DNA (deoxyribonucleic acid) I. Watson and Crick II. DNA Structure A. Components of DNA B. Patterns...
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DNA (deoxyribonucleic acid)
I. Watson and CrickII. DNA Structure
A. Components of DNAB. Patterns of base pairing
III. DNA replicationA. Assembly of nucleotide
strandsB. Replication enzymes
IV. Organization of DNA in chromosomesWatson and Crick
Rosalind Franklin Maurice Wilkins
nucleotide
base
Linus Pauling
DNA structureII. DNA Structure
A. Monomers of DNA
B. Patterns of base pairing
Antiparallel
nucleotide
base
DNA structure
Who, among the following, was not a co-discoverer of thestructure of DNA? a. Linus Pauling b. Rosalind Franklinc. Maurice Wilkins d. Francis Crick
To what carbon of deoxyribose does adenine attach?a. 1’ b. 2’ c. 3’ d. 4’ e. 5’
To what carbon of deoxyribose does a new nucleotide attach?a. 1’ b. 2’ c. 3’ d. 4’ e. 5’
The two jobs of DNASelf replication and genetic code
III. DNA replicationA. Assembly of nucleotide
strandsB. Replication enzymes
Enzymes: DNA polymerases
After DNA rep, sister chromatids stay attached at centromere
Repair enzymes
III. DNA replication
IV. Organization of DNA in chromosomes
homologous
3 bases/ amino acid10,000 bases/ protein (1 gene)
3,000,000,000 base pairs/ genome
22,000 genes/ genome
Histone proteins
Human Genome Project
How many bases does it take to code for one amino acid?a. 1 b. 2 c. 3 d. 5
Approximately, how many genes in the human genome?a. 10, 000 b. 20, 000 c. 30, 000 d. 60, 000
What is the role of histone proteins?a. They neutralize the negative charges of DNAb. They allow DNA to coil up tightlyc. Both a and bd. Neither a or b
DNA sequences in the human genome
DNA fascinating fact
What are the most common elements of our DNA?a. Coding sequencesb. Regulatory sequencesc. Intronsd. Transposons
What are transposons?a. DNA segments between exonsb. Random repetitive DNAc. DNA coding sequencesd. DNA segments that make copies of themselves
I. Protein synthesisA. Transcription
- Amanita and RNA polymeraseB. Classes of RNA/ RNA versus DNAC. Translation
1. The genetic code2. Translation, the final steps
II. MutationsA. Types of mutationsB. Origins of mutations
III. Regulation of gene activityIV. Viruses
Protein synthesis
RNA versus DNA
RNA versus DNA
3 types of RNA
Overview of protein synthesis
Transcription: same language
Translation: different language
pp 191-198
Overview of protein synthesis
A. Transcription
No Thymine, instead RNA has Uracil
Puff
Introns and exons
Collagen gene has 50 introns
Osteogenesis imperfecta
SNURPS
Exon shuffling
Replication versus transcription
In replication, DNA unzips
In replication, DNA nucleotides are brought in
In replication, both sides of the helix are replicated
In replication, DNA polymerases do all the work
The ultimate purpose of replication is
DNA replication takes place in
DNA doesn’t leave the nucleus RNA is processed
Amanita and RNA polymerase
Messenger RNADNA: TAC CAT GAG ACT … ATC mRNA: AUG GUA CUC UGA …
UAG
Ribosomal RNA and ribosomes
Ribosomal RNA and ribosomes
Transfer RNA
Codons and anticodonsDNA: TAC CAT GAG ACT … ATC
mRNA: AUG GUA CUC UGA … UAGtRNA: UAC CAU GAG ACU … AUC
C. Translation1. The genetic code2. Translation, the final
steps
Codons wobble
Which RNA carries amino acids from a pool to the ribosome for assembly?
a. tRNA b. rRNA c. mRNA d. vRNA
How many coding codons are there?a. 20 b. 30 c. 61 d. 64
Which of the following is not a difference between RNA and DNA?a. The sugar is differentb. The nucleotides are differentc. The helix structure is differentd. The bond between phosphate and sugar is different
2. Translation, the final steps
2. Translation, the final steps
II. MutationsMutation = change in nucleotide sequence
Mutations can be: bad
neutralgood
Three examples of gene mutations1. Point mutation
2. Frameshift mutation
Most mutations are caused by errors in DNA replicationMutagens
Mutations in coding and non-coding regions
Selected againstDrift Selected for
Mutations in somatic and germ cells
3. Gene duplication
Point mutations ACT GAG TCATGA
Example: Sickle cell trait
TTC AGG
A and B blood types
Frameshift mutations (type of point mutation)
Insertion ACT GAG CAT
TGA
DeletionACT GAG CATTGA
A CT CGTA.. … …
_ TCG TA. … ..
O type blood
Gene duplication
Causes
1. Uneven crossing over
2. Replication slippage
Gene duplication
Entire genome duplicated3N
B. Origins of mutationsmutagens
Errors in DNA replication
viruses
Environmental insults
III. Viruses
HIV Flu
Cold Ebola
2. RNA virusesRetroviruses:Reverse transcription
Reverse transcriptase
A. Diversity1. DNA viruses
Small Pox
RNA DNA
Infect more cells
B. Viruses structure and function
protein coat
viral DNA or RNA
Living or non-living?
C. HIV1. Pandemic
C. HIV2. structure
• 2 strands of RNA
• 3 enzymes• Protein coat• Lipid membrane• HIV target cell?
• Helper T cells
• 9 genes
• Macrophages
2. infection cycle
HIV evolution and reverse transcriptase
HIV target?
CCR5
HIV resistance in humans
HIV replication
• infection and budding
• origin
polio virus
HIVSIV
The end