Genetics: Transcription, Translation, and Genetic Code Principles
Classified in Biology
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True or False Statements:
a) Transcription and translation occur in the nucleus. | TF |
b) During transcription, an RNA molecule is formed. | TF |
c) Each RNA molecule can carry any amino acid. | TF |
Characteristics of the Genetic Code
- Universality: The specificity of the genetic code has been conserved from very early stages of evolution.
- Degenerate: A particular codon always codes for the same amino acid.
- Specificity: Each codon corresponds to a single amino acid.
- Nonoverlapping and Commaless: The code is read from a fixed starting point as a continuous sequence of bases, taken 3 at a time.
Amino Acid Calculation:
The shortest gene discovered in human chromosome 19 consists of 1000 nucleotides, 666 nucleotides of which are introns. What is the maximum number of amino acids in the protein encoded by the gene? 1000 - 666 (introns do not code for genes, only exons) = 334 / 3 (for every 3 nucleotides, 1 amino acid is produced) = 111 amino acids.
a. Defect in thymine dimer repair results in xeroderma pigmentosum. | T/F |
b. Defective mismatch repair results in Lynch syndrome. | T/F |
c. Defects in adenine dimer repair results in hereditary nonpolyposis colorectal cancer. | T/F |
a) mRNA is the most homogenous type of RNA. | T/F |
b) In the prokaryotic cytosol, there are these rRNA species (23S, 16S, 5S). | T/F |
c) tRNA are the smallest of the three major species of RNA molecules. | T/F |
d) mRNA comprises about 7% of RNA in cells. | T/F |
a) When glucose is the only sugar available, the lac operon is repressed. | T/F |
b) When only lactose is available, the lac operon is induced. | T/F |
c) When both glucose and lactose are available, the lac operon is induced. | T/F |
a) Huntington's disease is caused by a missense mutation. | T/F |
b) Myotonic dystrophy is caused by CUG triple repeats in mRNA. | T/F |
c) Cystic fibrosis is caused by a deletion of a nucleotide from the regulatory region of the gene. | T/F |
Genetic Code Characteristics:
1. Genetic code is characterized as:
- Specificity
- Universality
- Degeneracy
- Nonoverlapping
- Comaless
Amino Acid Calculation:
1. The shortest gene discovered in human chromosome 22 consists of 1000 nucleotides, 333 nucleotides of which are introns. What is the maximum number of amino acids in the protein encoded by the gene? 1000 - 333 (introns do not code for genes, only exons) = 667 / 3 (for every 3 nucleotides, 1 amino acid is produced) = 222 amino acids.
a) The RNA of telomerase serves as a primer. | T/F |
b) The direction of synthesis is 5' → 3'. | T/F |
c) The polymerase of telomerase is an RNA-directed DNA polymerase. | T/F |