47 Questions
Which molecule carries instructions from DNA to the rest of the ribosome?
mRNA
Which site on the ribosome is responsible for the initiation of protein synthesis?
P site
Which of the following is NOT a step in protein synthesis?
Translation
What is the role of tRNA in protein synthesis?
Brings in new amino acids to match codons
Which type of RNA is part of the structure of a ribosome?
rRNA
What is the end product of protein synthesis?
A primary structure of a protein
Which of the following is true about amino acids?
They are encoded directly by the codons of the universal genetic code
What are peptides?
Short polymer chains formed by amino acids
What is a codon?
A sequence of three nucleotides that form a unit of genetic code
Which of the following is true about the genetic code?
It can be decoded unambiguously from protein sequence
What are stop codons?
Codons that signal the end of a sequence
Which of the following is a characteristic of Type 1 diabetes?
Insulin independence
What type of mutation occurs when there is a change in the base that leads to a change in the amino acid?
Missense mutation
Which of the following diseases is caused by a frameshift mutation?
Hemoglobin Wayne
Which antibiotic inhibits the initiation of protein synthesis in prokaryotes?
Streptomycin
Which antibiotic binds to the 50S ribosomal subunit in prokaryotes?
Erythromycin
Which antibiotic inhibits the incoming tRNA to the A site at the 30S subunit in prokaryotes?
Tetracycline
Which antibiotic acts as a premature terminator of protein synthesis in both prokaryotes and eukaryotes?
Puromycin
Which of the following antibiotics can affect mitochondrial eukaryotic RNA processes?
Chloramphenicol
What is the role of the P site on the ribosome during protein synthesis?
Initiation
Which of the following is NOT a R- group modification that can occur to a protein precursor?
Glycosylation
What can C-peptide levels help determine in patients with diabetes?
Insulin production
Which of the following is true about peptide bonds?
Peptide bonds form between amino acids
Which of the following is true about stop codons?
Stop codons are sequences of three nucleotides
Which of the following is true about C-peptide levels in Type 1 diabetes?
A very low C-peptide level confirms Type 1 diabetes and insulin dependence.
Which type of mutation is caused by the alteration in the 3rd base of a codon?
Silent mutation
Which antibiotic acts as a premature terminator of protein synthesis in both prokaryotes and eukaryotes?
Puromycin
Which antibiotics bind to the 30S subunit of the ribosome?
Aminoglycosides and Tetracyclines
Which of the following diseases is caused by a nonsense genetic codon change resulting in a mutation in proteins?
a-thalassemia
Which of the following is true about essential amino acids?
Essential amino acids must be obtained from the diet
What is a peptide bond?
A peptide bond is a short polymer chain of amino acids
What are the three stop codons?
UAA, UGA, UAG
Which of the following is true about the large and small subunit of ribosomes in prokaryotes?
The large subunit is 50S and the small subunit is 30S
Which of the following is true about the large and small subunits of ribosomes in eukaryotes?
The large subunit is 60S and the small subunit is 40S
Which of the following is true about the end products of protein synthesis?
They are primary structures of proteins
Which of the following antibiotics binds to the 30S subunit of the ribosome?
Streptomycin
What is the consequence of a very low C-peptide level in a patient?
All of the above
Which type of mutation is characterized by a change in the base leading to a change in the amino acid?
Missense mutation
Which antibiotic inhibits the elongation step of protein synthesis in both Gram-positive and Gram-negative bacteria?
Chloramphenicol
Which of the following is a consequence of using prokaryotic antibiotics on mitochondrial eukaryotic RNA processes?
Mitochondrial dysfunction
Which of the following is a characteristic of a nonsense mutation?
Formation of a premature termination codon
Which of the following antibiotics acts as a premature terminator of protein synthesis by mimicking tRNA and binding to the A site?
Puromycin
All positively charged except?
Serine
A basic amino structure consists of a central alpha carbon covalently bonded to a carboxyl group, an amine group, a hydrogen, and a variable R group.
True
Translation consumes 90% of the cells energy using 4 ATP per amino acid
True
where does "O" linked glycosylation occur? and with what amino acids?
Serine/ Threonine in golgi
constant spring is caused by?
glutamine at 142
Study Notes
Protein Synthesis Overview
- mRNA carries instructions from DNA to ribosomes for protein synthesis.
- The P site on the ribosome is responsible for the initiation of protein synthesis.
- Key steps in protein synthesis include initiation, elongation, and termination, while any step outside these is not part of the process.
tRNA and Ribosomal RNA
- tRNA transports amino acids to the ribosome, matching them to the codons on mRNA.
- rRNA is a structural component of ribosomes, essential for their function.
Protein Synthesis Products
- The end product of protein synthesis is a polypeptide chain that folds into a functional protein.
- Amino acids are the building blocks of proteins, and each amino acid is encoded by a specific codon.
Codons and Genetic Code
- A codon is a sequence of three nucleotides on mRNA that corresponds to a specific amino acid.
- The genetic code is universal, with specific codons representing the same amino acids across different organisms.
Stop Codons and Mutations
- Stop codons (UAA, UAG, UGA) signal the termination of protein synthesis.
- Type 1 diabetes is characterized by insufficient insulin production.
- A missense mutation causes a change in the amino acid due to a base alteration.
Antibiotics and Their Effects on Protein Synthesis
- Certain antibiotics inhibit protein synthesis by targeting specific ribosomal subunits:
- Streptomycin binds to the 30S subunit, inhibiting incoming tRNA to the A site.
- Chloramphenicol binds to the 50S subunit, interfering with peptide bond formation.
- Puromycin acts as a premature terminator of protein synthesis in both prokaryotes and eukaryotes.
C-Peptide and Diabetes
- C-peptide levels can help differentiate between Type 1 and Type 2 diabetes; low levels indicate Type 1 diabetes.
- Very low C-peptide levels suggest low endogenous insulin production.
Peptide Bonds and Modifications
- A peptide bond links amino acids, forming the backbone of proteins.
- R-group modifications to proteins include phosphorylation and glycosylation, which affect protein function.
Characteristics of Mutations
- A nonsense mutation leads to a premature stop in protein synthesis.
- Alterations in the third base of a codon often result in silent mutations without changing the amino acid.
Energy Consumption
- Translation, the process of protein synthesis, consumes approximately 90% of a cell's energy, requiring 4 ATP molecules per amino acid added to the chain.
Glycosylation
- "O-linked" glycosylation occurs in the Golgi apparatus and primarily involves serine and threonine residues in proteins.
Test your knowledge on the building blocks of proteins with this quiz on amino acids. Learn about the 20 biologically active amino acids and their role in protein synthesis. Discover the essential amino acids and their importance in human biology.
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