All AP Biology Resources
Example Questions
Example Question #72 : Central Dogma
What is the process in which the DNA molecule separates into two strands then produces two new complementary strands following the rules of base pairing.
Reformation
Translation
Transcription
Replication
Replication
Replication is the process in which the DNA molecule produces two new complementary strands. Transcription produces a messenger RNA, and translation produces a chain of amino acids that become a protein.
Example Question #37 : Understand Steps Of Replication
What is the primary enzyme involved in DNA replication?
DNA polymerase
ATP synthase
Transciptase
RNA polymerase
DNA polymerase
DNA polymerase is the primary enzyme involved in DNA replication. It is responsible for adding nucleotides to the growing DNA chain in the 5' to 3' direction. This enzyme also has proofreading functionality, which allows it to remove nucleotides that are mispaired in the 3' to 5' direction and replace them with the correct nucleotide.
Example Question #38 : Understand Steps Of Replication
What DNA fragment would complement 5’ ATCGGTCAAT 3’ ?
5’ TAGCCAGTTA 3’
5’ GCTAACTGGC 3’
3’ ATCGGTCAAT 5’
3’ TAGCCAGTTA 5’
3’ GCTAACTGGC 5’
3’ TAGCCAGTTA 5’
The correct answer must complementary base pair with the fragment in the 3’ to 5’ direction because the strands run anti-parallel to each other. Only three of the given options that will run anti-parallel, but only one complements the DNA properly.
Example Question #2351 : Ap Biology
In DNA replication, which enzyme is responsible for separating the two strands of DNA apart?
Polymerase III
Helicase
Polymerase I
Single-stranded binding proteins
Primase
Helicase
The correct answer is Helicase because it is involved with the separation of the two strands of DNA by breaking the hydrogen bonds between them. Primase lays down the RNA primer so that the polymerase enzymes can attach and start adding complementary base pairs. SSBs are single stranded binding proteins which anchor the separated strands and keep them from annealing to each other.
Example Question #2352 : Ap Biology
A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.
in the rough endoplasmic reticulum
by ribosomes on the nuclear envelope
by free cytoplasmic ribosomes
in the mitochondria
in the plasma membrane
in the rough endoplasmic reticulum
The primary function of the ribosomes bound to the rough endoplasmic reticulum is to synthesize proteins for transport to the cell exterior or extracellular matrix. These ribosomes produce polypeptides that are packaged into vesicles by the Golgi apparatus and transported to the membrane. The vesicle then fuses with the membrane, either releasing proteins out of the cell or incorporating them into the cell membrane.
Nuclear ribosomes synthesize replication and transcription proteins into the nucleus, while cytoplasmic ribosomes produce cytoplasmic proteins.
Example Question #2353 : Ap Biology
Which of the following steps of DNA replication is inaccurate?
The enzyme topoisomerase creates breaks in the DNA backbone
A replication bubble with two replication forks is formed
The DNA strands are separated by the enzyme helicase
The primase enzyme lays down RNA primers
Okazaki fragments are joined by DNA polymerase
Okazaki fragments are joined by DNA polymerase
During DNA replication, helicase is responsible for unwinding the DNA helix and topoisomerase cleaves portions of the sugar-phosphate backbone to release tension in the strands. DNA polymerase then enters the replication bubble created by helicase. The bubble has two sides, each with a leading strand and a lagging strand. The leading strand at one side of the bubble is the lagging strand at the other, since DNA is anti-parallel. DNA polymerase can only synthesize in the 5'-to-3' direction; the strand oriented in the 3'-to-5' direction at the replication fork is known as the lagging strand since it must be replicated in pieces in the reverse direction. These pieces are known as Okazaki fragments.
DNA ligase is the protein responsible for fusing breaks in the sugar-phosphate backbone. It repairs the bonds broken by topoisomerase and creates phosphodiester bonds between Okazaki fragments.
Example Question #2354 : Ap Biology
What is heterochromatin?
DNA that cannot be transcribed
DNA that is not being translated
DNA that is being translated
DNA that can be transcribed
DNA that cannot be transcribed
Heterochromatin is “dark” chromatin that represents DNA that is not active in transcription. The fact that it is “dark” implies that it is condensed and inaccessible by polymerases. Heterochromatin is created when DNA is tightly wound around histones. This tight winding prevents transcription proteins from interacting with the DNA. Heterochromatin is most common in the nucleus during mitosis, when no transcription is taking place. In contrast, euchromatin is capable of being transcribed and is most common during interphase, when most cellular growth and production occurs.
Translation occurs outside of the nucleus and uses mRNA as a template, not DNA.
Example Question #1 : Understanding Prokaryotic Genes
What is the main difference between prokaryotic and eukaryotic genes?
Prokaryotic genes only have exons, but eukaryotic genes have exons and introns
Prokaryotic genes are not replicated, and only transcribed to RNA to then become protein
Prokaryotes have one large gene, but eukaryotes have many smaller genes
Prokaryotes do not have gene regulatory sequences, but eukaryotes do
Eukaryotes stores genes together in operons, but prokaryotes do not
Prokaryotic genes only have exons, but eukaryotic genes have exons and introns
The correct answer is that prokaryotes only have exons, whereas eukaryotes have exons and introns. As a result, in eukaryotes, when mRNA is transcribed from DNA, the introns have to be cut out of the newly synthesized mRNA strand. The exons, or coding sequences, are then joined together. Prokaryotes do not have to process their mRNA to this extent.
Example Question #1 : Understanding Prokaryotic Genes
A segment of prokaryotic DNA that binds transcription factors, usually as repressors that prevent transcription, are best known as __________.
Promoters
Exons
Untranslated regions
Enhancers
Operators
Operators
The correct answer is operator. In most operons, repressors bind operators to prevent transcription of downstream genes.
Promoters are sequences of DNA upstream of genes that usually promote transcription by recruiting polymerases and other transcription factors. Enhancers are distant DNA sequences that promote transcription, whereas exons are the coding segments of a gene.
Example Question #1 : Understand Regulation Of Transcription
What is the function of RNA polymerase in prokaryotes?
Transcribe RNA from a DNA template
Translate RNA to protein
None of the other answers
Replicate DNA during cell division
Repress transcription by binding operators
Transcribe RNA from a DNA template
The correct answer is transcribe RNA from a DNA template. RNA polymerases are DNA-dependent, meaning that they require a DNA template; however, the new daughter strand that they create is composed of RNA. This RNA will then be translated into a functional protein by prokaryotic ribosomes.
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