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Correct answer is (c) 3 ; 7

The explanation is: DENGUE VIRUS has 3 STRUCTURAL or surface PROTEINS namely the Capsid protein (C), the MEMBRANE protein (M) and the Envelope protein (E). It also has 7 non-structural proteins (NS proteins) namely NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5.

The correct answer is (B) Megavirus chilensis

Easiest explanation: Megavirus chilensis has the largest GENOME length of 1,259,197 base-pair with around 1120 proteins. Pithovirus sibericum is CURRENTLY the largest known virus with a length of 1500 nm and diameter 500 nm.

Right option is (c) Reverse Transcriptase enzyme

Explanation: The Dengue Virus is a retrovirus which contains RNA as its genetic material. So, to infect a human being by integrating its genome into the human DNA genome, it is necessary to CONVERT its RNA SEQUENCE into DNA. Reverse Transcriptase enzyme catalyzes the reverse transcription of viral RNA into DNA.

Right ANSWER is (d) All of the mentioned

Explanation: Viruses need a living system to survive and REPLICATE. They complete their LIFE cycle INSIDE the living host but otherwise REMAIN inert. Whole plant, cell lines and chick embryo act as appropriate living systems for the virus.

Right choice is (a) PROTOMERES

Best explanation: Capsomeres are the SUBUNITS of the protein coat enveloping the viral genome known as the Capsid. The Capsomeres assemble to FORM the capsid and are in turn MADE up of an assembly of smaller protein subunits known as Protomeres.

Right choice is (d) IMMUNOGENIC but not infectious

Easy EXPLANATION: An immunogenic organism can EVOKE the immune response when entered inside a host. Immunosuppressive organism can suppress the host immune response and infectious organism can cause infection to the host. VLP or Virus like particles are the outer protein COVERING of the virus with no viral genetic material. Hence, they can evoke host immune response but cannot cause infection to the host.

Correct CHOICE is (a) NEISSERIA gonorrheae

Explanation: Neisseria gonorrheae is an example of GRAM negative bacteria. HOWEVER, Mycoplasma pneumonia, Cornybacterium diptheriae, Streptococcus pyogene are some examples of Gram positive bacteria.

The CORRECT option is (a) T4 bacteriophage

The explanation is: T4 bacteriophage is among the largest bacteriophages. It is APPROXIMATELY 90-100 nm wide and 200 nm LONG. Its double stranded DNA genome is about 169 kb long and encodes 289 PROTEINS.

The CORRECT option is (d) Both Influenza and Measles

The explanation is: Measles and Influenza are diseases CAUSED by the INFECTION of VIRUSES. Typhoid is caused by a bacteria known as SALMONELLA typhi.

The correct answer is (d) Cauliflower Mosaic Virus

To EXPLAIN: Cauliflower Mosaic virus is a DNA virus with a NUCLEOTIDE sequence of 8024 nucleotides. TOBACCO Mosaic Virus, Potato Mosaic Virus and Tomato Mosaic Virus are RETROVIRUSES with RNA as its genetic material.

The CORRECT choice is (b) Provirus

Explanation: The virus infection is caused by the entry of entry of viral DNA into the host CELL. After this, the viral DNA is integrated into the host genome. This viral genetic material incorporated into host genome and able to replicate itself is CALLED as provirus.

Right OPTION is (c) Axoneme PRESENT in cilia; Axoneme ABSENT in flagella

The best I can explain: Inside both cilia and flagella, is a microtubule-based cytoskeleton called axoneme. Axoneme is the central STRAND of either a cilium or flagellum which is composed of an array of microtubules. Microtubules are arranged in nine pairs around TWO central microtubule (9+2 combination).

The correct answer is (a) Teichoic ACIDS

Explanation: Teichoic acids are PRESENT in Gram positive and absent in Gram negative bacteria and they stain purple by Gram stain. Periplasmic SPACE and OUTER membrane are present in Gram negative while they are absent in Gram positive bacteria. Lipolysaccharide content is HIGH in Gram negative and almost none in Gram positive.

The correct option is (a) Tubulin

Easy EXPLANATION: Tubulin proteins are the main building blocks of cilia in prokaryotic organisms. DYENIN forms bridges between NEIGHBOURING MICROTUBULE doublets in structure of cilia. Nexin is PRESENT between microtubule doublets and prevent them to slide over one another.

Correct OPTION is (c) It CONTAINS viral coat containing copies of multiple proteins

To elaborate: TMV or Tobacco MOSAIC Virus causes viral infection to the tobbacco plant. It is a rod-shaped HELICAL RNA virus which consists of a SINGLE strand of RNA placed centrally enveloped by a protein coat.

Right option is (c) GRAM negative bacteria cell wall is thin and SINGLE layered.

The best I can explain: The cell wall of Gram negative bacteria is THICK and two layered. HOWEVER, the cell wall of Gram positive bacteria is thick and single layered.

Correct option is (d) Helper T cell

For explanation I would say: HIV or Human IMMUNE deficiency Virus infects the Helper T CELLS present in the BLOOD. It recognizes the CD4 proteins on the surface of the helper T cells and THUS infects it. By doing this, HIV manipulates the very cells which activate both B cells and Cytotoxic T cells.

Correct OPTION is (b) Gram positive BACTERIA

To explain: EXOTOXINS are produced by Gram positive bacteria. ENDOTOXINS are produced by Gram negative bacteria.

Correct option is (b) CERTAIN cyanobacteria

The explanation: Certain cyanobacteria have the unique PROPERTY to fix nitrogen i.e., conversion of nitrogen gas into reduced ammonia. Certain cyanobacteria remain in a symbiotic relationship in the roots of LEGUME PLANTS such as peas and help in nitrogen fixation. Eg. RHIZOBIUM, Azotobacter, etc.

The correct option is (c) peritrichous; monotrichous

The BEST I can EXPLAIN: Monotrichous bacteria have single flagellum (eg. Vibrio cholerae). Lophotrichous bacteria have multiple flagella in same SPOT which helps in unidirectional movement. Peritrichous bacteria (eg. E.coli) has flagella projecting in all directions. AMPHITRICHOUS bacteria have single flagellum on OPPOSITE ends.

The correct option is (b) Proton- MOTIVE force

Easiest explanation: Proton motive force is the flow of protons or hydrogen ions across the bacterial cell MEMBRANE DUE to a concentration gradient set up by cell’s metabolism. This force drives the MOTOR engine at the base of the flagella and HELPS in flagellar movement.

Correct choice is (a) 2

For explanation: Gram positive BACTERIA have 2 basal rings in the FLAGELLA, one in the peptidoglycan layer and one in the plasma MEMBRANE. Gram negative bacteria have 4 basal rings in their flagella. The L ring is located in the plane in the outer membrane, P ring in the plane of peptidoglycan around flagellar ROD, MS ring that is located within and above cytoplasmic membrane and C ring extends into the CYTOPLASM.

Right option is (b) Human digestive tract

The explanation: Escherichia coli or E.coli is a Gram NEGATIVE, facultatively ANAEROBIC, rod-shaped BACTERIA. It mainly inhabits the human digestive tract and is commonly FOUND in the lower intestinal regions of warm-blooded ANIMALS such as humans.

Correct option is (B) Archaea

For EXPLANATION I WOULD say: Pseudopeptidoglycan is a cell wall component of some Archaea. It differs from bacterial peptidoglycan in chemical composition but has similar physical STRUCTURE and function as that of bacterial peptidoglycan.

The correct answer is (b) CHITIN

Explanation: Chitin is a polysaccharide that is present mainly in exoskeletons of Arthropods and are not a component of PLANT cell wall. Plant cell wall is majorly composed of cellulose, HEMICELLULOSES and pectin.

Right OPTION is (a) Proteasomes

The best I can explain: Proteasomes and protein DIGESTING structures PRESENT in both archaebacteria and eukaryotes. Proteasomes degrade unnecessary and damaged proteins by proteolysis. Plasmids are double STRANDED circular DNA found in prokaryotes whereas lysosomes and peroxisomes are only found in eukaryotes.

Right answer is (d) Both contain Golgi apparatus for protein trafficking

The explanation is: Prokaryotic CELLS do not have organelles such as Golgi Apparatus. However, the COMPOSITION of plasma MEMBRANE is the same. The metabolic PATHWAYS such as TCA cycle and glycolysis take place in both. Both contain DNA as the genetic material.

The correct CHOICE is (c) Nucleoid

For explanation I would say: Bacteria does not CONTAIN a true nucleus. Nucleoid is a poorly DEMARCATED region of the cell that contains the bacterial GENETIC material or bacterial DNA.

Right choice is (c) NUCLEIC Acids, Proteins

For EXPLANATION I would say: : Proteins and nucleic acids are the most important MACROMOLECULES out of the 4 building blocks of life, which includes Proteins, carbohydrates, LIPIDS and nucleic acids. Nucleic acids codes for the proteins (DNA & RNA) and proteins form the structural and functional parts of the cell.

Correct choice is (b) Sea-urchin

Easiest explanation: In his STUDIES, Hans Driesch USED sea urchin’s EMBRYO and FOUND that first two or FOUR cells could be isolated and can lead individually lead to the formation of complete new embryo.

The correct answer is (a) MECHANICAL

Explanation: Cells perform lot of bustling ACTIVITIES in their DAILY DISCOURSE. This requires a lot of mechanical activities, regulation, uptake etc. The motor protein is one class of proteins amongst many that HELP in the mechanical activities of the cell.

Right option is (a) Metabolism

The explanation: All the chemical REACTIONS that take PLACE inside the cell represent the cell’s metabolism. Nearly all chemical reactions INVOLVED in the metabolism require enzymes that HELP PACE up these reactions.

Right answer is (c) LIVER

The explanation is: GLUCOSE is released by liver into the blood stream which circulates throughout the body delivering chemical energy to all the cells of the body. This energy is stored in the form of ATP.

Correct choice is (d) Carbohydrates

The EXPLANATION is: The LIGHT energy which is converted to chemical energy by the photosynthetic pigments present in plant CELLS is stored in energy-rich carbohydrates LIKE SUCROSE and starch.

Correct option is (C) Oocytes

For explanation I would say: Oocytes UNDERGO irregular cell division where one daughter cell retains nearly all the cytoplasm which is later fertilized by a SPERM cell and gives rise to an embryo. The other cell only CONSISTS of half the genetic material and no cytoplasm.

Correct choice is (d) ACTIN

Easy explanation: The microvilli facilitate ABSORPTION of nutrients and project outwards from the apical CELL surface because of the presence of a skeleton made of filaments. These filaments are COMPOSED of the protein actin.

The correct answer is (b) Epithelial CELLS

The EXPLANATION: Epithelial cells line the INTESTINE and are responsible for the uptake and absorption of nutrients from the digestive tract. Microvilli are located at the APICAL END of these cells and mitochondria are located at the basal end.

Correct answer is (b) 1951

Best explanation: The first culture of human CELLS was performed by George and MARTHA Gey in 1951 at JOHN Hopkins University in 1951. HENRIETTA Lacks donated these cells from her malignant tumor named – HeLa cells.

Correct choice is (a) single-lens

Explanation: Antonie VAN Leeuwenhoek USED single-lens MICROSCOPE which he constructed by himself. The biconvex lens used was capable of MAGNIFYING 270 TIMES and a resolution of 1.35 micro-meters.

Right option is (c) 3

The explanation: The cell THEORY is based on three TENETS. Two of these were PROPOSED by Matthias SCHLEIDEN and Theodor Schwann and the third tenet by Rudolf Virchow.

The correct choice is (d) third tenet of cell theory

The explanation is: RUDOLF Virchow proposed the third tenet of cell theory that said; cells can only ARISE by DIVISION from a pre-existing cell. This was perceived as a convincing case by the scientific society.

Right answer is (a) True

The best explanation: SCHLEIDEN and Schwann’s ideas about the origin of life did not receive REVERENCE because both of them agreed that CELLS could arise from non-cellular MATERIAL.

Right OPTION is (c) Cell is the structural unit of life

For explanation I would say: THEODOR SCHWANN PROPOSED the cell theory, tenets of which include all organisms are composed of ONE or more cells and cell is the structural unit of life.

The CORRECT answer is (a) Matthias Schleiden

Easiest explanation: In 1838, German lawyer TURNED botanist Matthias Schleiden, proposed that plants were made of CELLS and that plant embryo arose from a single cell. Theodor Schwann, his colleague LATER proposed the cell theory.

Correct OPTION is (b) CORK

The best explanation: In the 16^th century, Robert HOOKE FIRST examined cork (part of barks of the trees) under a microscope. He saw it as a porous honeycomb like STRUCTURE. He called these pores as cells.