BIOLOGY 101 EXAM 3 |200 COMPLETE QUESTIONS WITH EXPERT
SOLUTIONS| 2026 LATEST UPDATED| A+
1. What is the difference between DNA and RNA (structure, function)? - (answer)
1. What region on the DNA strand must an RNA polymerase bind to first? - (answer)RNA
polymerase binds to the promoter, which is at the beginning of the gene.
RNA polymerase also unwinds (unzips) the two strands of DNA.
1. mRNA must be processed and modified before it can leave the nucleus. What are the three
modifications that must take place? - (answer)A "cap" structure is added to the 5' end of
mRNA(short sequence of modified nucleotides).
A poly-A tail structure is added to the 3' end of mRNA (100 to 200adenines).
The cap and tail protect mRNA from degradation and help ribosomes attach to 5' end of the
mRNA molecule.
Introns are sequences in genes that are not used for producing a protein. Introns are removed
from the mRNA.
,Exons are the sequences that specify amino acids
.Tip to Remember : Exons exit the nucleus, or Exons are expressed as a protein.
1. What is the difference between an intron and an exon? Which one exits the nucleus? -
(answer)Introns are sequences in genes that are not used for producing a protein. Introns are
removed from the mRNA.
Exons are the sequences that specify amino acids
.Tip to Remember : Exons exit the nucleus, or Exons are expressed as a protein.
1. What is a silent mutation? - (answer)mutations in DNA that do not have an observable effect
on the organism's phenotype.
1. What is a substitution mutation? - (answer)replacement of one DNA base pair with another.•
This can be silent if the mutated gene encodes the same protein as the original version
,1. What are insertion and deletion mutations? - (answer)An insertion mutation - adds one or
more nucleotides to a gene.
A deletion mutation - removes nucleotides.
1. Which of the following DNA strands is complementary to the DNA sequence below.
5'-ATCGTACG-3'
a. 5'-TACCATCC-5'
b. 3'-TAGCATGC-5'
c. 5'-TAGCATGC-3' - (answer)b. 3'-TAGCATGC-5'
Because it flipped the 5' and 3' with the complimentary base pairing.
What is a start codon? - (answer)The start codon is usually AUG (on the mRNA). (methionine)
1. What would be the first codon translated in the mRNA sequence below (circle your answer)?
5'-GGAUAACUAUGCCCAAA-3' - (answer)AUG
, This start codon attracts tRNA carrying the amino acid methionine.
Initiator tRNA molecule's anticodon matches up with the "START" codon in mRNA.
Then, the large ribosomal subunit binds.
A template strand of DNA in a gene reads:
DNA 3' GGG CAC TAT CGT 5'
What is the corresponding amino acid sequence?
Remember, we have to convert the DNA strand to an RNA strand first. Then use the chart below
to find the amino acids. - (answer)DNA 3' GGG CAC TAT CGT 5'
RNA 5' CCC GUG AUA GCA 3'
Amino Acids: Proline - Valine - Isoleucine - Alanine
SOLUTIONS| 2026 LATEST UPDATED| A+
1. What is the difference between DNA and RNA (structure, function)? - (answer)
1. What region on the DNA strand must an RNA polymerase bind to first? - (answer)RNA
polymerase binds to the promoter, which is at the beginning of the gene.
RNA polymerase also unwinds (unzips) the two strands of DNA.
1. mRNA must be processed and modified before it can leave the nucleus. What are the three
modifications that must take place? - (answer)A "cap" structure is added to the 5' end of
mRNA(short sequence of modified nucleotides).
A poly-A tail structure is added to the 3' end of mRNA (100 to 200adenines).
The cap and tail protect mRNA from degradation and help ribosomes attach to 5' end of the
mRNA molecule.
Introns are sequences in genes that are not used for producing a protein. Introns are removed
from the mRNA.
,Exons are the sequences that specify amino acids
.Tip to Remember : Exons exit the nucleus, or Exons are expressed as a protein.
1. What is the difference between an intron and an exon? Which one exits the nucleus? -
(answer)Introns are sequences in genes that are not used for producing a protein. Introns are
removed from the mRNA.
Exons are the sequences that specify amino acids
.Tip to Remember : Exons exit the nucleus, or Exons are expressed as a protein.
1. What is a silent mutation? - (answer)mutations in DNA that do not have an observable effect
on the organism's phenotype.
1. What is a substitution mutation? - (answer)replacement of one DNA base pair with another.•
This can be silent if the mutated gene encodes the same protein as the original version
,1. What are insertion and deletion mutations? - (answer)An insertion mutation - adds one or
more nucleotides to a gene.
A deletion mutation - removes nucleotides.
1. Which of the following DNA strands is complementary to the DNA sequence below.
5'-ATCGTACG-3'
a. 5'-TACCATCC-5'
b. 3'-TAGCATGC-5'
c. 5'-TAGCATGC-3' - (answer)b. 3'-TAGCATGC-5'
Because it flipped the 5' and 3' with the complimentary base pairing.
What is a start codon? - (answer)The start codon is usually AUG (on the mRNA). (methionine)
1. What would be the first codon translated in the mRNA sequence below (circle your answer)?
5'-GGAUAACUAUGCCCAAA-3' - (answer)AUG
, This start codon attracts tRNA carrying the amino acid methionine.
Initiator tRNA molecule's anticodon matches up with the "START" codon in mRNA.
Then, the large ribosomal subunit binds.
A template strand of DNA in a gene reads:
DNA 3' GGG CAC TAT CGT 5'
What is the corresponding amino acid sequence?
Remember, we have to convert the DNA strand to an RNA strand first. Then use the chart below
to find the amino acids. - (answer)DNA 3' GGG CAC TAT CGT 5'
RNA 5' CCC GUG AUA GCA 3'
Amino Acids: Proline - Valine - Isoleucine - Alanine
