Microbiology Ch.2

Gastric juices have a pH of 1 or 2. This would indicate which of the following?

numerous H+ ions and a low pH

Which of the following is true of ATP?

ATP stores energy in phosphate bonds.

This activity focuses on the base-pairing of DNA nucleotides and asks you to match nucleotides with the corresponding base-pair partner.

Adenine forms base pairs with Thymine. Cytosine forms base pairs with Guanine. Guanine forms base pairs with Cytosine. Thymine forms base pairs with Adenine.

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.

Which of the following statements is true regarding organic molecules?

Carbohydrates are a large and diverse group of molecules composed of carbon, hydrogen, and oxygen. Examples include glycogen and starch.

Which of the following is a major function of carbohydrates?

Carbohydrates are the primary source of energy for the cell.

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: Calcium, Sodium, Iron, Magnesium, and Potassium Anions: Chloride, Phosphate, Carbon dioxide (measured as bicarbonate, HCO3)

Based on your knowledge of DNA and RNA structure, drag each item to the appropriate box to indicate whether it best describes DNA or RNA.

DNA: the nitrogen-containing bases are adenine (A), cytosine (C), guanine (G), and thymine (T); the pentose sugar is deoxyribose; it is double-stranded in cells and most DNA viruses; it functions by determining the heredity of trait RNA: the nitrogen-containing bases are adenine (A), cytosine (C), guanine (G), and uracil (U); the pentose sugar is ribose; it is single-stranded in cells and most RNA viruses; it functions in protein synthesis

Two components are common to all four DNA nucleotides, and one component differs. Drag each of the following terms to the appropriate column to indicate whether that item is commonly found in all DNA nucleotides or only in specific DNA nucleotides

Found in all DNA nucleotides: deoxyribose sugar and phosphate. Found only in specific DNA nucleotides: cytosine, adenine, guanine, and thymine

Which of the following would have the greatest impact on blood glucose?

Jelly beans (GI value = 78)

What type of reaction is represented by the equation below? Molecule AB →Molecule A + Molecule B

decomposition reaction

Protein structure is directly related to the function of the protein. Which of the following is an accurate description of the level of structure in a protein?

Tertiary protein structure is the overall three-dimensional shape involving interactions between the side groups of various amino acids.

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).

Which of the following comparisons between sugar and sugar substitutes is incorrect?

They are structurally identical. Submit

Which of the following would not be considered an organic compound?

Water (H2O)

Which of the following statements about water is true?

Water is a product in dehydration synthesis reactions.

Which of the following correctly describes the structure of an atom?

a nucleus with positively charged protons, uncharged neutrons, and orbiting negatively charged electrons

Part complete 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 bond is best described as an intermolecular attraction due to partial charges formed in polar covalent bonds?

hydrogen bond

Which type of bond is found between Na+ and Cl- ions in NaCl?

ionic bond

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

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

Which of the following describes inorganic molecules?

small and structurally simple compounds, which typically lack carbon and in which ionic bonds may play an important role.