Gene regulation and gene mutation 22.5.15

Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

regulation and mutation:

regulation and mutation Daily Test 4 – 22.5.15

1:

1 . Which of the following is likely to be expressed? A) euchromatin B) heterochromatin C) DNA without methyl groups D) DNA with many methyl groups E) euchromatin and DNA without methyl groups is more likely to be expressed

2:

2 Which of the following is a method of posttranscriptional control? A) transcription factors B) the life span of a mRNA molecule C) differential processing of mRNA D) how fast the mRNA leaves the nucleus E) both differential processing and how fast mRNA leaves the nucleus are involved in posttranscriptional control.

3:

3 Which gene in an operon is incorrectly matched with its function? A) promoter--where RNA polymerase first binds to DNA B) regulator--binds to the repressor protein C) structural--makes mRNA by transcription D) operator--if unbound, allows RNA polymerase to bind to DNA E. All of these are correctly matched

4:

4 Which statement is NOT correct about the lac operon ? A) It regulates the production of a series of five enzymes. B) It is normally turned off if glucose is present. C) Lactose binds to the repressor protein and inactivates it. D) It is an inducible system. E) The structural genes make products that allow lactose metabolism.

5:

5 Which statement is NOT correct about the trp operon ? A) The structural genes make products that act in a metabolic pathway to produce tryptophan. B) It is normally turned off if tryptophan is present. C) Tryptophan acts as the corepressor . D) The regulator gene product is inactive by itself. E) Tryptophan binds to the repressor protein and inactivates it.

6:

6 Which statement is NOT true about genetic control in prokaryotes? A) RNA polymerase must bind to a promoter on the DNA to begin RNA synthesis. B) Most gene expression is regulated at the level of translation. C) An active repressor protein keeps RNA polymerase from binding to DNA. D) Structural genes produce enzymes that act in a metabolic pathway. E) Repressors control gene transcription by binding to operator sites.

7:

7 The universal regulatory mechanism in eukaryotes for controlling gene expression includes A) control of the genes transcribed and the rate they are transcribed. B) control of the processing of mRNA after it is transcribed from DNA but before it leaves the nucleus, and control of the rate it leaves the nucleus. C) control of mRNA in the cytoplasm after it leaves the nucleus, including changes to mRNA before translation begins. D) control of polypeptides after they have been synthesized but before they are functional. E) All of these mechanisms are used; there is no single universal mechanism.

8:

8 The first level of primary control in eukaryotic gene activity is _______ control. A) feedback B) translational C) transcriptional D) posttranscriptional E) posttranslational

9:

9 Which level of primary control in eukaryotic gene activity involves the life span of the mRNA molecule and the ability of the mRNA to bind to ribosomes ? A) feedback control B) translational control C) transcriptional control D) posttranscriptional control E) posttranslational control

10:

10 Which level of primary control in eukaryotic gene activity involves processing early RNA transcripts to mRNA and control of the rate at which mRNA leaves the nucleus? A) feedback control B) translational control C) transcriptional control D) posttranscriptional control E) posttranslational control

11:

11 Which level of primary control in eukaryotic gene activity involves changes in the polypeptide chain before it becomes functional? A) feedback control B) translational control C) transcriptional control D) posttranscriptional control E) posttranslational control

12:

12   14. A form of active chromatin might also be referred to as A) a Barr body. B) heterochromatin. C) a chromosome. D) euchromatin . E) None of these

13:

13 An enhancer site is A) part of an operon . B) found only in prokaryotes. C) located at a distance from the gene it affects. D) an attachment site for RNA polymerase. E) the location of transposons

14:

14 A form of gene regulation that occurs while RNA is still in the nucleus is A) differential intron removal and splicing. B) feedback control. C) binding of the repressor protein to DNA. D) enzymatic cleavage of a polypeptide. E) rate of binding to ribosomes .

15:

15 "Jumping genes" that have the ability to move within and between chromosomes are called A) introns . B) oncogenes . C) transposons . D) retroviruses. E) exons .

16:

16 A deletion of one base pair that alters the sequence of codons , as the loss of "A" in C-C-G-T-A-G-C... to form C-C-G-T-G-C... is called a(an) A) transposon . B) point mutation. C) carcinogen. D) oncogene . E) frameshift mutation.

17:

17 All of these are considered carcinogens EXCEPT A) cigarette smoke. B) ultraviolet light. C) cabbage and related vegetables. D) X-rays. E) mold-produced aflatoxin .

18:

18 21. An oncogene is A) a viral gene with no relation to the host cell's genes. B) a mutated form of a proto-oncogene. C) a bacterial gene that causes cancer in the host. D) always seen in human cancer cells. E) a gene that turns off cellular reproduction.

19:

19 . You are more likely to develop some forms of cancer if you: A) are exposed to higher doses of radiation including X rays. B) are exposed to carcinogens. C) have a high incidence of cancer in your family history leading to your hereditary lineage. D) are exposed to ultraviolet light. E) All of the choices are correct.

20:

20 . The ______ are associated with breast cancer as well as a substantial proportion of ovarian cancers. A) p53 gene B) BRCA1 and BRCA2 genes C) ras oncogene D) bcl-2 protein E) RB tumor-repressor gene

21:

21 The ______ stimulate(s) apoptosis. A) p53 gene B) BRCA1 and BRCA2 genes C) ras oncogene D) bcl-2 protein E) RB tumor-repressor gene

22:

22 Malfunction in the ____ is involved in retinoblastoma. A) p53 gene B) BRCA1 and BRCA2 genes C) ras oncogene D) bcl-2 protein E) RB allele

23:

23 A Barr body A) is only found in female cells. B) is due to an inactivated X chromosome. C) has the genes contained therein suppressed. D) is in the heterochromatin form E) All of the choices are correct.

24:

24 In transcriptional control in eukaryotic cells A) a different combination of DNA binding proteins (transcriptional factors) may regulate the activity of a particular gene. B) enhancers may be involved in the promotion as well as regulation of gene transcription. C) may be due to the phosphorylation of transcriptional factors by a kinase . D) enhances may be some distance from the promotor sites they control. E) All of the choices are correct.

25:

25 Transposons A) are specific DNA sequences that move within and between chromosomes. B) alter the expression of neighboring genes especially if the transposon is a regulator gene. C) have been discovered in corn, fruit flies, bacteria, and humans. D) compose a significant portion of the human genome. E) All of the choices are correct.

26:

26 Point mutations A) are due to a change in one DNA nucleotide. B) are a change in a specific codon . C) can cause a genetic disease such as sickle cell disease that is due to a base change that codes for valine rather than glutamate. D) may have no effect on an organism. E) All of the choices are correct.

27:

27 Frameshift mutations A) can occur when one or more nucleotides are inserted into a DNA sequence. B) can result in a completely new codon sequence that results in the production of non-functional proteins. C) applies to the reading frame (sequence of codons ) being changed. D) can occur when one of more nucleotides is deleted from a DNA sequence. E) All of the choices are correct.

28:

28 The portion of the DNA labeled “b” represents the A) promoter site B) operator site C) regulator gene D) repressor protein E) CAP site

29:

29 The portion of the DNA labeled “d” represents the A) promoter site B) operator site C) regulator gene D) repressor protein E) CAP site

30:

30 The repressor is labeled A) a B) b C) c D) d E) e

Answer key:

Answer key 1-e 2-e 3-b 4-a 5-e 6-b 7-e 8-c 9-b 10-d 11-e 12-d 13-c 14-a 15-c 16-e 17-c 18-b 19-e 20-b 21-a 22-e 23-e 24-e 25-e 26-e 27-e 28-c 29-b 30-e

authorStream Live Help