1. RNA and PROTEIN SYNTHESIS Chapter 13-1 & 13-2
© Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved

2. DNA’s code is used to make proteins, right?
Does DNA work alone?
Check out where DNA holds the code?
Check out where proteins are made?
So what other molecule is needed?

3. A. RNA- the Other Nucleic Acid
Also made of NUCLEOTIDES
Sugar is RIBOSE instead
of deoxyribose.
RNA is SINGLE stranded
Contains URACIL (U) instead
of thymine.

4. B. KINDS OF RIBONUCLEIC ACID (RNA)
1. Ribosomal RNA (rRNA) -Combines with proteins to form ribosomes 2. Transfer RNA (tRNA) -Matches mRNA codon to add correct amino acids during protein synthesis 3. Messenger RNA (mRNA) -Carries code from DNA to ribosomes
rRNA and t-RNA images from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved mRNA image from

5. C. Transcription – the process of making RNA from DNA
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
Section 12-
RNA polymerase
DNA
RNA
An enzyme, RNA polymerase,begins
transcription by binding to promoters (like
the ‘starting line’)

6. 2. The two strands of DNA are separated 3
2. The two strands of DNA are separated 3. Complementary RNA nucleotides are added to one strand (called the template) of DNA

7. 4. When RNA polymerase reaches the termination signal, transcription ends. 5. The RNA is released through the nucleus and DNA reforms.

8. See a video clip about TRANSCRIPTION (mcgraw-hill animation)

9. RNA’s require EDITING before use
Image by Riedell

10. D. Protein Synthesis – genetic info from DNA is used to make proteins in two steps
1. TRANSCRIPTION (DNA→ RNA) takes place in nucleus
2. TRANSLATION (RNA→ proteins)
takes place on ribosomes in cytoplasm

11. E. Why are proteins important?
Proteins determine the structure & function of the cell.
Proteins are made up of one or more polypeptides, each of which consists of a specific sequence of amino acids

12. F. HOW CAN JUST 4 BASES GIVE DIRECTIONS TO MAKE 20 AMINO ACIDS?
Message is read in groups of 3 = CODON
example: UCGCACGGU
UCG-CAC-GGU
Serine
- Histidine
- Glycine
- Codons represent different AMINO ACIDS

13. Some amino acids have more than one codon. START= AUG
 GG. The Genetic Code - used by most organisms to translate mRNA transcripts into proteins
64 possible codons
Some amino acids have more than one
codon.
START= AUG
3 codons for STOP

14. EACH tRNA carries only one kind of AMINO ACID ANTICODON on tRNA
matches up with
CODON
on mRNA
Images modified from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved

15. H. Translation - process where amino acids are assembled into polypeptides

16. 1. mRNA leaves nucleus & attaches to a ribosome 2
1. mRNA leaves nucleus & attaches to a ribosome 2. The start codon (AUG) on mRNA allows its complementary anticodon on tRNA to move in 3. A ribosome can hold another ‘codon-anticodon’ pairing so the two amino acids are linked by a peptide bond

17. 4. Then ribosome slides down mRNA to ‘read’ next codon and repeats the process 5. The polypeptide (a chain of amino acids) is complete when a stop codon is reached

18. Ribosomes
those that are free in cytoplasm produce proteins that will be used within cell.
Endoplasmic reticulum (ER)
proteins that are
exported outside cell
are produced by
ribosomes attached
to the ER

19. See a video clip about PROTEIN SYNTHESIS
TRANSLATION VIDEO (Choose Large video)

20. REPLICATION
DNA → DNA ____________
The Central Dogma Of Biology
DNA  RNA  Proteins
DNA → RNA ____________
RNA→ Protein ___________
TRANSCRIPTION
TRANSLATION

21. Mendel/flower images from: http://www. emc. maricopa
Mendel/flower images from: Blood cell by Riedell
GENES & PROTEINS
Proteins are the connection between the gene code in the DNA and how that gene is expressed.
A gene that codes for an enzyme (protein)
to make a pigment can control
the color of a flower.
A gene that codes for an enzyme (protein)
adds carbohydrates to glycoproteins to produce your blood type.
Enzymes catalyze and regulate chemical reactions so proteins build and operate all cell components.