Microbiology Case study Unit 1 & Inquizitive chapter 3&4

This molecule is essential for life, largely due to its unique properties.

H2O

Functional groups are key features of all organic molecules. Click on the sections of the images that represent functional groups.

H3N+,COO-, c-h(4)

Bacterial toxins often function by hijacking and/or altering essential biochemical functions of cells. Which of the following illustrate how toxins might affect cells?

Toxins are internalized through endocytosis, and once inside cells they bind and alter enzyme function. Toxins bind receptors on the cell surface and stimulate the cell to change its biochemical reactions. Secreted bacterial proteins insert themselves into cellular membranes, resulting in water loss.

Which cellular macromolecules are able to catalyze biochemical reactions?

RNA proteins

Page(s) 104-106 4.3 Nucleic Acids and Proteins Which types of bonds are responsible for the three-dimensional shape of individual proteins and the interactions between different proteins?

covalent bonds hydrogen bonds ionic bonds hydrophobic interactions

Cellular macromolecules have many functions in the cell. Many of them have one or more main functions, without which cells would be unable to survive. Match each type of cellular macromolecule with its functions. RNA DNA protein lipid carbohydrate

energy storage - carbohydrate, lipid,DNA cellular operations - RNA,Protein cell structure - protein, carbohydrate, lipid information - DNA, RNA

Which of the following images shows an example of an isotonic environment? Click or tap the appropriate place in the image.

first picture choice

Cells selectively allow certain molecules in or out. Match each molecule to the section of the image that matches its ability to permeate lipid bilayers.

first row -co2, O2 2nd row - Gycerol 3rd row- glucose, sucrose, Mg2+

Which type of amino acid would you expect to find in the middle of a protein? Correct Answer(s)

hydrophobic nonpolar

Think of the last time you mixed oil and vinegar. The oil and vinegar separate spontaneously. This same separation occurs in cells when triglycerides associate to form cytoplasmic inclusions. Which of the following is responsible for this phenomenon?

hydrophobic interactions polarity of water amphipathic character

Several different pathogen species may have the same shape (e.g., coccoid). What type of microscopy might be used to discriminate among them?

light microscopy with Gram stain fluorescence microscopy

In microscopy, what term refers to the smallest distance by which two objects can be separated and still be distinguished?

resolution

What type of microscopy was most likely used to create this image of a bacterial biofilm in the human intestine? 100um

scanning electron microscopy

Your professor describes a protein structure that consists of covalent bonds, hydrogen bonds, and ionic interactions. To which type of protein structure might she be referring?

tertiary quaternary

Eukaryotic cells disable pathogens that enter cells by which of the following?

lysosomes

Bacterial cells survive without organelles because they can use ________ to harvest energy through biochemical reactions.

membranes

Human cells rapidly take up intracellular bacterial pathogens, such as Shigella flexneri. These pathogens have many fates once inside a human cell but enter via the same route. What route into eukaryotic cells do bacterial pathogens take?

phagocytosis

In phase-contrast microscopy, the object is transparent and there is an illusion of dimensionality. Organelles appear lighter or darker.

phase-contrast microscopy

What type of microscopy was used to obtain this image?50um (Nucleous, Pseudopod)

phase-contrast microscopy

Table salt (NaCl) and many other essential micronutrients (such as Mg2+) dissolve readily in water. These compounds dissolve because they, like water, are _______.

polar

Free energy (ΔG) is how scientists calculate how likely it is that a reaction will be spontaneous. Link each of the following reaction descriptions with their free energy.

positive ΔG (+ΔG) endergonic,Keq < 1 negative ΔG (−ΔG) no additional energy required Correct label: reaction increases entropy Correct label: exergonic Correct label: Keq >1

Of the choices listed, what would be best for determining the location of the chromosome within a bacterial cell?

transmission electron microscopy

Which type(s) of microscopy allows the visualization of prokaryotic subcellular structures?

transmission electron microscopy

Oral rehydration therapy (ORT) is used to supplement ________ to patients with gastrointestinal infection with Vibrio cholerae (causative agent of cholera).

water ions

In fluorescence microscopy, the sample is labeled with a fluorophore. The fluorophore is excited with light of a specific wavelength, and it then emits light of a different wavelength. The emitted light is detected and the specimen thus observed. If the excitation wavelength is 600 nm, what might be the emission wavelength?

700 nm

When you hyperventilate, your blood pH decreases.

False

Which of the following images were generated with scanning electron microscopy?

2(5um) & 4 (100um)

Match each image with the type of microscopy used to produce it.

5um-dark-field microscopy 10um- bright-field microscopy 1um-scanning electron microscopy

If a bacterial cell has a length of 0.9 micrometers (µm), how many nanometers (nm) long is the cell?

900nm

Click on the bases that are present in both DNA and RNA.

Adenine, Guanine, cytosine,

Which of the following is true of the Gram stain?

All eukaryotic cells stain Gram-negative. Some prokaryotic cells stain Gram-negative and some prokaryotic cells stain Gram-positive.

Cellular membranes are -. - lipids pack tightly, - membrane fluidity, while -lipids pack loosely, - membrane fluidity. Bacterial membranes contain - molecules called - that maintain membrane - at high temperatures. Maintaining membrane fluidity is essential for maintaining cellular -.

Cellular membranes are dynamic. Saturated lipids pack tightly, decreasing membrane fluidity, while unsaturated lipids pack loosely, increasing membrane fluidity. Bacterial membranes contain stabilizing molecules called hopanoids that maintain membrane fluidity at high temperatures. Maintaining membrane fluidity is essential for maintaining cellular homeostasis.

Cellular membranes are - studded with -. Membranes contain - proteins that - the bilayer and - proteins that associate with - side of the bilayer. Membrane components, proteins and -, move freely - but - "flip-flop" - bilayers.

Cellular membranes are lipid bilayers studded with proteins. Membranes contain transmembrane proteins that span the bilayer and peripheral proteins that associate with one side of the bilayer. Membrane components, proteins and lipids, move freely laterally but rarely "flip-flop" between bilayers.

Using the Gram stain and light microscopy, you detect club-shaped, endospore-containing cells (shown in the image) in a sample collected from canned tomatoes. What most likely is the organism?

Clostridium botulinum

Salmonella enterica is brought into cells through membrane transport. Once inside of the cell, Salmonella is able to survive within cells for hours to days, often coordinating cellular functions outside the membrane compartment it is in. Which of the following is the best explanation for how Salmonella is able to do this?

Correct choiceSalmonella alters the character of the lysosome such that the low pH and lysosome-specific enzymes do not affect it.

Materials are brought through the membrane in several different ways. Match each method of entry to an example.

Ebola virus entering a cell endocytosis water crossing the cellular membrane osmosis Campylobacter jejuni entering the intestinal mucosa Correct label: phagocytosis gas exchange with the outside of the cell Correct label: diffusion lactose is brought into the cell Correct label: endocytosis

In this redox reaction, NAD+ is the reducing agent.

False

These images show the same organism, Giardia lamblia, visualized by different types of microscopy. Match the types of microscopy with the images they created. scanning electron microscopytransmission electron microscopyphase-contrast microscopyfluorescence microscopylight microscopy with stain

Flagella - Light microscopy with stain SEM 10um- Scanning electron microscopy LM 10um- Phase-contrast microscopy

The vast majority of living organisms are made up of which of the following?

H N O S P C

Which of the following microscopy techniques were used to obtain this image? LM 5um

Gram stain bright-field microscopy

Which of the following describe the microbes shown in this image?

Gram-negative bacilli

What host factors are playing a role in this patient? Urinary tract infections can be contracted through improper wiping techniques (front to back only!) after using the restroom or by subsequent touching of the genitals after using the restroom without proper hand washing hygiene. Underlying noninfectious diseases or conditions. A typical treatment for leukemia would include chemotherapy. Chemotherapy is known to weaken the patient's immune system. This would make Kerri more susceptible to infection while being treated for leukemia.

Host hygiene and behavior.

Practice associating specific situations with osmotic balance by matching each situation to the type of environment the cells are in.

Hypertonic solution - Escherichia coli in jar of honey on your kitchen counter & Vibrio fischeri cells living on the surface of a marine fish Hypotonic solution - Paramecium cells in fresh water lakes Isotonic soluiton- red blood cells in a healthy patient's bloodstream

Which of the following were created using a differential stain?

Mycobacterium tuberculosis, Flavobacterium capsulatum, legionella pneumophila

Kidney stones are technically crystals and are commonly formed of calcium oxalate. Which of the following situations best describes why patients get kidney stones?

Patients who have high-protein, low-fluid diets may suffer from kidney stones because the water concentration in the kidneys is too low.

Salmonella enterica is brought into cells through membrane transport. Once inside of the cell, Salmonella is able to survive within cells for hours to days, often coordinating cellular functions outside the membrane compartment it is in. Which of the following is the best explanation for how Salmonella is able to do this?

Salmonella alters the character of the lysosome such that the low pH and lysosome-specific enzymes do not affect it.

Bacterial toxins often function by hijacking and/or altering essential biochemical functions of cells. Which of the following illustrate how toxins might affect cells?

Secreted bacterial proteins insert themselves into cellular membranes, resulting in water loss. Toxins are internalized through endocytosis, and once inside cells they bind and alter enzyme function. Toxins bind receptors on the cell surface and stimulate the cell to change its biochemical reactions.

Why are stains used in light microscopy?

Stains can increase contrast. Stains can aid in species identification.

Which of the following results would you expect from a reaction where the enzyme was accidentally boiled?

The reaction rate would decrease.

Identify the reservoir of infection in this case.

The reservoir of infection in this case would be the female genital tract and perineum. This is the environment that normally harbors the pathogen.

Why would some bacteria stain Gram-negative?

They lack a peptidoglycan-containing cell wall. The cells are no longer in fresh culture.

Obligate intracellular bacteria, such as Coxiella burnetii (cause of Q fever), cannot reproduce outside of a host cell. How can they reproduce?

They stabilize intracellular vesicles to survive. They hijack the endomembrane system of the infected cell.

This picture shows the diffraction pattern of DNA, data that led to solving the structure of DNA. What method is used to obtain this kind of data?

X-ray crystallography

You are given a slide of a pathogen that is Gram-negative and whose subcellular structures can be observed with a light microscope. What most likely is this pathogen?

a fungus

Bacterial species can have characteristic shapes, such as cocci (spheres), bacilli (rods), or spirochetes. Match each shape with the correct image.spirochete, bacilli, cocci

bacili (SEM 2um), spirochete(SEM 1um), cocci (SEM 10um)

How do enzymes promote the completion of biochemical reactions?

by dropping the activation energy required for a reaction to proceed

How do bacterial cells maintain their permeability as temperatures rise?

by increasing the saturated/unsaturated lipid ratio in their membranes by replacing short-chain fatty acids with long-chain fatty acids by increasing the hopanoid concentration in the membrane

ATP and GTP are important energy-carrying nucleic acid molecules in the cell. Their energy lies in key chemical bonds in the molecules. Click on each region of the molecule that is commonly used to carry energy throughout the cell.

click the 3 rectangular shape only

Diffusion rates change in response to many factors. Match these changes to increasing or decreasing diffusion rates.

decreased membrane surface area Correct label: decreasing thicker membranes Correct label: decreasing molecule size increase Correct label: decreasing high concentration gradient Correct label: increasing temperature increase Correct label: increasing increased molecular charge Correct label: decreasing temperature decrease Correct label: decreasing increased membrane surface area Correct label: increasing thinner membranes Correct label: increasing

Cellular molecules are made up of many different types of bonds. Match the following bonds with their descriptions.

electrons shared equally Correct label: nonpolar covalent bond unequal electron sharing Correct label: polar covalent bond partial charge interactions Correct label: hydrogen charge attractions Correct label: ionic

Please match each type of imaging device with the range of resolution it provides.

human eye, light microscopy , scanning electron microscopy, transmission electron microscopy , x-ray crystallography

Which types of bonds are responsible for the three-dimensional shape of individual proteins and the interactions between different proteins?

ionic bonds hydrogen bonds covalent bonds hydrophobic interactions

PET (positron emission tomography) scanners produce three-dimensional reconstructions of the inside of a patient's body. Differentiation of regions of the body is done using tracer elements, which are injected into the patient. A tracer element contains a different number of neutrons than that of the corresponding naturally occurring element. What is the general term for tracer elements such as these?

isotope

Which type of amino acid would you expect to find in the middle of a protein?

nonpolar hydrophobic

What is being altered in the patient's cells when bacterial toxins that cause cells to secrete large concentrations of charged ions (such as Cl−) are introduced?

osmotic balance

Complete the following statement: environment enzymes narrow function denaturing tertiary ionic amino acid

pH changes in a(n) environment can alter the rate of reactions because enzymes only work within a narrow range of pH. Changes in pH can negatively affect protein function by denaturing a protein's tertiary structure. This often occurs when pH disrupts ionic bonds between amino acid side chains.

What type of bonds link amino acids to form the primary structure of a protein?

peptide bonds

For bacterial cells that stain Gram-positive, the Gram stain can be used to easily differentiate human cells from bacterial. In the following image, please identify the bacterial cells.

purple diplococci

How is contrast obtained in phase-contrast microscopy?

through exploiting differences in refractive indexes

What type of microscopy was used to obtain this micrograph of a bacterium?

transmission electron microspcopy

Which of the following are some of water's key chemical properties that contribute to its suitability for sustaining life?

universal solvent hydrogen bonding polarity