Assignment 1 (Chapters 1-2)

What is the vector for transmission of yellow fever?

Aedes aegypti mosquitoes

You have seen that most students are able to memorize the levels of structure in a protein--primary, secondary, tertiary, and quaternary. The question now becomes how to aid the students in visualizing and understanding that the sequence of amino acids will impart ionic or hydrogen bonding that will induce curves (alpha-helix) or folds (beta-sheets) in the amino acid chain. These curves and folds will be able to interact amongst each other and give the polypeptide (which is part of a protein or maybe the entire protein being made) a three-dimensional shape that will enable the polypeptide to bind to another polypeptide and form a complete protein. Rank the following groups in the order that they contribute to the structure of a protein.

Amino Acid sequence a-b-c-d-e Alpha-helix or beta sheet helix-sheet-turn-helix Polypeptide A joined to polypeptide B, which joins to polypeptide C.

Understanding the structural and molecular interactions that induce shape and function for a protein has been an obstacle for some of your students. You decide to plan a lesson to introduce them to the basic amino acid structure and then use that concept to introduce the different levels of protein structure. To reinforce your lesson on amino acids, you need to aid the students in understanding that most naturally occurring amino acids have a shared base structure. Each amino acid has an amine group, an alpha-carbon (or central carbon), an R-side group, and a carboxyl group. The R-side group is what gives each amino acid its distinctive characteristics--for example, whether the amino acid will be acidic or basic, hydrophilic or hydrophobic, or charged. Choose the statement that does NOT pertain to amino acids.

Amino Acids always contain a sulfur atom in their R-side group.

What effect do antacids have on stomach contents?

Antacids raise the pH of stomach contents.

An oxygen atom has two electron shells and 6 valence electrons. How many total electrons does this atom have?

8

What is a hypothesis?

A hypothesis is a possible answer to a scientific question.

You have isolated a microorganism that is green, photosynthetic, has a cell wall, and does NOT possess a nucleus. This organism is a(n) __________.

Bacterium

Which of the following is NOT a normal function of nucleotides?

Building blocks of proteins

An electrolyte panel is also ordered for the patient. This test predicts the health of other systems involved in regulating critical metabolic pathways, such as kidney and liver functions. The measurements of these electrolytes results in a calculation known as the anion gap, a sum total of metabolic buffering agents in the blood. Under normal, healthy conditions, the number of cations present is larger than the number of anions present (known as a positive anion gap). The formula to calculate the gap is as follows:Total cations - Total anions The normal range for the anion gap is < 11 mEq/L. From the previous question, we predict the gap to be skewed from the pH readout, since the patient's blood pH is high. Sort the following common electrolytes from the panel into the bins (cation) or (anion). Sort the following commonly measured electrolytes into the correct bin.

Cations: sodium, calcium, potassium, magnesium, iron Anions: Chloride, Phosphate, CO2

Vaccination came about when Jenner proved that infection with cowpox led to immunity for smallpox. How does vaccination with cowpox offer immunity to smallpox, a different and more serious disease?

Cowpox and smallpox share a very common protein structure.

Cranberry juice has a pH of 2.4, while grape juice has a pH of 3.3; which juice is more acidic?

Cranberry Juice

The tests for these uncommon pathogens are similar to the ones that have already been performed for the common viruses, but in this case, you will try to identify the DNA or proteins of specific viruses that are not often seen in clinics or hospitals in that area of the country. Each region of the country has certain viral pathogens that are spread throughout the human population that live in that area. When one of these viruses spreads to a new area, we consider it to be "emerging" in this new population of people. Some detective work and deductions will be required. By applying the scientific method, you can focus and refine your list of possible viral pathogens to experimentally test for. You'll begin your investigation by reviewing the patient's history and symptoms and formulating a hypothesis for possible causative agents. Based on what you know of the scientific method, what would you like to do next? Choose what your next step should be.

Design and run some tests or experiments

What is the best way to prevent the spread of yellow fever?

Drain standing water and sleep under mosquito netting.

Smallpox is the only disease to date that has been completely eradicated from the human population. This is due to the collective efforts of researchers, clinicians, and the World Health Organization. The history of this eradication is important and may lead to the eradication of other diseases that plague humans.

Earliest: Patients variolized against smallpox. Jenner observes milkmaids have immunity to smallpox. Jenner develops cowpox vaccine Vaccina virus discovered in vaccine Latest: Campaign to eradicate smallpox begins

__________ diseases are new to a population or are rapidly increasing in incidence or geographic range and are of particular concern to health care workers today.

Emerging

Which field of microbiology involves the study of microorganisms in their natural habitats?

Environmental microbiology

The long-term chemical energy storage molecules in plants are triglycerides.

False

A microorganism has the following characteristics: eukaryotic, multicellular, has cell walls, and grows in long filaments. What is its general classification?

Fungus

Which of the following are paired INCORRECTLY?

Gram: cholera

What was Leeuwenhoek's contribution to the science of microbiology?

He developed the first microscope.

Some critics of Spallanzani's experiments thought that the reason sealed flasks were unable to spontaneously generate microorganisms was that there was not enough air present to support life. How did Louis Pasteur respond to this claim?

He modified the experiment to include air as a treatment.

How did Francesco Reid attempt to disprove the theory of spontaneous generation?

He performed a series of experiments involving decaying meat and maggots.

Which of the following is NOT true of hydrogen bonds?

Hydrogen bonds are important only in the interaction between water molecules.

This kind of bacterial pneumonia can be difficult to diagnose. Often, patients (especially elderly adults) may not produce enough sputum for specimen sampling. Gram stains and culture of organisms are the mainstays of diagnostic tests, but they are often inconclusive within the time frame necessary to manage the patient's disease. As such, more rapid testing is needed to make efficient decisions on the etiology of the infection. For this reason, many hospital labs are turning to serology, the use of specific antibody binding, to hasten diagnosis. The immune system produces molecules known as antibodies during an infection. The antibodies float through the body and are attracted to the foreign molecule, known as an antigen. Each antibody interacts with a single specific antigen, so the bonding of an antibody to an antigen is based in molecular interactions. Serology testing involves mixing a patient sample with antibodies and observing a binding event based on chemical bonding principles. Based on the information given, which of the following would you interpret to be the best description of this interaction?

Ionic Bonding

A hydroxyl ________ acts as a base.

It has a high capacity for heat.

All of the following individuals showed that cleanliness played a role in human disease EXCEPT __________.

Jenner

Which scientist definitively ended the debate over spontaneous generation?

Louis Pasteur

Whose experiments supported the existence of a "life force" that causes inanimate matter to spontaneously come to life?

Needham

"Uncommon" or "emerging" pathogens are ones that are rarely seen in a clinical setting or are new to a geographic area. As a scientist, you will need to follow a logical pattern to determine what the unknown virus is. This logical process is one that all scientists are familiar with the scientific method. The scientific method is a process of determining what natural phenomenon is to be studied and developing a series of experiments to determine what is occurring. Order the steps of the scientific method as a virologist would implement them on the job. Put the following steps of the scientific method in order (from left to right) that should be followed to identify the virus that is causing this disease.

Observe a natural phenomenon or reaction. Devise an explanation of what you have observed. Experiment to support of refute your explanation. Record the results of your experiments. Determine whether your results support or refute your explanation. Determine whether you need to rewrite your explanation or it has withstand testing.

What is an emerging disease?

One that appears in a population for the first time.

Who studied fermentation?

Pasteur

Why is the disease called "yellow fever"?

Patients have yellow mucous membranes and an elevated temperature.

Since smallpox has been eradicated, the world has set its eyes on other diseases. However, this task it not an easy one. It will never be possible to eradicate every disease in the world, but it may be possible to knock out a few more. The World Health Organization is searching for another disease to eradicate. Which of the following will be the most likely candidate?

Polio only infects humans and is almost always symptomatic

One of the most common causes of pneumonia is Streptococcus pneumoniae, a gram-positive bacterium. Surrounding the bacterium is a thick structural component layer known as a capsule. This capsule is made up of repeating molecular units and serves as a sticky, protective macromolecule. There are over 84 known different molecular configurations of capsule, and it is the primary component of vaccines against this organism. The capsule is the antigen that we commonly detect in the serology testing referred to in the previous question. Based on the information given about capsules, which of the following types of molecules would you suspect comprises an S. pneumoniae capsule?

Polysaccharide Carbohydrate

The final tests ordered for the patient are a BUN (blood-urea-nitrogen) test, a procalcitonin test, and a CRP test. The BUN test measures kidney function and catabolism (an increased BUN signifies impairment, which is common in pneumonia). Calcitonin is a molecule derived from the splitting of a larger precursor molecule called procalcitonin. In healthy adults, the procalcitonin is converted to calcitonin, which then participates in calcium and phosphorus metabolism. The conversion of procalcitonin to calcitonin is inhibited by bacterial infection and immune responses; so, levels of procalcitonin are often elevated in patients with pneumonia. The other is test for CRP, which is synthesized by the liver and binds to phosphocholine on dead or damaged cells in order to mark those cells for immune responses. Measuring CRP level (normal levels are < 10 mg/ml) is a screen for infection and inflammation, because CRP levels can increase rapidly and markedly when processes go awry (in bacterial infection, CRP levels can range from 40 to 200 mg/ml). Various structural views of urea (for the BUN), procalcitonin, and CRP are shown below. Based on the functional groups and levels of structure you see, all these molecules are related to which macromolecule family? The figure shows three molecules. The first illustrates the urea structure which consists of a carbon atom bonded with two NH2 groups and an oxygen atom. Carbon atom bonds to the oxygen atom by a double bond. The second molecule is procalcitonin which consists of three connected structures: N-ProCT, Calcitonin, and Katacalcin. The third molecule illustrates the CRP structure which has quaternary structure.

Protein

Which of the following steps is NOT included in the scientific method?

Repeat an experiment until desired result is achieved.

The different between ribose sugar and deoxyribose sugars is that ________.

Ribose sugars have an extra oxygen atom

All viruses are different. They have different shapes, sizes, and methods for infection. Smallpox virus belongs to a family of viruses known as the poxviruses. Like you and your family, they share similarities, but they are also different in their own special way. Place the correct characteristics for the smallpox virus in the bin marked "Smallpox virus." Place all other characteristics not related to the smallpox virus in the bin marked "influenzavirus."

Smallpox: complex. DNA virus, replicates in cytoplasm, large virus Influenzavirus: simple, replicates in nucleus, RNA virus, small virus

During the formation of nucleic acid, such as DNA, the phosphate group of a new nucleotide covalently binds to _____ of existing string of nucleotides.

The 3' carbon

While the lab is working on the diagnosis for the patient, the critical care team is assessing his basic functions. Since any living organism carries out chemical reactions, an infection skews the body's "normal" laboratory test values as the microbes compromise the body's functions. Another test ordered for the patient is an arterial blood gas (ABG) test. ABGs are performed to measure the pH, and amount of oxygen and carbon dioxide in the blood. The body carefully regulates and maintains blood pH within a very narrow range of 7.35 to 7.45. Abnormal pH values might signify that a patient is not regulating the level of carbon dioxide (CO2). Our patient with pneumonia has a blood pH of 7.52, and the partial pressure of CO2 in his blood is decreasing, likely because he is hyperventilating. Which of the following would be the best description of this situation?

The patient is in respiratory alkalosis (overly alkaline)

If the results from an experiment contradicted the hypothesis, what should be a scientist's next step?

The scientist should reject or modify the hypothesis.

What is spontaneous generation?

The theory that living organisms may arise from nonliving matter.

How would oysters tainted with Vibro vulnificus taste?

There is no change in the flavor of tainted oysters.

What is the common trait of all lipids?

They are at least partially hydrophobic.

What did the work of Lister and Ehrlich have in common?

They both explored the use of chemicals in the prevention and treatment of infectious diseases.

Which of the following is NOT a characteristic of saturated fats?

They contain at least one double bond.

Which of the following is NOT a characteristic of phospholipids?

They contain fatty acids that associate with water.

For viruses to thrive on Earth, they need to keep moving from host to host. For this reason, a virus must use techniques for infecting new hosts and then spreading to others. Smallpox is very capable of spreading from one person to another. Below is a list of ways viruses can spread from one person to another. Place the ways in which smallpox most frequently spreads into the bin labeled "Most Frequent Transmission," place less frequent ways to transmit smallpox in the bin labeled "Less Frequent Transmission," and place all other methods in the bin labeled "Transmission Unlikely."

Transmission unlikely: Eating undercooked beef, drinking contaminated water, sexual intercourse Less Frequent: soiled sheets, shaking hands More Frequent: coughing, sneezing

One of the products of dehydration synthesis reactions is water.

True

The side groups of amino acids can interact with each other and with other molecules.

True

Which nitrogenous base is found only in RNA?

Uracil

he eliminated air from his flasks by sealing them

a bacterium had been proven to cause a disease

Sucrose is an example of which of the following?

a disaccharide

Microorganisms that thrive in acidic environments are called ___________.

acidophiles

A hydroxyl ________ acts as a base.

anion

Nucleosides differ from a nucleotides in that nucleosides ______.

are missing a phosphate.

Which of the following refers to the use of bacteria or other microbes to detoxify pollutants?

bioremediation

An acid dissociates in water to release

both anions and hydrogen ions.

Put the following steps of Koch's postulates in order: a. The suspected infectious agent must be isolated and grown outside the host. b. The suspected infectious agent causes the disease when it is introduced to a healthy, experimental host. c. The suspected infectious agent must be found in every case of the disease. d. The suspected infectious agent must be found in the diseased experimental host.

c,a,b,d

When conducting an experiment, it is generally necessary to include ________ groups that are treated exactly the same as treatment groups except for the condition being tested.

control

the nucleotide _____ is an important signaling molecule within many cells.

cyclic adenosine monophosphate

Amino acids are joined together in a specific type of dehydration synthesis reaction that results in the formation of a peptide bond. This bond links the carboxyl group of one amino acid to the amino group of another amino acid. The formation of a peptide bond to link two amino acids together is a special type of __________. Choose from the following the answer that best finishes this statement.

dehydration synthesis reaction that removes a hydroxyl group from the carboxyl end of the amino acid and reforms the bond with the nitrogen from the amino group that has lost a hydrogen atom

Which parts of the atoms interact in a chemical reaction?

electrons

You have successfully completed the experiments and analyzed your results. Your analysis has allowed you to refine you hypothesis and remove all but one virus strain from your list of possible causative agents. With your success at identifying the viral pathogen, you will now need to begin the long process of characterization, the studying of all aspects of an organism to determine whether this virus is truly new or has been isolated and identified before. The characterization will begin with studying the genome of this pathogen. Sequencing machines will determine the order of the nucleic acids that make up the viral genome, and computers will be able to analyze this sequence to determine the genes available for this virus. What is the area of biology that studies the nucleic acid makeup of an organism? Pick the area of biology that studies DNA and chromosomes.

genetics

Which of the following is an example of a polysaccharide?

glycogen

All of the following individuals showed that cleanliness played a role in human disease EXCEPT __________.

he eliminated air from his flasks by sealing them

The reverse of a dehydration synthesis reaction is a(n) ________ reaction.

hydrolytic

Which of the following is the most alkaline (basic) pH?

pH 13.0

All of the following are components of an amino acid EXCEPT a(n)

pentose group

Each nucleotide is composed of a(n) _____.

pentose sugar, phosphate, and nitrogenous base

Which of the following is NOT a type of lipid?

peptidoglycan

Lipids found in the membranes of all eukaryotic cells are

phospholipids

Which of the following is a bond in which electrons are shared unequally?

polar covalent bond

A protein is a ________ of amino acids.

polymer

Which of the following is found in nucleic acids?

purine

Which of the following techniques could be used to produce a yeast capable of making viral proteins?

recombinant DNA technology

All of the following bases are found in RNA molecules EXCEPT

thymine

Organisms use carbohydrates in all of the following ways EXCEPT

to keep membrane flexible at low temperatures.

Yellow fever is caused by a(n) ___________.

virus

The high amount of energy stored within a molecule of the nucleotide adenosine triphosphate may be found ________.

within the phosphate-phosphate bonds.

While writing your lecture notes, you are trying to develop a way to impart to your students how the removal of a water molecule, a hydroxyl and a hydrogen atom, will be used in making macromolecules. A molecule is a collection of atoms joined through different types of bonds. A macromolecule is the joining of numerous molecules into something that is relatively quite large. The addition of a molecule to a macromolecule, as well as the removal of a molecule from the macromolecule, involves a molecule of water. From past experience you are aware that when you state this to your students many will unfortunately assume you are referring to liquid water. Your students must understand that in biological reactions water, H2O, is actually a hydroxyl group (-OH) and a hydrogen atom (H+) that will be removed or added when altering macromolecules. A dehydration synthesis (removal of water) reforms atomic bonds between molecules to create a larger macromolecule. In a dehydration reaction, a hydroxyl group is removed from one reactant molecule while a hydrogen atom is stripped from another reactant molecule. Reactant (with hydroxyl group) + Reactant (with hydrogen ion) = Product + H2O The open bonds will be reformed joining the two molecules, while the hydroxyl and hydrogen atom will be released as water. The reverse of a dehydration synthesis is a hydrolysis reaction, in which a bond between two molecules is stressed by an enzyme and a hydroxyl group when a hydrogen atom is added into the bond. Whereas a dehydration synthesis creates a macromolecule, a hydrolysis reaction breaks one apart. The figure shows two reactions: hydrolysis and dehydration synthesis. A dehydration synthesis reaction reforms atomic bonds between molecules to create a larger macromolecule. In a dehydration reaction, a hydroxyl group is removed from one reactant molecule while a hydrogen atom is stripped from another reactant molecule. The open bonds will be reformed joining the two molecules while the hydroxyl and the hydrogen atom will be released in a form of water. The reverse of dehydration synthesis is a hydrolysis reaction in which a bond between two molecules is stressed by an enzyme and a hydroxyl group and a hydrogen atom are added to the bond. The result of the hydrolysis reaction is 2 molecules, one of which has the hydroxyl and another has the hydrogen atom within its structure. The source of the hydroxyl and hydrogen is a molecule of water. Whereas dehydration synthesis creates a macromolecule using energy, a hydrolysis reaction breaks one molecule apart with releasing energy. Choose from the following statements the one that best describes the reactions illustrated in the figure above.

Using energy, an enzyme removes a hydroxyl group from the carboxyl group of one amino acid and a hydrogen atom from the amino group of another amino acid to join the amino acids in a dehydration synthesis reaction that releases water. Alternatively, another enzyme breaks the peptide bond and uses a water molecule to join a hydroxyl group to the carboxyl group of one amino acid and a hydrogen atom to the amino group of another amino acid in a hydrolysis reaction.

Who is credited with the discovery of the cause of yellow fever?

Walter Reed

Which of the following is a true statement concerning bacteria and archaea?

While some bacteria are pathogenic to humans, no archaea are known to cause human diseases.

In the late 1800s, a researcher by the name of Robert Koch developed a series of postulates (guidelines) that can be used to prove that a given pathogen is the true cause of a disease. Koch's Postulates 1. The suspected causative agent must be found in every case of the disease and be absent from healthy hosts. 2. The agent must be isolated and grown outside the host. 3. When the agent is introduced to a healthy, susceptible host, the host must get the disease. 4. The same agent must be found in the diseased experimental host. Which of the following steps does NOT follow one of Koch's postulates? Pick step that does NOT follow the postulates.

You give a patient an antibiotic to treat an infection.