1 Using Gel Electrophoresis to analyze DNA, RNA and proteins.
RNA And PROTEIN SYNTHESIS. What DNA is for…… Making Proteins Why is this important?
Transcript of RNA And PROTEIN SYNTHESIS. What DNA is for…… Making Proteins Why is this important?
RNA
And PROTEIN SYNTHESIS
What DNA is for……
• Making Proteins
• Why is this important?
Proteins Serve as…• Enzymes that catalyze biochemical
reactions (catalyst speeds up chem. Rx)
Proteins Serve as…• Enzymes that catalyze biochemical
reactions
• Structural or mechanical factors– actin and myosin in muscle
Proteins Serve as…• Enzymes that catalyze biochemical
reactions
• Structural or mechanical factors– actin and myosin in muscle– Makes up cytoskeleton
Proteins Serve as…• Enzymes that catalyze biochemical
reactions
• Structural or mechanical factors– actin and myosin in muscle– Makes up cytoskeleton– Cell signaling, immune responses, cell
adhesion, cell cycle
Proteins Serve as…• Enzymes that catalyze biochemical
reactions• Structural or mechanical factors
– actin and myosin in muscle– Makes up cytoskeleton– Cell signaling, immune responses, cell
adhesion, cell cycle– Necessity in animals' diets,
• Can’t synthesize (make) some amino acids, must eat
So How are Proteins Made?
• Remember, proteins are a chain of amino acids that are folded up into a particular shape.
So How are Proteins Made?
• DNA has all codes (GENES) for any protein that’s needed
• Humans: Abt. 25,000 genes in 23 pairs of chromosomes.
Ribonucleic Acid (RNA)
• Compared to DNA:– Similar, built as a chain of nucleotides– Unlike DNA:
• Has Uracil (U), not Thymine (T) (so it has A, U, G, C)
• 5 Carbon Sugar is Ribose, not Deoxyribose• Is single stranded• Is shorter
Comparing the nucleic acids…
DNA RNADeoxyribose sugar Ribose sugar
Double-sided Single-sided
Guanine, Cytosine, Adenine,
& Thymine
Guanine, Cytosine, Adenine,
& Uracil
Millions of base pairs long
100’s / 1000’s ofbases long
In nucleus In nuc. and cyt.
Ribonucleic Acid (RNA)
• 3 types of RNA:– Messenger RNA (mRNA)
• It’s the message carrier
– Transfer RNA (tRNA)• It transfers amino acids to the ribosomes
– Ribosomal RNA (rRNA)• It makes up actual ribosomes
TRANSCRIPTION
• DNA never leaves nucleus:1. DNA is opened / read by RNA Polymerase
2. Template side is copied (transcription) into mRNA
3. DNA closes back
4.mRNA leaves nucleus through pore
Animation
How mRNA is madeRNA Polymerase (an enzyme) opens DNA, assembles mRNA nucleotides floating around in nucleoplasm (5’ to 3’ direction)
How mRNA is madeAs mRNA strand is assembled, it lengthens until a stop signal cuts it off. RNA Polymerase then detaches, DNA closes.
How mRNA is madeThis process is Transcription (copying, rewriting) movie
RNA Polymerase
producing (transcribing) mRNA
TRANSLATION1. The mRNA moves to a ribosome;
bases read in 3’s (triplets,or codons)
2. tRNA floating in cytoplasm match up their anticodons to mRNA codons, delivering one amino acid at a time…
3. Amino acids link together (chain) then fold to make protein. Animation
mRNA connects to Ribosome
• Ribosome: assembly site for a.a. chains
• mRNA moves thru ribosome; bases read in triplets (codons)
• tRNA floating in cytoplasm match up their anticodons to mRNA codons, delivering one amino acid at a time…
movie1 movie2 movie3
movie4
Codons and their Amino Acids
A Codon Chart is very simple to use. For this circle type chart, go from the largest to smallest letters when reading your codon.
For example, A-G-C codes for Serine
Transfer
RNA
(model)
Transfer
RNA
(mapped)
Transfer
RNA
(mapped & modeled)
A Protein Forms
• tRNAs deliver the proper a.a’s., forming chain.
• Each a.a. bonded together by peptide bond
• a.a. chains always – Begin with the A-U-G codon (methionine)– End with one of three STOP codons
mRNA
Ribosome
New polypeptide chain of a.a. : Protein
A New Protein is Born
The Protein is Completed
• The a.a. chain folds into its proper shape, then sent to where it’s needed…movie
• How proteins may be used in different cells… x
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