GTC MICROBIOLOGY TEST PAPER UPDATED QUESTIONS
AND ANSWERS GRADED A+
✔✔resistance plasmid - ✔✔carries genes to resistance to one or more antimicrobial
drug or heavy metal
✔✔virulence plasmid - ✔✔carries instructions for structures, enzymes or toxins that
enable bacteria to become pathogenic
✔✔fertility plasmid - ✔✔carry instructions for conjugation
✔✔helicase - ✔✔enzyme that unwinds DNA and breaks the hydrogen bonds between
the bases
✔✔gyrase - ✔✔enzyme that removes supercoils by cutting DNA then rotates cut ends
to opposite direction and then rejoins cut ends
✔✔primase - ✔✔creates a primer made of RNA
✔✔DNA polymerase III - ✔✔reads the original template strand of DNA; creates a new
complementary strand of DNA by bonding together individual nucleotide bases one at a
time
✔✔leading strand - ✔✔replication towards the replication fork (continuous)
✔✔lagging strand - ✔✔replication away from the replication fork (discontinuous);
Okazaki fragments
✔✔ligase - ✔✔connects the Okazaki fragments; ends in a continuous piece of DNA
✔✔transcription - ✔✔making of RNA from DNA
✔✔translation - ✔✔making protein from mRNA
✔✔RNA primer, mRNA, rRNA, tRNA - ✔✔4 types of RNA
✔✔RNA primer - ✔✔used to start DNA synthesis
✔✔mRNA - ✔✔carries DNA to the ribosome
✔✔rRNA - ✔✔RNA that makes up the subunits of the ribosome
✔✔tRNA - ✔✔will bring specific amino acids to the ribosome
, ✔✔1 - ✔✔transcription makes a copy of how many genes?
✔✔process of transcription - ✔✔1. initiation: promoter and RNA polymerase bind
2. elongation: RNA polymerase makes the mRNA from the antisense DNA strand
3. termination: RNA polymerase reaches a termination sequence
✔✔antisense - ✔✔the side of the DNA that is copied to make mRNA
✔✔mirror image of DNA gene, single-stranded, contains ribose instead of deoxyribose,
contains uracil instead of thymine - ✔✔characteristics of mRNA
✔✔anticodon - ✔✔3 bases on tRNA
✔✔mRNA and amino acid - ✔✔tRNA can bind to:
✔✔steps of translation - ✔✔1. mRNA binds to the ribosome
2. there is an initiator codon (AUG) on mRNA
3. the code on mRNA (codon) determines which tRNA (anticodon) can bind to it
4. Each tRNA has an amino acid attached to it. Two amino acids are attached via
dehydration synthesis and a peptide bond forms.
5. The tRNA is then free to go and get another amino acid.
6. Process continues until the terminator codon is reached.
✔✔A site - ✔✔where the tRNA with its amino acid bind to mRNA (arrival)
✔✔P site - ✔✔where the peptide bond is formed on tRNA
✔✔E site - ✔✔where the tRNA leaves to get another amino acid (exit)
✔✔steps in translation - ✔✔1. initiation: typically the start codon is AUG (A)
2. elongation: peptide bonds are formed between amino acids (P)
3. termination: stop codon signifies that the peptide chain is complete (E)
✔✔introns - ✔✔Eukaryotic mRNA contains introns and exons. Which is removed prior
to translation?
✔✔nonsense codon - ✔✔a codon that causes the termination of translation
✔✔inducers and repressors - ✔✔regulation of gene expression occurs through:
✔✔repressors - ✔✔bind to the DNA and stop the translation of mRNA
✔✔inducers - ✔✔initiate gene expression
AND ANSWERS GRADED A+
✔✔resistance plasmid - ✔✔carries genes to resistance to one or more antimicrobial
drug or heavy metal
✔✔virulence plasmid - ✔✔carries instructions for structures, enzymes or toxins that
enable bacteria to become pathogenic
✔✔fertility plasmid - ✔✔carry instructions for conjugation
✔✔helicase - ✔✔enzyme that unwinds DNA and breaks the hydrogen bonds between
the bases
✔✔gyrase - ✔✔enzyme that removes supercoils by cutting DNA then rotates cut ends
to opposite direction and then rejoins cut ends
✔✔primase - ✔✔creates a primer made of RNA
✔✔DNA polymerase III - ✔✔reads the original template strand of DNA; creates a new
complementary strand of DNA by bonding together individual nucleotide bases one at a
time
✔✔leading strand - ✔✔replication towards the replication fork (continuous)
✔✔lagging strand - ✔✔replication away from the replication fork (discontinuous);
Okazaki fragments
✔✔ligase - ✔✔connects the Okazaki fragments; ends in a continuous piece of DNA
✔✔transcription - ✔✔making of RNA from DNA
✔✔translation - ✔✔making protein from mRNA
✔✔RNA primer, mRNA, rRNA, tRNA - ✔✔4 types of RNA
✔✔RNA primer - ✔✔used to start DNA synthesis
✔✔mRNA - ✔✔carries DNA to the ribosome
✔✔rRNA - ✔✔RNA that makes up the subunits of the ribosome
✔✔tRNA - ✔✔will bring specific amino acids to the ribosome
, ✔✔1 - ✔✔transcription makes a copy of how many genes?
✔✔process of transcription - ✔✔1. initiation: promoter and RNA polymerase bind
2. elongation: RNA polymerase makes the mRNA from the antisense DNA strand
3. termination: RNA polymerase reaches a termination sequence
✔✔antisense - ✔✔the side of the DNA that is copied to make mRNA
✔✔mirror image of DNA gene, single-stranded, contains ribose instead of deoxyribose,
contains uracil instead of thymine - ✔✔characteristics of mRNA
✔✔anticodon - ✔✔3 bases on tRNA
✔✔mRNA and amino acid - ✔✔tRNA can bind to:
✔✔steps of translation - ✔✔1. mRNA binds to the ribosome
2. there is an initiator codon (AUG) on mRNA
3. the code on mRNA (codon) determines which tRNA (anticodon) can bind to it
4. Each tRNA has an amino acid attached to it. Two amino acids are attached via
dehydration synthesis and a peptide bond forms.
5. The tRNA is then free to go and get another amino acid.
6. Process continues until the terminator codon is reached.
✔✔A site - ✔✔where the tRNA with its amino acid bind to mRNA (arrival)
✔✔P site - ✔✔where the peptide bond is formed on tRNA
✔✔E site - ✔✔where the tRNA leaves to get another amino acid (exit)
✔✔steps in translation - ✔✔1. initiation: typically the start codon is AUG (A)
2. elongation: peptide bonds are formed between amino acids (P)
3. termination: stop codon signifies that the peptide chain is complete (E)
✔✔introns - ✔✔Eukaryotic mRNA contains introns and exons. Which is removed prior
to translation?
✔✔nonsense codon - ✔✔a codon that causes the termination of translation
✔✔inducers and repressors - ✔✔regulation of gene expression occurs through:
✔✔repressors - ✔✔bind to the DNA and stop the translation of mRNA
✔✔inducers - ✔✔initiate gene expression
