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Protein Synthesis
Regulation of Gene Expression
DNA Replication
Mutations
Misc/Review
100
What parts of the cell are involved in protein synthesis?
Nucleus, Ribosomes, Endoplasmic Reticulum, Golgi Bodies
100
What would happen if the repressor of an inducible operon were mutated so that it could not bind to the operator? a. irriversible binding of the prepressor to the promoter b. reduced transcription of the operon's genes c. buildup of a substrate for the pathway controlled by the operon d. continuous transcription of the operon's genes.
What is D
100
If a DNA has 27 % of its bases as A, then what are the percentages of the rest of its' bases?
27 % T, 23% C, 23% G.
100
Why are silent mutations called silent?
They are changes that result in the production of the same amino acid.
100
How can cells have the same DNA sequence yet produce different proteins?
What is differential gene expression
200
How does a a cell know where to start reading the DNA?
It looks for the TATA box and transcription factors.
200
Which of the following is an example of post-transcriptional control of gene expression? a. The addition of methyl groups to cytosine bases of DNA b. the binding of transcription factors to a promoter c. the removal of introns and the splicing together of exons d. the folding of DNA to form heterochromatin
What is C
200
What is the purpose of helicases?
Enzymes that untwist the double helix at replication forks.
200
In certain phages and bacteria, there is a recombination system that specifically promotes the mutation of a DNA fragment. These mutation events appear to act as genetic switches allowing the alternate expression of different sets of genes which, in general, code for surface proteins. A rearrangement in the linear sequence of genes as shown in the diagram is known as ABCDEF. . . / ABDCEF. . . A) duplication B) deletion C) inversion D) translocation
What is C
200
What controls whether a gene is expressed in a cell?
What are transcription factors, activators, or repressors
300
How is mRNA modified before it leaves the nucleus?
It receives a 5' cap and a poly-A tail.
300
What happens when SiRNA or miRNA bind to mRNA?
The target mRNA is broken apart or not allowed to be translated.
300
Why does DNA replication create a leading strand and a lagging strand?
DNA can only be created in the 5'-3' direction, so the 3' - 5' direction is created in okazaki fragments.
300
Why are insertion and deletion called frameshift mutations?
They change the order of all of the codons afterwards.
300
Repressible operons are usually involved in what type of pathways?
What are anabolic pathways
400
Which of the following mutations would be "most" likely to have a harmful effect on an organism? A) a nucleotide-pair substitution B) a deletion of three nucleotides near the middle of a gene C) a single nucleotide deletion in the middle of an intron D) a single nucleotide deletion near the end of the coding sequence E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence
What is E
400
What is ubiquitin, and how does it help in post-transcriptional processing?
A small protein that the cell attaches to proteins that it wants to get rid of. Proteasomes then break the proteins apart.
400
What are telomeres and what do they do?
multiple repetitions of one short DNA sequence that protect the ends of genes.
400
What is the difference between missense and nonsense mutations.
Missense changes one amino acid to another. Nonsense causes translation to stop.
400
Why are very few lactose-utilizing enzymes produced, when lactose and glucose are present?
What is RNA polymerase has a low affinity for the lac promoter because CAP only binds to DNA in the absence of glucuse
500
What is the purpose of the spliceosome?
To remove introns (non-coding regions) and join exons.
500
What is one way that the cell modifies access to chromatin?
Acetlyation or methylation
500
What was the purpose of the experiment performed by Alfred Hershey and Martha Chase?
What is to test whether protein or DNA was the genetic material of phage T2
500
Sickle-cell anemia is caused by a single point mutation in DNA, causing valine to be translated instead of glutamic acid. Why is the structure of sickle-cell hemoglobin so different than wild-type hemoglobin, even though only one amino acid has been changed?
What is a hydrophobic amino acid is substituted for a hydrophilic amino acid, causing the hemoglobin to crystallize and form fibers
500
What does the concentration of bicoid mRNA to the anterior end of a fruit-fly determine?
What is the formation of head-specific structures