Chapter 9 and 10
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Transcript of Chapter 9 and 10
Chapter 9 and 10
DNA: Genetic MaterialHow 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/products/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 surviveTranscription 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
• More severe type of mutation
Insertion: • Original- The fat cat ate
the wee rat.• Insertion - The fat cat
xlw ate the wee rat.
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