micro eoc review questions ch 1,3,4,5

8/4/2019 Micro EOC Review Questions CH 1,3,4,5

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Review CH 1

EOC Questions: Review:2, 3cef, 4, 5, 6acghl, 7; MC:1-5, 10; CT: 2, 4; CA: 1, 2

2. Some proponents of spontaneous generation believed that air is necessary for life. They thought that

Spallanzani did not really disprove spontaneous generation because he her-metically sealed his flasks to keep air

out. How did Pasteurs experiments address the air question without allowing the microbes in the air to ruin his

experiment?Pastuers S-neck flasks allowed air to get into the broth but the curves of the S trapped the bacteria before it could

enter into the broth.

3. Briefly state the role played by microorganisms in each of the following:

c. normal microbiota- normal microbial are microorganisms found on the human body and do not usually cause

disease. They are usually beneficial

e. human insulin production- Organic matter in sewage is decomposed by bacteria into carbon dioxide, nitrates,

phosphates, sulfate, and other inorganic compounds in a wastewater treatment plant.

f. vaccine production- Recombinant DNA techniques have resulted in insertion of the gene for insulin production

into bacteria. These bacteria can produce human insulin inexpensively.

4. Into which field of microbiology would the following scien-tists best fit?

Studies biodegration of toxic wastes- biotechnology, microbial genetics

Studies the causative agent of Ebola hemorrhagic fever- virology

Studies the production of human proteins by bacteria- biotechnology, microbial genetics, molecular biology

Studies the symptoms of AIDS- Immunology

Studies the production of toxin E.coli- microbial physiology

Studies the life cycle ofCytosporidium- microbial ecology

Develops gene therapy for a disease ____ immunology, microbial genetics

Studies the fungus Candida albicans- mycology

5. Match the following microorganisms to their descriptions.

___ Archaea ( g) Prokaryote without peptidoglycan cell wall___ Algae ( d) Cell wall made of cellulose; photosynthetic

___ Bacteria ( c) Cell wall made of peptidoglycan

___ Fungi ( b) Cell wall made of chitin

___ Helminths ( f) Multicellular animals

___ Protozoa ( e) Unicellular, complex cell structure lacking a cell wall

___ Viruses ( a) Not composed of cells

6. Match the following people to their contribution toward the advancement of microbiology.

Flemming- c) Discovered penicillin

Jenner- a) Developed vaccine against smallpox

Lister- g) First to use disinfectants in surgical procedures

Van Leeuwenhook- h) First to observe bacteria

7. The genus name of a bacterium is erwinia and the specific epithet is amylovora. Write the scientific name of this

organism correctly. Using this name as an example, explain how scientific names are chosen.

Erwinia amylovora is the correct way to write this scientific name. Scientific names can be derived from the names

of scientists. In this case, Erwinia is derived from Erwin F. Smith, an American plant pathologist. Scientific names

also can describe the organism, its habitat, or its niche. E. amylovora is a pathogen of plants ( amylo- starch; vora

eat).


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1. Which of the following is a scientific name?

a. Mycobacterium tuberculosis

b. Tubercle bacillus

2. Which of the following is not a characteristic of bacteria?

a. are prokaryotic

b. have peptidoglycan cell wallsc. have the same shape

d. grow by binary fission

e. have the ability to move

3. Which of the following is the most important element of Kochs germ theory of disease? The animal shows

disease symptoms when

a. the animal has been in contact with a sick animal.

b. the animal has a lowered resistance.

c. a microorganism is observed in the animal.

d. a microorganism is inoculated into the animal.

e. microorganisms can be cultured from the animal.

4. Recombinant DNA is

a. DNA in bacteria.

b. the study of how genes work.

c. the DNA resulting when genes of two different organisms are mixed.

d. the use of bacteria in the production of foods.

e. the production of proteins by genes.

5. Which of the following statements is the best definition of biogenesis?

a. Nonliving matter gives rise to living organisms.

b. Living cells can only arise from preexisting cells.

c. A vital force is necessary for life.

d. Air is necessary for living organisms.

e. Microorganisms can be generated from nonliving matter.

10. Which of the following statements about E. coli is not true?

a. E. coli was the first disease- causing bacterium identified by Koch.

b. E. coli is part of the normal microbiota of humans.

c. E. coli is beneficial in human intestines.

d. A disease- causing strain of E. coli causes bloody diarrhea.

e. none of the above

CT:

2. Even though the germ theory of disease was not demonstrated until 1876, why did Semmelweis ( 1840) and

Lister ( 1867) argue for the use of aseptic techniques?

Though the theory was not completely known, Semmelweis and Lister observed healthier or more positive results

from their patients with their new procedures. Semmekweiss was the father of hand washing. He observed that

women in hospitals who were giving birth contracted child bed fever and died. He made the connection between

the doctors in the hospital who would complete a surgery and not wash their hands and the deliver a baby. Lister

that carbonic acid kills bacteria so he began treating surgical wounds with it and it reduced the incedents of

infections and death.


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4. People believed all microbial diseases would be controlled by the 21st century. Name one emerging infections

disease. List three reasons why we are identifying new diseases now.

H1N1 is an new emerging disease. We are identifying new diseases now because 1. Evolution of existing

organisms 2. The spread of disease to new regions because of advances made in transportation 3. Increased

exposure to new infections in areas that are undergoing ecological changes such as deforestation/construction

CA:1. The prevalence of arthritis in the United States is 1 in 100,000 children. However, 1 in 10 children in Lyme, Con-

necticut, developed arthritis between June and September in 1973. Allen Steere, a rheumatologist at Yale

University, investigated the cases in Lyme and found that 25% of the patients remembered having a skin rash

during their arthritic episode and that the disease was treatable with penicillin. Steere concluded that this was a

new infectious disease and did not have an environmental, genetic, or immunologic cause.

a. What was the factor that caused Steere to reach his conclusion?

Penecillin is an antibiotic; if it was used successfully for treatment, then a microorganism was responsible for the

symptoms. Antibiotics are used to treat infections caused by microbes

b. What is the disease? Lyme Disease

c. Why was the disease more prevalent between June and September?With the warmer summer climate in the

New England region and lack of school, children would play outside. The pathogen Borrelia burgdorferiis carried

by ticks located outside where children play.

2. In 1864, Lister observed that patients recovered completely from simple fractures, but compound fractures had

disastrous consequences. He knew that the application of phenol ( carbolic acid) to fields in the town of Carlisle

prevented cattle disease. In 1864, Lister treated compound fractures with phenol, and his patients recovered

without complications. How was Lister influenced by Pasteurs work? Why was Kochs work still needed?

Pasteurs work gave evidence that air itself was not responsible for such phenomena as rotting food and abnormal

growths. Inspired by this, Lister took it one step further in that what was responsible could be contained or

destroyed. Theorizing that phenol stifled such a cause that resulted in cattle disease, Lister applied this to patients

with compound fractures. Although Lister was able to come up with procedures to increase healthy recoveries of

such patients, Kochs work was still necessary to actually identify microorganisms which caused disease.

CH3

EOC Questions: Review: 1 - 5, 7 -13; MC:1, 3, 6-8, 10; CT: 1, 3, 4; CA: 2, 3, 4

1. Fill in the following blanks.

1 um= 10-6

m

1 nm=10 -9 m

1 um= 103nm

2. Which type of microscope would be best to use to observe each of the following?

a. a stained bacterial smear compound microscope

b. unstained bacterial cells when the cells are small and no detail is needed - darkfield microscope

c. unstained live tissue when it is desirable to see some in-tracellular detail- phase-contrast

d. a sample that emits light when illuminated with ultravio-let light- florescent

e. intracellular detail of a cell that is 1 um long - electron

f. unstained live cells in which intracellular structures are shown in color- differential interference contrast

microscope

3. Label the parts of the compound light microscope in the figure below:


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a. ocular lense

d. condenser

b. objective lenses

e. illuminator

c. diaphragm

4. Calculate the total magnification of the nucleus of a cell being observed through a compound light microscope

with a 10 ocular lens and an oil immersion lens.

5. An electron microscope differs from a light microscope in that ___a beam of electrons________ focused by

______magnets_____ is used instead of light, and the image is viewed on _____tv like screen______ instead of

through the ocular lenses.

7. Why do basic dyes stain bacterial cells? Why dont acidic dyes stain bacterial cells?

Bacterial cells have a slightly negative charge, and the colored positive ion of a basic dye is attracted to the

negative charge of the cell. Acid dyes do not stain bacterial cells because the negatively charged colored ion is

repelled by the like charge of the cell.

8. When is it most appropriate to use each of the following?

a. a simple stain - A simple stain is used to determine cell shape and arrangement.

c. a negative stain -A negative stain does not distort the cell and is used to determine cell shape, size, and the

presence of a capsule.

b. a differential stain -A differential stain is used to distinguish kinds of bacteria based on their reaction to the

differential stain.

d. a flagella stain - A flagella stain is used to determine the number and arrangement of flagella.

9. Why is a mordant used in the Gram stain? In the flagella stain?

In a Gram stain, the mordant combines with the basic dye to form a complex that will not wash out of gram-

positive cells. In a flagella stain, the mordant accumulates on the flagella so that they can be seen with a light

microscope.

10. What is the purpose of a counterstain in the acid- fast stain?

A counterstain stains the colorless non acid- fast cells so that they are easily seen through a microscope.

11. What is the purpose of a decolorizer in the Gram stain? In the acid- fast stain?

In the Gram stain, the decolorizer removes the color from gram- negative cells.

In the acid- fast stain, the decolorizer removes the color from non acid- fast cells.


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12. Choose from the following terms to fill in the blanks: counterstain, decolorizer, mordant, primary stain.

Endospore: safranin is the counterstain.

Gram: safranin is the counterstain.

13. Fill in the following table regarding the Gram stain:

MC

1. Assume you stain Bacillus by applying malachite green with heat and then counterstain with safranin. Through

the microscope, the green structures are

a. cell walls.

d. flagella.

b. capsules.

e. impossible to identify.

c. endospores.

3. Carbolfuchsin can be used as a simple stain and a negative stain. As a simple stain, the pH is

a. 2.

b. higher than the negative stain.

c. lower than the negative stain.

d. the same as the negative stain.

6. Which of the following pairs is mismatched?

a. capsule negative stainb. cell arrangement simple stain

c. cell size negative stain

d. Gram stain bacterial identification

e. none of the above

7. Assume you stain Clostridium by applying a basic stain, carbolfuchsin, with heat, decolorizing with acid- alcohol,

and counterstaining with an acidic stain, nigrosin. Through the microscope, the endospores are _____ 1______,

and the cells are stained _____ 2______.

a. 1 red; 2 black

d. 1 red; 2 colorless

b. 1 black; 2 colorless

e. 1 black; 2 red

c. 1 colorless; 2 black

8. Assume that you are viewing a Gram- stained field of red cocci and blue bacilli through the microscope. You can

safely conclude that you have

a. made a mistake in staining.

d. young bacterial cells.

b. two different species.

e. none of the above c. old bacterial cells.


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10. Which of the following is not a modification of a compound light microscope?

a. brightfield microscopy

b. darkfield microscopy

c. electron microscopy

d. phase- contrast microscopy

e. fluorescence microscopy

CT

1. In a Gram stain, one step could be omitted and still allow differentiation between gram- positive and gram-

negative cells. What is that one step?

A counter stain could be omitted because the gram positive bacteria would still be stained purple. The gram-

negative bacteria would be colorless after the alcohol wash.

3. Why isnt the Gram stain used on acid- fast bacteria? If you did Gram stain acid- fast bacteria, what would their

Gram reaction be? What is the Gram reaction of non acid- fast bacteria?

Acid fast bacteria have cell walls that contain a high concentration of hydrophobic waxy lipid (mycolic acid) which

prevents the uptake of dyes, including the gram stains. All mycobacteria are stained this way including TB microbe

and leprosy microbe. If a gram stain was done on acid-fast bacteria, the stain would not be taken up. Non-acidfast cells lose their primary stain when rinsed with acid-alcohol and are counterstained with a different color basic

stain. A gram positive bacterium retains dye and stays purple. Gram negative bacteria will be pink/red

4. Endospores can be seen as refractile structures in unstained cells and as colorless areas in Gram- stained cells.

Why is it necessary to do an endospore stain to verify the presence of endospores?

Endospores strongly resist application of simple stains or dyes and hence appear as nonstaining entities in Gram-

stain preparations. They might appear to be artifacts in gram-stained cells. They can be detected under light

microscopes but cant be differentiated from inclusions of stored material.

CA

2. Laboratory diagnosis of Neisseria gonorrhoeae infection is based on microscopic examination of Gram- stained

pus. Locate the bacteria in this light micrograph. What is the disease?

Diplococci bacteria responsible for the sexually transmitted disease gonorrhoea.[1]

A diplococcus (plural diplococci)

is a round bacterium (a coccus) that typically occurs in pairs of two joined cells
http://en.wikipedia.org/wiki/Diplococcihttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Sexually_transmitted_diseasehttp://en.wikipedia.org/wiki/Gonorrhoeahttp://en.wikipedia.org/wiki/Neisseria_gonorrhoeae#cite_note-Sherris-0http://en.wikipedia.org/wiki/Neisseria_gonorrhoeae#cite_note-Sherris-0http://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Coccushttp://en.wikipedia.org/wiki/Coccushttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Neisseria_gonorrhoeae#cite_note-Sherris-0http://en.wikipedia.org/wiki/Gonorrhoeahttp://en.wikipedia.org/wiki/Sexually_transmitted_diseasehttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Diplococci


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3. Assume that you are viewing a Gram- stained sample of vaginal discharge. Large ( 10 um) nucleated red cells are

coated with small ( 0.5 um 1.5 um) blue cells on their surfaces. What is the most likely explanation for the red and

blue cells?

The large nucleated red cells are human cells and the blue cells on the surface are gram-positive bacteria.

4. A sputum sample from Calle, a 30- year- old Asian elephant, was smeared onto a slide and air dried. The smear

was fixed, covered with carbolfuchsin, and heated for 5 minutes. After washing with water, acid- alcohol wasplaced on the smear for 30 seconds. Finally, the smear was stained with methy-lene blue for 30 seconds, washed

with water, and dried. On examination at 1000 x, the zoo veterinarian saw red rods on the slide. What infections

do the results suggest? ( Calle was treated and recovered.)

The results suggest TB because an acid-fast stain was used. Acid-fast microorganisms retain the red color of the

carbolfuchsin because the carbolfuchsin is more soluble in the cell wall lipids that in acid-alcohol.

CH4

EOC Questions: Review: 1 - 5, 7, 9, 10, 14; MC:1- 7, 9; CT: 5; CA: 1

1. Diagram each of the following flagellar arrangements:

a. lophotrichous

b. monotrichous

c. peritrichous

2. Endospore formation is called __________. It is initiated by __________. Formation of a new cell from an

endospore is called __________. This process is triggered by __________.

Endospore formation is called sporogenesis. It is initiated by certain adverse environmental conditions. Formation

of a new cell from an endospore is called germination. This process is triggered by favorable growth conditions.

3. Draw the bacterial shapes listed in a, b, and c. Show how d, e, and f are special conditions of a, b, and c,

respectively.

a. spiral

b. bacillus

c. coccus

d. spirochetes

e. streptobacilli


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f. staphylococci

4. Match the structures to their functions.

____ cell wall d. protection from osmotic lysis

____ endospore f. resting

____ fimbriae a. attachment to surfaces

____ flagella c. motility

____ glycocalyx - e. protection from phagocytes, a. attachment to surfaces

____ pili - i. transfer of genetic material

____ plasma membrane h. selective permeability b. cell wall formation

____ ribosomes g. protein synthesis

5. Why is an endospore called a resting structure? Of what advantage is an endospore to a bacterial cell?

An endospore is called a resting structure because it is a method of one cell resting, or surviving, as opposed to

growing and reproducing. The protective endospore wall allows a bacterium to withstand adverse conditions in the

environment.

7. Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis?

Mycoplasmas do not have cell walls.

9. Answer the following questions using the diagrams pro-vided, which represent cross sections of bacterial cell

walls.

a. Which diagram represents a gram- positive bacterium? How can you tell?a. Diagram ( a) refers to a gram- positive bacterium because the lipopolysaccharide phospholipids lipoprotein

layer is absent.

b. Explain how the Gram stain works to distinguish be-tween these two types of cell walls.

The gram- negative bacterium initially retains the violet stain, but it is released when the outer membrane is dis-

solved by the decolorizing agent. After the dye iodine complex enters, it becomes trapped by the peptidoglycan of

gram- positive cells.


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c. Why does penicillin have no effect on most gram-negative cells?

The outer layer of the gram- negative cells prevents peni-cillin from entering the cells. d

d. How do essential molecules enter cells through each wall?

Essential molecules diffuse through the gram- positive wall. Porins and specific channel proteins in the gram-

negative outer membrane allow passage of small water-soluble molecules.

e. Which cell wall is toxic to humans?

. Gram- negative.

10. Starch is readily metabolized by many cells, but a starch molecule is too large to cross the plasma membrane.

How does a cell obtain the glucose molecules from a starch polymer? How does the cell transport these glucose

mole-cules across the plasma membrane?

An extracellular enzyme ( amylase) hydrolyzes starch into disaccharides ( maltose) and monosaccharides ( glucose).

A carrier enzyme ( maltase) hydrolyzes maltose and moves one glucose into the cell. Glucose can be transported

by group translocation as glucose- 6- phosphate.

14. The antibiotic erythromycin binds with the 50S portion of a ribosome. What effect does this have on a

prokaryotic cell? A eukaryotic cell?

Erythromycin inhibits protein synthesis in a prokaryotic cell; it will inhibit protein synthesis in mitochondria and

chloroplasts.

MC

1. Which of the following is not a distinguishing characteristic of prokaryotic cells?

a. They usually have a single, circular chromosome.

b. They lack membrane- enclosed organelles.

c. They have cell walls containing peptidoglycan.

d. Their DNA is not associated with histones

. e. They lack a plasma membrane.

Use the following choices to answer questions 2 -4.

a. No change will result; the solution is isotonic.

b. Water will move into the cell.

c. Water will move out of the cell.

d. The cell will undergo osmotic lysis.

e. Sucrose will move into the cell from an area of higher concentration to one of lower concentration.

2. Which statement best describes what happens when a gram- positive bacterium is placed in distilled water and

penicillin?

d. The cell will undergo osmotic lysis.

3. Which statement best describes what happens when a gram- negative bacterium is placed in distilled water and

penicillin?

b. Water will move into the cell.

4. Which statement best describes what happens when a gram- positive bacterium is placed in an aqueous

solution of lysozyme and 10% sucrose?

a. No change will result; the solution is isotonic.


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5. Which of the following statements best describes what hap-pens to a cell exposed to polymyxins that destroy

phospho-lipids?

a. In an isotonic solution, nothing will happen.

b. In a hypotonic solution, the cell will lyse.

c. Water will move into the cell.

d. Intracellular contents will leak from the cell.

e. Any of the above might happen.

6. Which of the following is not true about fimbriae?

a. They are composed of protein.

b. They may be used for attachment.

c. They are found on gram- negative cells.

d. They are composed of pilin.

e. They may be used for motility.

7. Which of the following pairs is mismatched?

a. glycocalyx adherence

b. pili reproduction

c. membrane DNA synthesis

d. cell wall protection

e. plasma membrane transport

9. You have isolated a motile, gram- positive cell with no vis-ible nucleus. You can assume this cell has

a. ribosomes.

d. a Golgi complex.

b. mitochondria

e. all of the above

c. an endoplasmic reticulum.

CT

5. When E. coli cells are exposed to a hypertonic solution, the bacteria produce a transporter protein that can

move K ( potassium ions) into the cell. Of what value is the active transport of K , which requires ATP?

The hypertonic solution means that there is a greater concentration of solutes outside the membrane than inside.

Bacteria exposed to hypertonic conditions shrink and collapse because water leaves the cell by osmosis. The cell

uses APT, or energy, to move potassium ions, which are positive into the cell. This increases the concentration of

solutes inside the membrane and therefore decreases the concentration gradient so water doesnt want to move

out of the cell.

CA

1. A child with a bloodborne Neisseria infection was treated with gentamicin. After treatment, Neisseria could not

be cultured from her blood, indicating that the bacteria were killed. However, her symptoms became worse.

Annually, nearly half of similar patients die. Explain why antibiotic treatment made her symptoms increase.

Niesseria is a gram-negativeinfection. Because it's bean-shaped and paired capsules it creates a protection.Without a host neisseria cannot survive long outside of the host cell where they are exposed to drying, cold,

acidity, or light. Because it is gram negative and lives within a host cell, when destroyed by gentamycin, it releases

a harmful endotoxin A. Which can only be released by the destruction of a gram negative cell because it has the

lipopolysachrides layer (Lipid A) Lipid A is an endotoxin which is toxic in the bloodsteam and GI tract. It can cause

shock,vasodilation,inflammation, and blood clotting in humans. Which is the cause of her worsening symptoms.

Although gram negative cells are more susceptible to antibiotic therapy, when they are destroyed kills you by the

release of Endotoxin A.
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Certain antibiotics, such as penicillin, destroy bacteria by interfering with the formation of the peptide cross-

bridges of peptidoglycan, thus pre-venting the formation of a functional cell wall. Most gram- negative bacteria are

not as susceptible to peni-cillin as gram- positive bacteria are because the outer membrane of gram- negative

bacteria forms a barrier that inhibits the entry of this and other substances, and gram-negative bacteria have

fewer peptide cross- bridges. How-ever, gram- negative bacteria are quite susceptible to some lactam antibiotics

that penetrate the outer membrane better than penicillin. Endotoxins differ from exotoxins in several ways. Endo-

toxins are part of the outer portion of the cell wall of gram-negative bacteria ( see Figure 15.4b). Endotoxins arereleased when gram-negative bacteria die and their cell walls undergo lysis, thus liberating the endotoxin.

(Endotoxins are also released during bacterial multiplication.) Antibiotics used to treat diseases caused by gram-

negative bacteria can lyse the bacterial cells; this reaction releases endotoxin and may lead to an immediate

worsening of the symptoms, but the condition usually improves as the endotoxin breaks down.

CH5

EOC Questions: Review: 1 - 3, 5 , 6, 8b,c, 15, 17, 18a,b; MC:1, 4, 5, 7, 8; CT: 1, 3, 4

1. Define metabolism.

Metabolism is the sum of all chemical reactions that occur within a living organism.

2. Distinguish between catabolism and anabolism. How are these processes related?

Catabolic reactions break down organic compounds and release energy, while anabolic reactions use the products

of catabolism and energy to build cell material.

3. Using the diagrams below, show:

a. where the substrate will bind.

b. where the competitive inhibitor will bind.

C. where the noncompetitive inhibitor will bind.

d. which of the four elements could be the inhibitor in feed-back inhibition.

5. Why are most enzymes active at one particular temperature? Why are enzymes less active below this

temperature? What happens above this temperature?


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The optimum temperature for an enzyme is one that favors movement of molecules so the enzyme can find its

substrate. Lower temperatures will decrease the rate of collisions and the rate of reactions. Increased

temperatures will denature the enzyme.

6. List four compounds that can be made from pyruvic acid by an organism that uses fermentation only.

Ethyl alcohol, lactic acid, butyl alcohol, acetone, and glycerol are some of the possible products. Refer to Table 5.4

and Figure 5.18b.

Use the diagrams for questions 8 16.

8. Name the pathways diagrammed in b, and c of the figure to the left.

( b) is glycolysis,

( c) is the Krebs cycle.

15. Where is NADH ( or FADH2 or NADPH) used and pro-duced in these pathways?

17. There are three mechanisms for the phosphorylation of ADP to produce ATP. Write the name of the

mechanism that describes each of the reactions in the following table.


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18. Define oxidation- reduction, and differentiate between the following terms:

a. aerobic and anaerobic respiration

b. respiration and fermentation

MC

1. Which substance in the following reaction is being reduced?

a. acetaldehyde

b. NADH

c. ethanol

d. NAD

4. Which of the following compounds has the greatest amount of energy for a cell?

a. CO2

d. O2b. ATP

e. lactic acid

c. glucose

5. Which of the following is the best definition of the Krebs cycle?

a. the oxidation of pyruvic acid

b. the way cells produce CO2

c. a series of chemical reactions in which NADH is pro-duced from the oxidation of pyruvic acid

d. a method of producing ATP by phosphorylating ADP

e. a series of chemical reactions in which ATP is produced from the oxidation of pyruvic acid.

8. Which culture produces the most ATP?

a. E. coli growing in glucose broth at 35 C with O2 for 5 days

b. E. coli growing in glucose broth at 35 C without O2 for 5 days

c. both a and b

d. neither a nor b


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CT: 1, 3, 4

1. Write your own definition of the chemiosmotic mechanism of ATP generation. On Figure 5.16, mark the

following using the appropriate letter:

Chemiosmotic- The mechanism of ATP synthesis using the electron transport chain is called chemiosmosis. In

chemiosmosis, the energy re-leased when a substance moves along a gradient is used to synthesize ATP. The

substance in this case refers to pro-tons. In respiration, chemiosmosis is responsible for most of the ATP that isgenerated. The steps of chemiosmosis are as follows ( Figures 5.15 and 5.16):

1. As energetic electrons from NADH ( or chlorophyll) pass down the electron transport chain, some of the carriers

in the chain pump actively transport protons across the membrane. Such carrier molecules are called proton

pumps.

2. The phospholipid membrane is normally impermeable to protons, so this one- directional pumping establishes a

proton gradient ( a difference in the concentrations of protons on the two sides of the membrane). In addi-tion to

a concentration gradient, there is an electrical charge gradient. The excess H on one side of the membrane makes

that side positively charged com-pared with the other side. The resulting electrochemi-cal gradient has potential

energy, called the proton motive force.

3. The protons on the side of the membrane with the higher proton concentration can diffuse across the

membrane only through special protein channels that contain an enzyme called ATP synthase ( adenosine

triphosphatase). When this flow occurs, energy is re-leased and is used by the enzyme to synthesize ATP from ADP


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a. the acidic side of the membrane

b. the side with a positive electrical charge

c. potential energy

d. kinetic energy

3. Why must NADH be reoxidized? How does this happen in an organism that uses respiration? Fermentation?

NADH must be reoxidized

4. The following graph shows the normal rate of reaction of an enzyme and its substrate ( blue) and the rate when

an excess of competitive inhibitor is present ( red). Explain why the graph appears as it does

Chemical inhibitors fill the active site of a normal enzyme and compete with the normal substrates for an active

site. Competitor inhibitors that bind reversibly slow the enzymes interaction with its substrate. If you increase the

substrate concentration, there will be more substrates than competitive inhibitors to attach to the enzymes active

sites thus increasing the reaction rate.

micro eoc review questions ch 1,3,4,5

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