Quiz by yp-with answers

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Quiz by yp-with answers

  1. 1. Answer the following questions:1) Mesosomes are the internal extensions of the cell membrane and fold into the cytoplasm.2) Mating between genetically very closely related individuals are called inbreeding.3) Haploid cells have one complete set of chromosomes. In animals, gametes (male) spermatozoa and female ovum are haploid.4) The three forms of pyrimidines present in nucleic acids are Cytosine, Thymine and Uracil5) In general cow milk constitutes .......% water, ........ % lactose, ........% protein and .........% fat.6) The cow milk dominantly constitutes the following three indigenous enzymes: Lipoprotein lipase Alkaline phosphatase Plasmin7) Cow milk contains various saturated and unsaturated fatty acids. The unsaturated fatty acids available in the cow milk are Oleic acid and linoleic acid8) What is the name of the first cloned sheep? Dolly9) Media containing bile salts as selective agent are: MacConkey Agar and Eosin Methylene blue (EMB) Agar for isolating intestinal pathogens. These types of media are termed as selective media. (MacConkeys is a selective medium that inhibits the growth of Gram-positive bacteria due to the presence of crystal violet and bile salts. Gram-negative bacteria grow well on MAC. MacConkey’s contains two additives that make it differential; neutral red (a pH indicator) and lactose (a disaccharide). Bacteria, known as “lactose fermenters”, eat the media’s lactose, and, in the process, create an acidic end product that causes the pH indicator, neutral red, to turn pink. With MacConkey’s, it is not the media that changes color, but rather the actual colonies of lactose fermenting bacteria that appear pink. Non-lactose fermenting bacteria will be colorless (or, if they have any color, will be their natural colour rather than pink).10) Sabouraud dextrose agar is used for growing fungi. It is recommended for skin and nail fungi, as well as other species that are human pathogens.11) The entire broth medium contains agar as one of the essential components. (True/False). It’s only a solidifying/hardening agent and most organisms can’t utilize it as food.12) A solution with a pH of 2 has more H+ ions than a solution with pH of 8.13) Good laboratory practices (work practices) allow bringing and eating food on the working bench in biotech laboratories. (True/False)14) The media containing complex organic substances such as blood serum, haemoglobin or special growth factors that certain species must have in order to grow are called Enriched media.
  2. 2. 15) Autoclaving can be achieved at 121 0C temperature and 15lb/in2 saturated steam pressure for 15 minutes.16) Genetic analysis of bacteria would be G+C contents. (True/False)17) Messenger RNA is formed by transcription of a gene on the DNA template strand.18) The base pairs are held together primarily by H-bond.19) Nitrogen bases found in DNA and RNA are cyclic compounds that come in two forms; purines and pyrimidines. Two types of purines are Adenine and Guanine20) The extra chromosomal DNA in bacteria is called plasmid.21) Which gene is incorporated into plasmids to detect recombinant cells? - a gene for antibiotic resistance.22) A nucleotide contains which of the following? a) Pentose sugar b) Nitrogen base c) Phosphate d) b and c only e) All the above23) What is the smallest unit of heredity? – gene24) Which is not true in the case of PC-1 Lab? - Appropriate for students and teaching labs - Suitable for working with m/orgs where the hazard level is very low - Work may be carried out on the open bench. - Provides safeguards to minimize the risk of infection to individuals, the community and the environment.25) Which is true for PC-4? - This level of facility with its practices and equipments is applicable to work with very dangerous micro-organisms - This level of facility with its practices and equipments is applicable to work with exotic or indigenous m/orgs where there is a risk of serious infection to human, animals or plants - This level of facility with its practices and equipments is applicable to work with micro- organisms associated with human, animal or plant diseases of moderate severity. - This level of facility with its practices and equipments is applicable to work with micro- organisms of low hazard level26) Sarcines are the cocci that come in packets of eight cells.27) The space between Peptidoglycan layer and plasma membrane is periplasmic space.28) The cell wall of Gram positive bacteria is thicker than that of the Gram negative.29) The cells that naturally have no walls or have very little wall material include members of the genus Mycoplasma and related organisms.30) Mycoplasma are the smallest known bacteria that can grow and reproduce outside the living hosts cells.
  3. 3. 31) Cells that can grow at very high temperature (80 – 1200C) are called hyperthermophiles .32) The bacteria that can grow at low pH values of 1-2 and hence cause many problem in human stomach is Helicobacter pylori.33) The solution containing normal salt concentration is called isotonic.34) Those bacteria which grow with or without oxygen are called facultative anaerobes.35) Those bacteria that can’t use oxygen but are not killed in presence of some amount of oxygen are called aerotolerant anaerobes.36) Reactive oxygen are found in: peroxide, singlet oxygen and oxygen radicals.37) What are the five essential structural components of bacterial cells ?38) A coating or layer of molecules external to the cell wall which serves as a protective, adhesive and receptor functions is called glycocalyx.39) An elongated hollow appendages used in transfer of DNA to the other cells and also helps in cell adhesion is called pilus.40) Specialized appendage attached to the cell by a basal body that holds a long rotating filament is called flagella.41) Fine hair like bristles from the cell surface that help in adhesion to other cells and surfaces is called fimbriae.42) Stored nutrients such as fat, phosphate or glycogen deposited in dense crystals that can be tapped into when needed is called inclusion or granule.43) Cell wall is a semi-rigid casing that provides structural support and shape to the cell.44) A thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials into and out of the cell pool is called cell membrane.45) Tiny particles composed of proteins and RNA and are the sites of protein synthesis: ribosomes.46) Which is not the function of capsules? - Attachment to surfaces - Protection against phagocytic engulfment - Protection against desiccation - Reserve of nutrients - Mediates DNA transfer during conjugation47) What are the parts of a flagellum? – filament, basal body and hook.
  4. 4. 48) What are the arrangements of flagella in bacteria? - Monotrichous, amphitrichous, lophotrichous, peritrichous49) The type of arrangement in which flagella are dispersed randomly over the surface of the cells is called - peritrichous50) Flagellated bacteria can detect and move in response to the chemical signals. This behaviour is called chemotaxis.51) A flagellum rotates counter clock wise, the cell itself swims in a smooth linear direction towards the stimulus. This is called a run.52) Runs are interrupted by tumbles.53) E. coli is peritrichous. (amphitrichous/peritrichous/lophotrichous/monotrichous).54) Pilus is made up of a special protein pilin.55) Pilli are generally found in Gram positive/Gram negative bacteria.56) The external covering of bacteria called envelope has three basic layers: glycocalyx, cell wall, cell membrane.57) A capsule is bound more tightly to the cell than a slime layer.58) Capsules are formed by some pathogenic bacteria. Three examples: Streptococcus pneumonia, Haemophilus influenza and Bacillus anthracis.59) The cell wall of most bacteria gain their relatively rigid quality from a unique macromolecule called Peptidoglycan.60) Peptidoglycan is composed of repeating units of long glycan chains cross-linked by short peptide fragments to provide a strong but flexible support framework.61) The peptidoglycan layer of Gram positive bacterial cell wall is thick. (True/False)62) Gram positive cell wall consists of acidic polysaccharides including Teichoic acid and lipoteichoic acid.63) Teichoic acid is a polymer of ribitol or glycerol and phosphate.64) Lipotechoic acid is similar in structure like Teichoic acid but is attached to the lipids in the plasma membrane.65) Teichoic acid and lipoteichoic acid function in cell wall maintenance and enlargement during cell division and they also contribute to the acidic charge on the cell surface.66) The uppermost layer of outer membrane in Gram negative bacteria contains lipopolysaccharide.67) The Gram negative cell wall is more impervious to some antibiotic and chemicals such as dyes and disinfectants due to the presence of outer membrane.
  5. 5. 68) Alcohol- based compounds which can dissolve the lipids in the outer membrane can easily damage the integrity of the cell.69) The lipids in the cell wall of Gram negative bacteria can stimulate the anaphylaxis and fever in human beings. So it is called as endotoxin.70) The causative agent of bacterial meningitis: Haemophilus influenza, Neisseria meningitides, Klebsiella pneumonia, Streptococcus pneumonia and E.coli.71) The causative agent of typhoid fever is Salmonella typhi.72) One is the difference in Gram positive and Gram negative bacterial cell wall is the presence of a special protein in Gram negative cell wall. This is called porin.73) Mycobacterium and Nacordia contain PG and stain as Gram positive but bulk of their cell wall is composed of unique lipids called mycolic acid which stain with Acid fast colour.74) The thickness of cytoplasmic membrane is 5-10 nm.75) Cell membrane is primarily composed of phospholipids and proteins.76) Mesosomes are internal pouches in cell membrane prominent in Gram positive bacteria.77) Which of the following is not a spore forming bacteria? a) B. anthracis b) B. subtilis c) Cl. botulinum d) Cl. perfringens e) E.coli78) Which of the following is not eukaryote? a) Bacteria b) Yeast c) Protozoa d) mold79) Long thin filaments of fungi are called hyphae.80) The discrete mound of cells that is formed from a single cell is called a colony. It consists of just one species of micro organisms.81) Agar is a complex polysaccharide isolated from red algae, Gelidium and is widely used in liquefiable solid media.82) The sterilized medium are cooled to about 45-50 degree C, then poured aseptically onto sterile petri plates.83) Sterilization also includes the destruction of endospores (True/False).84) Bacteria that require growth factors and complex nutrients are termed fastidious.85) Selenite and brilliant green dye are used in media to isolate Salmonella from faeces.86) Mannitol salt agar is used to isolate Staphylococcus because they can grow in presence of 7.5% sodium chloride whereas many other species are inhibited by such high salt concentration.87) The mordant used in Gram’s staining is iodine.
  6. 6. 88) Those bacteria which retain crystal violet colour and appear violet during Gram’s staining are called Gram positive.89)

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