chain elongates until the stop
codon is reached; the components
then separate.
Small ribosomal
subunit
Peptide bond
Completed
polypeptide
Stop
codon
Large
ribosomal
subunit
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-19
1 of 6
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Thymine
Start codon
mRNA strand
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-19
2 of 6
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
The small and large ribosomal subunits
interlock around the mRNA strand.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Thymine
Start codon
mRNA strand
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Large
ribosomal
subunit
Figure 3-19
3 of 6
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
The small and large ribosomal subunits
interlock around the mRNA strand.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Thymine
Start codon
mRNA strand
Large
ribosomal
subunit
A second tRNA arrives at the
adjacent binding site of the
ribosome. The anticodon of the
second tRNA binds to the next mRNA
codon.
Stop
codon
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-19
4 of 6
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
The small and large ribosomal subunits
interlock around the mRNA strand.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Thymine
Start codon
A second tRNA arrives at the
adjacent binding site of the
ribosome. The anticodon of the
second tRNA binds to the next mRNA
codon.
mRNA strand
Large
ribosomal
subunit
The first amino acid is detached from
its tRNA and is joined to the second
amino acid by a peptide bond. The
ribosome moves one codon farther
along the mRNA strand; the first tRNA
detaches as another tRNA arrives.
Peptide bond
Stop
codon
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-19
5 of 6
NUCLEUS
mRNA
The mRNA strand binds to the small
ribosomal subunit and is joined at the
start codon by the first tRNA, which
carries the amino acid methionine.
Binding occurs between complementary base pairs of the codon and
anticodon.
The small and large ribosomal subunits
interlock around the mRNA strand.
Amino acid
KEY
Adenine
Small
ribosomal
subunit
tRNA
Anticodon
tRNA binding sites
Guanine
Cytosine
Uracil (RNA)
Large
ribosomal
subunit
Thymine
Start codon
A second tRNA arrives at the
adjacent binding site of the
ribosome. The anticodon of the
second tRNA binds to the next mRNA
codon.
mRNA strand
The first amino acid is detached from
its tRNA and is joined to the second
amino acid by a peptide bond. The
ribosome moves one codon farther
along the mRNA strand; the first tRNA
detaches as another tRNA arrives.
The chain elongates until the stop
codon is reached; the components
then separate.
Small ribosomal
subunit
Peptide bond
Completed
polypeptide
Stop
codon
Large
ribosomal
subunit
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3-19
6 of 6
Page
299
Answer all questions
Chapter 11, Section 3
Any
change in the DNA sequence
May
have large effect or no effect
be helpful or harmful
cause cancer
lead to natural selection and evolution
occur in reproductive cells or body cells
Change
in a single base pair in the DNA
Ie: THE DOG BIT THE CAT
THE DOG BIT THE CAR
Single
base is added or deleted from DNA
Shifts the reading of codons by one base
Ie: THE DOG BIT THE CAT
THE DOG BIT ETH ECA T
Disrupt
distribution of genes to gametes
during meiosis
Cause nondisjunction
Homologous chromosomes cannot pair correctly
when they have an extra or are missing a part
Deletion
ABC DEF GHI
ABC DFG HI
Insertion
ABC DEF GHI
ABC BCD EFG HI
Inversion
ABC DEF GHI
ADC BEF GHI
Translocation
ABC DEF GHI and WXYZ
WXA BCD EFG HI and YZ
Page
305
Answer all questions
Page
306
Answer all questions
Anything
that is capable of causing mutations
Ie: radiation (X-Rays, UV light, nuclear
energy), chemicals, high temperatures
Mistakes
rarely happen
When they do, there are repair mechanisms
Enzymes
Greater
exposure to mutagen, less chance
the mistake will be corrected
19
Multiple Choice
12 Completion
5 Short Answer/Essay