BIOLOGY CH13 TEST REVIEW
CHAPTER 13: DNA, RNA, and Proteins
Essential Questions:
Who discovered DNA?
What is DNA?
How is DNA related to traits?
What is the Central Dogma of Biology?
NAME______________________________
DNA- The Genetic Material
DNA stores the information that tells cells which proteins to make
Your proteins give you your physical/chemical/ identity
Your DNA is different from everyone else’s DNA on earth
The Central Dogma of Biology
DNA is transcribed into RNA->RNA is translated into Proteins
Proteins give you your traits or Phenotype
Searching for the Genetic Material
Griffith - Discovered the transformation of harmless R strain Bacteria by heat killed S bacteria
Avery – Identified DNA as the transformative agent
Hershey & Chase –Studied bacteriophages and proved DNA was the source of hereditary information
Who Discovered the Structure of DNA?
James Watson & Francis Crick discovered the structure of DNA after observing an X-ray picture
of it taken by Rosalind Franklin
The Structure of DNA
DNA is a polymer of Nucleotides- remember a polymer is like a chain of beads
DNA is made of 2 chains, twisted together and coiled into an alpha double helix
The Base on one chain “complements” and makes a bond with the base on the opposite chain
The DNA Double Helix is composed of 2 interconnected nucleotide chains
The nucleotide chains are composed of a Sugar-Phosphate backbone, with bases in the middle
The Nucleotides are joined by Phosphodiester bonds
Each Nucleotide contains 1 Nitrogenous base + 1 phosphate group + 1 sugar
In DNA the sugar is deoxyribose
There are 4 different Nucleotides abbreviated as A, T G, or C
Identified by their Nitrogenous Bases:
Adenine Guanine (the pyrimidines)
Cytosine Thymine (the purines)
The Bases are said to “complement” one another - A binds T, G binds C according to Chargraff’s
Rules
The bases are bound to each other by hydrogen bonds.
DNA Replication
Why does DNA replicate?
Cells get worn out, new cells must be made (REMEMBER MITOSIS)
New cells must make exact copies of themselves
Copies of replicated genes can be passed on to offspring (MEIOSIS TOO!)
How is DNA Replicated?
1.
2.
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6.
7.
Helicase breaks hydrogen bonds in the middle of the strand, creating a
replication fork
Unpaired bases form new bonds with free nucleotides in the cell
New strand is rewound together by DNA Polymerase, creating 2 identical
DNA molecules
Sometimes replication errors make a mistake (A bonds to a G);
There are 3 x 109 bases in the average cell
Takes about 4 hours for a cell to replicate its DNA
The process is SEMI-Conservative, ie each new DNA molecule has one old
strand
Transcription
DNA is located in the nucleus of the cell
DNA CANNOT leave the nucleus of the cell because it is double stranded
What is RNA?
A nucleic acid that is similar to DNA
Ribose is the sugar
Instead of thymine, URACIL
Single stranded
Steps of Transcription
1. DNA strand unwinds via RNAPolymerase (not helicase!!!)
2. Free nucleotides bond to bases, except U in RNA bonds to A from DNA
3. RNA polymerase joins single stranded RNA together
4.Messenger RNA (mRNA) moves to the ribosome in the cytoplasm (or on the
Rough ER)
Translation (Protein Synthesis) ESSENTIAL QUESTIONS
What is protein synthesis?
The Conversion of RNA to Amino Acids which make up proteins
Why is it called translation?
The genetic code (ATCG) is translated into a protein
Where does it occur? At the ribosome in the cytoplasm
Why is it called translation? The genetic code (ATCG) is translated into a
protein
Translation and the Genetic Code
RNA is composed of 3 letter “words” called CODONS
Each codon of RNA represents a specific Amino Acid
For instance AUG is the start codon, and UUU represents the amino acid Phe
(phenylalanine)
Translation and the Genetic Code- Genetic Code Problem
If the DNA code is
AAT GCG TTT CGC ATA TAT
Then the RNA compliment is
___ ___ ___ ___ ___ ___
and the Amino Acid sequence that results is
____ ____ ____ ____ ____ ____
How Does Translation Occur?
The 3 Steps of Translation
1. Initiation
A. Ribosome attaches to mRNA (each 3 bases is called a codon)
B. tRNA brings anticodon and AA to ribosome
2. Elongation
A. More tRNA’s bring more AA’s to ribosome
B. AA’s connected together to make polypeptides (by peptide bonds)
3. Termination
A. Ribosome reaches a STOP signal on mRNA
B. Polypeptide (protein) is broken off and becomes part of the human body
C. Golgi apparatus modifies completed protein; ER transports it in/out of cell
The processes of transcription and translation are the same in all living
organisms!
WHAT DOES A PROTEN LOOK LIKE WHEN ITS DONE!
Remember the Protein is a POLYMER of Amino Acids!!
Here each amino acid is represented by a single Letter like R T or G
The protein folds on itself to form a specific structure that has a specific
function
Here are some others
Remember the most common type of
protein are ENZYMES!
BIOLOGY CH13 DNA, RNA & PROTEINS
NAME________________________
USE THE VOCABULARY LIST AND FOLLOWING DIAGRAM TO COMPARE AND
CONTRAST THE STRUCTURE AND FUNCTION OF DNA AND RNA
USING YOUR DIAGRAM COMPOSE A PARAGRAPH THAT DESCRIBES AT LEAST 1
SIMILARITY AND 2 DIFFERENCES BETWEEN DNA AND RNA
BIOLOGY CH13 DNA, RNA & PROTEINS
NAME________________________
USE THE VOCABULARY LIST AND FOLLOWING DIAGRAM TO COMPARE AND
CONTRAST THE PROCESSES OF TRANSCRIPTION AND TRANSLATION
USING YOUR DIAGRAM COMPOSE A PARAGRAPH THAT DESCRIBES AT LEAST 1
SIMILARITY AND 2 DIFFERENCES BETWEEN TRANSCRIPTION AND TANSLATION
BIOLOGY CH13 TEST REVIEW
VOCABULARY
CHAPTER 13: DNA, RNA, and Proteins
The Central Dogma of Biology DNA is transcribed into RNA->RNA is translated into Proteins
Griffith - Discovered the transformation of harmless R strain Bacteria by heat killed S bacteria
Avery – Identified DNA as the transformative agent
Hershey & Chase –Studied bacteriophages and proved DNA was the source of hereditary information
James Watson & Francis Crick deduced the structure of DNA
Rosalind Franklin used x ray crystallography to image the structure of DNA
DNA- Deoxyribonucleic Acid
DNA- is a polymer of Nucleotides- remember a polymer is like a chain of beads
DNA- is made of 2 chains, twisted together and coiled into an alpha double helix
DNA- Double Helix is composed of 2 interconnected nucleotide chains
Nucleotide Chains are composed of a Sugar-Phosphate backbone, with bases in the middle
Phosphodiester bonds join nucleotides
Nucleotide contains 1 Nitrogenous base + 1 phosphate group + 1 sugar
Deoxyribose the sugar in DNA
4 different Nucleotides abbreviated as A, T G, or C
The pyrimidines
-Adenine Guanine
The purines -Cytosine Thymine
Chargraff’s Rules - A binds T, G binds C according to
Hydrogen bonds.- join the bases across the helix
MITOSIS
-Cell division
MEIOSIS
gamete formation
DNA Replication- is semi conservative!
Helicase breaks hydrogen bonds in the middle of the strand, creating a replication fork
DNA Polymerase, creates 2 identical DNA molecules
Transcription- DNA copied to RNA, occurs in nucleus
RNA- A nucleic acid that is similar to DNA, Ribose is the sugar, instead of thymine, URACIL, single
stranded
Steps of Transcription
RNAPolymerase (RNApol)– Unwinds DNA strand and copies it into RNA
Uracil RNA base replacing Thymine
Messenger RNA (mRNA) DNA transcript or copy moves to the ribosome in the cytoplasm (or on the
Rough ER)
Translation (Protein Synthesis) - The Conversion of mRNA to Amino Acids which make up proteins
The Genetic code (ATCG) is translated into a amino acids
CODON- a 3 letter sequence of mRNA that codes for a particular Amino Acid
Amino Acid -the components that make Proteins
tRNA (transferRNA)- the RNA that carries amino acids to the ribosome
Anti-Codon – the 3 letter sequence of tRNA that corresponds to the mRNA CODON
AUG - the start codon
Translation – conversion of mRNA into a Protein
Initiation- Ribosome attaches to mRNA (each 3 bases is called a codon), tRNA brings anticodon and AA
to ribosome
Elongation- More tRNA’s bring more AA’s to ribosome, AA’s connected together to make polypeptides
(by peptide bonds)
Termination- Ribosome reaches a STOP signal on mRNA
Enzymes- the most common type of protein