Question

1. Interrupted coding sequences include long sequences of bases that
   do NOT code for amino acids. These noncoding sequences, called ________, are found in ________ cells.

1. exons; prokaryotic
2. introns; prokaryotic
3. exons; eukaryotic
4. introns; eukaryotic
5. none of these are correct

2. Which of the following is TRUE about cytoplasmic inheritance?

1. It refers to chromosomal genes.
2. It is independent of the gender of the parent.
3. It follows Mendel’s law of segregation.
4. It originates from plasmids in the cytoplasm.
5. It is based on the widely different amount of cytoplasm that male and female parents provide when gametes are formed.

3. Aneuploidy describes

1. a phenomenon that only occurs in plants.
2. a condition in which an extra chromosome is present or one is absent.
3. a disomy in somatic cells.
4. an uncommon condition in humans.
5. a mutation with a beneficial effect.

4. If cultured normal human cells are treated with telomerase, the cells are most likely to

1. undergo more cell divisions than normal.
2. undergo fewer cell divisions than normal.
3. die almost immediately.
4. undergo more active gene expression.
5. enter meiosis.

5. Which of the following are produced by meiosis?

1. haploid cells
2. eggs
3. sperm
4. plant spores
5. all of these

6. A mutation that replaces one amino acid in a protein with another is called a ________ mutation.

1. frameshift
2. recombinant
3. nonsense
4. missense
5. neutral

7. In a repressible operon under negative control, the repressor protein functions to

1. stimulate transcription in the presence of a corepressor.
2. turn off transcription in the presence of an inducer.
3. stimulate transcription in the presence of a coactivator.
4. turn off transcription in the presence of a corepressor.
5. It doesn’t function in this situation.

8. Which of the following is TRUE about X-linked recessive genetic diseases?

1. They affect more males than females.
2. They affect more females than males.
3. The disease phenotype is not gender correlated.
4. Males may have the corresponding allele on the Y chromosome.
5. An individual with two copies of the gene may not be symptomatic for the given disease.

9. Bacterial gene regulation occurs mainly at the ________ level.

1. translational
2. transcriptional
3. posttranscriptional
4. feedback inhibition
5. posttranslational

10. Mitosis results in two daughter cells. When comparing the genetic information of the parent cell with that of the two daughter cells,

1. all three are identical.
2. the two daughter cells are identical but slightly different from the parent cell.
3. all three are slightly different.
4. the parent cell and one daughter cell are identical, while the second daughter cell is slightly different.
5. outcome patterns vary.

11. What purpose do restriction enzymes play in bacterial cells?

1. They prevent the overproduction of mRNA in the bacterial cell.
2. They attack bacteriophage DNA when it enters the cell.
3. They promote bonding of the RNA polymerase to the promoter.
4. They limit the rate of bacterial replication.
5. They connect Okazaki fragments.

12. One of the mRNA codons specifying the amino acid leucine is
    5’–CUA–3’. Its corresponding anticodon is

1. 5’–GAT–3’.
2. 3’–AUC–5’.
3. 3’–GAU–5’.
4. 3’–GAT–5’.
5. 5’–GAU–3’.

13. An operon is

1. a repressor that binds to a promoter.
2. a molecule that switches a gene off or on.
3. a gene that cannot be repressed or enhanced.
4. a functional unit of promoter, operator, and structural genes in bacteria.
5. none of the above.

14. If the two genes are unlinked, an organism with the genotype of AaBb can produce gametes containing

1. either Aa or Bb.
2. AB, Ab, aB, or ab.
3. AaBb.
4. AB or ab.
5. none of the above.

15. Which of the following is NOT correct about miRNA?

1. It is involved with posttranscriptional regulation in eukaryotes.
2. It leads to one type of RNA interference.
3. Its name is derived from “mitochondrial RNA.”
4. It binds to a complementary mRNA sequence.
5. It is found in many different organisms, and can silence gene expression.

16. A densely staining region of highly compacted chromatin is known as ________ and is generally________.

1. heterochromatin; not transcribed
2. homochromatin; not transcribed
3. histone-dependent chromatin; transcribed
4. primary chromatin; transcribed
5. euchromatin; not transcribed

17. Which of the following is TRUE about DNA methylation?

1. Genes are silenced through methylation of all four bases.
2. It is a method of translational regulation.
3. It can silence large groups of genes.
4. It is common in most prokaryotes.
5. It leads to genomic imprinting, which is reversible.

18. Retroviruses make ________ by the process of ________.

1. RNA copies of DNA; reverse transcription
2. DNA copies of RNA; reverse transcription
3. genetic probes; Southern blotting
4. genetic probes; Northern blotting
5. telomerase; mutagenesis

19. In DNA replication, the ________ strand grows towards the replication fork, while the ________ strand grows away from
    the replication fork.

1. mRNA; leading
2. leading; lagging
3. leading; template
4. lagging; template
5. lagging; leading

20. Which of the following is not necessarily related to tumour formation?

1. an overactive MYC gene
2. proto-oncogenes
3. inactive tumour-suppressor genes
4. cell de-differentiation
5. metastasis

21. The total number of unique, three-base combinations of the four nucleic acid bases in DNA is

1. 12.
2. 16.
3. 20.
4. 64.
5. 256.

22. The purpose of cloning is

1. to sequence a particular gene.
2. to obtain large numbers of a particular gene.
3. to obtain plasmids with a variety of genes.
4. to insert genes into plasmids
5. all of the above.

23. Which of the following is NOT correct for PCR?

1. It produces large amounts of DNA in a host, usually a bacterium.
2. It requires the presence of primers.
3. It can produce DNA from the root of a single human hair.
4. Some steps are carried out at high temperatures.
5. It works with a heat resistant DNA polymerase.

24. Which of the following pairs of molecules alternate to form the backbone of a polynucleotide chain?

1. adenine and thymine
2. cytosine and guanine
3. sugar and phosphate
4. base and sugar
5. base and phosphate

25. Which of the following is FALSE concerning the human genome?

1. It contains about 25,000 genes.
2. It contains about 3.2 billion base pairs.
3. Only 2% of the genome codes for proteins.
4. It has very few introns.
5. 25,000 genes may produce up to 100,000 proteins.

26. Which of the following terms is not related to histones?

1. chromosomes
2. proteins
3. prokaryotes
4. nucleosomes
5. solenoid

27. Generation time refers to

1. the number of years it takes for a generation to die.
2. the amount of time required to replicate the DNA in a cell.
3. the time it takes to complete one cell cycle.
4. the time required for an individual in a species to achieve sexual maturity.
5. the time it takes for meiosis to go to completion.

28. Two chains of DNA must run in ________ direction(s) and must be ________ in order to bond with each other.

1. the same; uncomplementary
2. opposite; uncomplementary
3. parallel; uncomplementary
4. parallel; complementary
5. antiparallel; complementary

29. The inducer of the lactose operon in E. coli is

1. CAP.
2. cAMP.
3. allolactose.
4. glucose.
5. galactose.

30. Codons refer to triplet base sequences in the

1. mRNA.
2. nontemplate strand of DNA.
3. template strand of DNA.
4. tRNA.
5. rRNA.

Answer 1

Answer 1:

In eukaryotic cells, the DNA is arranged into exons and introns. The exons are coding regions, whereas the introns are non-coding regions of DNA. In prokaryotes, this arrangement is not found. Hence the correct choice should be (d) :

Interrupted coding sequences include long sequences of bases that do NOT code for amino acids. These noncoding sequences, called ____introns____, are found in ___eukaryotic_____ cells.

Answer 2:

Cytoplasmic inheritance is associated with the transmission of extra-nuclear genes. For example, plasmid, mitochondrial genes, etc. The correct choice should be:

(d) It originates from plasmids in the cytoplasm.

Answer 3:

Aneuploidy means the phenomenon by which a cell has an extra chromosome or a less chromosome. For example, having 45 or 47 chromosomes instead of 46 chromosomes in human cells.