dna, rna, and protein synthesis chapter 10 table of contents section 1 discovery of dna section 2...
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DNA, RNA, and Protein SynthesisChapter 10
Table of Contents
Section 1 Discovery of DNA
Section 2 DNA Structure
Section 3 DNA Replication
Section 4 Protein Synthesis
Standards
• SPI 3210.4.1 Identify the structure and function of DNA.
• SPI 3210.4.2 Associate the process of DNA replication with its biological significance.
• SPI 3210.4.3 Recognize the interactions between DNA and RNA during protein synthesis.
Chapter 10 DNA, RNA, and Protein Synthesis
Section 1 Discovery of DNAChapter 10
Objectives
• Relate how Fred Griffith’s bacterial experiments showed that a hereditary factor was involved in transformation.
• Summarize how Avery’s experiments led his group to conclude that DNA is responsible for transformation in bacteria.
• Describe how Hershey and Chase’s experiment led to the conclusion that DNA, not protein, is the hereditary molecule in viruses.
Section 1 Discovery of DNAChapter 10
Griffith’s Experiments
• Griffith’s experiments showed that hereditary material can pass from one bacterial cell to another.
• The transfer of genetic material from one cell to another cell or from one organism to another organism is called transformation.
Chapter 10
Griffith’s Discovery of Transformation
Section 1 Discovery of DNA
Chapter 10
Visual Concept
Transformation
Section 1 Discovery of DNA
Section 1 Discovery of DNAChapter 10
Avery’s Experiments
• Avery’s work showed that DNA is the hereditary material that transfers information between bacterial cells.
#https://www.youtube.com/watch?v=t9xBHPz_3ro
Section 1 Discovery of DNAChapter 10
Hershey-Chase Experiment
• Hershey and Chase confirmed that DNA, and not protein, is the hereditary material.
Chapter 10
The Hershey-Chase Experiment
Section 1 Discovery of DNA
Chapter 10
Click below to watch the Visual Concept.
Hershey and Chase’s Experiments
Section 1 Discovery of DNA
Section 2 DNA StructureChapter 10
Objectives
• Evaluate the contributions of Franklin and Wilkins in helping Watson and Crick discover DNA’s double helix structure.
• Describe the three parts of a nucleotide.
• Summarize the role of covalent and hydrogen bonds in the structure of DNA.
• Relate the role of the base-pairing rules to the structure of DNA.
Section 2 DNA StructureChapter 10
DNA Double Helix
• Watson and Crick created a model of DNA by using Franklin’s and Wilkins’s DNA diffraction X-rays.
Chapter 10Section 2 DNA Structure
Possible issues?
Section 2 DNA StructureChapter 10
DNA Double Helix
• DNA is made of two nucleotide strands that wrap around each other in the shape of a double helix.
Section 2 DNA StructureChapter 10
DNA Double Helix, continued
• A DNA nucleotide is made of a 5-carbon deoxyribose sugar, a phosphate group, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), or thymine (T).
Section 2 DNA StructureChapter 10
DNA Nucleotides, continued
• Bonds Hold DNA Together– Nucleotides along each DNA strand are linked by
covalent bonds. – Complementary nitrogenous bases are bonded by
hydrogen bonds.
Section 2 DNA StructureChapter 10
Complementary Bases
• Hydrogen bonding between the complementary base pairs, G-C and A-T, holds the two strands of a DNA molecule together.
Section 3 DNA ReplicationChapter 10
Objectives
• Summarize the process of DNA replication.
• Identify the role of enzymes in the replication of DNA.
• Describe how complementary base pairing guides DNA replication.
• Compare the number of replication forks in prokaryotic and eukaryotic cells during DNA replication.
• Describe how errors are corrected during DNA replication.
Section 3 DNA ReplicationChapter 10
How DNA Replication Occurs
• DNA replication is the process by which DNA is copied in a cell before a cell divides.
Section 3 DNA ReplicationChapter 10
How DNA Replication Occurs, continued
• Steps of DNA Replication – Replication begins with the separation of the DNA
strands by helicases. – Then, DNA polymerases form new strands by
adding complementary nucleotides to each of the original strands.
Chapter 10
DNA Replication Visual Concept:
Section 3 DNA Replication
Section 3 DNA ReplicationChapter 10
How DNA Replication Occurs, continued
• Each new DNA molecule is made of one strand of nucleotides from the original DNA molecule and one new strand. This is called semi-conservative replication.
Chapter 10
Replication Forks Increase the Speed of Replication
Section 3 DNA Replication
Section 3 DNA ReplicationChapter 10
DNA Errors in Replication
• Changes in DNA are called mutations.
• DNA proofreading and repair prevent many replication errors.
Section 3 DNA ReplicationChapter 10
DNA Errors in Replication, continued
• DNA Replication and Cancer– Unrepaired mutations that affect genes that control
cell division can cause diseases such as cancer.
Section 4 Protein SynthesisChapter 10
Objectives
• Outline the flow of genetic information in cells from DNA to protein.
• Compare the structure of RNA with that of DNA.
• Describe the importance of the genetic code.
• Compare the role of mRNA, rRNA,and tRNA in translation.
• Identify the importance of learning about the human genome.
Section 4 Protein SynthesisChapter 10
Flow of Genetic Information
• The flow of genetic information can be symbolized as DNA RNA protein.
10-4 RNA and Protein SynthesisRNA, like DNA, consists of long chains of nucleotides.Three differences between DNA and RNA
- the sugar is ribose- single stranded- contains uracil instead of thymine
*base pairings are A-U and C-G
Chapter 10
Section 4 Protein SynthesisChapter 10
RNA Structure and Function
• RNA has the sugar ribose instead of deoxyribose and uracil in place of thymine.
• RNA is single stranded and is shorter than DNA.
Chapter 10
Click below to watch the Visual Concept.
Comparing DNA and RNA
Section 4 Protein Synthesis
Section 4 Protein SynthesisChapter 10
RNA Structure and Function, continued
• Types of RNA– Cells have three major
types of RNA: • messenger RNA
(mRNA)• ribosomal RNA
(rRNA)• transfer RNA
(tRNA)
Section 4 Protein SynthesisChapter 10
RNA Structure and Function, continued
• mRNA carries the genetic “message” from the nucleus to the cytosol.
• rRNA is the major component of ribosomes.• tRNA carries specific amino acids, helping to form
polypeptides.
10-4 RNA and Protein Synthesis
Chapter 10
10-4 Messenger RNA (mRNA)
1. Single, uncoiled, straight strand of nucleic acid
2. Found in the nucleus & cytoplasm
3. Copies DNA’s instructions & carries them to the ribosomes where proteins can be made
4. mRNA’s base sequence is translated into the amino acid sequence of a protein
5. Three consecutive bases on mRNA called a codon (e.g. UAA, CGC, AGU)
6. Reusable
Chapter 10
10-4 RNA and Protein Synthesis
Ribosome
Ribosomal RNA
Chapter 10
10-4 Ribosomal RNA (rRNA)•Globular shape •Helps make up the structure of the ribosomes •Ribosomes are the site of translation (making polypeptides)
•rRNA & protein make up the large •& small subunits of ribosomes
Chapter 10
10-4 RNA and Protein Synthesis
Amino acid
Chapter 10
10-4 Transfer RNA (tRNA)Single stranded molecule containing 80 nucleotides in the shape of a cloverleaf/hairpin
- Carries amino acids in the cytoplasm to ribosomes for protein assembly-Three bases on tRNA that are complementary to a codon on mRNA are called anticodons (e.g. codon- UUA; anticodon- AAU) - Amino Acid attachment site across from anticodon site on tRNA -Enters a ribosome & reads mRNA codons and links together correct sequence of amino acids to make a protein -Reusable
Chapter 10
10-4 Transcription
RNADNA
RNApolymerase
Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)
Chapter 10
10-4 Transcription
Transcription: the copying of the DNA into a complementary strand of RNA- uses the enzyme RNA polymerase
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.
The enzyme binds to the region DNA known as the promoter region.
Chapter 10
10-4 Transcription
1.DNA helicase (enzyme) uncoils the DNA molecule2.RNA polymerase (enzyme) binds to a region of DNA called the promoter which has the start codon AUG to code for the amino acid methionine3.Promoters mark the beginning of a DNA chain in prokaryotes, but mark the beginning of 1 to several related genes in eukaryotes4.The 2 DNA strands separate, but only one will serve as the template & be copied5.Free nucleotides are joined to the template by RNA polymerase in the 5’ to 3’ direction to form the mRNA strand6.mRNA sequence is built until the enzyme reaches an area on DNA called the termination signal 7.RNA polymerase breaks loose from DNA and the newly made mRNA8.Eukaryotic mRNA is modified (unneeded sections snipped out by enzymes & rejoined) before leaving the nucleus through nuclear pores, but prokaryotic RNA is not
All 3 types of RNA called transcripts are produced by this method
Chapter 10
10-4 RNA and Protein Synthesis
RNA EditingBefore it leaves the nucleus, RNA is
edited. Splicing occurs by removing introns and fusing exons together.
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10-4 RNA and Protein Synthesis
The Genetic Code
The genetic code is read in three letter segments called codons.
There are 64 different codon possibilities that code for only 20 amino acids
-AUG is the start codon
-there are 3 stop codons-
UAA, UAG, UGA
Transcription – Processing of Gene Information
10-4 RNA and Protein Synthesis
10-4 Translation
Translation: the decoding of mRNA into an amino acid sequence
During translation, the cell uses information from messenger RNA to produce proteins
- anticodon: the three letter sequence on tRNA that binds with mRNA
Chapter 10
10-4 Translation
1. mRNA brings the copied DNA code from the nucleus to the cytoplasm
2. mRNA attaches to one end of a ribosome; called initiation3. tRNAs attach the correct amino acid floating in the cytoplasm to
themselves4. tRNA with its attached amino acid has 2 binding sites where they
join the ribosome5. The tRNA anticodon “reads” & temporarily attaches to the mRNA
codon in the ribosome6. Two amino acids at a time are linked together by peptide bonds
to make polypeptide -chains (protein subunits); called elongation7. Ribosomes) move along the mRNA strand until they reach a stop
codon (UAA, UGA, or UAG); called termination 8. tRNA’s break loose from amino acid, leave the ribosome, &
return to cytoplasm to pick up another amino acid
Chapter 10
tRNA
Ribosome
mRNA
Lysine
Translation direction
Chapter 10
10-4 Translation
Polypeptide
Ribosome
tRNA
mRNA
Chapter 10
Chapter 10 Section 4 Protein Synthesis
Chapter 10
Visual Concept
Types of RNA
Section 4 Protein Synthesis
Section 4 Protein SynthesisChapter 10
Transcription
• During transcription, DNA acts as a template for directing the synthesis of RNA.
Chapter 10
Transcription
Section 4 Protein Synthesis
Section 4 Protein SynthesisChapter 10
Genetic Code
• The nearly universal genetic code identifies the specific amino acids coded for by each three-nucleotide mRNA codon.
Section 4 Protein SynthesisChapter 10
Translation
• Steps of Translation– During translation, amino acids are assembled
from information encoded in mRNA. – As the mRNA codons move through the ribosome,
tRNAs add specific amino acids to the growing polypeptide chain.
– The process continues until a stop codon is reached and the newly made protein is released.
Chapter 10
Translation: Assembling Proteins Video
Section 4 Protein Synthesis
Section 4 Protein SynthesisChapter 10
The Human Genome
• The entire gene sequence of the human genome, the complete genetic content, is now known.
• To learn where and when human cells use each of the proteins coded for in the approximately 30,000 genes in the human genome will take much more analysis.
http://www.changethethought.com/tag/human-genome/
Chapter 10 Section 4 Protein Synthesis