All Free Biology MCQs with Answers

• A. Probes
• B. Palindromes
• C. Plasmids
• D. Prions

Explanation: Plasmids are small, circular, double-stranded DNA molecules, which are used in DNA recombinant technology by modifying the plasmid and then introducing them into cells.

• A. Helicase
• B. Reverse Transcriptase
• C. Restriction Enzyme
• D. DNA Polymerase

Explanation: Restriction enzymes are used to separate DNA molecules at specific points, and can be used to separate specific genes.

• A. DNA Polymerase I
• B. Taq Polymerase
• C. DNA Polymerase III
• D. RNA Polymerase

Explanation: Taq polymerase is an enzyme used in DNA synthesis and proves to be most active at 70 to 80 degree Celsius, and can function even near 100 degree celsius.

• A. Hypercholesterolemia
• B. Coronary Artery Angioplasty
• C. Cystic Fibrosis
• D. Severe Combined Immunodeficiency Syndrome (SCID)

Explanation: Gene therapy using liposomes is used to treat cystic fibrosis. Liposomes are microscopic vesicles of lipoproteins, used to deliver the normal gene into the patient's cells.

• A. Hypercholesterolemia
• B. Severe Combined Immunodeficiency Syndrome (SCID)
• C. Cystic Fibrosis
• D. Coronary Artery Angioplasty

Explanation: Gene therapy for SCID involves the removal of bone marrow stem cells from the patient. These cells are injected with the with a retrovirus which carries the normal gene into the cells. The stem cells are returned to the patient, and they start producing the needed enzyme.

• A. DNA ligase
• B. Primer
• C. Heat
• D. Helicase

Explanation: In PCR (polymerase chain reaction), the two strands of DNA are separated by raising the temperature. The process of heating the DNA to separate the strands is called denaturation. It allows the DNA to become single-stranded and available for further steps in PCR.

• A. Lambda phage
• B. Gamma phage
• C. T2 phage
• D. T4 phage

Explanation: Modified Lambda phages are used as a vector to introduce foreign DNA into a cell due to their efficiency at packaging and injecting DNA into the cell.

• A. Viruses
• B. Bacteria
• C. Fungi
• D. Plants

Explanation: Restriction endonucleases cleave into fragments near or at recognition sites. They are found in bacteria as a defence mechanism against viruses.

• A. pBR 101
• B. EcoR1
• C. EcoR3
• D. Both pBR 101 and EcoR3

Explanation: EcoRI is a restriction of endonuclease enzymes isolated from species. It is a restriction enzyme that cleaves DNA double helices into fragments at specific sites, and it is also a part of the restriction-modification system. Like all enzymes, a restriction enzyme works shape-to-shape matching. When it comes into contact with a DNA sequence with a shape that matches a part of the enzyme, called the recognition site, it wraps around the DNA and causes a break in both strands of the DNA molecule.

• A. RNA
• B. EcoR1
• C. Template RNA
• D. Template DNA

Explanation: The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases present on each strand of the original DNA molecule. During DNA replication, the template is generated by enzymes known as helicases. DNA polymerase then synthesized the DNA using a DNA template.