1. From Gene to Protein
A.P. Biology

2. What do genes code for? How does DNA code for cells & bodies? DNA
cells and bodies are made from the instructions in DNA
DNA
proteins
cells
bodies 2

3. transcription and translation
The “Central Dogma”
Flow of genetic information in a cell
How do we move information from DNA to proteins?
transcription
translation
DNA
RNA
protein
trait
To get from the chemical language of DNA to the chemical language of proteins requires 2 major stages:
transcription and translation
DNA gets all the glory, but proteins do all the work!
replication 3

4. RNA
Contains ribose instead of deoxyribose
Single stranded
Nucleotide uracil replaces thymine

5. DNA and RNA RNA DNA Nucleotide (monomer) Single Stranded
Sugar, Phosphate Group & Nitrogenous Base (A T C G)
A with T; C with G
Sugar- Pentose
Deoxyribose
Double Stranded
Anti-parallel
Complementary (One can be a template for another strand)
Single Stranded
Nucleotide (monomer)
Sugar, Phosphate Group & Nitrogenous Base (A U C G) A with U; C with G
Sugar- Pentose
Ribose sugar
3 types of RNA

6. 3 Types of RNA
Messenger RNA = mRNA
-Carries DNA sequence from the nucleus to the ribosome
Ribosomal RNA = rRNA
-Component of ribosome
Transfer RNA = tRNA
-Carries amino acid (anticodon) to the codon on mRNA sequence

7. Basic Principles of Transcription and Translation
Transcription (takes place in nucleus)
Is the synthesis of RNA under the direction of DNA
Produces messenger RNA (mRNA)
Translation (takes place outside the nucleus)
Is the actual synthesis of a polypeptide, which occurs under the direction of mRNA
Occurs on ribosomes

8. In prokaryotes Transcription and translation occur together
Prokaryotic cell. In a cell lacking a nucleus, mRNA produced by transcription is immediately translated without additional processing.
(a)
TRANSLATION
TRANSCRIPTION
DNA
mRNA
Ribosome
Polypeptide

9. In eukaryotes RNA transcripts are modified before becoming true mRNA
Figure 17.3b
Eukaryotic cell. The nucleus provides a separate compartment for transcription. The original RNA transcript, called pre-mRNA, is processed in various
ways before leaving the nucleus as mRNA.
(b)
TRANSCRIPTION
RNA PROCESSING
TRANSLATION
mRNA
DNA
Pre-mRNA
Polypeptide
Ribosome
Nuclear
envelope