Free Biotechnology MCQs with Answers

• A. has been copied many times in a test tube
• B. has been joined together from two different sources
• C. has lost one of its two strands
• D. has been broken down into nucleotides

Explanation: A gene cut from one organism is inserted into the DNA of another, usually a bacterial plasmid, so the molecule carries sequences that…

• A. cut DNA at a specific base sequence, often leaving sticky ends
• B. join two DNA fragments together
• C. translate mRNA into protein
• D. unwind the double helix during replication

Explanation: Each enzyme recognises its own short palindromic sequence and cuts both strands there, and a staggered cut leaves short single stranded…

• A. restriction endonuclease
• B. reverse transcriptase
• C. DNA ligase
• D. helicase

Explanation: Sticky ends pair by hydrogen bonds only, which is not strong enough to hold, so ligase forms the covalent phosphodiester bonds in the…

• A. a ribosome
• B. a mitochondrion
• C. a molecule of messenger RNA
• D. a plasmid

Explanation: A plasmid is a small circular piece of DNA separate from the bacterial chromosome that replicates on its own and can be taken up from the…

• A. genetically engineered bacteria carrying the human insulin gene
• B. extraction from the pancreas of cattle and pigs
• C. chemical synthesis from amino acids in a factory
• D. collecting it from the urine of healthy donors

Explanation: The human gene is inserted into a bacterium such as Escherichia coli, which is then grown in a fermenter and makes insulin identical to…

• A. cut DNA into fragments of known length
• B. make millions of copies of a specific DNA sequence in a few hours
• C. read the amino acid sequence of a protein
• D. insert a gene into a human cell

Explanation: Repeated cycles of heating to separate the strands, cooling so that primers bind, and extension by a heat stable polymerase double the…

• A. they are heated during the run
• B. they carry no charge and drift at random
• C. the phosphate groups of the backbone give DNA a negative charge
• D. the gel pushes them mechanically

Explanation: Every nucleotide carries a negatively charged phosphate, so all DNA fragments move towards the anode, and the gel acts as a sieve in which…

• A. every person has a completely different genetic code
• B. only criminals have unusual DNA sequences
• C. DNA differs between the cells of one person's body
• D. the number of repeats in certain non coding sequences differs between individuals

Explanation: Short tandem repeats in non coding DNA vary greatly in number from person to person, so the pattern of band sizes is effectively unique…

• A. introducing a normal copy of the faulty gene into the patient's cells
• B. removing the affected organ
• C. giving the patient a protein rich diet
• D. vaccinating the patient against the disease

Explanation: A working allele is delivered, usually inside a modified virus or a liposome, so that the patient's own cells can make the missing…

• A. fertilising an egg in a test tube
• B. transferring the nucleus of an adult body cell into an enucleated egg cell
• C. inserting a human gene into a sheep embryo
• D. splitting a very early embryo into two

Explanation: Somatic cell nuclear transfer showed for the first time that the nucleus of a fully differentiated adult cell can be reprogrammed to…

• A. a mixture of antibodies collected from immunised animals
• B. bacteria carrying an antibody gene on a plasmid
• C. a hybridoma made by fusing a single B lymphocyte with a cancer cell
• D. the plasma of recovered patients

Explanation: The B cell supplies the specificity for one antigen and the tumour cell supplies the ability to divide indefinitely, so the fused…

• A. has been cloned from an adult cell
• B. has twice the normal number of chromosomes
• C. has been produced by crossing two closely related species
• D. carries a functional gene deliberately transferred from another species

Explanation: Transgenic animals and plants express a foreign gene, examples being goats that secrete a human clotting factor in their milk and crops…

• A. produce a protein toxic to the insect pests that attack it
• B. fix nitrogen from the air
• C. survive without any water
• D. ripen its bolls faster

Explanation: The gene comes from Bacillus thuringiensis and codes for a crystal protein that kills bollworm larvae feeding on the plant, so far less…

• A. curing all inherited diseases
• B. determining the complete base sequence of human DNA
• C. producing the first cloned human being
• D. creating an artificial human chromosome

Explanation: The project, completed in draft form in 2001, established the order of roughly three billion base pairs and located about twenty thousand…

• A. cannot be rejected by any patient
• B. are found only in bone marrow
• C. are unspecialised and can divide and differentiate into several types of cell
• D. contain twice as many genes as ordinary cells

Explanation: Because they are not yet committed, stem cells can be directed to replace tissue that the body cannot regenerate, such as heart muscle…

• A. killing whole hepatitis B viruses with formalin
• B. growing the virus in chick embryos
• C. collecting antibodies from recovered patients
• D. inserting the gene for a viral surface protein into yeast, which then makes that protein

Explanation: Only the surface antigen is produced, so the vaccine can provoke an immune response with no possibility of causing the disease and with no…

• A. expressing the human interferon gene in cultured microorganisms
• B. chemical synthesis from simple sugars
• C. purifying it from the milk of cows
• D. growing viruses in the laboratory and collecting their protein

Explanation: Cloning the gene into bacteria or yeast turned a protein that could only be obtained in microgram amounts into one that can be produced by…

• A. The modified gene will change the DNA of the person eating the crop
• B. The introduced gene may spread by pollen to wild relatives or to non modified fields
• C. GM crops cannot reproduce at all
• D. GM crops always give lower yields than ordinary varieties

Explanation: Gene flow through pollen is a documented and measurable risk, and it can create herbicide resistant weeds or contaminate the crop of a…

• A. DNA ligase
• B. restriction endonuclease
• C. reverse transcriptase
• D. DNA helicase

Explanation: Reverse transcriptase, taken from retroviruses, builds a complementary DNA strand on an RNA template, and since the introns have already…

• A. The success rate of nuclear transfer is very low
• B. Cloned animals have often shown health problems
• C. The technique needs a large number of donor eggs
• D. A cloned child would be created as a copy of someone else rather than as an individual

Explanation: The first three statements are practical limitations that better technique might eventually overcome, whereas the last concerns human…