Answer:(a)

Glyoxysomes are specialized peroxisomes found in plants (particularly in the fat storage tissues of germinating seeds) and also in filamentous fungi. Seeds that contain fats and oils include corn, soybean, sunflower, peanut and pumpkin. Castor is oil seed glyoxysomes (as all peroxisomes) contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. The seedling uses these sugars synthesized from fats until it is mature enough to produce them by photosynthesis Answer : (b)

A sap vacuole refers to the fluid found within the central vacuole of a cell and is more commonly known as cell sap. Cell sap is a dilute fluid made up of water, amino acids, glucose and salts. a - 5 Many wall-less protozoa have an organelle, the contractile vacuole complex (CVC), that collects and expels excess water. b - 3 A food vacuole is a membrane-enclosed cell vacuole with a digestive function, containing material taken up in by the process of phagocytosis. c - 1 Gas vacuoles are aggregates of hollow cylindrical structures called gas vesicles. They are located inside some bacteria. The inflation and deflation of the vesicles provides buoyancy, allowing the bacterium to float at a desired depth in the water. d- 2 Sphaerosomes(=spherosomes) or Oleosomes are small cell organelles bounded by single membrane which take part in storage and synthesis of lipid. d- 4 Answer : (a)

In the 1930s–1950s Joachim Hämmerling conducted experiments in which he demonstrated Acetabularia's genetic information is contained in the nucleus. J. Hammerling, a German biologist, demonstrated in 1934 that the nucleus determines the characters of the cell and ultimately the characters of the individual. Answer : (a)

Plant cells have a rigid cell wall that surrounds the cell membrane. Animal cells do not have a cell wall. A plant cell contains a large, singular vacuole that is used for storage and maintaining the shape of the cell. In contrast, animal cells have many, smaller vacuoles Both animal and plant cells have mitochondria, but only plant cells have chloroplasts. Plants don't get their sugar from eating food, so they need to make sugar from sunlight. This process (photosynthesis) takes place in the chloroplast. Answer : (b)

chromosome puff. A localised separation of polytene chromosomes (e.g., chromosomes of Drosophila melanogaster) that represents a site of active RNA synthesis—i.e., transcription—which, when very large, is known as a Balbiani ring. RNA polymerase is an enzyme that produces RNA and catalyzes the initiation and elongation of RNA chains from a DNA template. RNA is created using a process known as transcription. The RNA polymerase is a key component to this process DNA polymerase is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, the building blocks of DNA. These enzymes are essential for DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule In eukaryotic cells, DNA polymerases can be found in the nucleus, mitochondria and chloroplasts (mitochondria and chloroplasts have circular DNA molecules). In prokaryotic cells, the DNA polymerases are located in the cytoplasm (there aren't any compartiments). In biochemistry, a ligase is an enzyme that can catalyze the joining of two large molecules by forming a new chemical bond, Ecdysone a steroid hormone that controls moulting in insects and other arthropods. It is synthesized in the prothoracic gland from dietary cholesterol in response to the prothoracicotropic hormone (PTTH) signal produced by specific brain cells. Answer : (d)

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

Subterminal meaning is near the end of a chain or other structure not at the end. Acrocentric chromosome: A chromosome in which the centromere is located quite near one end of the chromosome. Humans normally have five pairs of acrocentric chromosomes. Answer : (a)

The waste products generated in cells are accumulated in vacuoles. Thus, vacuoles protect other organelles of the cell from harmful effects of wastes. The vacuoles help in maintaining an acidic internal pH in cells. Apart from maintaining the cell pH, vacuoles also maintain the turgor and hydrostatic pressure. Vacuoles do the crucial job of isolating toxic sunstanced from the rest of the cell components. During the process of autophagy, vacuoles maintain a balance between biogenesis and degradation of substances in cells. Destroying the bacteria that attack cells is an important function performed by vacuoles. The food vacuoles found in amoeba perform the important job of digestion. Answer : (c)

J Hammerling (1953) carried the grafting experiments involving exchange of nucleus (located at the base) in Acetabularia. He proved the role of nucleus in heredity, growth, etc Answer : (b)

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)

Cell membranes are made primarily of phospholipids and proteins and are typically described as phospholipid bi-layers Answer : (a)

Robert Brown, (born December 21, 1773, Montrose, Angus, Scotland—died June 10, 1858, London, England), Scottish botanist best known for his descriptions of cell nuclei and of the continuous motion of minute particles in solution, which came to be called Brownian motion. Answer : (d)

Semi autonomous organelles are organelles with DNA. In eukaryotic cells, mitochondrion and chloroplast are semi autonomous organelles as it posses its own DNA. Answer : (d)

Extrachromosomal DNA is any DNA that is found outside the nucleus of a cell. It is also referred to as extranuclear DNA or cytoplasmic DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP). Answer : (a)

1Thalakoid membrane,and 2 cloroplast membrane Total 3 membrane Answer : (c)

De Robertis and Franchi (1953) first discovered microtubules in the axoplasm of nerve fibers. They are found in the cytoplasmic matrix of all eukaryotic cells. They are also present in structures like centrioles, basal bodies, cilia or flagella, sensory hair, spindle apparatus, chromosome fibres, nerve processes, sperm tail etc. They are absent in prokaryotic cells. Answer : (a)

Chromatin was discovered by Walther Flemming in the 1880s, who noticed that the dense nucleic substance greatly absorbed certain dyes Answer : (b)

Succinate dehydrogenase or succinate-coenzyme Q reductase (SQR) or Complex II is an enzyme complex, bound to the inner mitochondrial membrane of mammalian mitochondria and many bacterial cells. It is the only enzyme that participates in both the citric acid cycle and the electron transport chain. Answer : (c)

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. In this context they are possibly involved in spindle assembly during mitosis. The centrosome is positioned in the cytoplasm outside the nucleus but often near to it. Answer : (b)

Ribosomes are particles made of RNA and protein that reside in the cytoplasm of both prokaryotic and eukaryotic cells, as well as in the matrix of mitochondria and the stroma of chloroplasts. Answer : (b)

RNA is a polymer with a ribose and phosphate backbone and four different bases: adenine, guanine, cytosine, and uracil. The first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. Answer : (d)

Cell membranes are represented according to a fluid-mosaic model, due to the fact that they are: Fluid – the phospholipid bilayer is viscous and individual phospholipids can move position Mosaic – the phospholipid bilayer is embedded with proteins, resulting in a mosaic of components Answer : (c)

First formed cell wall Outermost layer Comparatively thin and flexible Answer : (d)

Cavities or thin areas within the thick secondary wall are called pits. Pits are left during process of secondary wall formation. Answer : (d)

The Golgi apparatus modifies and sorts proteins for transport throughout the cell. The Golgi apparatus is often found in close proximity to the ER in cells. The Golgi processes proteins made by the endoplasmic reticulum (ER) before sending them out to the cell. Answer : (a)

lamellae model or Sandwich model “Sandwitch model” proposed by Danielli and Davson (1935), the plasma membrane exhibit trilaminar structure i.e., a lipid layer is bounded by protein layer on both the sides. In this model, proteins are usually represented in globular form. Subsequently electron microscopic studies favour the idea of trilaminar structure of plasma membrane. Answer : (c)

Elaioplasts are a type of leucoplast that is specialized for the storage of lipids in plants. Answer : (b)

cystolith a stalk-like crystal of calcium carbonate formed inside an epidermal cell by crystal growth on to an ingrowth from the cell wall A cell containing a cystolith is known as a lithocyst Answer : (a)

Answer : (b)

A plant cell has A large vacuole and rigid cell wall Centrioles. Found only in animal cells, Animal cells each have a centrosome and lysosomes, whereas plant cells do not. Answer : (a)

telocentric chromosomes, i.e., with terminal or near-terminal centromeres and which are rod-shaped at metaphase or anaphase, Centric fusion refers to the situation in which two telocentric chromosomes appear to have become fused at or close to their centromeres to form one metacentric chromosome, which is V-shaped at metaphase or anaphase. Answer : (d)

Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. Answer : (c)

In order to organize the large amount of DNA within the nucleus, proteins called histones are attached to chromosomes; the DNA is wrapped around these histones to form a structure resembling beads on a string. These protein-chromosome complexes are called chromatin. Chromatin is a complex of DNA and protein found in eukaryotic cells. A chromatid is one-half of two identical copies of a replicated chromosome. Chromosome a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. The nuclear lamina is a dense fibrillar network inside the nucleus of most cells. Answer : (d)

Glycolipids are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues. Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. The carbohydrates are recognized by the cell adhesion molecules which are glycoproteins expressed on the cell surface. cell surface proteins can change their conformation (structure); opening or closing (permeability), allowing for some molecules to pass while blocking others. most important function lipids perform is as the building blocks of cellular membranes. Other functions include energy storage, insulation, cellular communication and protection Answer : (d)

glucose is directly taken, it does not have to be digested and thus acts as an instantsource of energy, while other are to be digested Sucrose doesn’t get broken down until it passes out of your stomach and enters your small intestine. Once there, the intestinal lining releases an enzyme called sucrase, which cleaves sucrose into one molecule of glucose and one molecule of fructose. From the small intestine, glucose is quickly absorbed into your bloodstream and transported to the far reaches of your body. In contrast, fructose requires a little more enzyme work in the liver before it’s reduced into glucose. Answer : (b)

Plasma membranes (PM) are derived from nuclear membranes (NM) or endoplasmic reticulum (ER) via the Golgi apparatus (GA) by a process of membrane flow and differentiation. Answer : (c)

Leucoplasts are colorless plastids found in endosperm, tubers, roots and other non-photosynthetic tissues of plants. leucoplast stroma is often less dense than chloroplasts stroma and contain several nucleoids with DNA fibrils. They serve various functions, for example, storage of starch, lipids, or proteins. Plastids of these three types are respectively known as amyloplasts, elaioplasts, and proteinoplasts. A leucoplast may also perform biosynthetic functions such as the synthesis of fatty acids, amino acids, and various other compounds. Lysosomes are single membrane formed by budding off of the Golgi apparatus, and the hydrolytic enzymes within them are formed in the endoplasmic reticulum. Option (a) is wrong statement The endoplasmic reticulum is a network of tubules and flattened sacs that serve a variety of functions in plant and animal cells. The endoplasmic reticulum serves many general functions, including the folding of protein molecules in sacs called cisternae and the transport of synthesized proteins in vesicles to the Golgi apparatus Spherosomes or Oleosomes are small cell organelles bounded by single membrane which take part in storage and synthesis of lipid. (d) Correct statement Answer : (a)

Answer : (a)

Packages of processing enzymes and newly made proteins that originate in the Endoplasmic reticulum fuse together to form the Golgi Answer : (a)

nucleus, chloroplast and mitochondria have DNA Answer : (b)

The process of moving sodium and potassium ions across the cell membrance 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)

Rough ER is found throughout the cell but the density is higher near the nucleus and the Golgi apparatus. Ribosomes on the rough endoplasmic reticulum are called 'membrane bound' and are responsible for the assembly of many proteins. This process is called translation. Answer : (b)

Nucleolus is a small dense spherical structure in the nucleus of a cell during interphase. This structure is made up of proteins and ribonucleic acids (RNA). Its main function is to rewrite ribosomal RNA (rRNA) and combine it with proteins Answer : (c)

Histones are basic proteins, and their positive charges allow them to associate with DNA, which is negatively charged. Some histones function as spools for the thread-like DNA to wrap around. Under the microscope in its extended form, chromatin looks like beads on a string. The beads are called nucleosomes. Answer : (c)

The demerits of cell theory are Structure of virus- Schleiden and Schwann could not explain the structure and functioning of virus cell. They said that the function of body is coordinated function of cell which is not true in the case of virus because it only starts it's functioning when hosted by bacterial, plant or animal cell. Prokaryotic cells- The cell theory do not holds true in the case of Pk cells because they do not have any well defined nucleus. Multinucleate condition- The cell theory says that each cell have A NUCLEUS, but there are certain cells like tapetal cells that are coenocytic. Cells without nucleus- Acc to cell theory there should be a nucleus in every cell, but human RBCs, sieve tubes of angiosperm are some of the cells lacking nucleus. Answer : (c)

In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes, and plasma (cell) membrane among others. Answer : (d)

Regions of chromatin where active transcription is taking place (called euchromatin) are less condensed than regions where transcription is inactive or is being actively inhibited or repressed (called heterochromatin) Answer : (c)

Singer and Nicolson (1972) proposed fluid mosaic model of plasma membrane. According to this model plasma membrane contains a lipid bilayer, which are interrupted by protein molecules. Some proteins attached at the polar surface of lipid (called, extrinsic proteins) while other partialy penetrate the lipid bilayer (called, intrinsic proteins). Intrinsic proteins are tightly binded whereas the extrinsic proteins are loosely binded to the lipid bilayer Answer : (b)

Peroxisomes contain enzymes that oxidize certain molecules normally found in the cell, notably fatty acids and amino acids. Lysosomes are membrane-enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids Ribosomes a minute particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins 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 Answer : (b)