prepared with lots of help from friends... metsada pasmanik-chor, zohar yakhini and numerous web...
Post on 21-Dec-2015
214 Views
Preview:
TRANSCRIPT
Prepared with lots of help from friends...Metsada Pasmanik-Chor, Zohar Yakhini and NUMEROUS WEB RESOURCES.
BioInformatics / Computational Biology Introduction & Biological Terms.
• A Few Basic Concepts of Molecular Biology:• Genetic material - DNA & RNA.
• DNA is a sequence of bases (A,C,T,G).
• Watson-Crick–ery.
• Proteins.
• The central dogma of molecular biology.
• Bio-Informatics Tools Freely available on the web: Highlights.
Outline
One chromosome, (sometimes circular).
Prokaryotes vs. Eukaryotes
http://departments.oxy.edu/biology/bio130/lectures_2000/11-13-00_lecture.htm
Cell Size and Shape10-9 m
All organisms are made of cells - basic unit of life (1014 cells in the human body; metabolism, replication).
Cells in all organisms have same type ofgenetic material.
The Eukaryotic Cellcytoskeleton:
* In plants: chloroplast & cell wall.
http://www.biosci.uga.edu/almanac/bio_103/notes/may_15.html
http://www.accessexcellence.org/AE/AEPC/NIH/gene03.html
• Each human cell contains 23 pairs of chromosomes.• Chromosomes can be distinguished by size and by unique banding patterns.• This set is from a male, since it contains a Y chromosome. • Females have two X chromosomes.
DNA - the Genetic Material
http://www.dnaftb.org/dnaftb/9/concept/index.html
Different genes are activated in different cells, creating the specific proteins that give a particular cell type its character.
Different Eukaryotic Cell Types
http://www.accessexcellence.org/AE/AEPC/NIH/gene03.html
Example: Tissues in Stomach
• Cells originate from one embrio cell and have identical DNA.• Different cell types: Metabolism, regulation, function.
http://www.dnaftb.org/dnaftb/17/animation/index.html
control region
gene - coding region
• CONTROL REGIONS - Usually are adjacent to genes. Determine when expressed, to what extend. • “JUNK DNA” - Unknown function.
DNA Structure
centromere
telomere
Source: Alberts et al
DNA is made of 4 subunits (nucleotides).Each nucleotide contains: sugar, phosphate group and a base.
DNA - (deoxyribonucleic acid - THE Double Helix)
Conclusion: DNA strands are complementary (1953).
Watson-Crick Complementarity
HumanSheepTurtleSea urchinWheat
E. coli
DNA source% of each base
Purines/Pyrimidines
Base ratios
PurinesPyrimidines
A binds to TC binds to G
AATGCTTAGTCTTACGAATCAG
Perfect match
AATGCGTAGTCTTACGAATCAG
One base mismatch
Watson-Crick Complementarity
• Genes carry the instructions for cellular proteins.
• Variations in the code is the source for cellular variations.
• Disease and susceptibility to disease can be caused by changes in the DNA (mutations).
• DNA is identical in all cells of an individual, almost identical among different individuals of same species (99.9%), and very similar in related species (human vs chimpanzee - 98% identity).
• Only 3% of cellular DNA has a known function !
Variability - facts
Humanindividuality
http://www.brc.dcs.gla.ac.uk/~drg/seminars/bioinformatics/sld032.htm
Hereditary mutations: Carried in the DNA of the reproductive cells.
The mutation will be present in all of the offspring's body cells.
http://www.accessexcellence.org/AE/AEPC/NIH/gene07.html
Acquired mutations:Developed in the DNA during a person's lifetime.
If the mutation arises in a body cell, copies of the mutation will exist only in descendants of that particular cell.
RNA is very similar to DNA but has: • Only one strand.• Ribose as a sugar. • Uracil (U) instead of Thymine (T).
RNA - ribonucleic acid Some viruses store genetic information in form of RNA.
In eukaryotes, RNA is formedfrom DNA in a process called
transcription where elimination of introns(splicing) occurs
splicing
Chromosomal DNA
Splicing - RNA Synthesis and Processing
mRNA
www.albany.edu/~achm110/ mrna.gif
MaturemRNA
Poly A tail
introns
Transcriptionby RNA polymerase
exons
The seven green loops stand for introns
The eight blue bands stand for exons
Promoter/enhancer
exons
Stop signal
Gene
intronssplicing
http://www1.imim.es/courses/Lisboa01/slide1.5_splicing.html
Splicing - RNA Synthesis and Processing
Used in translation:tRNA - Small RNA, serves as “adaptor” between mRNA and amino acids.rRNA - One of the structural components of the ribosome (the translation machine from mRNA to proteins).
Types of RNA
http://www.dnaftb.org/dnaftb/24/concept/index.html
http://www.dnaftb.org/dnaftb/21/animation/index.html
mRNA - A copy of a gene (without introns), encoding protein sequence.
See animation at:
Genes can be turned ON and OFF
http://www.dnaftb.org/dnaftb/33/concept/index.html
nitiationofranscriptionbyolymerase
http://www1.imim.es/courses/Lisboa01/slide1.4_transcription.html
The Genetic Code: From 43 = 64 Codons to 20 AA.
5’ 3’
4 nucleotide types
20 amino acids
3 letter code 64 Codons
http://cbms.st-and.ac.uk/academics/ryan/Teaching/medsci/Medsci5.htm
The Genetic Code: From 43 = 64 Codons to 20 AA.
Amino Acid Relative Frequencies-Mammals
http://cbms.st-and.ac.uk/academics/ryan/Teaching/molbiol/Bioinf_files/v3_document.htm
5’ ACGTGTAGTTGCCGTGACG 3’3’ TGCACATCAACGGCACTGC 5’
A DNA sequence with direction shown
NN PKRGACMLTNQFKRKSACQ C C
A protein sequence with ends indicated
Nucleotides vs Amino Acids Code
Translation in Eukaryotes
http://www1.imim.es/courses/Lisboa01/slide1.6_translation.html Animation: http://cbms.st-and.ac.uk/academics/ryan/Teaching/medsci/Medsci6.htm
What Determines Cell Structure and Function ?
• Unique protein expression by each cell type.
• Proteins are ~60% of dry mass of living cell.
• Proteins determine function.
How is this controlled ?
Levels of Eukaryotic Gene Regulation
http://www.library.csi.cuny.edu/~davis/Bioinfo_326/lectures/centralDogmaProteins/centralDogma.html
Central Dogma
Transcription
mRNA
Cells express different subset of the genes in different tissues and under different conditions.
Gene (DNA)
Translation
Protein
DNA RNA Protein
Symptomes (Phenotype)
The Central Dogma of Molecular Biology
Replication-DNA duplication
Transcription-RNA synthesisNucleus
Cytoplasm
Translation-Protein synthesis
http://www.accessexcellence.com/AB/GG/central.html
http://www.nature.com/nrg/journal/v3/n1/slideshow/nrg703_bx1.html
1 gene
Many mRNA transcripts
Many protein types
Central Dogma in the 21st
Century.
top related