MB C7 Self Quiz

tokia's version from 2016-04-29 03:59


Question Answer
5. Semiconservative replicationeach chromosome consists of one strad old (parental) and one of newly synthesized DNA
AnticodonThree bases that are complementary to a particular mRNA codon
TranslationProduction of polypeptide chain from the RNA template
Replication forkPoint where the helix separates during DNA replication
TranscriptionmRNA synthesized from a DNA template
Okazaki fragmentRNA-primed short discontinously synthesized DNA fragment known as the lagging strand
6. From the DNA template sequence 3-ATGCAGTAG-5.What is the complementary messenger RNA sequence transfer RNA anticodon sequences and corresponding amino acids...Is there a terminator (nonsense) codon in the sequence...If so what is itmRNA=UACGUCAUC;tRNA anticodons=ATG...CAG...UAG;amino acids=methionine...glutamine...stop;There is a terminator (nonsense) codon=AUC
7. What type of RNA is involved in protein synthesismRNA


Question Answer
8. What type of RNA carries and transfers amino acids from the cytoplasm to the ribosome for placement in the synthesis of a polypeptide chaintransfer RNA
9. What type of RNA carries the genetic information required for protein synthesisMessenger RNA
10. What is the significance of the presence of mechanisms to regulate metabolismIn their evolution bacteria and all other organisms have developed mechanisms to turn reactions on and off in accordance with their needs.All cells try to limit their waste of energy and materials.Control mechanisms have evolved to regulate metabolic activity so as to produce only what is needed ot to squander energy and not to excessively produce wasteful amounts of enzymes and materials
11. What factors distinguish the two basic regulatory mechanismsThe mechanisms that control metabolism either regulate pre-existing enzyme directly or regulate the synthesis of an enzyme by turning on or off the corresponding gene that codes for the particular enzyme


Question Answer
12. Enzyme repressionPresence of a synthetic product inhibits its further synthesis by inactivating its operon
Feedback inhibitionEnd product of a biochemical pathway directly inhibits the first enzyme in the pathway
Catabolite repressionPresence of preferred nutrient represses synthesis of enzymes that would be used to metabolize an alternative substance
Enzyme inductionPresence of a substrate induces the activation of a gene which produces the corresponding enzyme
RepressorA protein that binds to the operator preventing transcription of adjacent genes
OperonSequence of closely associated genes and regulatory sites that regulate enzyme production


Question Answer
13. InducerLactose
Place where repressor binds to shut off operonOperator
Substance that binds to promoter site to start transcriptionRNA polymerase
Combines with repressor to keep operon "on"Lactose
Z...Y...A...Structural genes
May be located some distance from the operon and is not under control of the promoterRegulator gene
Protein that binds to operator preventing transcription of structural genesRepressor
14. Bacteria typically use repression to controlAnabolic pathways
15. Catabolite repression is regulated by the concentration ofGlucose
16. Two daughter cells would inherit which of the following changes from the parent cella change in chromosomal DNA


Question Answer
17. A frameshift mutation occurs following theInsertion of one base...Insertion of more than one base...Deletion of one base...Deletion of more than one base
18. Radiation causes damage by causing the formation of dimers ofCytosine and thymidine
19. The antibiotic streptomcin inhibits bacterial growth by binding to a protein in the 30S (subunit) of the ribosome.Based on this information streptomycin inhibitsTranslation in prokaryotes
20. Suppose a point mutation occured in the third position of a codon in a DNA template coding for a protein changing it from TTT to TTC.What would be the consequences of this mutationThere would be no change in the amino acid at this position because of the redundancy of the genetic code.Such point mutations are known as "silent mutations" because although the genotype is different the phenotype remains the same


Question Answer
21. The sequence of bases in DNA can be altered by chemical mutagens.These cause changes byActing as base analogs and being incorporated into DNA...Adding methyl grops to bases leading to error in base paring...Removing an amino group from a base...BEing inserted into double-stranded DNA
22. Why are bacteria useful in the study of mutationsMicroorganisms are useful in the study of mutations because of their short generation times and their relatively low expense inmaintaining large population of mutant organisms
How do spontaneous and induced mutations differA spontaneous mutation is a random mutation that occurs in the absence of any agent known to cause changes in DNA.Induced mutations are produced by agents called mutagens that increase the mutation rate above the spontaneous mutation rate
What two tests are used to distinguish between the spontaneity or induction of a mutation and how do they workThe fluctuation test demonstrates that resistance to chemical substances occurs spontaneously rather than being induced.Replicating does the same as the fluctuation test but in addition allows one to isolate mutant bacterial colonies without exposing them to the substance to which they are resistant
What is the Ames test and what is it used forThe Ames test is used to detect the ability od auxotrophic bacteria to revert back to their original sinthetic ability. The etst is used for screening chemicals which may be mutagens;this may indicate their potential for being carcinogenic in man


Question Answer
23. DNA damage in the form of dimers induced byUV light can be paired by many bacteria using photoreactivation which occurs when the bacteria get back into the presence of visible light or by dark repair hich can occur in the presence or absence of visible light and requires several controlled reactionslight repair...enzyme-controlled
24. Which of the following is NOT associated with prokaryotic cellsIntrons and exons
25. The process used in the laboratory to produce millions of copies of DNA isPolymerase chain reaction...(PCR)
26. Name and the describe the effects of the following mutations (a)frameshift (b)print (c) frameshift