Central DogmaCentral DogmaDNA RNA DNA RNA Protein Protein
What are chromosomes? Where are they found?
Chromosome
Histones
DNA
double
helix
What is a gene?What is a gene? A sequence of A sequence of
DNA that codes DNA that codes for a protein and for a protein and thus determines a thus determines a trait.trait.
Where do we get our Where do we get our genes?genes?
It’s all in the DNA, It’s all in the DNA, and it’s and it’s hereditary!hereditary!
That means That means different different combinations of combinations of genes from mom genes from mom and dad make you and dad make you and all your and all your siblings!siblings!
Hydrogen bonds
Nucleotide
Sugar-phosphate backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
DNA
Adenine Guanine Cytosine Thymine
Deoxyribose sugar
Phosphate group
DNA
Nitrogen Base
Nu
cle
oti
de
What are the rules of What are the rules of BASE BASE PAIRINGPAIRING??
In a DNA molecule, every In a DNA molecule, every nitrogenous base is paired:nitrogenous base is paired:– Adenine pairs with Adenine pairs with ThymineThymine– Guanine pairs with Guanine pairs with CytosineCytosine– Thymine pairs with Thymine pairs with AdenineAdenine– Cytosine pairs with Cytosine pairs with GuanineGuanine
RNARNA
Serves as a Serves as a messenger messenger between the between the nucleusnucleus and the and the ribosomesribosomes..
Carries Carries information in information in order to make order to make proteinsproteins from from aminoamino acidsacids..
RNA StructureRNA Structure
A= AdenineA= Adenine G= GuanineG= Guanine C= CytosineC= Cytosine U= UracilU= Uracil UracilUracil replaces replaces
ThymineThymine SingleSingle
stranded.stranded.
from to to make up
Concept MapSection 12-3
also called which functions to also called also called which functions towhich functions to
can be
RNA
Messenger RNA Ribosomal RNA Transfer RNA
mRNA Carry instructions
rRNACombine
with proteins tRNABring
amino acids toribosome
DNA Ribosome Ribosomes
Go to Section:
ReviewReview
Fill in the missing nitrogen bases to Fill in the missing nitrogen bases to make this DNA double-stranded.make this DNA double-stranded.
Use the green DNA strand as a Use the green DNA strand as a template to transcribe RNA:template to transcribe RNA:
TAC-ACG-TCC-ATA-CAT-GGT-CCA-ATTTAC-ACG-TCC-ATA-CAT-GGT-CCA-ATT
ATG-ATG- -TAA -TAA
Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)
Transcription
TranscriptionTranscriptionDNA is DNA is transcribedtranscribed into into RNARNA1.1. RNA polymerase attaches to RNA polymerase attaches to
DNA and unzips it.DNA and unzips it.
2.2. One strand of DNA is used as a One strand of DNA is used as a template.template.
3.3. RNA polymerase attaches RNA polymerase attaches nucleotides to the template to nucleotides to the template to make a single strand of RNA.make a single strand of RNA.
What does it mean to What does it mean to transcribe?transcribe? To transcribe means to rewrite in To transcribe means to rewrite in
a different script (lettering)a different script (lettering) Remember DNA consists of A, Remember DNA consists of A, TT, ,
G, CG, C RNA consists of A, RNA consists of A, UU, G, C, G, C
TranscriptionTranscription
Codons (Found on Codons (Found on mRNA)mRNA) CodonsCodons consist of three consist of three
nucleotides that nucleotides that code forcode for a a particular particular amino acidamino acid
Example: Example: – UCGCACGGU should be read as…UCGCACGGU should be read as…– UCG-CAC-GGU which codes forUCG-CAC-GGU which codes for– Serine-Histidine-Glycine Serine-Histidine-Glycine
Anticodons (Found on Anticodons (Found on tRNA)tRNA) AnticodonsAnticodons consist of three consist of three
unpaired nucleotides that are unpaired nucleotides that are complementary complementary toto one mRNA one mRNA codoncodon
FunctionsFunctions to attach tRNA to mRNA to attach tRNA to mRNA so that amino acids can attach to so that amino acids can attach to one anotherone another
Example:Example:– (1) mRNA: UCG-CAC-GGU(1) mRNA: UCG-CAC-GGU– (3) tRNA: AGC GUG CCA(3) tRNA: AGC GUG CCA
TRANSCRIPTION & TRANSCRIPTION & TRANSLATIONTRANSLATION
TranslationTranslation
1.1. mRNA attaches to ribosomemRNA attaches to ribosome
2.2. tRNA brings amino acids to mRNAtRNA brings amino acids to mRNA
3.3. Anticodons (on tRNA) bind to codons Anticodons (on tRNA) bind to codons (on mRNA) starting at “start” codon, (on mRNA) starting at “start” codon, AUGAUG
4.4. Ribosome joins the amino acids Ribosome joins the amino acids together to make a polypeptide chain together to make a polypeptide chain (protein) until a “stop” codon is (protein) until a “stop” codon is reached.reached.
Translation
Translation cont.
Genetic CodeGenetic Code