dna and rna
DESCRIPTION
DNA and RNA . What does DNA look like? What are the elements that makeup DNA?. DNA Structure = String of nucleotides (sugar, phosphate, base) *Adenine *Thymine *Guanine *Cytosine. purines - adenine, guanine pyrimidines - cytosine, thymine. DNA Nucleotides. Purines. Pyrimidines. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/1.jpg)
DNA and RNA
What does DNA look like?What are the elements that makeup DNA?
![Page 2: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/2.jpg)
DNA Structure= String of nucleotides (sugar, phosphate, base)
*Adenine*Thymine*Guanine*Cytosine
• purines - adenine, guanine• pyrimidines - cytosine,
thymine
![Page 3: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/3.jpg)
Purines Pyrimidines
Adenine Guanine Cytosine Thymine
Phosphate group Deoxyribose
DNA Nucleotides
![Page 4: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/4.jpg)
Francis Crick and James Watson (1953)
Twisted Double Helix
Hydrogen Bonds are the “glue” that keeps
the two strands together
Each strand of the helix is a chain of nucleotides
What holds the strands together?
![Page 5: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/5.jpg)
Always Together….Great CoupleD
E
N
I
N
E
H
Y
M
I
N
E
U
A
N
I
N
E
Y
T
O
S
I
N
E
A & T G & C
![Page 6: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/6.jpg)
Hydrogen bonds
Nucleotide
Sugar-phosphate backbone
KeyAdenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Structure of DNA
![Page 7: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/7.jpg)
How is DNA organized in a chromosome?
Remember Chromatin??DNA tightly coiled around proteins forming Chromatin which pack together to form thick fibers.
What exactly is chromatin?
ONE nucleus of ONE human cell = more than 1 meter of DNA!!!
![Page 8: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/8.jpg)
Chromosome
E. coli bacteriumBases on the chromosome
Prokaryotic Chromosome Structure
Section 12-2
![Page 9: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/9.jpg)
Figure 12-10 Chromosome Structure of Eukaryotes
Chromosome
Supercoils
Coils
Nucleosome
Histones
DNA
double
helix
![Page 10: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/10.jpg)
How can DNA use its double-stranded structure to its advantage for replication???
![Page 11: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/11.jpg)
“Something Old…Something New”
![Page 12: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/12.jpg)
DNA Replication When does this occur in the cell cycle?
1) Enzymes un-twist and unzip the molecule (break H bonds between base pairs).
2) Each strand serves as a template (something “OLD”)
3) Free nitrogen bases form bonds and make complementary strands (Something “NEW”)
Template
4) DNA Polymerase bonds the nucleotides and proofreads the molecule
![Page 13: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/13.jpg)
DNA Replication
Growth
Growth
Replication fork
DNA polymerase
New strand
Original strand DNA
polymerase
Nitrogenous bases
Replication fork
Original strand
New strand
![Page 14: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/14.jpg)
DNA vs. RNA RNA – also a long chain of nucleotides (5-
carbon sugar, phosphate group, nitrogenous base)
Differences:1. RNA sugar = ribose, instead of deoxyribose2. RNA – usually single-stranded3. RNA has uracil to replace thymine (so U
binds with A)
“Always United & Great Couple”
![Page 15: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/15.jpg)
RNA is in charge of assembling Amino Acids into Proteins
![Page 16: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/16.jpg)
From DNA(Gene) to Protein
rRNA - ribosomal RNA - location of protein synthesis uses tRNA to make proteins
The players:
DNA - sequences of nitrogen bases forms the genetic code
mRNA - messenger RNA - makes a copy of the DNA in the nucleus and brings it to the rRNA
tRNA - transfer RNA - reads the mRNA and brings specific amino acids to the rRNA
![Page 17: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/17.jpg)
Step 1: Transcription = recording the message Occurs in nucleus New mRNA strand forms from one of DNA
strands (creating the message) Let’s Practice…
![Page 18: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/18.jpg)
Transcription Practice
Transcribe the DNA molecule below:
ATTATCGCGTAATGCTAATAGCTAATAGCGCATTACGATTATCG
Template
AUUAUCGCGUAAUGCUAAUAGC
mRNA
transcript
![Page 19: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/19.jpg)
RNADNA
RNApolymerase
Figure 12–14 TranscriptionAdenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)
![Page 20: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/20.jpg)
Step 2: Editing of mRNA
Introns are removed – non coding regions of the DNA molecule
Exons remain – sequences that will be expressed
![Page 21: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/21.jpg)
Step 3: Translation = Protein Synthesis Occurs at ribosome tRNA reads mRNA which has message from
genetic code (DNA) Genetic code is read 3 letters at a time, so
each word is 3 bases long
![Page 22: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/22.jpg)
Every 3 letters is a CODON
Each codon codes for a specific amino acid.
What does an Amino Acid do again? Helps make proteins!
• We need codons for Protein Synthesis (Translation)• They are like directions to make proteins
• Every set of directions tells you where to START and where to STOP
• We too have these, we call them the “start and stop codons”
![Page 23: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/23.jpg)
Codons to remember…
START is always: AUG
STOP is always: UAA UAG UGA
![Page 24: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/24.jpg)
Translation Explained
tRNA UAC mRNA AUGCGCAUAACGCAU
Start Codon
methionine
![Page 25: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/25.jpg)
Alternate sequence:
There are 20 different amino acids to be coded for.
There are 64 possible codons.
Start codon
Stop codon
![Page 26: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/26.jpg)
Figure 12–17 The Genetic Code
![Page 27: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/27.jpg)
Translation Practice
Make a polypeptide (chain of amino acids) chain from the mRNA molecule
AUGAUCGCGUAUUGCUACUAG - mRNA
methionine-isoleucine-alanine-tyrosine-cysteine-tyrosine STOP
![Page 28: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/28.jpg)
Figure 12–18 TranslationSection 12-3
![Page 29: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/29.jpg)
Figure 12–18 Translation (continued)
Section 12-3
![Page 30: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/30.jpg)
Mutations - changes in the DNA sequence Gene mutation- changes in a single gene
• Point Mutations - substitution of one nucleotide for another
• Frame Shift Mutations - shifting of the genetic code due to insertion or deletion of nucleotide
Chromosomal mutation changes in the entire chromosome (containing many genes)
![Page 31: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/31.jpg)
Deletion
Duplication
Inversion
Translocation
Figure 12–20 Chromosomal Mutations
![Page 32: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/32.jpg)
Mutation AnalogyTHE FAT CAT ATE THE RAT
substitution THE FAT CAT ATE THE CAT *The letter “C” was substituted for the “R”
insertion THE FAT CAT ATE THE RAT THC EFA TCA TAT ETH ERA T
*Because the “C” was added, all other letters shifted down, thereby changing the amino acids that are made.C
Deletion THE F T CAT ATE THE RATTHE FTC ATA TET HER AT*Again, the amino acids will change b/c the “F” was removed
A
![Page 33: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/33.jpg)
Mutation Practice
What will the new amino acid be if the 5th nucleotide is substituted with an adenine?
AUGA CGCGUAUUGCUACUAG - mRNAU
What will the new amino acid sequence be if a guanine is inserted between the 9th and 10th nucleotide ?
ASPARAGINE
GGUA = VALINE
![Page 34: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/34.jpg)
When a mutation occurs…
If the amino acid sequence is stopped early (a STOP codon is reached) = Nonsense
If the amino acid sequence continues but the wrong amino acids are coded for = Missense
![Page 35: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/35.jpg)
Putting it all together
What is the amino acid sequence that forms from the following DNA molecule? (DNA synthesis)
TACTACACCGTATAACAGGGCCTAGCAACT
Template
ATGATGTGGCATATTGTCCCGGATCGTTGA
![Page 36: DNA and RNA](https://reader035.vdocuments.site/reader035/viewer/2022062812/5681634e550346895dd3ec6a/html5/thumbnails/36.jpg)
(Transcription)DNA - TACTACACCGTATAACAGGGCCTAGCAACT
mRNA - AUGAUGUGGCAUAUUGUCCCGGAUCGUUGA
(Translation)
amino acid sequence
methionine-methionine-tryptophan-histidine-isoleucine-valine-proline-aspartic acid-arginine-stop