Genetics multiple choice test sample - (Mar/20/2017 )

Hello fellow scientists,

I am studying for a first year undergraduate genetics exam, my teacher has provided us with 20 multiple choice questions as a very general preparation for the 60 MCQ in the exam.

I have done some of them already, while others are not as easy for me. I'm gonna post the whole test here anyways, if you know the answer to some of the questions feel free to post them. By no means I am asking you to solve the whole test. 

Thank you in advance, my classmates were not very helpful.

 

1. In the lac operon of Escherichia coli

 

A.    A null mutation in Lac I prevents expression of beta-galactosidase

B.    Mutations in Lac O result in constitutive expression of beta-galactosidase

C.    Lac O encodes a trans-acting factor

D.    The Lac I gene is constitutively expressed

E.    The Lac I gene is induced by allolactose

 

2. The analysis of morphogenesis in bacteriophage T4 showed that:

 

A.    Capsid assembly is a linear pathway

B.    Phage tails have to be made before phage heads

C.    Tail fibres are the last components to be added

D.    Heads are assembled before DNA is inserted into them

E.    Gene products are involved that are not included in the structure of the capsid

 

3. Gene therapy for the treatment of inherited disorders

 

1. Involves correction of mutant genes in human eggs, prior to fertilization.
2. Involves delivery of DNA to humans by inhalation of genetically engineered viruses
3. Has been used to treat haemophilia
4. Has been used to treat cystic fibrosis
5. Has been used to treat adenosine deaminase deficiency

 

4. In studies of human ancestry

 

1. Genetic markers on the Y-chromosome enable paternal descent to be inferred
2. Genetic variation in mitochondrial genomes enables paternal descent to be inferred
3. Genetic variation on the Y chromosome is more frequently the result of mutation than recombination
4. Genetic variation on autosomes is more frequently the result of recombination than mutation
5. Genetic markers on the X-chromosome were used to identify the descendants of Genghis Khan

 

5. In the early development of a zygote of Drosophila melanogaster:

 

1. The anterior/posterior axis is set up without maternal inputs
2. The genome of the zygote is not initially important
3. The dorsal/ventral axis is determined by gravity
4. The egg is asymmetrical before it is fertilised
5. Maternal information is needed to set up the left-right axis

6. Transposons

 

1. Are found in human genomes
2. Are mobile genetic elements
3. Do not contribute to evolutionary change
4. Cause mutant phenotypes that are always stably inherited
5. Do not occur in bacterial genomes

 

 

7. The transcription of protein-coding genes in eukaryotes

 

A.    Is inhibited by cycloheximide.

B.    Is inhibited by alpha-amanitin.

C.    Is carried out by RNA polymerase II

D.    Occurs only in the cell nucleus

E.    Can be analysed using promoter-reporter fusions.

 

8. The Lac operon of Escherichia coli is regulated:

 

A.    By altering the copy number of the lacZ gene

B.    By monitoring the availability of alternative sources of carbon

C.    At the level of translation

D.    By monitoring the concentration of allolactose

E.    By monitoring the availability of oxygen

 

9. Gene expression in eukaryotes may be regulated by:

 

A.    Changes in the number of copies of a gene contained in a cell

B.    Alteration of the structure of DNA/protein complexes in chromosomes

C.    Transcription factors

D.    Post-translational modification of proteins

E.    Mutation

 

10. Concerning 18S, 5.8S and 28S ribosomal RNA in eukaryotes

 

A.    They are transcribed separately

B.    They are encoded by genes in long tandem arrays

C.    They are co-translated

D.    They are produced by post-transcriptional cleavage

E.    They are encoded by genes located at centromeres

 

11. In autosomal recessive conditions, there is:

 

A.    A greater chance that females will be affected.

B.    A 50% chance that a carrier will pass on the affected allele to a child.

C.    A 50% chance that the unaffected sib of an affected child will be a carrier.

D.    A 25% chance that a child of two carrier parents will be affected by the condition.

E.    A 50% chance that an affected parent will pass on the condition to a child.

 

12. RNA splicing

 

A.    Involves the removal of introns.

B.    Requires the action of DNA ligase

C.    Involves the formation of 3'-5' phosphodiester bonds

D.    Involves the formation of 2'-5' phosphodiester bonds

E.    Occurs in the formation of ribosomal RNA

 

13: In the plant Arabidopsis thaliana:

1. Floral organ development has been studied using homoeotic mutations
2. Floral organ development is regulated by 4 genes, each expressed exclusively in the 4 whorls of the flower
3. Mutant plants deficient in the "B-function" have flowers that lack sepals
4. Mutant plants deficient in the "C-function" have flowers that produce additional whorls of petals
5. Complementation tests have been used to determine the numbers of genes that regulate floral organ development

 

14. Cystic fibrosis is a severe inherited disease caused by an autosomal recessive mutation on chromosome 7. In Caucasian populations, approximately 1 in 23 will be a heterozygous carrier.

 

1. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 500
2. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 2000
3. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 50
4. Carriers of the defective CF allele can be identified by PCR analysis
5. A standard approach to the control of CF is to sterilise carriers of the mutant allele

 

15. Concerning X-linked inheritance in humans:

 

1. Males have two X chromosome
2. There is no crossing over in males on any chromosome
3. Females are hemizygous for genes on the X chromosome
4. X-linked conditions are commoner in males than in females
5. Charcot-Marie-Tooth disorder is a sex-linked recessive condition

 

16.  In the fruit fly Drosophila melanogaster

 

A.    A fly carrying two mutant alleles of the bicoid gene does not show normal anterior-posterior development

B.    A fly whose father carried two mutant alleles of the bicoid gene does not show normal anterior-posterior development

C.    A fly whose mother carried two mutant alleles of the bicoid gene does not show normal anterior-posterior development

D.    A fly carrying two mutant alleles of the Antennipedia gene has legs in place of antennae

E.    A fly whose mother carries two copies of the Antennipedia  gene has legs in place of antennae

 

17. Concentration gradients of morphogenetic proteins

 

A.    Regulate cell fate in Caenorhabditis elegans

B.    Determine polarity in Drosophila melanogaster

C.    Determine polarity in Caenorhabditis elegans

D.    Regulate head assembly of bacteriophage T4

E.    Are set up by asymmetric distribution of mRNA in Drosophila embryos

 

18. Concerning human inherited conditions

 

A.    Red-green colour blindness is a sex-linked condition

B.    Male pattern baldness is a sex-linked condition

C.    All male offspring of females who carry the defective allele responsible for haemophilia will be haemophiliacs

D.    Heterozygotes carrying a single mutant allele of the gene associated with Huntington's disease will suffer from the disease.

E.    Severe combined immune deficiency can be treated by "gene therapy"

 

 

 

 

19. Amphibia such as salamanders have much larger genomes than most mammals because:

 

1. They have more heterochromatin
2. They are evolutionarily more advanced
3. They have more genes
4. They have bigger introns
5. They have more repetitive DNA

 

20. Promoter and regulatory sites in upstream regions of human genes may be located and analysed by

 

1. DNA fingerprinting
2. Promoter-reporter fusions expressed in cultured HeLa cells
3. Promoter-reporter fusions expressed in E. coli
4. DNA footprinting
5. RNA fingerprinting

So... what do you think and why?  The aim here is for you to learn by understanding, not by us telling you the answers.

bob1 on Mon Mar 20 16:14:00 2017 said:

So... what do you think and why?  The aim here is for you to learn by understanding, not by us telling you the answers.

That is what I thought, but I am asking for help, something that our teacher allows us to do, but if you think this is immoral you can definitely ignore the thread.

It's not a question of morality; it is about you learning/understanding. If you know some of the answers (as you say), then why don't you post them and why you think that is the answer? It may be that you are incorrect in your assumptions, or that there is an expanded answer that you would find useful, which we could then provide.

 

With your posit as it is, I could randomly assign letters and supply those as answers - and you could take those as the correct answer (or not), leaving you no better off... my aim was to help, but if you don't want help, then I'm happy to ignore this post.

bob1 on Mon Mar 20 17:12:47 2017 said:

It's not a question of morality; it is about you learning/understanding. If you know some of the answers (as you say), then why don't you post them and why you think that is the answer? It may be that you are incorrect in your assumptions, or that there is an expanded answer that you would find useful, which we could then provide.

 

With your posit as it is, I could randomly assign letters and supply those as answers - and you could take those as the correct answer (or not), leaving you no better off... my aim was to help, but if you don't want help, then I'm happy to ignore this post.

 

Ok, these are my answers, Green for true, Red for false.

 

1. In the lac operon of Escherichia coli

 

A.    A null mutation in Lac I prevents expression of beta-galactosidase

B.    Mutations in Lac O result in constitutive expression of beta-galactosidase

C.    Lac O encodes a trans-acting factor

D.    The Lac I gene is constitutively expressed

E.    The Lac I gene is induced by allolactose

 

2. The analysis of morphogenesis in bacteriophage T4 showed that:

 

A.    Capsid assembly is a linear pathway

B.    Phage tails have to be made before phage heads

C.    Tail fibres are the last components to be added

D.    Heads are assembled before DNA is inserted into them

E.    Gene products are involved that are not included in the structure of the capsid

 

3. Gene therapy for the treatment of inherited disorders

 

A.    Involves correction of mutant genes in human eggs, prior to fertilization.

B.    Involves delivery of DNA to humans by inhalation of genetically engineered viruses

C.    Has been used to treat haemophilia

D.    Has been used to treat cystic fibrosis

E.    Has been used to treat adenosine deaminase deficiency

 

4. In studies of human ancestry

 

1. Genetic markers on the Y-chromosome enable paternal descent to be inferred
2. Genetic variation in mitochondrial genomes enables paternal descent to be inferred
3. Genetic variation on the Y chromosome is more frequently the result of mutation than recombination
4. Genetic variation on autosomes is more frequently the result of recombination than mutation
5. Genetic markers on the X-chromosome were used to identify the descendants of Genghis Khan

 

5. In the early development of a zygote of Drosophila melanogaster:

 

1. The anterior/posterior axis is set up without maternal inputs
2. The genome of the zygote is not initially important
3. The dorsal/ventral axis is determined by gravity
4. The egg is asymmetrical before it is fertilised
5. Maternal information is needed to set up the left-right axis

 

6. Transposons

 

1. Are found in human genomes
2. Are mobile genetic elements
3. Do not contribute to evolutionary change
4. Cause mutant phenotypes that are always stably inherited
5. Do not occur in bacterial genomes

 

7. The transcription of protein-coding genes in eukaryotes

 

A.    Is inhibited by cycloheximide.

B.    Is inhibited by alpha-amanitin.

C.    Is carried out by RNA polymerase II

D.    Occurs only in the cell nucleus

E.    Can be analysed using promoter-reporter fusions.

 

 

 

8. The Lac operon of Escherichia coli is regulated:

 

A.    By altering the copy number of the lacZ gene

B.    By monitoring the availability of alternative sources of carbon

C.    At the level of translation

D.    By monitoring the concentration of allolactose

E.    By monitoring the availability of oxygen

 

9. Gene expression in eukaryotes may be regulated by:

 

A.    Changes in the number of copies of a gene contained in a cell

B.    Alteration of the structure of DNA/protein complexes in chromosomes

C.    Transcription factors

D.    Post-translational modification of proteins

E.    Mutation

 

10. Concerning 18S, 5.8S and 28S ribosomal RNA in eukaryotes

 

A.    They are transcribed separately

B.    They are encoded by genes in long tandem arrays

C.    They are co-translated

D.    They are produced by post-transcriptional cleavage

E.    They are encoded by genes located at centromeres

 

11. In autosomal recessive conditions, there is:

 

A.    A greater chance that females will be affected.

B.    A 50% chance that a carrier will pass on the affected allele to a child.

C.    A 50% chance that the unaffected sib of an affected child will be a carrier.

D.    A 25% chance that a child of two carrier parents will be affected by the condition.

E.    A 50% chance that an affected parent will pass on the condition to a child.

 

12. RNA splicing

 

A.    Involves the removal of introns.

B.    Requires the action of DNA ligase

C.    Involves the formation of 3'-5' phosphodiester bonds

D.    Involves the formation of 2'-5' phosphodiester bonds

E.    Occurs in the formation of ribosomal RNA

 

13: In the plant Arabidopsis thaliana:

 

1. Floral organ development has been studied using homoeotic mutations
2. Floral organ development is regulated by 4 genes, each expressed exclusively in the 4 whorls of the flower
3. Mutant plants deficient in the "B-function" have flowers that lack sepals
4. Mutant plants deficient in the "C-function" have flowers that produce additional whorls of petals
5. Complementation tests have been used to determine the numbers of genes that regulate floral organ development

 

14. Cystic fibrosis is a severe inherited disease caused by an autosomal recessive mutation on chromosome 7. In Caucasian populations, approximately 1 in 23 will be a heterozygous carrier.

 

1. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 500
2. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 2000
3. The likelihood of a (Caucasian) newborn infant having CF is approximately 1 in 50
4. Carriers of the defective CF allele can be identified by PCR analysis
5. A standard approach to the control of CF is to sterilise carriers of the mutant allele

 

15. Concerning X-linked inheritance in humans:

 

1. Males have two X chromosome
2. There is no crossing over in males on any chromosome
3. Females are hemizygous for genes on the X chromosome
4. X-linked conditions are commoner in males than in females
5. Charcot-Marie-Tooth disorder is a sex-linked recessive condition

 

16.  In the fruit fly Drosophila melanogaster

 

A.    A fly carrying two mutant alleles of the bicoid gene does not show normal anterior-posterior development

B.    A fly whose father carried two mutant alleles of the bicoid gene does not show normal anterior-posterior development

C.    A fly whose mother carried two mutant alleles of the bicoid gene does not show normal anterior-posterior development

D.    A fly carrying two mutant alleles of the Antennipedia gene has legs in place of antennae

E.    A fly whose mother carries two copies of the Antennipedia  gene has legs in place of antennae

 

17. Concentration gradients of morphogenetic proteins

 

A.    Regulate cell fate in Caenorhabditis elegans

B.    Determine polarity in Drosophila melanogaster

C.    Determine polarity in Caenorhabditis elegans

D.    Regulate head assembly of bacteriophage T4

E.    Are set up by asymmetric distribution of mRNA in Drosophila embryos

 

18. Concerning human inherited conditions

 

A.    Red-green colour blindness is a sex-linked condition

B.    Male pattern baldness is a sex-linked condition

C.    All male offspring of females who carry the defective allele responsible for haemophilia will be haemophiliacs

D.    Heterozygotes carrying a single mutant allele of the gene associated with Huntington's disease will suffer from the disease.

E.    Severe combined immune deficiency can be treated by "gene therapy"

 

19. Amphibia such as salamanders have much larger genomes than most mammals because:

 

1. They have more heterochromatin
2. They are evolutionarily more advanced
3. They have more genes
4. They have bigger introns
5. They have more repetitive DNA

 

20. Promoter and regulatory sites in upstream regions of human genes may be located and analysed by

 

1. DNA fingerprinting
2. Promoter-reporter fusions expressed in cultured HeLa cells
3. Promoter-reporter fusions expressed in E. coli
4. DNA footprinting
5. RNA fingerprinting

 

Some are incomplete, you can ignore those. Thank you very much for this

Well, and now those you are not sure of, try to explain how far did you go in finding answers for them. Take it maybe by a single question.
For example 6. Transposons, why are you not able to select correct and incorrect answers, did you read some textbook containing some information about transposones?

Are you unsure about some of the statements? Why? Plase elaborate.

We can help you by guiding to correct answer, but for example in this case, you can open even wikipedia and be able to decide already. So either you don't no a think about them, so you should look it up, or you did, but you are not sure. With that, we can help.