Exam Micro Questions

How can prokaytoic cells be smaller than eukayrotic cells and still carry on all functions of life?

Prokaytoic have a good surface area to volume ratio. All their chemical activity occurs in the cell membrane and cytoplasm. They have all they need for minial function.

Name a use for each of four elements carbon,nitrogen, sulfur, and phosphorus.

Carbon- needed for all organic compounds that make up the cell.Half the dry weight of bacteria. Nitrogen & Sulfur: Protein synthesis Phosphorus: Synthesis nucleic acids

Explain the products of the Kerb-cycle:

Complete oxidation of Acetyle coA Production of NADH and FADH2 Remove co2

How do archea and bacteria differ and are similiar.

Similar: Single celled. Difference: Archea cell wall composition is psedomurien (just NAG) Bacteria cell wall compositiohn is NAG and NAM

Compare and Contrast prokayotic and eukaryotic plasma memebranes:

Similiar: In function and basic sructure. Different: Prokayotic: No carbohydrates, lack sterols. Eukaryotic : Carbohydrates, sterols, act as a receptor.

Fermentation:

Small amounts of atp, release energy from sugars & amino acids, does not use kreb cycle, does not require oxygen.

Outline the three ways that ATP is generated:

Substrate Phosphorylation: ATP is generated from phosphorylation of ADP. Oxidative Phosphorylation: Electrons are transferred from organic compounds to one group of electron carriers, electrons then are passed through a series of different electron carries to molecules of O2. Photophosphorylation: Through the use of light ATP is generated from ADP, and Pi

Factors that influence enzymatic acitvity:

Tempature: Elevation above a certain temperature can cause the enzyme to denature. pH: Dependent on environment extreme changes in pH can cause the enzyme to denature. Substrate concenctration: Inceasce in concentration and increase of reaction, but can reach a maxium where all the proteins/enzymes are working effectively.

Under what conditions do Endospores form?

When conditions are harsh to the cell - freezing & boiling. Endospores dehydrate the cell.

Why are drugs that target cell all synthesis useful?

Without the cell wall of bacteria will be suspecticle of destruction by chemicals outside the plasma memebrane.

Which of the following is not a characteristic of biofilms? a. Antibotic resistance b.hydrogel c.iron deficiny d. quorum sensing

a. Antibotic resistance

Use the following choices to answer questions 7-10 a. E coli goriwng in glucose broth at 35 degrees celcius with oxygen for 5 days b. E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days. c. Both a and b d. neither a or b 8. Which culture produces the most ATP?

a. E coli in glucose broth at 35 deegrees celcius with oxygen for 5 days.

Compare and Contrast prokayotic and eukaroytic cell walls and glycocalyxes.

Prokayotic Slime & Capsule. May allow bacteria to attach to surfaces, Glycocalyx is made of polysaccharides or polypeptides. Serve as a source of nurtients. Eukayotic Glycocalyx is over the plasma membrane. Helps for cell to cell recgoinition.

All of the energy-producing biochemical reactions that occur in cells, such as photophosphorylation and glycolysis are _________ reactions.

oxidation

Use the following choices to answer questions 7-10 a. E coli goriwng in glucose broth at 35 degrees celcius with oxygen for 5 days b. E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days. c. Both a and b d. neither a or b 9. Which culture uses NAD+

c. Both A and B

Pretranscriptional regulation:

repression decreases, tpically on but have to be able to turn off.

Which of the following types of media would not be used to culture aerobes? a. Selective media b. Reducing media c. Enrichment media d. differential media e. complex media

c. Enrichment media

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 assoicated with histones e. They lack a plasma membrane.

e. They lack a plasma membrane

Pseudomonas has a plasmid containing the mer operon, which includes the gene for mercuric reductase. This enzyme catalyzes the reduction of the mercuric ionsHg2 to the uncharged form of mercury, Hg0. Hg2 is quite toxic to cells; Hg0 is not. 1. What do you suppose is the inducer for this operon? 2.Why would a cell bring a toxin? 3.What is the value of the mer operon to Pseudomonas?

1- Presence of mercury ions. 2- I do not understand what is your question? 3- It helps Pseudomonas survive in mercury rich environments.

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 the cell d. The cell will undergo osmotic lysis e. Surcose 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 place in distilled water and pencillian? 3. Which statement best describes what happens when a gram negative bacterium is placed in distilled water and pencillian? 4.Which statement best describes what happens when a gram positive bacteria is placed in a aqueous solutiohn of lysozyme and 10% surcose?

2. D. The cell will undergo osmotic lysis. 3.B.Water will move into the cell. 4.A. No change will result: the solution is isotonic.

Flask A contains yeast cells in glucose minimal salts broth incubated at 30 degrees C with aeration. Flask B contains yeast cells in glucose minimal salts broth incubated at 30 degrees C in an anaerobic jar. The yeasts are facultative anaerobes. c. Which culture had the shorter generation time?

A

Flask A contains yeast cells in glucose minimal salts broth incubated at 30 degrees C with aeration. Flask B contains yeast cells in glucose minimal salts broth incubated at 30 degrees C in an anaerobic jar. The yeasts are facultative anaerobes. d. Which culture had the greater cell mass?

A

Flask A contains yeast cells in glucose minimal salts broth incubated at 30 degrees C with aeration. Flask B contains yeast cells in glucose minimal salts broth incubated at 30 degrees C in an anaerobic jar. The yeasts are facultative anaerobes. e. Which culture had the higher absorbance?

A

Flask A contains yeast cells in glucose minimal salts broth incubated at 30 degrees C with aeration. Flask B contains yeast cells in glucose minimal salts broth incubated at 30 degrees C in an anaerobic jar. The yeasts are facultative anaerobes. a. Which culture produces the most ATP?

A

You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has a.ribosomes b.mitochondria c. An endoplasmic reticulum d. a golgi complex e. All of the above

A. Ribosomes

Describe the major tyoes of anabolism and their relationship to catabolism.

Anabolic processes produce peptides, proteins, polysaccharides, lipids and nucleic acids. These molecules comprise all the materials of living cells, such as membranes and chromosomes, as well as the specialized products of specific types of cells, such as enzymes, antibodies , hormones, and neurotransmitters

The componets of an enzyme:

Are cataylist that speed up a chemical reaction without being permantly altered. Apoenzyme: A protein portion Cofactor:Non-protein portion of an enzyme Holoenzyme: is the cofactor of apoenzyme, apoenzyme will not function without holoenzyme.

Binary fission:

Asexual production in prokayrotic cells growth in two cells.

Flask A contains yeast cells in glucose minimal salts broth incubated at 30 degrees C with aeration. Flask B contains yeast cells in glucose minimal salts broth incubated at 30 degrees C in an anaerobic jar. The yeasts are facultative anaerobes. b. Which culture produces the most alcohol?

B

The antibotic amphotherican B disrupts plasma membranes by combining with sterols; it will affect all of the following except a. Animal cells b. Gram-negative bacterial cells c. Fungal cells d. mycoplasma cells e. plant cells

B. Gram-negative bacterial cells.

Which of the following pairs is mismatched? a. Glycocalyx- adherence b. Pili- reproduction c. Cell wall- toxin d. Cell- production e. Plasma membrane - transport

B. Pili-reproduction

Explain the importance of osmotic pressure to microbial growth:

Bacteria require water to grow. 80-90% composition is water. Halophiles: Fine in a salt environment Obligate halophile: need high salt content in environment Facultative halophile: doesnt need, but can grow

Activate V.S Group translocation:

Both move materials across the plasma membrane with energy. In group transolcation the substrate is changed once crossed from the plasma membrane.

How do bacteria move?

By flagella, or pili pulls bacteria when retracted.

Briefly describe the componets of DNA and explain its functional relationship to RNA protein:

DNA passes Genetic information to RNA(through transcription) on how to make a protein, then the RNA goes to a ribosome and a polypeptide chain is made (through translation)which eventually folds into a Protein.

Mechanism by which lactose controls the lac operon:

DNA polyermase

Use the following choices to answer questions 7-10 a. E coli goriwng in glucose broth at 35 degrees celcius with oxygen for 5 days b. E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days. c. Both a and b d. neither a or b 10. Which culture uses the most glucose?

E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days.

Which of the following pairs is mismatched a. Metachromatic granules - stored phosphates b. Polysacchride granules - stored strach c. Lipid inclusions - poly B- hydroxybutyric acid d. Sulfer granules - energy reserve e. Ribosomes- protein storage

E. Ribosomes- protein storage.

Which of the following is false about fimbraie? a. They are composed of protein b. They may be used for attachment c. They are found on gran-negative organisms d. They are composed of pillin e. They may be used for motility.

E. They may be used for motility.

Differentriate Prokaryotic and Eukayotic Flagella:

Eukaryotic flagella move in a wave motion and anchored in the plasma membrane. Prokaytoic Flagella rotate.

Compare and Contrast prokayotic and eukaryotic cytoplasm:

Eukaryotic: Ctyoplasma contains microfilaments and intermediate filaments. Formation of the cytoskeleton Cytoskeleteon: Transports substances throughout the cell and provides support and shape Cytoplasmic Streaming:

Chemically defined media:

Exact chemical composition is known. Energy source, carbon, nitrogen,sulfur, phosphrus needed.

Suppose you inoculate three flasks of minimal salts broth with E. coli. Flask A contains glucose. Flask B contains glucose and lactose. Flask C contains lactose. After a few hours of incubation, you test the flasks for the presence of B-galactosidase. Which flask(s) do you predict will have this enzyme?

Flask C- with lactose

Gram Positive or Gram negative cell wall is toxic to humans?

Gram Negative. Pencillian does not effect gram Negative bacteria because of its outer layer.

Where is the DNA located in the prokayotic cell?

In the nucleiod.

In 1985, a 0.5-mm cell was discovered in surgeonfish and named Epulopiscium fishelsoni. It was presumed to be a protozoan. In 1993, researchers determined that Epulopiscium was actually a gram-positive bacterium.Why do you suppose this organism was initially identified as a protozoan? What evidence would change the classification to bacterium?

It was initially presumed to be protozoan because of the size of bacteria. It was changed to a bacteria because there was a precence of a thick peptidoglycan wall, and protozoan does not.

When E. Coli cells are exposed to hypertonic solution, the bacteria produce a transporter protein that can move K+ into the cell. Of what value is the active transport of K+, which requires ATP?

K+ ions is what allows for proteins to be transported, without the ions active transport will be positively charged and reaction will not work.

Complex media:

Made of nutrients including yeasts, meat, plants, mostly protein.

Define metabolism, describe the fundamental difference between anabolism and catabolism.

Metabolism: The sum of all chemical reactions within a living organism. Anabolism: The building of complex organic molescules from silver ones. Catabolism: The breakdown of complex organic compounds into simpler ones.

Chemisomosis:

Move proteins down their concentration gradient to make ATP from ADP using ATP synthase.

Why are mycoplasmas resistant to antibotics that interfere with cell wall sythesis?

Mycoplasma lacks a cell wall.

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

NAD+ is needed to pick up more electrons. NADH is usually reoxidized in respiration. NADH can be reoixdized in fermentation.

Identify the functions of pentose phosphate and Enter- Doudoroff pathway.

Pentose Phosphate: Operates with glycolysis and provides a means for the breakdown of five carbob sugars, pentose and glucose. NADPH, NUCLEIC ACID, E. FACEALIS. Enter- Doudoroff pathway: Does not involve glycolysis Production of 2 NADPH, and 1 ATP.

What is the role of the promotor, terminator, and mRNA in transciption:

Promotor: is the specific sequence of DNA where RNA polymerase binds and begins transcribing. Terminator: Sequence of DNA where RNA polymerase nucleotides and ends transcrpition.

Why are bacterial capsules medicially important?

Protect pathogenic bacteria from phagotcyotis of host cell.

Mechanism by which lactose inhibits the lac operon:

Repression

What is the general functions of inclusions?

Reserve deposits Metachromatic Granules: Stain blue with red dyes Polysaccharide Granules: When dyed with idione appear Glycogen granules: Reddish brown Starch granules: Blue

How are simple diffusion and faciliated diffusion different and similar?

Similar: Because they both involve movement down the concentration gradient. Different: Faciliated diffusion is aided by proteins.

By deep-freezing, bacteria can be stored without harm for extended periods. Why do refrigeration and freezing perserve foods?

The growth rate of bacteria slows down with decreasing temperatures. Bacterial will not spoil food quickly in a refrigrator.

What is the purpose of metabolic pathways?

The storage and release of energy from organic molecules by a series of controlld reactions rather than a single burst.

Transformation

Transfer of DNA from a donor to a recipient as naked DNA in a solution

Transduction

Transfer of DNA from a donor to a recipient cell by bacteriophae

An organism that has peroxidase and superoxide dismutase but lacks a catalyse is most likely an a.aerobe b. Aerotoleant anaerobe c. Obligate anaerobe

b. Aerotoleant anaerobe

Use the following choices to answer questions 7-10 a. E coli goriwng in glucose broth at 35 degrees celcius with oxygen for 5 days b. E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days. c. Both a and b d. neither a or b 7. Which culture produces the most latic acid?

b. E coli growing in glucose broth at 35 degrees celcius without oxygen for 5 days.

Assume you inoculated 100 facultatively anaerobic cells onto nutrient agar and incubated the plate aerobically. You then inoculated 100 cells of the same spieces onto nutrient agar and incubated the second plate anaerobically. After incubaiton for 24 hours, you should have a. More colonies on the aerobic plate b. More colonies on the anaerobic plate c. The same number of colonies on both plates

c. The same number of colonies on both plates

Describe the chemical reaction of glycolycis:

the oxidation of glucose to pyruvic acid and produces ATP and NADH Glycolysis. In the Preparatory Stage of Glycolysis: 2 ATP are used and Glucose is split to form 2 glyceraldehyde-‐3-‐ phosphate In the Energy-‐Conserving Stage of Glycolysis:2 glyceraldehyde-‐3-‐phosphate are oxidized to 2 pyruvic acid, 4 ATP are produced, 2 NADH are produced.