Cell Biology: Ribosomes

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What is the sedimentation rate unit used to describe the size, weight, and shape of a particle?

RNA unit

Micrometer unit

Centrifugation unit

Svedberg unit (correct)

What is the composition of ribosomes?

Both proteins and pieces of RNA (correct)

Only RNA molecules

Only proteins

Only carbohydrates

What is the function of the 16S rRNA molecule?

To code for proteins

To synthesize proteins

To identify bacteria (correct)

To regulate gene expression

What is the primary challenge in identifying pathogenic bacteria using traditional methods?

Pathogens grow poorly on solid culture medium Signup and view all the answers

What is the purpose of PCR?

To amplify specific DNA sequences Signup and view all the answers

What is the advantage of molecular methods in identifying bacteria?

They can overcome the limitations of traditional methods Signup and view all the answers

What is the function of an automatic DNA sequencer?

To determine the order of nucleotides in a DNA sequence Signup and view all the answers

Why are molecular methods necessary for some bacterial species?

They offer the only reliable means of identification Signup and view all the answers

What is the purpose of identifying the sequence of the 16S rRNA gene?

To identify possible pathogens Signup and view all the answers

What is the goal of the lab exercise?

To identify a bacterial sample received from a clinician Signup and view all the answers

What is the limitation of traditional methods in identifying bacteria?

They are limited by the growth requirements of the bacteria Signup and view all the answers

What is the primary goal of comparing a newly isolated DNA molecule with all other known sequences?

To determine whether the new sequence bears similarity to another known sequence Signup and view all the answers

What is the purpose of accessing a comprehensive and up-to-date sequence database?

To compare a newly isolated DNA molecule with known sequences Signup and view all the answers

What is the result of assigning 1 point for each base pair that matches exactly and 0 points for each base pair that does not in the hypothetical system described?

The more nucleotides that match, the higher is the score Signup and view all the answers

What is the collaboration between GenBank, the EMBL nucleotide sequence database, and the DNA Database of Japan (DDBJ) involved in?

Collecting and sharing new sequence data and updates Signup and view all the answers

What is the purpose of BLAST search results analysis?

To determine whether the new sequence bears similarity to another known sequence Signup and view all the answers

How many points would be assigned to the following sequences: CGGCAT and CGCGAT using the hypothetical system?

4 points Signup and view all the answers

What is the optimal temperature for Taq polymerase to synthesize complementary strands?

72°C Signup and view all the answers

What is the purpose of MgCl2 in PCR?

To encourage binding of polymerase to DNA at primer points Signup and view all the answers

What is the purpose of the initial denaturation step in PCR?

To denature the double-stranded DNA Signup and view all the answers

What is the size of the amplicons of the 16S rRNA gene in bacterial cells?

1,500 bp Signup and view all the answers

What is the purpose of the extension step in PCR?

To synthesize complementary strands Signup and view all the answers

What is the confirmatory method used to verify the success of PCR?

Agarose Gel Electrophoresis (AGE) Signup and view all the answers

What is the purpose of the denaturation step in PCR?

To break hydrogen bonds between nucleotide bases Signup and view all the answers

What is the optimal temperature range for the annealing step in PCR?

45–65°C Signup and view all the answers

What is the primary advantage of DNA sequencing over other molecular techniques?

It enables characterization of DNA at a molecular level Signup and view all the answers

What is the purpose of adding a primer to the PCR reaction mixture?

To bind specifically to the target sequence Signup and view all the answers

What is the primary consideration when selecting a hybridization temperature for PCR?

The primer length and base composition Signup and view all the answers

Who is credited with the development of dideoxynucleotide chain-termination sequencing?

Fred Sanger Signup and view all the answers