BIOL 1001 Chapter : Chapter 12 Gene Expression
• Chapter 12
Gene Expression and Regulation Part 1 of 2
How does your GENOTYPE BECOME YOUR PHENOTYPE
Information by itself does no good
A blueprint doesn’t build a house...
Genetic information is TRANSCRIBED INTO RNA AND TRANSLATED INTO
PROTEIN
Fig. 12.2
1. DNA is transcribed into RNA
2. RNA is translated into protein
PROTEIN SYNTHESIS OCCURS ON RIBOSOMES
The message is carried by MESSENGER RNA (ribonucleic acid)
-DNA is in the NUCLEUS (for eukaryotes)
-So DNA cannot directly guide protein synthesis
The message must be carried from the DNA in the nucleus to the
ribosomes in the cytoplasm
RNA (ribonucleic acid)
RNA differs structurally from DNA:
Usually SINGLE STRANDED
RNA contains the sugar ribose instead of DEOXYRIBOSE
RNA uses the base URACIL (U) instead of THYMINE (T)
Three types of RNA aid in protein synthesis
1. MESSENGER RNA (mRNA)
2. RIBOSOMAL RNA (rRNA)
3. TRANSFER RNA (tRNA)
• Comparing nucleic acids: DNA and RNA Table 12.1
Major types of RNA (ribonucleic acid): mRNA (messenger) Fig. 12.1
carries the code for PROTEIN SYNTHESIS FROM DNA TO RIBOSOMES
Groups of three bases called CODONS specify which amino acid will be
added to a polypeptide chain during TRANSLATION
-Major types of RNA (ribonucleic acid): rRNA (ribosomal)
-rRNA and proteins form RIBOSOMES
-Ribosomes are the SITE OF PROTEIN SYNTHESIS during translation
-Made of one large and one small SUBUNIT Fig. 12.1
Major types of RNA (ribonucleic acid): tRNA (transfer)
Carries AMINO ACIDS TO THE RIBOSOMES for protein synthesis during
TRANSLATION
tRNA are specific for each amino acid: ANTICODONS BIND TO CODONS
ON mRNA directing the correct amino acid to be attached to the
growing polypeptide chain. Fig. 12.1
• Genetic information is transcribed into RNA and translated into
protein. Fig. 12.2
DNA is transcribed into RNA
RNA is translated into protein
• Transcription (from nucleotide sequence to nucleotide sequence)
DNA → RNA
A gene is a SEGMENT OF DNA THAT CAN BE COPIED
(TRANSCRIBED) INTO RNA
Occurs in the NUCLEUS
Translation (from nucleotide sequence to amino acid sequence)
RNA → PROTEIN
Occurs in the CYTOPLASM
• Transcription: DNA → RNA
Occurs in the nucleus
Transcription consists of three steps
1. INITIATION
2. ELONGATION
3. TERMINATION
Corresponds to three spots on most genes
A PROMOTER region
The “BODY” of the gene
A TERMINATION SIGNAL
• Transcription: initiation
Initiation begins when RNA POLYMERASE binds to the PROMOTER
REGION OF A GENE
RNA polymerase – ENZYME THAT SNTHESIZED RNA
Promoters (in eukaryotes) consist of two main parts
- The area that RNA polymerase binds
-TATAAA box
Document Summary
Gene expression and regulation part 1 of 2. Genetic information is transcribed into rna and translated into. 12. 2: dna is transcribed into rna, rna is translated into protein. The message is carried by messenger rna (ribonucleic acid) The message must be carried from the dna in the nucleus to the ribosomes in the cytoplasm. Rna contains the sugar ribose instead of deoxyribose. Rna uses the base uracil (u) instead of thymine (t) Three types of rna aid in protein synthesis: messenger rna (mrna, ribosomal rna (rrna, transfer rna (trna, comparing nucleic acids: dna and rna table 12. 1. Major types of rna (ribonucleic acid): mrna (messenger) fig. 12. 1 carries the code for protein synthesis from dna to ribosomes. Groups of three bases called codons specify which amino acid will be added to a polypeptide chain during translation. Major types of rna (ribonucleic acid): rrna (ribosomal) Ribosomes are the site of protein synthesis during translation.
