BIOL2051 lab quizzes 1-4

When you calculate population standard deviation, you take the square root of the summed squared differences divided by the total number of observations minus 1. Select one: True False

False

You cannot use a colony from a streak plate to determine the colony morphology. Select one: True False

False

When viewing prepared slides of stained flagellated bacteria, you must put oil on the coverslip to view with 100x. Select one: True False

True

When you take an isolated colony from a streak plate to streak onto another plate, you are subculturing cells. Select one: True False

True

While making a smear, aseptic technique must be used. Select one: True False

True

When a turf of flagella are attached at one end, the flagella arrangement is called _____________________. When a bacterium has one or more flagella at each end of the cell, the flagella arrangement is called __________________. Select one: a. peritrichous; lophotrichous b. amphitrichous; lophotrichous c. lophotrichous; amphitrichous d. monotrichous; peritrichous e. peritrichous; amphitrichous

c. lophotrichous; amphitrichous

How will you secure the coverslip to the depression slide for the hanging drop method? Select one: a. with glue b. with saliva c. with petroleum jelly d. with immersion oil

c. with petroleum jelly

Beige would describe the pigmentation of ______________________. Select one: a. Streptomyces coelicolor b. Escherichia coli c. Micrococcus luteus d. Serratia marcescens

b. Escherichia coli

What term describes a group of spherical bacterial cells? Select one: a. Spiral b. Streptococci c. Streptobacilli d. Staphylobacilli e. All of the above

b. Streptococci

If you only see growth in quadrant 1 of your streak plate, what may have happened? Select one: a. You added more bacteria from the broth for each quadrant. b. You did not streak back into quadrant 1 far enough while streaking quadrant 2. c. You went too far back into quadrant 1 while streaking quadrant 2.

b. You did not streak back into quadrant 1 far enough while streaking quadrant 2.

You will perform a Gram stain from your ____________ plate. Select one: a. streak b. EMB c. sporulating d. stock

a. streak

Match the term with the best description from the drop-down list. 1.Stage 2.Eye pieces 3.Coarse focus knob 4.The oil-immersion objective 5.Fine focus knob

1. Place the slide holding the smear on this 2. Fixed magnification at 10X 3. Use this knob first when focusing with all objectives 4. 100X 5. Use this knob when using the 100X objective

If you do not wait until the loop turns red in the flame, your loop may not be dry heat sterilized. Select one: True False

True

M. smegmatis is a BioSafety Level 1 organism. Select one: True False

True

When performing aseptic technique, if you take the cap off the tube and don't know where to put it, it is okay to place it on the bench top. Select one: True False

False

Decolorization with acid alcohol removes the carbolfuchsin from the acid-fast cells. Select one: True False

False

Gram stain all 4 of your biofilm slides. Select one: True False

False

Immersion oil which is placed between the specimen and the objective increases magnification. Select one: True False

False

Microscope slides do not make good surfaces for biofilm formation. Select one: True False

False

Most bacterial cells are smaller than 0.2 microns. Select one: True False

False

Bacterial biofilms form tight aggregates that do not allow any water, nutrients, or antibiotics to penetrate at all. Select one: True False

False

Biofilms consist of only one type of organism because signals are species specific. Select one: True False

False

Why is a counterstain added? Select one: To stop the effects of the ethanol In order to see Gram negative cells To make the gram positive cells brighter

In order to see Gram negative cells

A cloudy slide with an obvious film on the surface is good evidence of biofilm formation on the microscope slide that was submerged in a water sample for a week. Select one: True False

True

A culture of Gram positive cells older than 72 hours may not produce a good Gram stain because older cells do not retain the crystal violet bound to the iodine as well as younger cells. Select one: True False

True

A smear is the first step in making a simple stain. Select one: True False

True

Botulism in infants has been associated with the consumption of honey contaminated with endospores from Clostridium. Select one: True False

True

If we had grown E. coli on a plate with different media than used in class, we might have seen a change in colony size, shape, or color. Select one: True False

True

Which of the following statements is true? Select one or more: a. Every molecule is known in defined media. b. Complex media is used for routine culturing because it is easier to make. c. If an extract from yeast, plant, or animal is used in the media then it is complex.

a. Every molecule is known in defined media. b. Complex media is used for routine culturing because it is easier to make. c. If an extract from yeast, plant, or animal is used in the media then it is complex.

While performing the acid-fast stain you accidentally forgot to add the methylene blue. The non-acid-fast bacteria will appear pink. Select one: a. False b. True

a. False

S. linguale is __________________ Select one: a. Gram negative spiral b. Gram negative coccus c. Gram positive coccus d. Gram negative rod

a. Gram negative spiral

Which of the following are in accordance with aseptic technique? (Choose the best answer.) Select one or more: a. Hold the culture tube top in the same hand with which you hold the loop. b. Pass mouth of tube through flame rather than holding the tube in the flame. c. Always wash the bench top when entering the lab. d. Keep only necessary materials on the bench top.

a. Hold the culture tube top in the same hand with which you hold the loop. b. Pass mouth of tube through flame rather than holding the tube in the flame. c. Always wash the bench top when entering the lab. d. Keep only necessary materials on the bench top.

A doctor going into surgery vigorously washes his hands well and then suits up with gloves. Why might he still need gloves even if he washed his hands really well, even with antibiotic soap? Select one or more: a. Normal flora may be harmful when introduced into tissues or the bloodstream. b. More of doctor's normal flora has been exposed. c. The patient has their own transient flora. d. Washing hands do not rid them entirely of bacteria.

a. Normal flora may be harmful when introduced into tissues or the bloodstream. b. More of doctor's normal flora has been exposed. c. The patient has their own transient flora. d. Washing hands do not rid them entirely of bacteria.

You do a Gram stain on a known mixed culture and all you see are red-stained bacteria. It had been a long time since you did a Gram stain, and you did not have a written procedure to follow so you may have messed up a step. Choose all of the following scenarios which could be true. Select one or more: a. You forgot to add iodine b. You may have decolorized too long c. The culture could contain Stapylococci that are older than 24 hrs d. The culture contains only Gram-negative bacteria

a. You forgot to add iodine b. You may have decolorized too long c. The culture could contain Stapylococci that are older than 24 hrs d. The culture contains only Gram-negative bacteria

The purpose of the condenser on the microscope is to: Select one: a. collects and concentrates light b. regulates light c. allows minimum light rays to pass through d. allows maximum light rays to pass through e. condense the wavelength of light

a. collects and concentrates light

The stage of biofilm formation following attachment is Select one: a. colonization b. invasion c. penetration d. development

a. colonization

Which type of microscopy uses only diffracted light rays from the specimen to contribute to the visible image? As a result, how does the image appear? Select one: a. darkfield, image light on dark background b. darkfield, image seen only after staining c. phase-contrast, images have significant contrast d. phase-contrast, images light on dark background e. brightfield, images are dark after staining

a. darkfield, image light on dark background

Under what conditions does sporulation occur? Select one: a. harsh environmental conditions b. favorable environmental conditions c. plenty of nutrients or water d. optimal growth conditions e. when time is right to reproduce

a. harsh environmental conditions

Which of the following will you perform with a mixed broth culture for day 1 of experiment 3 Obtaining a Pure Culture? Select one or more: a. make a smear and perform a simple stain b. inoculate a broth c. perform a streak plate d. make a smear and perform a Gram stain

a. make a smear and perform a simple stain c. perform a streak plate

Which of the following terms does not describe the elevation of a colony? Select one: a. smooth b. flat c. umbonate d. convex

a. smooth

Which of the following is not needed for the endospore stain? Select one: a. clothes pin b. carbolfuchsin c. paper square d. malachite green e. microscope slide

b. carbolfuchsin

Mycobacterium bacteria are considered acid-fast because the cells Select one: a. are hydrophobic b. retain carbol fuchsin after decolorizing with acid-alcohol c. need gentle heat to take up the Carbol-fuchsin d. cannot be stained with methylene blue e. All of the above

b. retain carbol fuchsin after decolorizing with acid-alcohol

How many flagella does Chlamydomonas reinhardtii have? Select one: a. 0 b. many c. 2 d. 1

c. 2

Why do you need to keep the slide on the slide warmer for a FULL 5 minutes? Select one or more: a. Because the cells will lyse if left on for less than 5 minutes. b. Because the cellular morphology will be destroyed. c. Because your smear might wash off during staining. d. Because the cells will not be heat fixed if on for less than 5 minutes.

c. Because your smear might wash off during staining. d. Because the cells will not be heat fixed if on for less than 5 minutes.

Allergies have been bothering you lately. As you were inoculating your streak plate with E. coli you sneeze. With a plate in one hand and an inoculating loop in the other you were unable to quickly cover your mouth. You tried to sneeze into your arm but your unstifled sneeze was greater than your arm could shield. Following incubation of your plate, what do you expect to see on the plate next lab? Select one or more: a. Nothing because you did not inoculate the plate. b. Nothing because the media in the plate was sterilized. c. Microorganisms are in the air transiently so there could be growth from contaminates in the air. d. There will be E. coli along with bacteria from your mouth on the plate.

c. Microorganisms are in the air transiently so there could be growth from contaminates in the air. d. There will be E. coli along with bacteria from your mouth on the plate.

What does the iodine do in a Gram stain? Select one: a. seals the outside of the cell to prevent the stain from leaving Gram-positive cells b. binds to the counterstain and prevents the stain from leaving the Gram-negative cells c. binds to the primary stain and prevents the stain from leaving the cells with a thick peptidoglycan cell wall d. decolorizes Gram-negative cells

c. binds to the primary stain and prevents the stain from leaving the cells with a thick peptidoglycan cell wall

Put the Gram stain procedure in order: i. crystal violet, ii. methylene blue, iii. iodine, iv. ethanol, v. methanol, vi. safranin, vii. teichoic acids Select one: a. ii, v, iii, vii b. ii, iv, iii, vi c. i, iii, iv, vi d. i, iv, iii, vi e. iii, v, ii, i, vi

c. i, iii, iv, vi

If you made a streak plate from a pure culture, how many different colony morphologies could you expect? Select one: a. none b. 2 c. 4 d. 1 e. 3

d. 1

Which of the following statements is correct? Select one: a. Crystal violet is considered a differential stain. b. Sporulation occurs when there are plenty of nutrients and water available. c. In a gram stain, ethanol is used as the mordant. d. Bacillus species are capable of undergoing sporulation. e. Endospores are considered reproductive structure.

d. Bacillus species are capable of undergoing sporulation.

Which of the following statements is completely correct? Select one: a. Gram+ bacteria will stain purple and have little peptidoglycan in their cell walls b. Gram- bacteria will stain purple and have little peptidoglycan in their cell walls c. Gram- bacteria have techoic acids and have many layers of peptidoglycan in their cell walls d. Gram+ bacteria have techoic acids and have many layers of peptidoglycan in their cell walls e. Gram+ bacteria will stain orange and have an outer me

d. Gram+ bacteria have techoic acids and have many layers of peptidoglycan in their cell walls

Crystal violet is Select one: a. a simple stain b. a differential stain c. used in the Gram stain d. All of the above. e. Answer choices a and c.

e. Answer choices a and c.

Which of the following statements is NOT correct? Select one: a. In an endospore and an acid-fast stain, heat is used to drive the primary stain into the cells. b. Botulism is a disease that is caused by an endospore forming bacterial species. c. Clostridium and Bacillus are two genera that commonly form endospores. d. The complex of dipicolonic acid and calcium gives the endospores its heat resistant properties. e. Under optimal growth conditions, vegetative cells are said to be in a cryptobiotic state.

e. Under optimal growth conditions, vegetative cells are said to be in a cryptobiotic state.