DNA ( Deoxyribonucleic acid ) 1 DNA structure DNA replication DNA repair.
Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA...
-
Upload
laurel-anderson -
Category
Documents
-
view
234 -
download
0
Transcript of Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA...
![Page 1: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/1.jpg)
Chapter 10- Molecular Biology of Genes
• Adenine• AIDS• Anticodon• Bacteriophages• Codon• Cytosine• DNA ligase• DNA polymerase• Double helix• Guanine• HIV• Lysogenic cycle• Lytic cycle• mRNA• Mutagen• Mutagenesis• Mutation• Nucleotides
• Phages• Promoter• Prophage• Reading frame• Retrovirus• Reverse transcriptase• RNA polymerase• rRNA
RNA splicing• Stop codon• Sugar-phosphate backbone• Terminator• Thymine• Transcription• Translation• Triplet code• tRNA• Uracil
![Page 2: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/2.jpg)
Transformation Experiment• Griffith’s- 1928
– He wanted to learn what was transferred that made a bacteria become virulent and able to cause pneumonia
– He hypothesized some factor (maybe a gene) was transferred– 2 strains of bacteria
• S- strain = killed mice, R-strain = mice lived
– Transformation occurred- harmless bacteria was turned into disease-causing bacteria
![Page 3: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/3.jpg)
Griffith’s Experiment
![Page 4: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/4.jpg)
![Page 5: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/5.jpg)
Next problem:
• 1940’s- – scientists knew that DNA and protein made up
chromosomes but they didn’t know which one was the genetic material
• Much evidence at first pointed to protein
![Page 6: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/6.jpg)
DNA (not protein)• Hershey and Chase- 1952
– Used bacteriophages- virus that infects bacteria• They are composed of DNA, RNA, protein coat• Virus adheres to bacteria and injects genetic information into it, viral genes
act to produce new bacteriophages, cell bursts and new virus come out
![Page 7: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/7.jpg)
– Needed to figure out which part entered the cell so they would know if genes were made of protein or DNA
• Grew viruses in cultures with radioactive phosphorus or sulfur, used as markers
• DNA contains no S, protein contains no P• If S found in bacteria – viral protein was injected• If P found in bacteria - viral DNA was injected
![Page 8: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/8.jpg)
– Concluded DNA was the genetic material (not protein)
![Page 9: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/9.jpg)
What do we know about DNA?
• Made up of nucleotides– Phosphate group– 5-C sugar (deoxyribose)– Nitrogen base- A, T, C, G– Backbone is made up of sugar and phosphate– Bases stick off the sides
![Page 10: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/10.jpg)
The bases:
• Purines- have 2 rings– Adenine, Guanine
• Pyrimidines- have 1 ring– Cytosine, Thymine
![Page 11: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/11.jpg)
There was a race to determine DNA structure
• Chargaff– Percentages of A’s and T’s were almost equal
as were percentages of C’s and G’s
• Franklin– used X-ray diffraction and recorded pattern,
gave clues to the structure• Pattern showed that it twisted around itself
![Page 12: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/12.jpg)
• Watson and Crick-tried to figure out structure with models
• When they saw Rosalind’s photos they figured out the structure of DNA, which solved the mystery of how it carries information and how it was copied
– the double helix “twisted ladder”• Held together by hydrogen bonds between bases• This pairing of bases explained Chargraff’s rule
![Page 13: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/13.jpg)
DNA Replication
• Each strand serves as a template to make a new complementary strand
• Each DNA strand has 3’ and 5’ end– DNA can only grow in the 5’ 3’
direction
![Page 14: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/14.jpg)
DNA Replication
• Origin of replication- site where DNA replication starts– Replication proceeds in both directions forming a “bubble”
![Page 15: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/15.jpg)
DNA Replication
• DNA polymerase- adds new nucleotides onto existing ones
• DNA ligase- joins new pieces of DNA together
• DNA polyermase and ligase are also involved in proofreading and fixing damaged DNA
• DNA replication involves many other proteins, it is surprisingly fast and accurate
![Page 16: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/16.jpg)
DNA Replication
![Page 17: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/17.jpg)
How information is transferred in a cell:
• Central dogma of biology
• DNA RNA protein
• Transcription- transfer of information from DNA to an RNA molecule
• Translation- transfer of RNA information to a protein molecule
![Page 18: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/18.jpg)
• Beadle and Tatum’s experiment about lack of growth without certain enzymes yielded the 1 gene = 1 polypeptide hypothesis
![Page 19: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/19.jpg)
RNA
• Made during transcription
• Single-stranded nucleic acid
• Bases: A, U (uracil), C, G
![Page 20: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/20.jpg)
3 Types of RNA• mRNA- messenger
– Processed before it leaves the nucleus– G cap and tail chain of A’s is added– Introns are spliced out (RNA splicing)– Introns- intervening sequence in a gene (junk)– Exons- expressed part of a gene
![Page 21: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/21.jpg)
• tRNA- transfer– match amino acid with correct codons– One end of tRNA has anticodon (complementary
sequence to codon) – tRNA’s are available for each amino acid– Uses ATP to drive binding reaction
![Page 22: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/22.jpg)
• rRNA- ribosomal– along with proteins make up the ribosome where
protein synthesis takes place
![Page 23: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/23.jpg)
The letters make a code• Transcription and translation rely on 3-
letter “words” called codons
• Each codon codes for 1 amino acid
![Page 24: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/24.jpg)
Where does transcription and translation occur?
• Prokaryotes: both happen in the cytoplasm
• Eukaryotes: transcription- in the nucleus and translation- in the cytoplasm
![Page 25: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/25.jpg)
Transcription
• Occurs in nucleus (we will be discussing eukayotes)• 1 strand serves as template, RNA polyermase binds and
RNA nucleotides join together to create a n RNA molecule
• Promoters- sequences that tell RNA pol where to bind• Stages:
– Initiation- RNA pol binds and starts transcription, – Elongation- continuation of RNA synthesis, – Termination- RNA pol reaches terminator sequence
and RNA pol detaches
![Page 26: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/26.jpg)
![Page 27: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/27.jpg)
Translation• Initiation- mRNA binds to ribosomal subunit
– Initiator tRNA binds to start codon and is carrying Methionine– Larger ribosome subunit binds and initiator tRNA binds to P site
• Elongation- anticodon on tRNA recognizes codon on mRNA and pairs in A site– Peptide bond forms between amino acids in A and P site,
ribosome catalyzes bond– P site tRNA leaves and A site tRNA moves over, now next tRNA
can bind to A site
• Termination- stops when a stop codon is reached (UAG, UAA, UGA)
![Page 28: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/28.jpg)
![Page 29: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/29.jpg)
![Page 30: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/30.jpg)
![Page 31: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/31.jpg)
Why do through transcription and translation?
• DNA RNA protein– Controls the way genotypes produce
phenotypes
![Page 32: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/32.jpg)
What happens if a mistake is made?
• Mutations- change in the DNA sequence– bases can be substituted for one another– Bases can be deleted or inserted– ** not always a bad thing, also creates new variety that could
possibly benefit – Reading frame- triplet codon, can be affected by insertions and
deletions– Mutatgenesis- creation of mutations– Mutatgen- sources of mutations, chemicals, radiation
![Page 33: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/33.jpg)
![Page 34: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/34.jpg)
![Page 35: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/35.jpg)
Viruses can affect transcription and translation
• A virus is just a package of genetic information• Types of viral reproduction
– Lytic cycle- leads to a cell filled with viruses lysing (breaking open)
– Lysogenic cycle- cell with viral DNA in it’s genome divides• When phage DNA enters cell it is called a prophage
![Page 36: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/36.jpg)
![Page 37: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/37.jpg)
![Page 38: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/38.jpg)
RNA Viruses
• glycoprotein attaches to host membrane• RNA enters cell• enzymes remove RNA protein coat• complementary strand is made• new strand has instructions to make new proteins and viral RNA• new protein coat assembles on new RNA• lastly viruses leave cell coated in host’s plasma cell membrane
![Page 39: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/39.jpg)
![Page 40: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/40.jpg)
Plant Viruses
• Can stunt growth, lower crop yields• Plant viruses must pass outer layer of plant, so wind
damage, injury or insects allow for entrance• Some insects also carry viruses to plants, as well as
pruning shears may hold virus
![Page 41: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/41.jpg)
Animal Viruses
• Influenza, hepatitis, chicken pox, herpes, mumps, measles, AIDS, polio
![Page 42: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/42.jpg)
How do new ones arise?
• Fragments of cellular nucleic acid that could move from one cell to another, possible on the surfaces of injured cells
• Today- mutations of existing viruses is the source of new ones
• Also passing existing viruses to new hosts, via dust containing viruses
• RNA viruses mutate faster because there is not DNA proofreading happening
![Page 43: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/43.jpg)
HIV Virus
• Acquired immune deficiency syndrome• Human immunodeficiency virus
• Affects WBC’s of immune system, can’t fight off infection
• Contains 2 RNA copies, instead of usual 1• It’s a retrovirus, RNA virus that produces DNA using
reverse transcriptase (enzyme that does the process)• Viral DNA enters nucleus and then viral DNA is
transcribed and translated making more viral proteins which then assemble and leave cell to infect others
![Page 44: Chapter 10- Molecular Biology of Genes Adenine AIDS Anticodon Bacteriophages Codon Cytosine DNA ligase DNA polymerase Double helix Guanine HIV Lysogenic.](https://reader035.fdocuments.in/reader035/viewer/2022081419/5697bfd71a28abf838cae90c/html5/thumbnails/44.jpg)