Embed Size (px)
Citation preview
End Show
Slide 1 of 39
Copyright Pearson Prentice Hall
Biology Biology
End Show
Slide 2 of 39
Copyright Pearson Prentice Hall
12-3 RNA and Protein Synthesis 12–3 RNA and Protein Synthesis
End Show
Slide 3 of 39
Copyright Pearson Prentice Hall
Essential Question What is transcription and
translation and how do they take place?
End Show
12–3 RNA and Protein Synthesis
Slide 4 of 39
Copyright Pearson Prentice Hall
12–3 RNA and Protein Synthesis
Genes are coded DNA instructions that control the production of proteins.
Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA.
RNA contains coded information for making proteins.
End Show
12–3 RNA and Protein Synthesis
Slide 5 of 39
Copyright Pearson Prentice Hall
The Structure of RNA
The Structure of RNA
RNA consists of a long chain of nucleotides.
Each nucleotide is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base.
End Show
12–3 RNA and Protein Synthesis
Slide 6 of 39
Copyright Pearson Prentice Hall
The Structure of RNA
There are three main differences between RNA and DNA:
• The sugar in RNA is ribose instead of deoxyribose.
• RNA is generally single-stranded.
• RNA contains uracil in place of thymine.
End Show
12–3 RNA and Protein Synthesis
Slide 7 of 39
Copyright Pearson Prentice Hall
Types of RNA
What are the three main types of RNA?
End Show
12–3 RNA and Protein Synthesis
Slide 8 of 39
Copyright Pearson Prentice Hall
Types of RNA
Types of RNA
There are three main types of RNA: • messenger RNA • ribosomal RNA • transfer RNA
End Show
12–3 RNA and Protein Synthesis
Slide 9 of 39
Copyright Pearson Prentice Hall
Types of RNA
Messenger RNA (mRNA) carries copies of instructions for assembling amino acids into proteins.
End Show
12–3 RNA and Protein Synthesis
Slide 10 of 39
Copyright Pearson Prentice Hall
Types of RNA
Ribosomes are made up of proteins and ribosomal RNA (rRNA).
Ribosome
Ribosomal RNA
End Show
12–3 RNA and Protein Synthesis
Slide 11 of 39
Copyright Pearson Prentice Hall
Types of RNA
During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome.
Amino acid
Transfer RNA
End Show
12–3 RNA and Protein Synthesis
Slide 12 of 39
Copyright Pearson Prentice Hall
Transcription
What is transcription?
End Show
12–3 RNA and Protein Synthesis
Slide 13 of 39
Copyright Pearson Prentice Hall
Transcription
Transcription
RNA molecules are produced by copying part of a nucleotide sequence of DNA into a complementary sequence in RNA. This process is called transcription.
Transcription requires the enzyme RNA polymerase.
End Show
12–3 RNA and Protein Synthesis
Slide 14 of 39
Copyright Pearson Prentice Hall
Transcription
During transcription, RNA polymerase binds to DNA and separates the DNA strands.
RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA.
End Show
12–3 RNA and Protein Synthesis
Slide 15 of 39
Copyright Pearson Prentice Hall
Transcription
RNA polymerase binds only to regions of DNA known as promoters.
Promoters are signals in DNA that indicate to the enzyme where to bind to make RNA.
End Show
12–3 RNA and Protein Synthesis
Slide 16 of 39
Copyright Pearson Prentice Hall
Transcription
RNA
RNA polymerase
DNA
End Show
12–3 RNA and Protein Synthesis
Slide 17 of 39
Copyright Pearson Prentice Hall
RNA Editing
RNA Editing
The DNA of eukaryotic genes contains sequences of nucleotides, called introns, that are not involved in coding for proteins.
The DNA sequences that code for proteins are called exons.
When RNA molecules are formed, introns and exons are copied from DNA.
End Show
12–3 RNA and Protein Synthesis
Slide 18 of 39
Copyright Pearson Prentice Hall
RNA Editing
The introns are cut out of RNA molecules.
The exons are the spliced together to form mRNA.
Exon Intron DNA
Pre-mRNA
mRNA
Cap Tail
End Show
12–3 RNA and Protein Synthesis
Slide 19 of 39
Copyright Pearson Prentice Hall
The Genetic Code
The Genetic Code
The genetic code is the “language” of mRNA instructions.
The code is written using four “letters” (the bases: A, U, C, and G).
End Show
12–3 RNA and Protein Synthesis
Slide 20 of 39
Copyright Pearson Prentice Hall
The Genetic Code
A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid.
End Show
12–3 RNA and Protein Synthesis
Slide 21 of 39
Copyright Pearson Prentice Hall
The Genetic Code
Each codon specifies a particular amino acid that is to be placed on the polypeptide chain.
Some amino acids can be specified by more than one codon.
End Show
12–3 RNA and Protein Synthesis
Slide 22 of 39
Copyright Pearson Prentice Hall
The Genetic Code
End Show
12–3 RNA and Protein Synthesis
Slide 23 of 39
Copyright Pearson Prentice Hall
The Genetic Code
There is one codon AUG that can either specify the amino acid methionine or serve as a “start” codon for protein synthesis.
There are three “stop” codons that do not code for any amino acid. These “stop” codons signify the end of a polypeptide.
End Show
12–3 RNA and Protein Synthesis
Slide 24 of 39
Copyright Pearson Prentice Hall
Translation
What is translation?
End Show
12–3 RNA and Protein Synthesis
Slide 25 of 39
Copyright Pearson Prentice Hall
Translation
Translation Translation is the decoding of an mRNA message into a polypeptide chain (protein).
Translation takes place on ribosomes.
During translation, the cell uses information from messenger RNA to produce proteins.
End Show
12–3 RNA and Protein Synthesis
Slide 26 of 39
Copyright Pearson Prentice Hall
Translation
Nucleus
mRNA
Messenger RNA is transcribed in the nucleus, and then enters the cytoplasm where it attaches to a ribosome.
End Show
12–3 RNA and Protein Synthesis
Slide 27 of 39
Copyright Pearson Prentice Hall
Translation
Translation begins when an mRNA molecule attaches to a ribosome.
As each codon of the mRNA molecule moves through the ribosome, the proper amino acid is brought into the ribosome by tRNA.
In the ribosome, the amino acid is transferred to the growing polypeptide chain.
End Show
12–3 RNA and Protein Synthesis
Slide 28 of 39
Copyright Pearson Prentice Hall
Translation
Each tRNA molecule carries only one kind of amino acid.
In addition to an amino acid, each tRNA molecule has three unpaired bases.
These bases, called the anticodon, are complementary to one mRNA codon.
End Show
12–3 RNA and Protein Synthesis
Slide 29 of 39
Copyright Pearson Prentice Hall
Translation
Lysine tRNA Phenylalanine
Methionine
Ribosome
mRNA Start codon
The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.
End Show
12–3 RNA and Protein Synthesis
Slide 30 of 39
Copyright Pearson Prentice Hall
Translation
Protein Synthesis tRNA
Ribosome mRNA
Lysine
Translation direction
End Show
12–3 RNA and Protein Synthesis
Slide 31 of 39
Copyright Pearson Prentice Hall
Translation
The process continues until the ribosome reaches a stop codon.
Polypeptide
Ribosome
tRNA
mRNA
End Show
12–3 RNA and Protein Synthesis
Slide 32 of 39
Copyright Pearson Prentice Hall
The Roles of RNA and DNA
The Roles of RNA and DNA
The cell uses the DNA “master plan” to prepare RNA “blueprints.” The DNA stays in the nucleus.
The RNA molecules go to the protein building sites in the cytoplasm—the ribosomes.
End Show
12–3 RNA and Protein Synthesis
Slide 33 of 39
Copyright Pearson Prentice Hall
Genes and Proteins
Genes and Proteins
Genes contain instructions for assembling proteins.
Many proteins are enzymes, which catalyze and regulate chemical reactions.
Proteins are each specifically designed to build or operate a component of a living cell.
End Show
12–3 RNA and Protein Synthesis
Slide 34 of 39
Copyright Pearson Prentice Hall
Genes and Proteins
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.
Codon Codon Codon
Codon Codon Codon
mRNA
Alanine Arginine Leucine
Amino acids within a polypeptide
Single strand of DNA
End Show
- or - Continue to: Click to Launch:
Slide 35 of 39
Copyright Pearson Prentice Hall
12–3
End Show
Slide 36 of 39
Copyright Pearson Prentice Hall
12–3
The role of a master plan in a building is similar to the role of which molecule?
a. messenger RNA
b. DNA
c. transfer RNA
d. ribosomal RNA
End Show
Slide 37 of 39
Copyright Pearson Prentice Hall
12–3
A base that is present in RNA but NOT in DNA is
a. thymine.
b. uracil.
c. cytosine.
d. adenine.
End Show
Slide 38 of 39
Copyright Pearson Prentice Hall
12–3
The nucleic acid responsible for bringing individual amino acids to the ribosome is
a. transfer RNA.
b. DNA.
c. messenger RNA.
d. ribosomal RNA.
End Show
Slide 39 of 39
Copyright Pearson Prentice Hall
12–3
A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the
a. intron.
b. exon.
c. promoter.
d. codon.
End Show
Slide 40 of 39
Copyright Pearson Prentice Hall
12–3
A codon typically carries sufficient information to specify a(an)
a. single base pair in RNA.
b. single amino acid.
c. entire protein.
d. single base pair in DNA.
END OF SECTION
