Answer : (d)

Desmosomes are intercellular junctions that provide strong adhesion between cells. Because they also link intracellularly to the intermediate filament cytoskeleton they form the adhesive bonds in a network that gives mechanical strength to tissues. Answer : (d)

Raphid: a needle-shaped crystal of calcium oxalate occurring in clusters within the tissues of certain plants. Answer : (a)

All prokaryotes have 70S (where S=Svedberg units) ribosomes The 70S ribosome is made up of a 50S and 30S subunits. The 50S subunit contains the 23S and 5S rRNA while the 30S subunit contains the 16S rRNA. Answer : (c)

S=Svedberg units The svedberg is the most important measure used to distinguish ribosomes. Ribosomes consist of two major components: the small ribosomal subunits, which read the RNA, and the large subunits, which join amino acids to form a polypeptide chain Answer : (b)

Lampbrush chromosomes are a special form of chromosome found in the growing oocytes (immature eggs) of most animals, Chromosomes transform into the lampbrush form during the diplotene stage of meiotic prophase I due to an active transcription of many genes. Answer : (d)

Ectoplasm: the more viscous, clear outer layer of the cytoplasm in amoeboid cells. Endoplasm: the more fluid, granular inner layer of the cytoplasm in amoeboid cells. Plasmalemma: a plasma membrane which bounds a cell, especially one immediately within the wall of a plant cell. Answer : (a)

Acid phosphatase is stored in lysosomes Answer : (b)

Middle lamella is a pectin layer and is made up of calcium and magnesium pectates. Its function is to strengthen the cell wall of two adjoining cells. Main element present in the middle lamella is Calcium Answer : (a)

Plasmodesmata is a narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them. Answer : (d)

The endoplasmic reticulum is an organelle that is responsible for the synthesis of lipids and the modification of proteins Answer : (b)

Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA Answer : (b)

Mitochondria and Chloroplasts both have 70s Ribosome, since they are evolved from prokaryotic bacteria and developed a symbiotic relationship with the cell. Answer : (c)

Golgi apparatus is the important site of formation of glycoproteins and glycolipids Glycoproteins are simply proteins with a sugar attached to them. The sugars can be attached to a protein in two locations in the cell, the endoplasmic reticulum, which produces N-linked sugars, and the Golgi apparatus, which produces O-linked sugars. Glycolipids are synthesized in the golgi-apparatus where the majority are transported to membranes to maintain the bilayer Answer : (c)

The vacuoles of plant cells are bounded by a single semipermeable membrane known as tonoplast. These vacuoles contain water, phenol, flavonols, anthocyanins, alkaloids and storage products such as sugars and proteins. The vacuoles of animal cells are bounded by a lipoproteinaceous membrane and their function is storage, transmission of materials and maintenance of internal pressure of cell. So correct option is membrane-bound and contains water and excretory substances Answer : (d)

Schleiden was the botanist who examined a large number of plants and observed that all plants are composed of different kinds of cells which form the tissues of the plant, Answer : (a)

The term "chromosome" was first suggested in 1888 by the German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz (1836–1921). Answer : (c)

Temporary storage vacuoles of lipids found in the Golgi apparatus. Golgi apparatus also called Lipochondria or Dalton complex or dictyosomes. Answer : (c)

Mitochondrial cristae acts as sites for oxidation-reduction reaction. Cristae are folds of the inner mitochondrial membrane. The electron transport chain and chemiosmosis take place on this membrane as part of cellular respiration to create ATP. Answer : (d)

Energy made available in catabolic reactions is immediately stored in ATP Answer : (c)

Mitochondria, often referred to as the “powerhouses of the cell”, were first discovered in 1857 by physiologist Albert von Kolliker, and later coined “bioblasts” (life germs) by Richard Altman in 1886. The organelles were then renamed “mitochondria” by Carl Benda twelve years later. Answer : (b)

Both prokaryotic and eukaryotic cells have structures in common. All cells have a plasma membrane, ribosomes, cytoplasm, and DNA. The plasma membrane, or cell membrane, is the phospholipid layer that surrounds the cell and protects it from the outside environment. Answer : (a)

Ribosomes were first observed in the mid-1950s by Romanian-American cell biologist George Emil Palade, using an electron microscope, as dense particles or granules. Answer : (c)

Glycogen is mainly stored in the liver and the muscles and provides the body with a readily available source of energy if blood glucose levels decrease. Answer : (d)

The Golgi body present in the cytoplasm of most of the eukaryotic cells is the organelle called as the export house of the cells, because it can store packs and easily dispatch or secrete the necessary substances synthesized by the endoplasmic reticulum effectively for different purposes. Answer : (b)

Protoplast, is a biological term coined by Hanstein in 1880 to refer to the entire cell, excluding the cell wall. Answer : (b)

Hammerling's nucleocytoplasmic experiments state that the cytoplasm is the centre for all the metabolic activities in the cell and the nucleus is the controlling centre. This experiment was conducted using Acetabularia. Acetabularia is a genus unicellular or single-celled green algae belonging to the family Polyphysaceae which are found in subtropical waters. They are gigantic in size and complex in form, therefore, used in experiments in cell biology. So, the correct answer is ' Acetabularia'. Answer : (a)

Golgi body or dictyosome has a stack of single membrane bound cisternae with swollen ends, network of tubules and vesicles Cisternae are parallel membrane lined narrow sacs which are interconnected. Golgi body has two faces- concave or distal or maturing (M) face or trans face towards cell membrane and cis or convex or proximal or forming (F) face towards rough ER and nuclear membrane New cistemae are formed from SER and added from F-face Answer : (a)

Telocentric: Centromere placement very close to the top, p arms barely visible if visible at all. Acrocentric: q arms are still much longer than the p arms, but the p arms are longer than those in telocentric. Submetacentric: p and q arms are very close in length but not equal Metacentric: p and q arms are equal in length. Answer : (a)

The process of moving sodium and potassium ions across the cell membrane is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+ -ATPase Answer : (d)

Hammerling's nucleocytoplasmic experiments state that the cytoplasm is the centre for all the metabolic activities in the cell and the nucleus is the controlling centre Answer : (b)

Answer : (b)

The longest cell in the human body is the neuron. The cell body of a motor neuron is approximately 100 microns (0.1 millimeter) in diameter and as you now know, the axon is about 1 meter (1,000 millimeter) in length. So, the axon of a motor neuron is 10,000 times as long as the cell body is wide. Answer : (a)

Cellulose is a molecule, consisting of hundreds – and sometimes even thousands – of carbon, hydrogen and oxygen atoms. Cellulose is the main substance in the walls of plant cells, helping plants to remain stiff and upright. Humans cannot digest cellulose, but it is important in the diet as fibre. Answer : (b)

The centromere is the specialized DNA sequence of a chromosome that links a pair of sister chromatids Answer : (a)

Late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. Answer : (c)

The cytoskeleton of a cell is made up of microtubules, actin filaments, and intermediate filaments. These structures give the cell its shape and help organize the cell's parts. In addition, they provide a basis for movement and cell division. Answer : (d)

In animal cells centrioles are located in, and form part of, the centrosome where they are paired structures lying at right angles to one another Answer : (a)

Desmosomes connect adjacent cells when cadherins in the plasma membrane connect to intermediate filaments. Gap junctions are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances. Answer : (c)

A plant cell has a potential to develop into the full plant. This property of the plant cell is called as totipotency. The basis of tissue culture is to grow a large number of cells in a sterile controlled environ-ment. The cells are obtained from the stem, root or other plant parts and are allowed to grow in culture medium containing mineral nutrients, vi¬tamins and hormones to encourage cell division and growth. As a result, the cells in culture will produce an unorganised proliferative mass of cells which is known as callus tissue. Answer : (c)

Centrioles are absent from the cells of higher plants. Answer : (b)

Centrosomes and lysosomes are found in animal cells, but do not exist within plant cells. Answer : (a)

A telocentric chromosome is a chromosome in which the centromere is located at the terminal end of the chromosome and their shape is similar to the letter I. An acrocentric chromosome is a chromosome in which the centromere is located near to one end of the chromosome. Metacentric chromosomes are X-shaped chromosomes and the centromere are present in the centre (medial) so that the two arms are equal. A submetacentric chromosome is a chromosome in which the centromere is located near the slightly away from the centre and the two arms are slightly unequal in length and form L-shape So, the correct answer is 'Metacentric'. Answer : (c)

The term nucleic acid is the overall name for DNA and RNA. Histones are highly basic proteins found in eukaryotic cell nuclei that pack and order the DNA into structural units called nucleosomes Answer : (a)

Glycerol is a simple trihydric alcohol. Maltase, enzyme that catalyzes the hydrolysis of the disaccharide maltose to the simple sugar glucose. The principal dietary carbohydrates are sugars and complex carbohydrates. The sugars include monosaccharides, such as glucose and fructose, and disaccharides, such as sucrose (table sugar), maltose, and lactose (milk sugar). Answer : (c)

lysosome. ly•so•some. a particle in the cytoplasm of cells containing a number of digestive enzymes capable of breaking down most of the constituents of living matter. Origin of lysosome. lyso-, pertaining to dissolving from Classical Greek lysis (see lysis) + -some Answer : (b)

DNA wraps around histone proteins, forming nucleosomes and the so-called "beads on a string" structure (euchromatin). Multiple histones wrap into a 30-nanometer fibre consisting of nucleosome arrays in their most compact form Answer : (a)

The inner mitochondrial membrane contains many copies of a protein called the F0-F1, ATPase. Enzymes of the citric acid cycle such as succinic dehydrogenase and Isocitrate dehydrogenase are present in the inner mitochondrial membrane. Or TCA enzyme Answer : (d)

Messenger RNA (mRNA) is synthesized in the nucleus using the nucleotide sequence of DNA as a template. Answer : (a)

ATP is required for Active process During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport. Answer : (a)