UA BSC 315 EXAM 2 STUDY GUIDE: UA
BSC 315, 2025/2026 WITH
CORRECT/ACCURATE ANSWERS
Describe the four phenotypic classes that occur in the F2 progeny
of F1 dihybrids - CORRECT ANSWERS- Two are parental and two
are recombinant
What are three major chemical differences between RNA and
DNA? - CORRECT ANSWERS- Ribose sugar instead of deoxyribose
Uracil (U) instead of Thymine (T)
Most RNAs are single stranded
Transcription generates a _____________ polarity RNA chain using
DNA as a template - CORRECT ANSWERS- 5'-to-3'
What enzyme catalyzes transcription? - CORRECT ANSWERS- RNA
polymerase
Promoters - CORRECT ANSWERS- DNA sequences that provide
the signal to RNA polymerase for starting transcription
,Terminators - CORRECT ANSWERS- RNA sequences that provide
the signal to RNA polymerase for stopping transcription
What are the two kinds of terminators in bacteria? - CORRECT
ANSWERS- Extrinsic - requires rho factor
Intrinsic - doesn't require additional factors, forms a hairpin loop
Sigma factor - CORRECT ANSWERS- Bacterial transcription
protein that increases RNA polymerase affinity to promoter but at
the same time decreases its affinity for the DNA
Core enzyme - CORRECT ANSWERS- RNA polymerase with
detached sigma factor
Where does RNA polymerase make strong conta - CORRECT
ANSWERS- -10 and -35 upstream of the beginning of
transcription.
Exons - CORRECT ANSWERS- Sequences found in a gene's DNA
and mature mRNA
What are the types of RNA processing of transcripts that occur in
eukaryotes but do not occur in prokaryotes? - CORRECT
, ANSWERS- Modificaiton of 3' and 5' ends (5' methylates caps & 3'
polyA tails)
Deleted block of information within the mRNA sequence (splicing
of introns)
Introns - CORRECT ANSWERS- Sequences found in DNA but not in
mRNA
Alternative splicing - CORRECT ANSWERS- The splicing of pre-
mRNA in more than one way to create two or more different
polypeptides
Primary transcript - CORRECT ANSWERS- The initial RNA molecule
synthesized by RNA polymerase that contains both introns and
exons
mRNA splicing is catalyzed by the ______________________ -
CORRECT ANSWERS- spliceosome
Genetic code - CORRECT ANSWERS- The nucleotide triplets of
DNA and RNA molecules that carry genetic information in living
cells.
Codon - CORRECT ANSWERS- A sequence of three nucleotides
that together form a unit of genetic code in a DNA or RNA
molecule.
BSC 315, 2025/2026 WITH
CORRECT/ACCURATE ANSWERS
Describe the four phenotypic classes that occur in the F2 progeny
of F1 dihybrids - CORRECT ANSWERS- Two are parental and two
are recombinant
What are three major chemical differences between RNA and
DNA? - CORRECT ANSWERS- Ribose sugar instead of deoxyribose
Uracil (U) instead of Thymine (T)
Most RNAs are single stranded
Transcription generates a _____________ polarity RNA chain using
DNA as a template - CORRECT ANSWERS- 5'-to-3'
What enzyme catalyzes transcription? - CORRECT ANSWERS- RNA
polymerase
Promoters - CORRECT ANSWERS- DNA sequences that provide
the signal to RNA polymerase for starting transcription
,Terminators - CORRECT ANSWERS- RNA sequences that provide
the signal to RNA polymerase for stopping transcription
What are the two kinds of terminators in bacteria? - CORRECT
ANSWERS- Extrinsic - requires rho factor
Intrinsic - doesn't require additional factors, forms a hairpin loop
Sigma factor - CORRECT ANSWERS- Bacterial transcription
protein that increases RNA polymerase affinity to promoter but at
the same time decreases its affinity for the DNA
Core enzyme - CORRECT ANSWERS- RNA polymerase with
detached sigma factor
Where does RNA polymerase make strong conta - CORRECT
ANSWERS- -10 and -35 upstream of the beginning of
transcription.
Exons - CORRECT ANSWERS- Sequences found in a gene's DNA
and mature mRNA
What are the types of RNA processing of transcripts that occur in
eukaryotes but do not occur in prokaryotes? - CORRECT
, ANSWERS- Modificaiton of 3' and 5' ends (5' methylates caps & 3'
polyA tails)
Deleted block of information within the mRNA sequence (splicing
of introns)
Introns - CORRECT ANSWERS- Sequences found in DNA but not in
mRNA
Alternative splicing - CORRECT ANSWERS- The splicing of pre-
mRNA in more than one way to create two or more different
polypeptides
Primary transcript - CORRECT ANSWERS- The initial RNA molecule
synthesized by RNA polymerase that contains both introns and
exons
mRNA splicing is catalyzed by the ______________________ -
CORRECT ANSWERS- spliceosome
Genetic code - CORRECT ANSWERS- The nucleotide triplets of
DNA and RNA molecules that carry genetic information in living
cells.
Codon - CORRECT ANSWERS- A sequence of three nucleotides
that together form a unit of genetic code in a DNA or RNA
molecule.
