collinearity of gene and protein Flashcards
What does collinearity mean in the context of genes and proteins?
Collinearity means that the position of a mutation in the gene corresponds to the position of the altered amino acid in the protein.
What is the central dogma of molecular biology?
DNA → mRNA → Protein → Function → Cell/Organism. It explains the flow of genetic information from DNA to protein.
What are the four classes of amino acid R groups?
Neutral and non-polar (hydrophobic)
Neutral and polar (hydrophilic)
Acidic (negatively charged)
Basic (positively charged)
What is the significance of the R group in amino acids?
The R group determines the chemical properties of the amino acid, affects protein folding, and can influence protein function.
What is the difference between primary, secondary, tertiary, and quaternary protein structures?
Primary: Amino acid sequence.
Secondary: Local folding patterns like α-helix or β-pleated sheet.
Tertiary: 3D shape of a single polypeptide.
Quaternary: Association of multiple polypeptides.
How does a peptide bond form?
A peptide bond forms when the carboxyl group of one amino acid reacts with the amino group of another, releasing water.
What causes sickle cell anemia at the molecular level?
A mutation changes the sixth amino acid in hemoglobin from glutamate (hydrophilic) to valine (hydrophobic), altering the protein’s shape and function.
Why does the heterozygous form of sickle cell anemia confer malaria resistance?
Altered red blood cells inhibit the survival of malaria parasites.
What is a codon, and how many nucleotides does it consist of?
A codon is a sequence of three nucleotides that specifies a single amino acid.
What are silent mutations?
Silent mutations are changes in DNA that do not alter the amino acid sequence or the protein’s function.
How many amino acids are found in living cells, and how are they encoded?
There are 20 amino acids, and they are encoded by triplets of nucleotides (codons).
What does the study of hemoglobin mutations illustrate about genes and proteins?
It shows how mutations in specific gene locations lead to predictable changes in protein structure and function.
Why do some amino acid substitutions not affect protein function?
Substitutions with similar properties (e.g., glutamate to aspartate) may not disrupt the protein’s shape or function.
What is the difference between α-chains and β-chains in hemoglobin?
They are different polypeptide chains that combine to form the tetrameric structure of hemoglobin.
How was collinearity demonstrated in the trpA cistron of E. coli?
By mapping mutations in the gene and comparing them to changes in the amino acid sequence, showing a consistent relationship.
