Download Chapter 9 and 10 - Grafton School District

Chapter 9 and 10
DNA: Genetic Material
How Proteins are made
James Watson and Francis Crick
• 1950’s
• Used past
experiments done
by other scientists
• Discovered the
structure of DNA
Characteristics of DNA
• Double Helix
(twisted staircase)
Nucleotides – make up DNA
• Subunits
• Contain 3 parts:
– A phosphate
– A sugar- Deoxyribose
– Nitrogen base
•
•
•
•
Adenine (A)
Guanine (G)
Thiamine (T)
Cytosine (C)
Nucleotide Pairing
• http://www.phsuccessnet.com/iText/pr
oducts/0-13-115075-8/index.html
• Adenine pairs with thymine
• Guanine pairs with cytosine
9-3 Replication of DNA
• Occurs during what phase of cell cycle?
• Steps:
– 2 original DNA stands unzip
– Free nucleotides in nucleus are added to
each strand
– Two identical molecules of DNA are
formed.
1. DNA unzips
Animation of DNA replication
Chapter 10: Making Proteins
• What is RNA?
– It is a copy of DNA
– RNA is used to build
proteins
– Single stranded
– No tymine
RNA nucleotides
• Ribonucleic Acid
• 3 parts:
– Sugar: ribose
– Single stranded
– Nitrogen bases:
•
•
•
•
Adenine
URACIL
Cytosine
guanine
RNA pairings
• Adenine pairs with Uracil
• Cytosine pairs with Guanine
Types of RNA
• mRNA – messenger RNA
• Made in nucleus, strand shape
tRNA – transfer RNA
•Found outside
nucleus
•Carries an
amino acid
The cell’s alive, it will survive
Transcription and translation are how
proteins are synthesized
Step 1 of Protein synthesis
• Transcription – construction of mRNA
– DNA strands separate a site of needed
protein code.
– RNA nucleotides are added to DNA. DNA
acts as a template.
– mRNA moves out of the nucleus into the
cytoplasm to the ribosome
Illustration of Transcription Biology:
Exploring Life
Step 2: Translation
• At the ribosome:
mRNA is read in
groups of 3.
• Codon – Group of 3
bases
Translation continued
• mRNA is read and
interpreted
• tRNA receives a
message to come to
the mRNA at
ribosome
• tRNA carries an
amino acid
• (anticodon)
Translation
• This continues until the mRNA is read
completely
• tRNA attaches to mRNA to attach the
amino acid to the protein chain
• tRNA them detaches leaving behind its
amino acid.
• Amino acid will form a protein.
Animation of translation
Mutations
• Changes in the DNA
sequence that affect
genetic information
• Result from changes
in a SINGLE gene
(not chromosome
abnormality)
Types of Gene mutations
• 1. point mutation
– One nucleotide
affected
– Examples:
• Substitution
•
•
Original - The fat cat ate the
wee rat.
Point Mutation - The fat hat ate
the wee rat.
Insert example diseases
Types of Mutations
• 2. Frameshift
mutations – one or
more bases are
inserted or deleted
Insertion:
• Original- The fat cat ate the
wee rat.
• Insertion - The fat cat xlw
ate the wee rat.
• More severe type of
mutation
Deletion:
• The fat cat ate the wee rat.
• Deletion - The fat ate the
wee rat.
Human Genome Project (Collins)
• A list of the three billion
pairs of human genome
(DNA)
• An international effort
• Completed by the July
of 2000 – “working
draft”
• Great implications in the
field of medicine.
(Cancer, Immune
Disorders, Hemophilia,
rheumatoid arthritis)
DNA Technology (Science)
•
Recombinant DNA technology –
combining genes from two different
organisms to make copies of “good”
gene.
Steps of Recombinant DNA
1. Cutting DNA using a RESTRICTION
ENZYME
2. Inserting the desired gene into a
vector
• Vector – a bacteria (plasmid) or yeast
3. Cloning of “new DNA”
Applications of Recombinant DNA
•
•
•
•
Agriculture – frost resistant strawberries
Industry – clean up oil spills
Medicine
Food industry – nutrasweet
DNA fingerprinting
• Useful in forensic
science
• Useful in medicine
Future of medicine
• predictive genetic tests for common
conditions i.e. cancer
• 2020, every tumor will undergo
“fingerprinting”, develop drugs to attack
the particular gene.
Cloning process ex. Dolly
The process of making Dolly