Chapter 9
DNA: The Genetic
Material
Read 192-198
Demo model (student race)
Lab Activity from Binder
DNA and RNA
Crossword puzzle
DNA/RNA Vocabulary (53-62)
53. anticodon
54. codon
55. base sequence
56. genetic code
57. RNA polymerase
58. transcription
59. translation
60. restriction enzyme
61. DNA replication
62. ribosomal RNA
I. Introduction
• Heredity- The transmission of traits from
one generation to the next
• Genetics- The study of heredity, usually at
the molecular level.
• Heredity occurs in the form of DNA which
is coiled into chromosomes.
• Humans have 46 chromosomes (23 pairs)
in each cell. These chromosomes are
located in the nucleus of each cell.
DNA coiled into a chromosome
II. HISTORY
•
Chromosomes have been observed
microscopically since 1850.
Chromosomes are composed of protein and
nucleic acid.
The structure of DNA was discovered by
James Watson (American) and Francis Crick
(British)
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Proposed in 1953 the model of DNA as
a“DOUBLE HELIX”
Won the Nobel Prize in Physiology in 1962 for their
discoveries
III. DNA
A. DNA Structure
NucleotideRepeating unit
of DNA
Has 3 parts:
Phosphate, deoxyribose sugar and base
Draw and label the structure
of DNA
What holds the 2
halves of the
ladder together?
A. Processes Involving DNA
1. Replication- See handout in binder
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DNA  DNA
Each new DNA produced has ½ from the
original strand and ½ that is newly built (semiconservative).
DNA always stays in the nucleus.
DNA helicase unzips the original DNA during
replication (breaks hydrogen bonds).
DNA polymerase forms the new halves of DNA
and proofread them for errors.
This process occurs once in a cell’s lifetime.
2. Transcription- See handout in binder
• DNA code is used as a template to produce
RNA
DNA  RNA (single strand)
• Only ½ of the DNA is used as a template.
This is called the sense strand. The other is
the non-sense strand.
• RNA polymerase builds the strand of RNA.
• RNA produced leaves the nucleus to enter
the cytoplasm.
• 3 types of RNA are produced: messenger
RNA (mRNA), ribosomal RNA (rRNA) and
transfer RNA (tRNA)
IV. Contrasting DNA and RNA
RNA
DNA
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2 strands
Deoxyribose sugar
Remains in Nucleus
Bases
– ATCG
– A-T
G-C
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1 strand
Ribose sugar
Exits nucleus
Bases
– AUGC
A-U
G-C
Chargraff’s Ratio: #C = #G
#A = #T
3 Types of RNA
1. mRNA (messenger)- carries the
DNA’s instructions for making proteins
out of the nucleus to the site of
translation (cytoplasm)
• Every 3 nucleotides on mRNA is called a
codon. Each codon codes for an
amino acid.
– See codon table
2. tRNA (transfer)- carries a specific
amino acid on one end and an anticodon
on the other end. The anticodon
complements the codon on mRNA.
Draw the tRNA structure:
3. rRNA (ribosomal)- Along with protein,
this makes up the structure of a ribosome.
How Proteins are made
(read 205-212)
Translation (protein synthesis)
1. Begins when mRNA leaves the nucleus and enters
the cytoplasm.
2. mRNA attaches to a ribosome.
3. At the start codon (AUG), a
tRNA brings the amino
acid into position.
When tRNA brings each
new AA, it bonds with the
adjacent AA by a peptide bond.
4. After amino acids have bonded, the tRNA
leaves.
5. This process continues until the STOP
codon is reached.
6. The new protein is released.
Draw the translation process
PROTEINS HAVE DEFINITE SHAPES.
IF THE SHAPES CHANGE,
THEY WON’T FUNCTION PROPERLY
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DNA code
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mRNA codon
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tRNA anticodon _____________
________________
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Amino acid
______________
TGA
_____________
____________
______________
_______________
UCU
_______________
_______________
tryptophan
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DNA code
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mRNA codon
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tRNA anticodon _____________
________________
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Amino acid
______________
CAT
_____________
____________
______________
_______________
GUU
_______________
_______________
methionine
After 4 replications of a DNA molecule, what
percentage of the resulting DNA molecules
contain at least 1 strand of the original
DNA?
CP Biology Article Presentation
• 4-5 minute summary of article summary
• DO NOT READ FROM THE SUMMARY – you can
use note cards if you want
• You need at least one visual that will help illustrate
points that you are making in your presentation –
posters, powerpoints (4-6 slides….Be creative!)
• If you do not do this correctly, you will have to redo
this in front of the class…do it right the first time!
• Do the week of January 23rd- volunteers first
• Dress appropriately for giving a presentation
TEST FRIDAY – Test Topics
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Notes on DNA/RNA
Vocab 62-71
Reading 192-198, 205-212
Semi Conservative Replication,
Transcription and Translation – Handouts
in Binder that we colored…
• DNA/RNA Lab
• Crossword, Text Questions 200,220
NOTEBOOK CONTENTS
2nd Quarter Notebook
• Daily Work
Check
– Too hot Not to Handle
Cover Sheet
•
• Assignment Sheet
• Grade Sheet w/
Tot. Pts
%
• Vocabulary 22 (primary
prod.) - 69 (microvilli)
• Notes
• Systems
• Life Processes (Digestive
System pg 83-85)
THIS IS 10% OF YOUR
QUARTER GRADE!!!
Grade
–
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–
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Ecosystems WS
CH 18 WS pg 57
CH 19 WS Human Impact
Ch 2 Chem of Life
Biochem Crossword
Enzyme WS
• Labs
– Pred/Prey Lab
-Beano Lab
– Enzyme Computer Lab
– Bat Graph