1. 12-3 RNA and Protein Synthesis
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2. 12–3 RNA and Protein Synthesis
DNA is located in the nucleus.
DNA is impermeable to the nuclear envelope.
-it is too large to fit through the nuclear membrane pores
Genes are segments of DNA which code for the production of proteins.
Ribosomes outside the nucleus make the proteins.
RNA contains coded information for making proteins.
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3. Do you see a problem with this scenario?
DNA has the code for making proteins but is too large to fit through the pores of the nuclear envelope and proteins are made outside the nucleus at the ribosomes. How does the code get to the ribosomes????
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4. RNA is the solution to this problem. RNA is DNA’s main man.
RNA is DNA’s “go to guy”.
RNA is DNA’s number one
“get it done person”.
One of RNA’s jobs is to copy DNA’s instructions and take those instructions
out of the nucleus to the ribosomes.
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The Structure of RNA
The Structure of RNA
RNA is a type of nucleic acid –Ribonucleic Acid
-made up of a long chain of nucleotides.
2. Each RNA nucleotide, like DNA’s, is made up of a:
1. a sugar
2. a phosphate group
3. a nitrogen base.
(Sounds familiar just like DNA’s nucleotides)
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The Structure of RNA
There are three main differences between RNA and DNA:
1. The sugar in RNA is ribose instead of deoxyribose.
2. RNA is a single-strand of nucleotides where as DNA is a double strand of nucleotides.
3. RNA contains uracil in place of DNA’s thymine.
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Types of RNA
There are three types of RNA
1. messenger RNA ~ mRNA
2. ribosomal RNA ~ rRNA
3. transfer RNA ~ tRNA
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Types of RNA
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.
Messenger RNA (mRNA) copies DNA’s code for making proteins and takes it’s copy to the ribosomes.
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Types of RNA
Ribosome
Ribosomal RNA
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA. Ribosomal RNA is combined with proteins to form ribosomes.
Ribosomal RNA (rRNA): makes up the ribosomes
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Types of RNA
Amino acid
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.
Transfer RNA
Transfer RNA (tRNA) transfers specific amino acids to the ribosome for the making of the proteins.
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Transcription
What is transcription?
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Transcription
Transcription
RNA copies DNA’s code in its own language and take the code to the ribosomes to make proteins.
What is DNA’s language?
A, T, G and C
What is RNA’s language?
A, U, G and C
Like all reactions in the cell, transcription requires enzymes, the enzyme RNA polymerase.
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13. Steps to Transcription:
1.During transcription, RNA polymerase attaches to DNA and separates the two sides of the DNA strands.
Steps to Transcription:
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2. RNA polymerase then adds RNA nucleotides to one side of the DNA molecule
-DNA is a double strand of nucleotides BUT only one side of the DNA molecule actually codes for making proteins.
-We call that side the sense side of DNA.
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2 sides of DNA
Sense side:
Has code for making
proteins.
Antisense side:
Has no code~ makes
no sense.
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3. RNA nucleotides are added to the sense side of DNA following the base pair rule:
Guinine bonds to Cytosine
Adenine bonds to DNA’s Thymine
Uracil bonds to Adenine
Sense side of DNA A T G G C U A C C G G C A T
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4. This single strand of RNA is now known as messenger RNA or mRNA and it now has a copy of DNA’s code for making proteins.
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5. Since mRNA is single stranded it can now take a copy of DNA’s code out of the nucleus to the ribosomes.
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The Genetic Code
Protein Synthesis:
The process of using mRNA’s copy of DNA’s code to make all necessary proteins.
Takes place where?
-at the ribosomes
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Proteins are made up of:
-long chains of amino acids
Total number of different amino acids that make up all proteins:
-20
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These 20 different amino acids bond in various orders (like the letters of the alphabet) to create all proteins.
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The Genetic Code
A codon consists of three RNA nucleotides in a row on mRNA that code for a particular amino acid.
A codon is a group of three nucleotides on messenger RNA that specify a particular amino acid.
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Start codon:
Three nitrogen bases in a row on mRNA that starts EVERY protein…..AUG
AUG is the start codon’s code and it codes for the amino acid Methionine which starts every protein
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Stop codon:
Three nitrogen bases in a row on mRNA that ends every protein.
Three different codons: UAA, UAG, UGA
Stop codon do not code for any amino acid
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Translation
What is translation?
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Translation
Translation:
-Process by which the ribosome reads mRNA’s code and makes a protein.
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Translation
Steps of translation:
1. mRNA leaves the nucleus and take its code to the ribosomes.
Nucleus
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
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2. Ribosome attaches to mRNA and moves along it looking for a start codon/AUG.
3. Transfer RNA/tRNA travels through the cytoplasm locating the appropriate amino acid.
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Anticodon:
anti =
opposite
An anticodon is three nitrogen bases on the end of tRNA .
Its code is opposite of mRNA’s codon.
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Translation
4. As the ribosome reads one codon at a time, tRNA brings down the appropriate amino acid.
Lysine
Phenylalanine
tRNA
Methionine
Ribosome
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
Start codon
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Translation
5. Amino acids bind together with peptide bonds forming a long chain.
Lysine
tRNA
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
Translation direction
Ribosome
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Translation
After a tRNA delivers its amino acid, it breaks away and goes out to find a new amino acid.
The process continues until the ribosome reads a stop codon.
Polypeptide
Ribosome
tRNA
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
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The long chain of amino acids
-now a polypeptide/protein made in its linear shape/straight line
The polypeptide breaks away and goes to the Golgi.
It needs to go to the golgi to acquire its unique 3-D shape before it can become functional.
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36. Amino acids within a polypeptide
Codon
Codon
Codon
Review:
The sequence of bases in DNA is used as a template for mRNA.
The codons of mRNA specify the sequence of amino acids in a protein.
Single strand of DNA
Codon
Codon
Codon
mRNA
This diagram illustrates how information for specifying the traits of an organism is carried in DNA. The sequence of bases in DNA is used as a template for mRNA. The codons of mRNA specify the sequence of amino acids in a protein, and proteins play a key role in producing an organism’s traits.
Alanine
Arginine
Leucine
Amino acids within a polypeptide
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37. Hyperlink of translation
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DNA Codon
mRNA codon
tRNA anticodon
Amino Acid
AAA
UUU
PHENYL
GTC
GGA
GLYCINE
METH/START
GAT
GUG
VALINE
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39. CHNOPS LAB DNA: TAC AGG GCG ATT mRNA:____________________
tRNA:______________________
Amino Acid sequence: ____________________________________
Trait: _____________________
AMINO ACID SEQUENCE
TRAIT
Methionine-threonine-glycine-tyrosine-
Hairless
Methionine- threonine-glycine-glycine
Hairy
Methionine- threonine-proline-proline
Plump
Methionine- tyrosine-glycine-lysine
Skinny
Methionine-serine-arginine
Four-eyed
Methionine-serine-tyrosine
Two-eyed
Methionine-glycine-arginine-lysine-proline
Long nose
Methionine- proline-arginine-lysine-proline
Short nose
Methionine-phenylalanine-lysine
No freckles
Methionine- phenylalanine-asparagine
Freckles
Methionine- glycine-arginine-arginine
Blue skin
Methionine- glycine-arginine-phenylalanine
Orange skin
Methionine-isoleucine-isoleucine-leucine
Male
Methionine-isoleucine-isoleucine-glycine
Female
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