Questions and Answers
What type of interaction is shown in box W?
What type of interactions are shown in V?
Which of the following statements concerning the interaction labeled Y is/are true?
What is the item labeled Z?
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The formation of a disulfide bond is an example of what type of reaction?
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Which of the following is NOT a valid interpretation of Met-enkephalin's primary structure?
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Which statement regarding O2 binding by myoglobin and hemoglobin is INCORRECT?
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Which statement regarding sickle cell anemia is FALSE?
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Which of the following statements about protein structure is INCORRECT?
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Which of the following statements is CORRECT about Enzyme A (Km = 10 micromolar) and Enzyme B (Km = 0.1 micromolar)?
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What is the effect of an enzyme on the equilibrium constant for the reaction it catalyzes?
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Which of the following is NOT an example of allosteric binding or regulation?
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Which of the following statements regarding enzymes is/are CORRECT?
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Which statements below correctly describe isozymes?
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Metal ions such as Zn++ and Mg++ are often required for enzyme activity. What are these ions examples of?
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Which of the following statements is FALSE concerning enzymes and their reactions?
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Which statement about phosphorylation is FALSE?
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In living organisms, related chemical reactions are often organized into metabolic pathways. Which of these is NOT usually a feature of a metabolic pathway?
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__________ are substrates for plants (autotrophs), __________ are substrates for animals (heterotrophs), while __________ is the source of all energy.
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Which phrase about an activated intermediate in an enzyme reaction is INCORRECT?
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Which statement about bioenergetics is INCORRECT?
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What is maltose?
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What is amylopectin?
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What is cellulose?
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Humans store glucose as what?
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What is lactose?
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What does digestion of starch and glycogen involve?
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Why is the branched-chain structure of glycogen a wise metabolic strategy?
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Which statement about carbohydrate digestion is CORRECT?
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Which statement about transport across membranes is INCORRECT?
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Absorption of glucose from the gut through the intestinal epithelial cells into the blood involves all of the following EXCEPT:
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Why can't humans obtain metabolic energy from cellulose?
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Individuals that present with bloating, diarrhea, and dehydration after consumption of dairy products are most likely deficient in what?
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Which statement is INCORRECT?
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Study Notes
Types of Interactions
- Interaction shown in box W is unspecified but represents a particular type of molecular interaction.
- Interaction shown in box V is also unspecified, highlighting another molecular interaction type.
Interaction Y
- Interaction Y is an ionic interaction, disrupted at a low pH of 1.0.
Item Z
- Item Z is part of a protein's secondary structure, folded into an alpha helix.
Disulfide Bonds
- Formation of a disulfide bond is categorized as an oxidation reaction.
Met-Enkephalin
- Met-enkephalin's sequence comprises Tyr-Gly-Gly-Phe-Met. The amino group of methionine is not bonded to another amino acid, which is a notable insight about its structure.
O2 Binding
- At low oxygen concentrations, hemoglobin displays a lower affinity for oxygen compared to myoglobin, which is an incorrect statement regarding oxygen binding.
Sickle Cell Anemia
- Sickle cell hemoglobin's oxygen binding capacity is reduced to half when compared to normal hemoglobin.
Protein Structure
- Fibrous proteins are characterized by their rigidity, not their ability to stretch easily, making this statement incorrect.
Enzyme Affinity
- Enzyme A exhibits a higher substrate affinity with a Km of 10 micromolar compared to enzyme B, which has a Km of 0.1 micromolar.
Enzymatic Equilibrium
- Enzymes do not alter the equilibrium constant of the reactions they catalyze.
Allosteric Binding
- Oxygen binding to myoglobin at low O2 concentrations does not qualify as allosteric regulation.
Enzyme Characteristics
- Enzymes enhance reaction speeds by decreasing activation energy and by raising the local concentration of substrates.
Isozymes
- Isozymes catalyze the same biochemical reactions and can be distinguished from each other via electrophoresis.
Cofactors
- Metal ions such as Zn++ and Mg++ function as essential cofactors for enzyme activities.
Substrate Specificity
- Most enzymes are specific and generally act on limited, chemically similar substrates.
Phosphorylation
- Phosphorylation is performed by kinases, not by phosphatases, indicating the falsity of that statement.
Metabolic Pathways
- Typical features of metabolic pathways do not usually include the regulation of each enzyme in the pathway.
Energy Sources
- Autotrophs utilize CO2 and water, while heterotrophs derive energy from glucose and O2, with solar energy serving as the primary energy source for ecosystems.
Activated Intermediates
- Activated intermediates in enzymatic reactions do not accumulate; they are transient.
Bioenergetics
- Incorrect statements about bioenergetics include misconceptions about spontaneous reactions and energy levels of products versus reactants.
Carbohydrates
- Maltose is a disaccharide with an alpha 1→4 glycosidic link.
- Amylopectin features alpha 1→4 and alpha 1→6 glycosidic links, while cellulose solely contains beta 1→4 glycosidic links.
- Humans store glucose in the form of glycogen.
- Lactose is a disaccharide comprised of glucose and galactose, typically found in milk.
Digestion and Absorption
- Starch and glycogen breakdown occurs through the hydrolysis of glycosidic bonds between glucose monomers, leading to efficient energy release.
- Glycogen's branched structure facilitates rapid glucose mobilization.
- Carbohydrate digestion features di-saccharidases active in the small intestine.
Membrane Transport
- Statements regarding membrane transport clarify that small hydrophobic molecules can diffuse freely, and energy is necessary for active transport against gradients.
- Absorption of glucose into the bloodstream does not involve immediate phosphorylation inside intestinal epithelial cells.
Cellulose Digestion
- Humans lack the enzyme to digest cellulose, which is attributed to the inability to break down beta 1→4 glycosidic links.
Lactase Deficiency
- Symptoms such as bloating and diarrhea after dairy ingestion indicate lactase deficiency, impeding lactose digestion.
Glucose Circulation
- Upon dietary glucose absorption, it does not directly enter red blood cells but goes through other metabolic processes.
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Prepare for your Biology Exam 3 with these flashcards. Each card presents important terms and definitions related to interactions in biology. Test your understanding and enhance your knowledge on essential concepts!
