Cellular Processes and Water Properties Quiz

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Questions and Answers

What is the primary role of ATP in cellular processes?

Transports oxygen within cells

Facilitates the breakdown of fats

Generates approximately 26-28 ATP molecules per glucose (correct)

Acts as a final electron acceptor

Which step does not involve pumping protons across the inner mitochondrial membrane?

Completion of cellular respiration

Transfer of electrons from CoQH2 to cytochrome c

Transfer of electrons from FADH2 to Coenzyme Q (correct)

Transfer of electrons from NADH to Coenzyme Q

How does ATP influence metabolic regulation?

By increasing oxygen consumption independent of demand

By permanently inhibiting enzyme activity

By promoting lipid accumulation in cells

By responding to changes in cellular energy demands (correct)

Which component acts as the final electron acceptor in cellular respiration?

Oxygen Signup and view all the answers

What role does heat generation play in cellular respiration?

Aids in thermoregulation and maintaining body temperature Signup and view all the answers

What is the primary reason for water's high boiling point compared to similar substances?

Hydrogen bonds between water molecules Signup and view all the answers

Which of the following best describes water's ability to dissolve many substances?

Its polarity and hydrogen bonding capability Signup and view all the answers

What ion concentration indicates a neutral solution in water at 25 ℃?

[H+] = [OH−] = 1.0×10−7 M Signup and view all the answers

How does water's high specific heat contribute to homeostasis?

It provides stability against temperature fluctuations. Signup and view all the answers

In the autoionization of water, what is the relationship between [H+] and [OH−] in acidic solutions?

[H+] > [OH−] Signup and view all the answers

What property of water allows it to adhere to pine needles?

Adhesion Signup and view all the answers

What characteristic of water contributes to its role in temperature regulation within environments?

It can absorb large amounts of heat without a significant temperature change. Signup and view all the answers

During the ionization of water, what does Kw represent?

The equilibrium constant for water's autoionization Signup and view all the answers

How do hydrogen bonds influence the structure of water molecules?

They allow molecules to connect and interact flexibly. Signup and view all the answers

What is the primary function of the heme degradation process?

Recycling of iron and detoxification Signup and view all the answers

Which enzyme is responsible for converting free heme to biliverdin?

Heme oxygenase-1 Signup and view all the answers

What occurs when all enzyme active sites become occupied?

The reaction rate reaches a saturation point. Signup and view all the answers

How does indirect bilirubin primarily travel in the bloodstream?

Bound to albumin Signup and view all the answers

What role do cofactors play in enzyme activity?

They are essential for many enzymes to be active. Signup and view all the answers

How do allosteric regulators affect enzyme activity?

They can either enhance or decrease activity depending on the regulator. Signup and view all the answers

What transformation occurs to indirect bilirubin in the liver?

It is converted to bilirubin diglucuronide Signup and view all the answers

What is a byproduct of the conversion of heme to biliverdin?

Iron (Fe²⁺) Signup and view all the answers

Which statement accurately reflects the role of ionic strength in enzyme activity?

Optimal ionic strength contributes to enzyme stability and substrate binding. Signup and view all the answers

Which property of indirect bilirubin makes it difficult for the body to excrete?

It is lipid-soluble Signup and view all the answers

Which class of enzymes is primarily responsible for catalyzing oxidation-reduction reactions?

Oxidoreductase Signup and view all the answers

In the heme degradation process, what role does carbon monoxide play?

Serves as a signaling molecule Signup and view all the answers

Which statement best describes the final product of heme degradation?

It is more water-soluble after conjugation in the liver Signup and view all the answers

What happens to enzymes when the temperature exceeds their optimal range?

Enzymes can denature and lose effectiveness. Signup and view all the answers

How does substrate concentration affect enzyme activity?

More substrate increases interaction opportunities until a saturation point. Signup and view all the answers

What effect does low temperature typically have on enzyme activity?

Enzyme activity generally decreases, resulting in slower reactions. Signup and view all the answers

What occurs to enzymes if the pH deviates from their optimal range?

Enzymes can denature and lose their functionality. Signup and view all the answers

What characterizes the optimal temperature range for most human enzymes?

Approximately 37°C for peak activity. Signup and view all the answers

What substance is formed when direct bilirubin is metabolized by gut bacteria in the intestines?

Urobilinogen Signup and view all the answers

Which factor can induce the enzyme Heme Oxygenase 1 (HO-1)?

Heavy metals Signup and view all the answers

What is the primary regulator of heme degradation?

Availability of heme Signup and view all the answers

What type of anemia is characterized by the bone marrow failing to produce enough red blood cells?

Aplastic Anemia Signup and view all the answers

Which of the following hormones is known to influence the expression of heme oxygenase?

Cortisol Signup and view all the answers

What contributes to the brown color of feces resulting from bilirubin metabolism?

Stercobilin Signup and view all the answers

Which type of anemia is often caused by genetic mutations in the alpha or beta-globin genes?

Thalassemia Signup and view all the answers

What physiological change occurs when there are increased levels of heme in the body?

Stimulation of its own degradation Signup and view all the answers

What is the primary cause of pre-hepatic jaundice?

Excessive hemolysis of red blood cells. Signup and view all the answers

How does liver dysfunction contribute to hepatic jaundice?

It impairs the conjugation and excretion of bilirubin. Signup and view all the answers

What symptoms are commonly associated with jaundice?

Yellowing of the skin and eyes, dark urine, and pale stools. Signup and view all the answers

What mechanism leads to the accumulation of unconjugated bilirubin in hemolysis?

The liver becomes overwhelmed and cannot process all the bilirubin efficiently. Signup and view all the answers

Which type of jaundice is caused by biliary obstruction?

Post-hepatic jaundice. Signup and view all the answers

What is the role of hemoglobin breakdown in the development of jaundice?

It leads to increased production of unconjugated bilirubin due to hemolysis. Signup and view all the answers

Name one example of a condition that can cause pre-hepatic jaundice.

Hemolytic anemia. Signup and view all the answers

What results from the accumulation of conjugated bilirubin in post-hepatic jaundice?

It causes elevated levels of conjugated bilirubin in the bloodstream. Signup and view all the answers

How does a high NADH/NAD⁺ ratio affect the conversion of acetoacetate?

It favors the conversion of acetoacetate to beta-hydroxybutyrate. Signup and view all the answers

What triggers ketogenesis during fasting?

Increased fatty acid oxidation and high acetyl-CoA levels trigger ketogenesis. Signup and view all the answers

Differentiate between primary and secondary hyperlipidemia.

Primary hyperlipidemia is due to genetic disorders, while secondary hyperlipidemia relates to conditions like diabetes or obesity. Signup and view all the answers

What are the symptoms commonly associated with ketoacidosis?

Symptoms include nausea, vomiting, abdominal pain, and confusion. Signup and view all the answers

What is the result of glucocerebroside accumulation in Gaucher Disease?

It results from an enzyme deficiency leading to harmful effects on the body. Signup and view all the answers

How do elevated free fatty acid levels affect beta-oxidation?

They promote beta-oxidation by providing more substrate for the process. Signup and view all the answers

What is the effect of insulin on beta-oxidation?

Insulin inhibits beta-oxidation and promotes the storage of fatty acids. Signup and view all the answers

Why is malonyl-CoA significant in the regulation of CPT I?

Malonyl-CoA inhibits CPT I, thus controlling the entry of fatty acids into mitochondria. Signup and view all the answers

Under what metabolic conditions does ketogenesis primarily occur?

Ketogenesis occurs during fasting, prolonged exercise, or low-carbohydrate diets. Signup and view all the answers

How does glucagon influence ketogenesis during fasting?

Glucagon stimulates ketogenesis by promoting lipolysis and fatty acid mobilization. Signup and view all the answers

What role do acetyl-CoA levels play in ketone body formation?

Increased acetyl-CoA from beta-oxidation drives the formation of ketone bodies. Signup and view all the answers

Describe the relationship between energy status and the electron transport chain.

High levels of NADH and FADH₂ inhibit the electron transport chain. Signup and view all the answers

What effect does nutritional status have on the regulation of beta-oxidation?

In a fasting state, beta-oxidation is upregulated, while it is downregulated in a fed state. Signup and view all the answers

What is the significance of heme in oxygen transport, and how does it function in hemoglobin?

Heme binds to oxygen in hemoglobin, facilitating its transport in the bloodstream. Signup and view all the answers

Explain the role of ALAS in the regulation of heme synthesis.

ALAS is the rate-limiting enzyme that initiates heme synthesis and is negatively regulated by heme levels through feedback inhibition. Signup and view all the answers

How does lead exposure affect heme synthesis at the level of ALAD and ferrochelatase?

Lead inhibits both ALAD and ferrochelatase, disrupting the production of heme by interfering with key enzymatic steps. Signup and view all the answers

Describe the connection between heme degradation and bilirubin metabolism.

Heme degradation produces biliverdin, which is then converted to bilirubin, a substance important for waste elimination from the body. Signup and view all the answers

In what way does the availability of iron influence the activity of ferrochelatase?

Ferrochelatase activity is dependent on iron availability, as it incorporates iron into protoporphyrin IX to complete heme synthesis. Signup and view all the answers

What is the primary outcome of glycolysis in terms of glucose metabolism?

Glycolysis converts glucose into pyruvate, generating a net production of 2 ATP and 2 NADH. Signup and view all the answers

Identify the step in glycolysis that acts as a major regulatory point and is influenced by ATP levels.

Phosphofructokinase-1 (PFK-1) is the major regulatory enzyme influenced by ATP levels. Signup and view all the answers

Explain the role of NAD+ in glycolysis.

NAD+ serves as an electron acceptor, getting reduced to NADH during the oxidation of glyceraldehyde 3-phosphate. Signup and view all the answers

What is the significance of the phosphorylation of glucose in step 1 of glycolysis?

Phosphorylation of glucose traps it inside the cell as glucose-6-phosphate, preventing it from leaving. Signup and view all the answers

In the absence of oxygen, what is the end product of glycolysis?

In the absence of oxygen, glycolysis produces lactate as the end product. Signup and view all the answers

Describe the condition that results from a deficiency in pyruvate kinase.

Pyruvate kinase deficiency can lead to hemolytic anemia, jaundice, and fatigue. Signup and view all the answers

What regulatory mechanism is prompted by ATP accumulation in glycolysis?

ATP accumulation signals feedback inhibition, slowing down glycolysis to prevent overproduction. Signup and view all the answers

How does the pentose phosphate pathway (PPP) differ from glycolysis?

The pentose phosphate pathway generates NADPH and ribose 5-phosphate, unlike glycolysis which focuses on ATP production. Signup and view all the answers

What is the primary purpose of the oxidative phase of the pentose phosphate pathway?

The oxidative phase of the PPP primarily generates NADPH for reductive biosynthesis. Signup and view all the answers

Name the enzyme that catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconolactone in the PPP.

Glucose-6-phosphate dehydrogenase (G6PD) catalyzes this reaction. Signup and view all the answers

What is gluconeogenesis and when does it primarily occur?

Gluconeogenesis is the metabolic pathway that synthesizes glucose from non-carbohydrate precursors, primarily occurring during fasting or intense exercise. Signup and view all the answers

Identify a medical condition resulting from a blockage in glycolysis and describe its impact.

Lactic acidosis can occur due to excessive glycolysis, causing an accumulation of lactic acid. Signup and view all the answers

How does NADPH influence the PPP's activity?

High levels of NADPH inhibit the pentose phosphate pathway, reducing its activity. Signup and view all the answers

What is produced as a byproduct of the glycolytic pathway along with ATP?

NADH is produced as a byproduct alongside ATP during glycolysis. Signup and view all the answers

What is the consequence of all enzyme active sites being occupied?

The reaction rate reaches a saturation point and does not increase with additional substrate. Signup and view all the answers

How do ionic strength and cofactors influence enzyme activity?

Optimal ionic strength enhances enzyme stability and substrate binding, while cofactors are essential for many enzymes to become active. Signup and view all the answers

What distinguishes activators from inhibitors in enzyme regulation?

Activators increase enzyme activity, while inhibitors decrease it. Signup and view all the answers

What is the role of allosteric regulation in enzyme functionality?

Allosteric regulation involves molecules binding to sites other than the active site, which can alter enzyme activity positively or negatively. Signup and view all the answers

What are the six main classes of enzymes as categorized by IUBMB?

The six classes are: Oxidoreductase, Transferase, Hydrolase, Lyase, Isomerase, and Ligase. Signup and view all the answers

Study Notes

Final Exam Information

Duration: 2 hours
Closed-book exam
Bring non-programmable calculators (per HKMU approved list)
Topics covered: Lectures 1-11 (primarily lectures 6-11)
Weight of final exam: 50% of overall grade

Final Exam Structure

Multiple Choice Questions (20%): 20 questions, 1 mark each
Short Questions (40%): 7 questions, different marks per question
Long Questions (40%): 5 questions, 10 marks each; choose 4 to answer

Example of Short Questions

Name the metabolite or enzyme from 1 to 6 in the TCA cycle diagram (provided in the slides) (Further short question examples provided in the slides)

Example of Long Questions

A 45-year-old male presents to the emergency department after several days of severe fasting and significant weight loss. He has a history of type 2 diabetes and reports fatigue, weakness, and confusion. Blood tests reveal elevated ketone levels and a high blood urea nitrogen (BUN) ratio. (Further long question examples provided, similar to a quiz format

Lecture 1: Water and Aqueous Systems

Chemical formula: H₂O
Polar molecule: Oxygen is negatively charged, while hydrogens are positively charged
Hydrogen bonds: Allow water molecules to interact with each other
Cohesion: Water molecules stick to each other
Adhesion: Water molecules stick to other molecules(e.g., water droplets on pine needles)
High boiling point: Due to hydrogen bonds
High specific heat: More energy to increase the temperature of water. Important for homeostasis.
Solvent for polar molecules: Water's polarity makes it an excellent solvent for many molecules necessary for life
Ionization of water: Water can act as either an acid or a base
Equilibrium constant (Kw): [H+][OH-]= 1.0x10⁻¹⁴ at 25°C

What is Buffer?

Definition: An aqueous solution that resists changes in pH
Preparation of buffer: mixing a large volume of a weak acid with its conjugate base, or a weak base with its conjugate acid
Example of a buffer: Phosphate buffer (H₂PO₄⁻ and HPO₄²⁻), maintains a physiological pH of 7.4
Blood buffer: Carbonic acid (H₂CO₃) and bicarbonate anion (HCO₃⁻)

Disorders of Acid-Base Balance

Acidosis: Blood pH falls below 7.35
Respiratory acidosis: Caused by CO₂ buildup due to respiratory issues(e.g., pneumonia, asthma)
Symptoms: Shortness of breath, confusion, drowsiness, cyanosis (bluish skin)
Metabolic acidosis: Caused by excess acids (e.g., diabetic ketoacidosis, renal failure)
Symptoms: Rapid breathing, fatigue, confusion, dizziness
Alkalosis: Blood pH rises above 7.45
Respiratory alkalosis: Caused by excessive CO₂ loss (due to hyperventilation)
Symptoms: Dizziness, tingling extremities, muscle cramps
Metabolic alkalosis: Caused by excess bicarbonate or loss of acids
Symptoms: Muscle twitching, hand tremors

Lecture 2: Carbohydrates, Protein, and Lipids

Monosaccharides: Glucose, galactose, mannose, fructose, ribose, deoxyribose
Disaccharides: Maltose, cellobiose, sucrose, lactose
Oligosaccharides: Glycoproteins, glycolipids
Polysaccharides: Starch, glycogen, cellulose, chitin, peptidoglycan, agarose, heparin, chondroitin

Proteins - Structure

Primary structure: Linear sequence of amino acids
Secondary structure: Interactions between amino acids - Alpha helix & Beta strands
Tertiary structure: Overall folding of polypeptide chains
Quaternary structure: Multiple folded protein subunits

Lipids - Classification

Glycerophospholipids
Sphingolipids
Glycolipids (Glycoglycerolipids and glycosphingolipids)

Fatty Acids

Saturated Fatty Acids: Do Not contain double bonds (e.g., butter fat)
Unsaturated Fatty Acids: Containing one or more double bonds (e.g. plant oils)
Monounsaturated Fatty Acids: Contain one double bond
Polyunsaturated Fatty Acids: Contain more than one double bond
Types of PUFAs: Omega-3 and Omega-6 fatty acids (Examples are given in slides).

Lecture 3: Nucleic Acids

DNA Structure: Double helix, deoxyribose sugar and phosphate backbone, nitrogenous bases (A,T,G,C)
RNA Structure: Single-stranded, ribose sugar and phosphate backbone, nitrogenous bases (A,U,G,C)
Functions of DNA
Storage of genetic information
Transmit genetic material through replication
Instruction of protein synthesis
Functions of RNA
Types of RNA: Messenger RNA (mRNA), Ribosomal RNA (rRNA), Transfer RNA (tRNA)
Properties of RNA: More reactive than DNA, unstable in alkaline conditions
RNA's mutation rate is relatively higher
RNA is more versatile than DNA

Lecture 4: Metabolism and Energy I: Tricarboxylic Acid (TCA) Cycle

Pyruvate oxidation (converting pyruvate into acetyl-CoA)
Occurs in the mitochondrial matrix
Enables the complete oxidation of glucose
Critical for ATP production
Acetyl-CoA
A metabolic intermediate involved in many metabolic pathways
Produced during the breakdown of glucose, fatty acids, and proteins
Energy production
Biosynthesis: precursor for fatty acids, cholesterol, and ketone bodies.
Amino acid metabolism: involved in amino acid metabolism
Sources of acetyl-CoA: Glycogen, Triglyceride, and Protein

Lecture 5: Metabolism and Energy II: Oxidative Phosphorylation

The process by which ATP is produced through the transfer of electrons in the electron transport chain
Components: Electron Transport Chain (ETC) and Chemiosmosis
ETC: Four main protein complexes, transferring electrons from carriers to oxygen, pumping protons (H+) into the intermembrane space
Chemiosmosis: Uses the established proton gradient by the ETC to create ATP by ATP synthase
Location: Inner mitochondrial membrane
How ATP is produced (Steps):
Proton gradient formation.
Proton flow through ATP synthase.
Rotation of F₀.
ATP formation.

Lecture 6: Carbohydrate Metabolism (Glycolysis)

Pathway used by all body cells to extract energy from glucose
Preparatory phase (Steps 1-5): Glucose is phosphorylated and converted into two 3-carbon units.
Payoff phase (Steps 6-10): These 3-carbon units are oxidized, and ATP is produced
Net ATP production: 2 ATP per glucose molecule
Significance: Crucial for anaerobic conditions and produces intermediates for other metabolic pathways
Regulation: Key regulatory enzymes (hexokinase, phosphofructokinase-1, pyruvate kinase)
Regulation by substrate availability, feedback inhibition.

Lecture 7: Protein and Lipid Metabolism

Steps of β-oxidation
Activation of fatty acids: Convert fatty acids into fatty acyl-CoA in the cytoplasm.
Transport into mitochondria: Fatty acyl-CoA is transported into mitochondria using the carnitine shuttle.
Four main steps: Oxidation, Hydration, Second Oxidation, Thiolysis
Energy Sources: Each cycle of β-oxidation produces one molecule of Acetyl-CoA, one molecule of FADH2, and one molecule of NADH.
Regulation of β-oxidation: Controlled by substrate availability, hormonal regulation, enzyme regulation, and energy status.
Protein Metabolism
Removal of amino groups via transamination to generate a-ketoacids
Urea cycle: Process by which ammonia is converted to urea for excretion.
Role of different enzymes

Lecture 8: Hemoglobin

Definition: Hemoglobin is a globular protein in red blood cells responsible for transporting oxygen in the blood.
Basic Parts of Hemoglobin: Globin proteins (alpha and beta chains) and Heme groups
Structure: Four globin chains, with each containing a heme group containing an iron atom.
Function: Transports oxygen, carries CO2, and maintains blood pH.
Quaternary structure: Tetramer composed of four subunits.
Role of hemoglobin: Transports oxygen to tissues, transports CO2 to lungs, and plays role in maintaining blood pH.
Heme Synthesis: The process of producing heme for hemoglobin.
Heme Degradation: The process of breaking down heme to simple molecules for recycling iron and eliminating byproducts.

Lecture 9: Enzyme I: Introduction to Enzymes

Definition: Enzymes are proteins that serve as biological catalysts
Importance of enzymes: Speed up biochemical reactions, are highly specific, control metabolic pathways, and play roles in diseases.
Substrate, and product: Substrate is the molecule that an enzyme in a biochemical reaction reacts upon; product is the final molecule produced
Enzyme structure: Enzymes have active sites where substrates bind for reactions
Factors affecting enzyme activity: Temperature, pH, Substrate concentration, inhibitors

Lecture 10: Enzyme II: Enzyme Kinetics and Inhibitors

Enzyme Kinetics: Study of rates of enzyme-catalyzed reactions in terms of substrate concentration.
Turnover number (kcat): The maximum number of substrate molecules converted to product per enzyme molecule per second.
Michaelis-Menten Equation: Mathematical equation describing reaction velocity in terms of substrate concentration, total enzyme concentration
Factors affecting enzyme activity: Substrate concentration, temperature, pH, inhibitors
Types of inhibitors: Competitive, Non-competitive, Uncompetitive.

Lecture 11: Enzyme III: Enzyme Diagnostics and Assay

Liver Enzymes: ALT, AST, GGT, ALP, diagnostics for liver health, liver disease, and possible damage.
Cardiac Enzymes: CK-MB, troponin I and T, myoglobin
Pancreatic Enzymes: Amylase, lipase, protease, helpful for assessing possible pancreatitis and gastrointestinal issues
Enzymes in Cancer Diagnosis: PSA, ALP, LDH, CEA

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Test your knowledge on the crucial roles of ATP in cellular processes and the unique properties of water. This quiz covers topics from cellular respiration to water's influence on temperature regulation and homeostasis. Dive in to assess your understanding of these fundamental biological concepts!