gene expression from a gene to a protein. central dogma (crick 1958) determines the genetic flow of...
TRANSCRIPT
![Page 1: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/1.jpg)
Gene Expression
From a gene to a protein
![Page 2: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/2.jpg)
Central Dogma
• (Crick 1958)• Determines the genetic flow of information
![Page 3: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/3.jpg)
![Page 4: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/4.jpg)
Central Dogma
First step in decoding a genetic message from DNA is to copy (transcribe) it into mRNA, which contains the code for making proteins
Second step in decoding, is to decode mRNA into a polypeptide chain which builds a protein.
![Page 5: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/5.jpg)
Functions of a Protein
Functions of Protein:Functions of Protein:
• StructuralStructural– muscle, hairmuscle, hair
• ChemicalChemical– antibodies, hormones, enzymes (regulate antibodies, hormones, enzymes (regulate
all chemical reactions in cells)all chemical reactions in cells)
![Page 6: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/6.jpg)
Proteins
• Proteins are made, from mRNA, by joining amino acids into long polypeptides (which are proteins)– There are only 20 naturally occurring amino
acids
![Page 7: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/7.jpg)
Review of DNA
• DNA is the genetic material
• DNA codes for different genes– Genes are codes for a protein which
determines different traits
![Page 8: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/8.jpg)
DNA is made up of nucleotidesWhich contain: - a phosphate group
- a sugar (deoxyribose)- a nitrogenous base
![Page 9: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/9.jpg)
Structure of DNA
![Page 10: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/10.jpg)
RNA
• Involved in protein synthesis
• Made up of nucleotides:
–A phosphate group
–A sugar (ribose)
–Nitrogenous bases (RNA only has A, U, C, G there is no T!)
![Page 11: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/11.jpg)
Types of RNA
• There are three main types:–Messenger RNA (mRNA)–Transfer RNA (tRNA)–Ribosomal RNA (rRNA)
![Page 12: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/12.jpg)
mRNA
• Messenger RNA (mRNA) carries copies of instructions for assembling amino acids into proteins.
![Page 13: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/13.jpg)
rRNA
• Ribosomes are made up of proteins and ribosomal RNA (rRNA).
![Page 14: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/14.jpg)
tRNA• During protein
construction, transfer RNA (tRNA) transfers each amino acid to the ribosome.
![Page 15: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/15.jpg)
Transcription• Flow of info: DNA -> mRNA
• Location: Nucleus
• mRNA is produced by copying part of the DNA
• Where does the mRNA go?– Cytoplasm/Ribosomes
![Page 16: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/16.jpg)
Transcription
• Messenger RNA is transcribed in the nucleus, and then enters the cytoplasm where it attaches to a ribosome.
![Page 17: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/17.jpg)
The Genetic Code
• The genetic code is read from mRNA
• mRNA is only 4 letters A, U, C, and G
• The code is read 3 letters/bases at a time• Codon= three consecutive nucleotides
which are specific for an animo acid
![Page 18: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/18.jpg)
Codons
![Page 19: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/19.jpg)
Translation
• Flow of info: mRNA -> Proteins
• Location: Cytoplasm/Ribosomes
• Translation is decoding mRNA into a polypeptide chain(protein)
![Page 20: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/20.jpg)
Step 1 Translation
• mRNA attaches to a ribosome
• The start codon (AUG) is located by tRNA
• The matching tRNA, containing the anitcodon UAC, will bind to AUG
• The tRNA carries the animo acid specific to the mRNA sequence AUG, which is methionine
![Page 21: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/21.jpg)
Step 2•The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.
![Page 22: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/22.jpg)
Step 3As each new tRNA enters the ribosome, one leaves. Before tRNA can leave the ribosome, the animo acidswill bond together to make a polypeptide chain
![Page 23: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/23.jpg)
Step 4The process continues until the ribosome
reaches a stop codon.
![Page 24: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/24.jpg)
Mutations• Changes in genetic material
• Many have little effect on gene expression or protein function
• A few can be harmful and then some are good– Harmful mutations can cause cancer and
genetic disorders– Good mutation can make altered proteins
which may be beneficial in different/changing environments
![Page 25: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/25.jpg)
Point Mutations
• Mutation of 1 or more nucleotides– Substitution – changing one base, usually
only changes one amino acid– Insertion – addition of 1 or more bases,
causes frameshifts– Deletion – removal of 1 or more bases,
causes frameshifts
![Page 26: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/26.jpg)
Point Mutations
![Page 27: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/27.jpg)
Kinds of Mutations
•Substitutions usually affect no more than a single amino acid.
![Page 28: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/28.jpg)
![Page 29: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/29.jpg)
Chromosomal Mutations
• Change in number or structure of a chromosome– Deletion – loss of all or part of a chromosome– Duplication – extra copies of parts of
chromosomes– Inversion – reverse direction of parts of
chromosomes– Translocation – chromosome breaks and
attaches to another
![Page 30: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/30.jpg)
Chromosomal Mutations
• Occur during Meiosis– Prophase I– Anaphase I or Anaphase II
![Page 31: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/31.jpg)
![Page 32: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/32.jpg)
Nondisjuction
• Error in meiosis in which chromosomes fail to separate.
![Page 33: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/33.jpg)
Changes to Chromosome Number
• Monosomy 2n-1– 45 chromosomes– Turners (XO)
• Trisomy 2n+1– 47 chromosomes– Down syndrome(trisomy 21), Klinefelters
(XXY), Triple X (XXX), Jacobs (XYY)
• Polyploidy (Triploid, Tetraploid, etc)
![Page 34: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/34.jpg)
Turners (45, XO)
• 1 in 3,000 female births• Sterile females
![Page 35: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/35.jpg)
Down Syndrome
•Mothers in early 20s 1 in 1,500 births•Mothers over 35 1 in 70 births•Mothers over 45 1 in 25 births
![Page 36: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/36.jpg)
Klinefelters (XXY)
• 2 in 1000 male births• Sterile males
![Page 37: Gene Expression From a gene to a protein. Central Dogma (Crick 1958) Determines the genetic flow of information](https://reader035.vdocuments.net/reader035/viewer/2022062517/56649eb35503460f94bbb583/html5/thumbnails/37.jpg)
Jacobs (XYY)
• 1 in 1000 male births
• Tall
• Lower mental ability
• Tendency for aggressiveness