Robert Brown discovery of the nucleus and its role helped to prove the cell theory, which states that all living organisms are composed of cells and cells come from pre-existing cells. Other discoveries and contributions of Brown include: The discovery and naming of over 2000 species of plants. Answer : (d)

The chloroplast is a plastid which contains chlorophyll (green pigment) within the thylakoid membranes of the organelle. This organelle is present in the green parts of plants where photosynthesis takes place. Chloroplasts have descended from specialized bacteria therefore, they have a membrane similar to bacteria and possess their own nucleic acids (DNA and RNA). These organelles utilize their DNA and RNA to produce proteins and enzymes required for their functioning. Answer : (d)

Answer:(b)

Metaphase can be characterised by the chromosomes that are least coiled which show maximum condensation and are shortest in length. Chromosomes are classified into four types by their shape in metaphase or in anaphase, which, in turn, is determined by the position of the centromere. It is the best stage to study the structure, size and number of chromosome in a celI. Idiogram/karyotype of chromosomes is prepared at metaphase. Answer : (b)

During the staining procedure, the Gram-positive bacteria retain crystal violet and appear blue. In contrast, Gram-negative lose crystal violet during the washing steps and hold only safranin to appear red. Bacterial species Bacillus and Escherichia are the example of the Gram-positive and Gram-negative respectively. Salmonella enterica is a gram-negative E. coli stains Gram-negative because its cell wall is composed of a thin peptidoglycan layer and an outer membrane. During the staining process, E. coli picks up the color of the counterstain safranin and stains pink meliloti is a Gram-negative Answer : (c)

In aerobic respiration, Mitochondrion absorbs oxygen and releases carbon dioxide and energy Answer : (d)

Mesosomes are areas in the cell membrane of prokaryotic (bacterial) cells that fold inward. They play a role in cellular respiration, the process that breaks down food to release energy. In Eukaryotes, the majority of this process occurs in mitochondria. Answer : (c)

Answer : (b)

Most amino acids are synthesized from α-ketoacids, and later transaminated from another amino acid, usually glutamate. The enzyme involved in this reaction is an aminotransferase. Answer : (d)

Cells make up organs and organs make up systems and systems make up organisms. Each cell must be able to perform as a part of a living organism. Cell specialization is required for cells to perform as a part of a whole living thing. Different cells do different jobs. Answer : (b)

A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Answer : (a)

The central vacuole is a membrane-bound organelle containing water and other enzymes that function during the life of the plant. Structurally, the central vacuole is surrounded by a phospholipid bilayer. Lytic vacuoles share similar properties with lysosomes found in animals. As such, they contain different types of hydrolytic enzymes responsible for the degradation of such molecules as nucleic acids, proteins and polysaccharides. Anthocyanins are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue or black. Latex is stored in vacuoles of rubber plants. Vacuoles of many plants store large amounts of amino acids, which are used as a reservoir of nitrogen. DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA). Answer : (d)

The permeases are membrane transport proteins, a class of multipass transmembrane proteins that allow the diffusion of a specific molecule in or out of the cell in the direction of a concentration gradient, a form of facilitated diffusion. Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals). It catalyzes the decomposition of hydrogen peroxide to water and oxygen. Gelatinase is a proteolytic enzyme that allows a living organism to hydrolyse gelatin into its sub-compounds (polypeptides, peptides, and amino acids) that can cross the cell membrane and be used by the organism. An amylase is an enzyme that catalyses the hydrolysis of starch into sugars. Answer : (d)

In mature grains, aleurone cells are characterized by a prominent nucleus and thick cell walls. In wheat, barley, rye, and oat, the cells walls are described as two layered. The cytoplasm is densely packed with aleurone grains (considered as protein bodies, storage protein) and lipid droplets (spherosomes). Answer : (c)

Chloroplast (plastid) is cellular organelle present in the cells of the green plant which contains a green pigment called chlorophyll and is responsible for photosynthesis in plants. Thylakoid is a small disk-like membrane-bound compartment within the chloroplasts which is a site of sunlight-dependent photosynthesis (light reaction). Answer : (b)

Autolysis is the destruction of cells and tissues of an organism by enzymes produced by the cells themselves. The function of lysosomes is to remove waste as well as destroying a cell after it has died, called autolysis Answer : (c)

Secretory cells have abundant amounts of rough (granular) endoplasmic reticulum, Answer : (b)

Glycolate biosynthesis occurs in the chloroplasts. In the peroxisomes, glycolate is oxidized with O2 uptake to glyoxylate by glycolate oxidase, and the glyoxylate is converted to glycine by glutamate Answer : (d)

Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies anthocyanins are the pigments that give red, purple, and blue plants their rich coloring. Answer : (b)

Long protein fibers called microtubules extend from the centrioles in all possible directions, forming what is called a spindle. The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis Answer : (a)

Answer:(d)

Book, Micrographia, was the first important work on microscopy, the study of minute objects through a microscope. First published in 1665, it contains large-scale, finely detailed illustrations of some of the specimens Hooke viewed under the microscopes he designed. a = iv. Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life), published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. b = iii, Geneticist Hugo de Vries in his Die Mutationstheorie (1901–03; The Mutation Theory), mutation theory joined two seemingly opposed traditions of evolutionary thought. c = i Louis Pasteur conducted a infamous experiment in which he used a glass flask with an S shaped neck, such as the one pictured. This S shaped flask became known as the 'swan neck flask”. d=ii Answer : (d)

The number of cells in a multicellular organism are directly proportional to the size of the body. On the other hand, it is a fact that cells vary greatly in their size. Answer : (d)

Meaning of tuft is bunch or collection of threads, Bacteria can be classified by the number of flagella and how the flagella are arranged on the cell surface as follows: Lophotrichous bacteria have multiple flagella located at the same spot on the bacteria's surfaces which act in concert to drive the bacteria in a single direction. Amphitrichous - One flagellum coming from each end of the cell (or two flagella in total) Peritrichous - Several flagella randomly distributed, coming from all around the perimeter of the cell. Atrichous bacteria are lacking flagella Answer : (d)

Protein synthesis in the cell is conducted by ribosomes that are found attached to the membrane of endoplasmic reticulum and microsomes, as well as in free state in the groundplasm. Answer : (b)

Sphaerosomes or Oleosomes are small cell organelles bounded by single membrane which take part in storage and synthesis of lipid. They were discovered by Perner. They are only found in plant cells. Answer : (d)

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands. Polytene chromosomes are first reported by E.G.Balbiani in 1881 Balbiani rings (BR) in principle are giant puffs in the polytene chromosomes of the salivary gland cells of larvae of Chironomus tentans. Answer : (d)

Chromoplasts synthesize and store pigments such as orange carotene, yellow xanthophylls, and various other red pigments. As such, their color varies depending on what pigment they contain Answer : (d)

The N-acetylmuramic acid component of the bacterial cell wall is derived from N-acetylglucosamine by the addition of a lactic acid substituent derived from phosphoenolpyruvate Answer : (b)

Vesicles transport the proteins from the ribosomes to the Golgi apparatus, a.k.a Golgi complex, where they are packaged into new vesicles. The vesicles migrate to the membrane and release their protein to the outside of the cell. Lysosomes digest and recycle the waste materials for reuse by the cell. Answer : (c)

Human blood contains a buffer of carbonic acid (H 2CO 3) and bicarbonate anion (HCO 3 -) in order to maintain blood pH between 7.35 and 7.45, as a value higher than 7.8 or lower than 6.8 can lead to death. In this buffer, hydronium and bicarbonate anion are in equilibrium with carbonic acid. Answer : (b)

Chlorophyll resides in the thylakoid membranes. The chlorophyll absorbs energy from sunlight, and it is this energy that drives the synthesis of food molecules in the chloroplast. Answer : (b)

Function Giving shape to cells and cellular membranes. Cell movement, which includes contraction in muscle cells and more. Transportation of specific organelles within the cell via microtubule "roadways" or "conveyor belts." Mitosis and meiosis: movement of chromosomes during cell division and creation of the mitotic spindle. Cyclosis is the movement of protoplasm within a cell. The primary cause of movement into the protoplasm is through osmosis. Osmosis is the process by which solvent molecules move across a semipermeable membrane Answer : (c)

The word "protoplasm" comes from the Greek protos for first, and plasma for thing formed, and was originally used in religious contexts.It was used in 1839 by J. E. Purkinje for the material of the animal embryo Answer : (d)

A ribosome is made out of RNA and proteins, and each ribosome consists of two separate RNA-protein complexes, known as the small and large subunits. Ribosomes are found in protista and monera Answer : (b)

Nonmembranous organelles are those cytoplasmic structures that (like membranous organelles) perform vital physiological functions for the cell but are not enclosed in membranes. These include ribosomes, centrioles, proteasomes. cytoskeleton, nucleolus, and centrosome. All prokaryotic organelles are nonmembranous Answer : (d)

The surface of rough endoplasmic reticulum is covered with ribosomes, giving it a bumpy appearance when viewed through the microscope. Answer : (c)

70S ribosomes are found in the cytoplasm of procaryotic cells and also in two cell organelles namely chloroplast and mitochondrion of eucaryotic cells. Answer : (d)

Answer:(b)

The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character. Plasma membranes range from 5 to 10 nm in thickness Answer : (d)

ER is of types based on the presence and absence of ribosomes on their surface. Smooth endoplasmic is not studded with ribosomes whereas, the rough endoplasmic reticulum is studded with ribosomes. Answer : (a)

In fluorescence microscopy, the object is stained with a fluorescent substance and when stained cell or all parts are observed through ordinary microscope using UV light, appear as luminous objects. This technique is helpful to show the fluidity of biomembranes. Answer : (b)

Ribosomes are cytoplasmic granules composed of ribosomal RNA (rRNA) and protein. Answer : (c)

Answer : (b)

A crista is a fold in the inner membrane of a mitochondrion. Answer : (c)

Cell's membrane potential, the reference point is the outside of the cell. Cells have negative intracellular potentials, the electrical force will tend to movement cations into the cell for a specific ion always tends to bring the membrane potential. Answer : (b)

The nucleolus is the largest structure found in the nucleus of the eukaryotic cells. They are the sites of ribosome synthesis and assembly. Bowman introduced the term 'nucleolus' but it was first reported by Fontana (1781). Answer : (a)

In C4 pathway, first product is 4 carbon compound hence called as C4. It was given by M.D. Hatch and Roger Slack and thus named as Hatch and Slack pathway. Theophrastus, Greek Peripatetic philosopher and pupil of Aristotle. Historia Plantarum (Theophrastus), a book on plants by Theophrastus, written between c. 350 BC and c. 287 BC Ernst Ruska, and Knoll German electrical engineer who invented the electron. Micrographia, was the first important work on microscopy, by Robert Hooke Answer : (b)

Answer : (d)

Lysosomes are membrane-bound, dense granular structures containing hydrolytic enzymes responsible mainly for intracellular and extracellular digestion. Answer : (c)