Quick Biochemistry - Nucleic Acids (Section 3)
1
In which direction does genetic information typically proceed?
2
What best describes the genetic code?
3
What is a consequence of the degeneracy of the genetic code?
Respuesta(B)
Multiple codons can specify the same amino acids
4
Regarding the genetic code, which statement is generally accepted?
5
To what nucleotide sequence is mRNA the complement?
6
During DNA replication, which enzyme is essential at the initial stage?
7
What is the smallest DNA unit capable of directing polypeptide synthesis?
8
What element signifies the end of RNA molecule synthesis, recognized by a termination protein?
9
Following the completion of RNA synthesis, which factor aids in the initiation of a new RNA molecule's production by recognizing a promoter?
10
During transcription in bacterial cells, what is required?
Respuesta(C)
Both the sigma unit and core enzymes of RNA polymerase are needed for accurate promoter site binding
11
Regarding RNA and DNA polymerases, which statement is accurate?
Respuesta(D)
All RNA and DNA polymerases only add nucleotides at the 3' end of the growing polynucleotide chain
12
Regarding eukaryotic nuclear chromosomal DNA, which characteristic is true?
Respuesta(A)
It is a linear and unbranched molecule
13
In an operon system, a repressor protein's primary function is to halt synthesis by attaching to
Respuesta(B)
A specific region of the operon, preventing structural gene transcription
14
Which sequence is the most common variation found in pribnow boxes?
15
The 5' end of an mRNA molecule typically has which of the following attached?
Respuesta(B)
7-Methylguanosine triphosphate
16
What is the first codon to be translated on an mRNA strand?
17
The codon AUG, which codes for methionine, is significant because it serves as a
18
During protein biosynthesis, which codons signal the termination of the polypeptide chain?
19
The formation of an initiation complex during protein synthesis necessitates which factor?
20
During protein synthesis in E. coli, what amino acid residue typically tags the amino terminal of all polypeptide chains initially?
21
Protein synthesis starts when what attaches?
Respuesta(A)
40S ribosome unit to mRNA
22
The beginning of protein synthesis needs what molecule?
23
Which enzyme helps add the correct amino acid to a tRNA?
Respuesta(B)
tRNA loading with amino acids
24
How many high-energy phosphate bonds are used to prepare amino acids for protein building?
25
What is the final product of translation?
26
During chain elongation, what is needed for an aminoacyl tRNA to bind to the A site?
Respuesta(A)
Correct codon recognition
27
What molecule is needed for the new aminoacyl tRNA to enter the A site?
28
Which enzyme helps a new amino acid attach to the existing chain?
29
When a new amino acid joins the chain, how many ATP molecules are used?
30
What molecules are needed for the peptidyl tRNA to move from the A site to the P site?
31
Within eukaryotic cells, which statement is accurate regarding translation?
Respuesta(B)
Cyclohexamide interferes with the elongation phase of translation
32
Amanitin, a toxin found in certain mushrooms, inhibits
33
Tetracylin disrupts polypeptide synthesis by
Respuesta(D)
Preventing aminoacyl tRNA from binding
34
In prokaryotic cells, the effect of chloramphenicol is
Respuesta(A)
To prematurely release the polypeptide chain
35
Streptomycin's impact on polypeptide synthesis involves
Respuesta(A)
Halting the initiation stage
36
Erythromycin targets ribosomes and prevents
37
The interaction of prokaryotic DNA-dependent RNA polymerase with gene promoter sites is blocked by which antibiotic?
38
During gene repression, which gene is transcribed?
39
In the lac operon, which gene exhibits continuous expression?
40
What is the smallest functional size of an operator needed for lac repressor binding?
41
For structural gene transcription initiation, which region must be accessible in lac operation?
42
In the lac operon model, what is the function of a protein molecule?
43
Catabolite repression is facilitated by a catabolite gene activator protein (CAP) combined with
44
What is the primary function of the enzyme DNA ligase?
Respuesta(B)
Connects the end of two DNA chains
45
What is the primary function of restriction endonucleases?
Respuesta(D)
Act as defensive enzymes to protect the host bacterial DNA from DNA of foreign organisms
46
Which type of mutation is most likely to be lethal?
Respuesta(B)
Insertion of one nucleotide
47
In a partial mRNA sequence, a mutation in the template DNA alters codon 91 to UAA. What kind of mutation is this?
48
Restriction endonucleases identify and cleave a particular sequence of
49
Positive control of induction is best defined as a control system where an operon operates
Respuesta(D)
Only after an inducer protein, which is activated by an inducer, switch it on
50
What describes the nature of Interferon?
Respuesta(D)
Requires expression of cellular genes
