Solved past paper bt 102

Q1. 1. What is flagellum? Give its functions?

Ans…… • Flagellum: Long filamentous structure that propels bacteria • Classification of bacteria based on flagella • Atrichous: No flagellum • Peritrichous: Distributed over the entire cell. Flagella are used for motility. Motility can be demonstrated by use of a cavity slide and a coverslip by hanging drop method shown in the diagram below: Bacteria exhibit two kinds of motility patterns:

Run and Tumble as seen below.

 Flagella move counterclockwise for forward thrust (run or swim)  Clockwise when tumbling

Q2. What is phosphorylation?

Anss… The addition of an inorganic phosphate group to a chemical compound is called phosphorylation. So, a phosphate is added to ADP to form ATP molecules in cells. In other words, energy derived from hydrogen containing organic molecules such as carbohydrates and fats is captured and concentrated in the form of ATP molecules

Q3.. Write three components of LPS?

Ans…Endotoxins: They are part of the outer portion of cell wall of gram negative bacteria. LPS is an example. LPS is released when gram negative cells die and their cell wall disrupts. Endotoxins cause release of cytokines (IL-1 and TNF) from macrophages. LPS and cytokine result in high fever. Endotoxins cause chills, fever, weakness, generalized aches, and, in some cases, shock (endotoxins cause vasodilation and blood pooling) and even death. Presence of LPS in fluids can be tested by limulus amebocytelysate assay which contains a clotting protein that clots when reacts with LPS.

Q4.. What is culture medium, culture and inoculums?

Ans…

Oculture:- This term is used to define growth of microbes. In other words, microbial growth in the lab is called a culture.  What is a culture medium? o A nutrient material that supports the growth of microbes in the lab is called a culture medium.

Inoculumn:-o Microbes introduced into a culture medium that initiate growth of organisms.

Q5.. Write down functions of cell membrane of bacteria?

Ans… We will not discuss cell membrane in detail as this is covered fully in basic biology course. So briefly, cell membrane is composed of a phospholipid molecules arranged tail to tail with heads facing away from each other. This makes lipid molecules to appear as a bilayer. So all membranes enclosing the organelle in the cell or the cell itself look as bilayer structures. This is the basic design of the plasma membrane. Protein and carbohydrates are also inserted into the plasma membrane as can be seen in the accompanying diagram.

• Selective permeable barrier • Passive and Active Transport • Respiration in microbes (bacteria) • Photosynthesis in microbes • Lipid synthesis • Cell wall parts are transported by a molecule called bactoprenol which is present in the plasma membrane. • PM has many receptors in it with which various ligands can bind and initiate signals for gene expression etc.

Q6. Write five types of bacteria which grow on optimal temperature?

Ans…

Q1.Three dfrnces between prokaryotes n eukaryotes?

Q2.: write the name of five layers of endospore?

Ans…Endospore and its various parts/structures • Exosporium: A thin delicate outermost covering of the spore • Spore coat: 2nd layer underneath the exosporium. It is thick and composed of several protein layers.  Resistant to chemicals  It contains enzymes for germination. Germination of spores into vegetative form occurs when environment becomes favorable for their growth. • Cortex: It is the 3rd layer from outside in. It has peptidoglycan in it.

• Spore cell wall or core wall: Surrounds the protoplast or spore core • Spore core: Contains nucleoid and ribosomes • Please see the diagram given below for details.

Q3. : write the name of three methods of glucose?

Ans.. Glucose is the most commonly used carb for all organisms. Microbes can derive energy from glucose in two ways: 1. Respiration (just remember, it is not breathing!) 2. Fermentation  Both these processes start with glycolysis but follow different subsequent pathways for deriving energy from glucose.  Respiration of glucose takes place in three general steps: • Glycolysis: Oxidation of glucose to pyruvicacid • Krebs cycle: Oxidation of acetyl CoA to CO2 • Electron Transport Chain: Coenzymes that carry electrons from Krebs cycle or glycolysis are oxidized to create ATP. • Respiration is further divided into two types:  Aerobic Respiration: If in the electron transport chain, the final electron acceptor is oxygen, it is called an aerobic respiration.

Q1.: Name two basic dyes?

Ans..Basic dye: The color is in the positive ion

Basic dyes are most commonly used for bacteria. Crystal violet • Methylene blue • Malachite green • Safranin

Q2. : Differentiate direct count and viable count?

Ans..

Q3. : Describe structural functions following: I. Ribosomesii.cell wall iii.flagella. 4

Ans..ribosomes:- Composed of proteins + ribosomal RNA  2 subunits • 70S ribosomes (when two units are combined into one unit)  50S: one rRNA  30S: two rRNA

 Several antibiotics act on ribosomes and inhibit protein synthesis • Streptomycin attach to 30S

Cell wall:-

Glagella:-

Q4:- Describe 5 bacterial which need oxygen for growth?

Ans…Based on the use and concentration of Oxygen, microbes can be classified into five groups: o Obligate Aerobes: Oxygen must be present for their growth. These organisms do not grow if O2 is not present in the medium. If you test these organisms in a tube containing nutrient agar, the growth will remain confined to the surface only (see the diagram for the concept).

 Mycobacterium tuberculosis is an example of such an organism.

o Facultative Anaerobes: These organisms prefer aerobic respiration; however, if oxygen is not available, they can use anaerobic respiration or fermentative modes for generating ATPs. These organisms will be present throughout the tube, however, more growth will be seen on the top (close to the surface) because these organisms prefer using oxygen if it is available.

Aerotolerant Aerobes: These organisms do not use oxygen and also are not bothered by the presence of oxygen. In other words, they have a better system to dispose of toxic oxygen compounds. They will grow evenly throughout the tube of medium as seen in the accompanying diagram.

o Obligate Anaerobes: Although, these organisms do not use oxygen, they cannot grow in the presence of oxygen. The reason is that oxygen creates toxic compounds which can kill these cells. Normally, oxygen toxic compounds are eliminated by the cells, however, strict anaerobe do not have a system to get rid of these toxic compounds when they are made in the cells. So using or not using oxygen is one thing and growing in the presence of oxygen (and not utilizing it) is another. The growth will remain confined to the bottom which has little oxygen. See the attached diagram.

Q5.: Define pilli and also its functions?

Ans… Cells have receptors with which adhesins or ligands of microbes attach. Adhesins may be located on a microbe’s glycocalyx or on other microbial surface structures, such as pili, fmbriae, and flagella. These are glycoproteins or lipoproteins composition wise.Used for DNA transfer from on bacterium to another: Conjugation (Sex pili)  Also function in twitching Motility  Gliding Motility is also the function of the pili.

Q6: Respiration of glucose?

Ans… Respiration of glucose takes place in three general steps: • Glycolysis: Oxidation of glucose to pyruvicacid • Krebs cycle: Oxidation of acetyl CoA to CO2 • Electron Transport Chain: Coenzymes that carry electrons from Krebs cycle or glycolysis are oxidized to create ATP. •

Q1.what is fluorochromates?

Ans…Fluorochromes are substances that absorb short wavelength of light and emit longer wavelength (visible light spectrum) o But how is this fluorescence created? Well, the fluorochromes are attached to antibodies that are specific to organisms. So, if an organism is present in the specimen, we can use specific antibodies to determine the presence of those organisms by use offluorochrome tagged antibodies. See the accompanying diagrams for details. Look for UV lamp (Mercury Lamp).

Q2.what is buffer?

Ans…Buffers in the culture o Bacteria grown in lab produce acids o Growth inhibited by acids o Buffers are used to maintain desired pH o Peptones and amino acids are used as buffers o Phosphates are also used for buffers

Q3.main components of polyliposacchrides?

Ans….Moreover, lipopolysaccharide is also integral part of Gram negative bacteria. This substance is exclusively present in the outer membrane and has pyrogenic properties. This is the reason that infection with Gram negative bacteria leads to relatively high fever. Please remember that there are other cytokines (Tissue necrosis factor, IL-1 and IL-6) also that cause fevers too.  Lipopolysaccharide molecule consists of 3 parts:

1. Lipid A: endotoxin

– Fever, vasodilation and shock

1. Core polysaccharidea. Structural support

2. O side chain

a. Antigenic much like teichoic acid in gram positive bacteria

Characteristics Gram Positive Gram Negative

Q4.components of media on the base of function?

Ans…Trace elements are not usually added in the growth medium, they are assumed to be present in complex media when you add meat extracts etc.

For microorganisms, they consist of providing trace elements and vitamins required by the microbe and especially definedcarbonandnitrogensources.Glucoseorglycerolare often used as carbon sources, andammoniumsaltsornitratesasinorganicnitrogen sources. An undefined medium has some complex ingredients, such asyeast extractor casein hydrolysate, which consist of a mixture of many chemical species in unknown proportions. Undefined media are sometimes chosen based on price and sometimes by necessity – some microorganisms have never been cultured on defined media.

Q5.chacteritics of metachromate granules?

Ans…Metachromatic Granules • Also called volutin, they stain red with certain dyes such as methylene blue. That is why they are called metachromatic (stain in different color as methylene blue gives blue color but the color on these granules is red). • Large inclusions • These inclusions contain inorganic phosphates. Inorganic phosphates are used up in ATP synthesis. • Characteristics of Corynebacterium diphtheria: This bacterium can be identified by the presence of these granules in it. 

Q1: What is resolution?

Ans… Resolution is the ability of the lenses to distinguish between two closely lying objects as separate. See the accompanying diagram for visual concept of resolution. o Light microscope resolving power is 0.2 µm.

Q2.: What is sportualtion?

Ans… Formation of spores takes place within a vegetative cell and the process is called sporulation or sporogenesis. It is initiated when nutrients become unavailable. In-growth of plasma membrane (spore septum) is the first step when an organism chooses to go for sporulation

Q3.3: What is culture, culture medium and inoculum?

Repwat

Q4.Difference between prokaryotes and eukaroytes?

Repeat

Q5.Nanme 5 kingdoms

Protistaplantaeanimalea fungi

Monera

6:Name of five bacterium to use oxygen growth.

Repeat

Q1Q.1 define phosphorylation

Repeat

Q2.what is apiphatic molecules?

Ans.. Peripheral Proteins, are found hanging outside the membrane  Loosely connected to the membrane  Soluble in water Integral proteins are inserted in the membrane or embedded in the membrane  Insoluble in water  Amphipathic in nature

Q3..3 Name three components of lipopolysaccharide Q.4 define the term culture medium, Inoculum and culture Q.5Write the five uses of cell membrane in bacteria Q.6 write the characteristics of metachromatic granules

Ans all repeated ques in previus

My today’s paper of bt102 Total question 26 mcqs 20 questions 6 Mcqs: Rings in gram – bacteria….. Magnification power of light microscope…… Half of Dry weight consists of ……. First diagram of microbes published in ………. Method of hot air sterilization ,……… Ribosome consists of ………… One mcqs was about ethylene oxide page number 152 of handouts.. Bacteria which grow in high salt concentration……. Alpha hemolysis makes …….colored halo One mcq about photoposphorylation Bacteria without flagella called…………

Question 1 What is flagellum?write functions 2

Ans..repeat

What are physical requirements for the growth of bacteria.3

Ans… Physical: • Temperature • pH • Osmotic Pressure

On page number 26 of the handouts and slide number 9

the image of electron microscope was given and we have to label that diagram.5

Megnetosomes characteristics 5 marks

Ans…Magnetosomes • Inclusions of iron oxide • Surrounded by invaginations of plasma membrane • Present in G negative bacteria• Act like a magnet. Bacteria can stick to iron containing rocks for nutrition. • Decompose H2O2 which is toxic for cells. 

Why solid medium is good than liquid medium for the growth of bacteria? 2

Ans…s solid medium provides surface for individual colonies to grow well separated from each other. A well isolated colony is assumed to be the progeny of a single cell

What is function of cell wall.

Ans..repeated

Two basic stains.2

Ans…repeated

Stages of Germination spore.3

• Spore germinates when it finds a conducive environment for its growth. Germination has 3 phases or stages:  Activation: It prepares the spore for germination.  Heat can activate the spore when appropriate moisture and nutrients are present in the environment.  Germination: Spore starts swelling and loosing its coats etc.  It becomes metabolically active.  Outgrowth: New components are made.

Five names of Microscopy5

Ans…dark field microscopy, phase contrast microscopy, flouresent microscopy, transmission electron microscopy, scaning electron microscopy,

Five names of walls of endospores5

repeaated

What are the physical and chemical methods for making Smear on the slide 3

Heating the slide is one way of fixing the smear. • Methyl alcohol can be used.

What is Microaerophiles2

Ans……Amicroaerophileis amicroorganismthat requiresoxygento survive, but requires environments containing lower levels of oxygen than are present in theatmosphere(i.e. <21% O2; typically 2–10% O2).[1][2]Many microaerophiles are alsocapnophiles, requiring an elevated concentration ofcarbon dioxide(e.g. 10% CO2in the case ofCampylobacterspecies).

BT102

Name three subgroup of spiral bacterium. (3)

Ans…There are manytypesofspiral-shapedbacteriamainly included in the phylum, Spirochaete. Within this phylum there are three families

Spiral-shaped bacteria are called spiral bacteria.These types of microorganisms come in three various forms, which include vibrio, spirillum and spirochete

Name three steps of respiration of glucose.(3)

Ans….repeated

Give the characteristic of microaerophlis.(2)

Ans…Microaerophiles can be cultivated in candle jars. Candle jars are containers into which a litcandleis introduced before sealing the container'sairtightlid. The candle's flame burns until extinguished by oxygen deprivation, creating a carbon dioxide-rich, oxygen-poor atmosphere.[4]Other methods of creating a microaerobic environment include using a gas-generating pack and gas exchange.[3]

Differentiate between differential and simple staining.(2)

Ans…. Simple Staining: only one stain is used.  Methylene Blue staining • Differential Staining: A couple of stains used.  Gram Staining • Special Staining:  Endospore staining

Simple staining:-A single stain is used. • Stain is washed off. • A mordant is added, sometimes. • Microbes seen under the microscope.  Examples of simple stains:  Methylene blue  Carbolfuchsin Crystal violet, and safranin

Differential staining:- Differential stains react differently with different kinds of bacteria. • Most common is Gram staining. • 1884, by Hans Christian Gram • Follow the diagram given below to see the steps involved in Gram’s staining Differential stains react differently with different kinds of bacteria. • Most common is Gram staining. • 1884, by Hans Christian Gram • Follow the diagram given below to see the steps involved in Gram’s staining

What are pilli.give its function.(5)

Ans….Conjugation requires direct cell to cell contact and cells have to be opposite mating types. Plasmids in G –ive cells have genes that code for sex pili because pili are needed to make a bridge between the two mating type cells. Since there is no pilus present in G +ve bacteria, they secrete sticky surface molecules instead which create contact between the two cells. The pilus along with two mating cells is shown in the diagram below

Used for DNA transfer from on bacterium to another: Conjugation (Sex pili)  Also function in twitching Motility  Gliding Motility is also the function of the pili.

Name the five layers of endospore.(5)

Ans…repeated

Two basic stains.

Anss…repeated

Stages of Germination spore.

Ans..repeated

Five names of Microscopy

Ans…repeated

Five names of walls of endospores

Ans….repeated

What are the physical and chemical methods for making Smear on the slide

repeated

What is Microaerophiles

Ans…Amicroaerophileis amicroorganismthat requiresoxygento survive, but requires environments containing lower levels of oxygen than are present in theatmosphere(i.e. <21% O2; typically 2–10% O2).[1][2]Many microaerophiles are alsocapnophiles, requiring an elevated concentration ofcarbon dioxide(e.g. 10% CO2in the case ofCampylobacterspecies).

BT102

MCQs Rings of G_ve(

bacteria Microscope first diagram was published in...??

Kingdom Monera contain..??

Sample or slide is placed on..??

Study of fungi is called..??

Syphilis is caused by..?

Short Question

Coenzyme and examples

Ans…Coenzymes such as NAD, NADP, FAD, FMN etc. are used as carriers of these electrons in oxidation reduction reactions. In many cellular oxidations, electrons and protons (hydrogen ions, H+) are removed at the same time.  This is equivalent to removal of hydrogen atoms. (Hydrogen has one electron and one proton).  Most biological oxidations involve the loss of hydrogen atoms, they are also called dehydrogenation reactions

Name five kingdoms(5

Ans…repeated

) Parts of endospor(5

Ans…repeated

) What is refractive index

Ans… Refractive Index: Ability of a medium to bend the light o Light rays move in a straight line through a single medium o Light rays bend when the pass from one medium to another o We use cedar wood oil to eliminate this bending of light in microscopy. Cedar wood oil has the same refractive index as that of the glass (1.5), so that the light rays do not bend when they pass through the specimen into the objective lens of the microscope. This provides a brighter and better image. o To further increase the image contrast, we stain the specimen with various dyes.

Parts of flagella.

Ans… A flagellum consists of the following 3 parts as shown in the accompanying diagram below: • Filament: It is made of a protein called flagellin, which makes H antigen that can be used for serovar identification in gram negative bacteria. • Hook: A different protein • Basal Body: The most complex  This is the diagram of a gram negative flagellum:  It has 4 rings in the basal body.  Gram negative cells have two plasma membranes (outer membrane is in addition to the actual inner plasma membrane).