1. DNA, RNA,
and Proteins

2. DNA and Protein Synthesis-REPEAT
DNA contains 4 bases. They are:
Adenine (A)-pairs with Thymine only
Thymine (T)-Pairs with adenine only
Guanine (G)-pairs with cytosine only
Cytosine (C)-pairs with guanine only
DNA contains the genetic information to
make amino acids
Amino acids combine to make proteins
These proteins determine the physical traits
of an organism and control cellular functions.
Proteins do everything,
and DNA gets all the
credit!
Think of them as tiny minions
who do all the work

3. Codon: three bases code for a specific protein: ex: AAA = Lysine
DNA and Protein Synthesis
Codon: three bases code for a specific protein:
ex: AAA = Lysine
The codons code for 20 amino acids
Just like the alphabet has 26 letters to make all
the words we know, the 20 amino acids make
all the different proteins found in living
organisms
This makes it possible to have 64 different combinations for amino acids
The codons are the template for protein synthesis
Protein synthesis is the production of protein
which takes place on the ribosomes in the
cytoplasm
**Protein is very important because it triggers many cell processes as we learned earlier

4. But… How does the information get from the DNA to the cytoplasm?
DNA and Protein Synthesis
But… How does the information get from the DNA to the cytoplasm?
mRNA

5. RNA
DNA must be decoded to work
The structure of RNA is similar to DNA but has 3 differences
Sugar in RNA is Ribose
RNA is single-stranded
Uracil replaces thymine

6. 3. Three main types of RNA
Messenger RNA (mRNA)-This contains instructions for joining amino acids to make proteins; three consecutive nucleotides make up a codon (a single amino acid). The complimentary trio is an anticodon
Ribosomal RNA (rRNA)-Assembles proteins into ribosomes
Transfer RNA (tRNA)-carries each amino acid to the ribosome according to a coded message from mRNA

7. Bring amino acids to ribosome
RNA Concept Map
Section 12-3
RNA
can be
Messenger RNA
Ribosomal RNA
Transfer RNA
also called
which functions to
also called
which functions to
also called
which functions to
mRNA
Carry instructions
rRNA
Combine
with proteins
tRNA
Bring amino acids to ribosome
from to
to make up
DNA
Ribosome
Ribosomes

8. Transcription-The process of copying DNA into RNA (for decoding of DNA) making it possible for a gene in DNA to be copied hundreds of times
The DNA strands separate or “unzip”)
Nucleotides of RNA match up and join the DNA strand-they are creating mRNA
**Bases pair up the same way except uracil binds with adenine instead of thymine
c. The completed RNA strand is released and moves into the cytoplasm

9. RNA polymerase DNA RNA Adenine (DNA and RNA) Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA polymerase
DNA
RNA

10. DNA G A T T A C A C U A A U G U mRNA
DNA and Protein Synthesis
Practice making mRNA using the DNA template
DNA
G A T T A C A
C U A A U G U
mRNA

11. 5. Translation -RNA is a molecule that contains instructions for making proteins. This process occurs on the ribosome.
mRNA moves into the cytoplasm and attaches to a ribosome (rRNA)
The rRNA decodes the message and sends out tRNA to pick up an amino acid
Each codon has an anticodon brought in by tRNA to compliments or pair up (CGA pairs with GCU) forming bonds (like puzzle pieces)
tRNA breaks away to allow another one to bring in a new anticodon
A long chain is built until a stop codon is reached (there are three possible types)

12. Translation

14. The Genetic Code Wheel

15. Codons and amino acids: This is the message from mRNA and is translated by rRNA and it tells tRNA what amino acid to pick up and add to the protein chain
Name the Amino Acid for each anticodon:
UAU
CCG
AGU
GCA
Tyrosine
Proline
Serine
Alanine
What do you think the DNA codon was for these anticodons?

16. Journal ; Determining the Sequence of a Gene
DNA contains the code of instructions for cells. Sometimes, an error occurs when the code is copied. Such errors are called mutations. 1. Copy the following information about Protein X: Methionine—Phenylalanine—Tryptophan—Asparagine—Isoleucine—STOP. 2. Use the Genetic Code Wheel to determine one possible sequence of RNA to code for this information. Write this code below the description of Protein X. Below this, write the DNA code that would produce this RNA sequence.

17. 3. Now, cause a mutation in the gene sequence that you just determined by deleting the fourth base in the DNA sequence. Write this new sequence. 4. Write the new RNA sequence that would be produced. Below that, write the amino acid sequence that would result from this mutation in your gene. Call this Protein Y. 5. Did this single deletion cause much change in your protein? Explain your answer.

18. 12-4: Mutations Mutations are changes in the genetic material.
A. Kinds of Mutations
1. gene mutations-mutations that produce changes in a single gene
a. point mutations- Gene mutations involving a change in one or a few nucleotides that occur at a single point in the DNA sequence.
1. substitutions-one base replaces another.

19. 2. Frameshift Mutations a
2. Frameshift Mutations a. The effects of insertions or deletions are more dramatic. b. The addition or deletion of a nucleotide causes a shift in the grouping of codons. c. Types 1. insertions- an extra base is inserted into a base sequence 2. deletions- loss of a single base is deleted and the reading frame is shifted

21. 3. chromosomal mutations- mutations that produce changes in the number or structure of chromosomes. a. Types 1. Deletion-the loss of all or part of a chromosome. 2. Duplication- produce extra copies of parts of a chromosome. 3. Translocation-occurs when part of one chromosome breaks off and attaches to another 4. Inversion- reverse the direction of parts of chromosomes.

23. B. Significance of Mutations
Many mutations have little or no effect on gene expression.
Some mutations are the cause of genetic disorders.
Beneficial mutations may produce proteins with new or altered activities that can be useful.
Example: Polyploidy is the condition in which an organism has extra sets of chromosome