DNA, RNA, and Protein Synthesis Chapter 10 Table of Contents Section 1 Discovery of DNA Section 2 DNA Structure Section 3 DNA Replication Section 4 Protein

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.


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


Chapter 10

Visual Concept

Transformation



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


Hershey-Chase Experiment

• Hershey and Chase confirmed that DNA, and not protein, is the hereditary material.

Chapter 10

The Hershey-Chase Experiment


Chapter 10

Click below to watch the Visual Concept.

Hershey and Chase’s Experiments


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.


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?


DNA Double Helix

• DNA is made of two nucleotide strands that wrap around each other in the shape of a double helix.


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).


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.


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.


How DNA Replication Occurs

• DNA replication is the process by which DNA is copied in a cell before a cell divides.


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:



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



DNA Errors in Replication

• Changes in DNA are called mutations.

• DNA proofreading and repair prevent many replication errors.


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.


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


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



RNA Structure and Function, continued

• Types of RNA– Cells have three major

types of RNA: • messenger RNA

(mRNA)• ribosomal RNA

(rRNA)• transfer RNA

(tRNA)


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


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


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


RNA EditingBefore it leaves the nucleus, RNA is

edited. Splicing occurs by removing introns and fusing exons together.

Chapter 10


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 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



Transcription

• During transcription, DNA acts as a template for directing the synthesis of RNA.

Chapter 10

Transcription



Genetic Code

• The nearly universal genetic code identifies the specific amino acids coded for by each three-nucleotide mRNA codon.


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



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

Documents

DNA, RNA, and Protein Synthesis Chapter 10 Table of Contents Section 1 Discovery of DNA Section 2 DNA Structure Section 3 DNA Replication Section 4 Protein