Study Guide Microbial Genetics (pt3)

Question 1

What transports and then transfers the amino acid to the developing peptide chain?

Answer 1

Transfer RNA

Question 2

What assists protein synthesis by serving as a “facilitator” for the mRNA and tRNA functions?

Answer 2

Ribosomal RNA

Question 3

How is the genetic code carried?

Answer 3

The mRNA carries the genetic code from the DNA to the ribosome

Question 4

How is each amino acid matched up with its genetic code?

Answer 4

From 1st base to 3rd base in the codon sequence.

A to U and C to G

Question 5

What is the transfer of the genetic code on DNA gene into an mRNA strand by means of DNA-dependent RNA polymerase

Answer 5

Transcription

Question 6

What are the steps of transcription?

Answer 6

1. DNA double-helix unwinds, exposing nucleotides
2. RNA polymerase binds to the DNA at promoter site
3. Complementary RNA nucleotides are joined together by RNA polymearse
4. Transcription ends when the RNA polymearse reaches the termination region of the gene
5. New single strand mRNA is released

Question 7

What is the synthesis of a polypeptide at the ribosome through linkage of amino acids in a sequence specified by a mRNA molecule?

Answer 7

Translation

Question 8

What are the steps of translation?

Answer 8

1. mRNA attaches to the ribosome with “start” codon
2. tRNA with anticodon matches mRNA codon, starting first amino acid
3. amino acids linked together, tRNA is released
4. Polypedtide chain released when “stop” codon is reached.

Question 9

What is are related genes that are regulated as a group/series?

Answer 9

Operon

Question 10

What gene codes for a “repressor” protein which can bind to the “operator” sight?

Answer 10

Repressor gene

Question 11

What is the region of the chromosome to which the RNA polymearse binds during transcription?

Answer 11

Promoter site

Question 12

What is the region of the chromosome which controls access of the RNA polymearse to the structural genes of the operon?

Answer 12

Operator site

Question 13

What are adjacent genes of the operon which direct the synthesis of proteins with related functions and which are regulated as a unit?

Answer 13

Genes of the operon

Question 14

What molecular event permits or prevents the transcription of the structural genes of an operon?

Answer 14

The operator

Question 15

What are the three types of mutations?

Answer 15

Base substitution, frameshift mutation, and Gross mutation

Question 16

Which mutation occurs when a single base is replaced with another, thus changing the codon and is usually not highly significant?

Answer 16

Base substitution

Question 17

Which mutation occurs when insertion or deletion of bases may shift the codon reading frame of the mRNA in the ribosome and is significantly different or nonfucntional protein?

Answer 17

Framshift mutation

Question 18

Which mutation occurs when gain or loss of entire gene segment, inversions or transpositions of gene sequences and results in major change, or no functional cell?

Answer 18

Gross mutation