Cellular Respiration and Oxidative Phosphorylation
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Questions and Answers

What is the primary function of the electron transport chain in oxidative phosphorylation?

  • To remove oxygen from the mitochondria
  • To create a proton gradient across the mitochondrial membrane (correct)
  • To produce glucose from carbon dioxide
  • To synthesize ATP directly from glucose

Which phase of oxidative phosphorylation is responsible for ATP synthesis through chemiosmosis?

  • Electron transport chain
  • Chemiosmosis (correct)
  • Photolysis
  • Substrate-level phosphorylation

What is the net ATP yield from glycolysis?

  • 2 ATP (correct)
  • 0 ATP
  • 4 ATP
  • 6 ATP

How much ATP is generated from 1 molecule of NADH during oxidative phosphorylation?

<p>2.5 ATP (C)</p> Signup and view all the answers

What is the average total yield of ATP per molecule of glucose during cellular respiration?

<p>30 ATP (B)</p> Signup and view all the answers

What purpose does the proton gradient serve in the mitochondrial membrane during cellular respiration?

<p>To drive ATP synthesis (C)</p> Signup and view all the answers

What is the total amount of ATP generated through substrate-level phosphorylation in the citric acid cycle?

<p>2 ATP per cycle (B)</p> Signup and view all the answers

Which of the following correctly describes FADH2's contribution to ATP yield?

<p>Each FADH2 produces 1.5 ATP (D)</p> Signup and view all the answers

What is the primary method of water intake in the body?

<p>Ingestion of foods and beverages (A)</p> Signup and view all the answers

What structure in the kidney is primarily responsible for filtering blood?

<p>Glomerular capsular space (B)</p> Signup and view all the answers

What percentage of water output is accounted for by urine?

<p>60% (D)</p> Signup and view all the answers

Which type of cells are responsible for forming the visceral layer of the glomerular capsule?

<p>Podocytes (A)</p> Signup and view all the answers

What triggers the release of ADH in the body?

<p>A rise in osmolality (A)</p> Signup and view all the answers

Which of the following describes a consequence of decreased osmolality?

<p>Inhibits thirst (D)</p> Signup and view all the answers

What happens to larger substances in the filtration process of the glomerulus?

<p>They remain in the bloodstream. (D)</p> Signup and view all the answers

Which part of the nephron receives the filtrate from the glomerular capsule?

<p>Proximal convoluted tubule (B)</p> Signup and view all the answers

What is the typical range of osmolality maintained in the body fluids?

<p>280–300 mOsm (D)</p> Signup and view all the answers

What is the function of the efferent arteriole in the kidney's filtration system?

<p>Drains blood from the glomerulus (B)</p> Signup and view all the answers

What happens to cells when excessive water is gained compared to solutes?

<p>Cells swell due to water influx. (D)</p> Signup and view all the answers

What characterizes edema in tissue?

<p>Accumulation of interstitial fluid causing swelling. (C)</p> Signup and view all the answers

Which ion is the predominant cation in extracellular fluid (ECF)?

<p>Sodium (Na+) (B)</p> Signup and view all the answers

What triggers aldosterone release from the adrenal cortex?

<p>Elevated potassium levels in extracellular fluid. (C)</p> Signup and view all the answers

How does sodium affect water distribution in the body?

<p>Water follows sodium due to osmotic pressure. (D)</p> Signup and view all the answers

What is the impact of changes in sodium levels on blood pressure?

<p>Variations in sodium levels affect plasma volume and blood pressure. (A)</p> Signup and view all the answers

What is the role of renin in sodium and fluid regulation?

<p>Promotes the production of angiotensin II. (A)</p> Signup and view all the answers

How does edema affect tissue function?

<p>Increases the distance for diffusion of substances. (C)</p> Signup and view all the answers

What is the normal pH of arterial blood?

<p>7.4 (C)</p> Signup and view all the answers

Which condition is indicated by arterial pH greater than 7.45?

<p>Alkalosis (C)</p> Signup and view all the answers

What are the main processes occurring in the renal tubule?

<p>Reabsorption (A), Secretion (C)</p> Signup and view all the answers

What part of the nephron is responsible for filtration?

<p>Renal corpuscle (C)</p> Signup and view all the answers

What is the pH of intracellular fluid (ICF)?

<p>7.0 (C)</p> Signup and view all the answers

Which of the following statements about acid-base balance is correct?

<p>Body closely regulates pH. (C)</p> Signup and view all the answers

What is the pH range for venous blood and interstitial fluid?

<p>7.35 - 7.45 (D)</p> Signup and view all the answers

Which structure in the nephron is responsible for reabsorption?

<p>Renal tubule (C)</p> Signup and view all the answers

Which cell types are found in the collecting duct?

<p>Principal cells and intercalated cells (A)</p> Signup and view all the answers

What occurs when the arterial pH drops below 7.35?

<p>Acidosis (D)</p> Signup and view all the answers

What type of epithelium lines the parietal layer of the glomerular capsule?

<p>Squamous epithelium (D)</p> Signup and view all the answers

Which nephron type features a glomerulus located further from the cortex-medulla junction?

<p>Cortical nephron (A)</p> Signup and view all the answers

What is the main function of the proximal convoluted tubule?

<p>Reabsorption of water and solutes (B)</p> Signup and view all the answers

What characterizes the distal convoluted tubule compared to the proximal convoluted tubule?

<p>It has a clear lumen. (B)</p> Signup and view all the answers

Which structure directly supplies blood to the peritubular capillaries?

<p>Afferent arteriole (A)</p> Signup and view all the answers

Which nephron is associated with a longer nephron loop and increased water reabsorption?

<p>Juxtamedullary nephron (B)</p> Signup and view all the answers

What connects the glomerulus to the collecting duct?

<p>Distal convoluted tubule (B)</p> Signup and view all the answers

Which vessel is involved in draining blood from the nephrons?

<p>Arcuate vein (D)</p> Signup and view all the answers

What is the functional significance of the glomerular capsular space?

<p>It is involved in the filtration of blood. (A)</p> Signup and view all the answers

Which of the following structures is primarily responsible for the reabsorption of water in the nephron?

<p>Collecting duct (B)</p> Signup and view all the answers

Flashcards

Oxidative phosphorylation

Two-phase process that uses high-energy electrons to create an H+ gradient, driving ATP synthesis.

Electron transport chain

Phase 1 of oxidative phosphorylation. Creates a proton gradient with high-energy electron transfer.

Chemiosmosis

Phase 2 of oxidative phosphorylation. Uses the energy of the proton gradient to create ATP.

ATP synthase

Enzyme that produces ATP using energy from the proton gradient.

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Glycolysis

Process that breaks down glucose into two pyruvate molecules, producing a small amount of ATP.

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Pyruvic acid

End product of glycolysis, used in further cellular respiration.

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Citric acid cycle

Part of cellular respiration that further breaks down molecules for ATP production

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ATP yield of cellular respiration

Approximately 30 ATP molecules per glucose molecule

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Water intake

The amount of water taken into the body. Most comes from ingested foods and drinks, with some from metabolism.

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Water output

The amount of water leaving the body. Primarily through urine, followed by insensible losses (skin/lungs), perspiration, and feces.

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ECF Osmolality

The concentration of dissolved particles in the extracellular fluid (the fluid outside the cells).

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Osmolality range

The body maintains extracellular fluid osmolality between 280-300 mOsm.

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Osmolality imbalance triggers

Changes in extracellular fluid osmolality trigger thirst and hormone (ADH) responses to maintain balance.

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Hypotonic Hydration

Excessive water intake causing cells to swell due to water moving into them (osmosis).

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ECF Osmotic Pressure

The pressure exerted by solutes in the extracellular fluid (ECF).

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Sodium's Role in Fluid Balance

Sodium is the most abundant cation in ECF and controls ECF volume and water distribution.

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Edema

Atypical buildup of interstitial fluid (IF), causing tissue swelling.

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Renin-Angiotensin Mechanism

A process where renin triggers angiotensin II, which in turn stimulates aldosterone release to reabsorb sodium from the kidneys.

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Aldosterone's Effect

Aldosterone increases sodium reabsorption in the kidneys, therefore increasing sodium in the body and affecting blood volume and pressure

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Angiotensin II

A hormone produced in the renin-angiotensin mechanism, responsible for increasing blood pressure.

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Interstitial Fluid (IF)

Fluid that surrounds cells in the body tissues, distinct from the extracellular fluid (ECF).

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Glomerular Filtration

The first step of urine formation where blood is filtered through the glomerulus, separating water and small solutes from larger molecules.

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Filtration Membrane

A specialized barrier in the glomerulus composed of three layers: endothelium, basement membrane, and podocytes. It prevents large molecules and blood cells from entering the filtrate.

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Glomerular Capillary

A tiny blood vessel within the glomerulus responsible for filtering blood.

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Podocytes

Specialized cells that wrap around the glomerular capillaries, forming part of the filtration membrane.

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Renal Corpuscle

The functional unit of the kidney responsible for filtering blood. It consists of the glomerulus and Bowman's capsule.

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pH

A measure of the acidity or alkalinity of a solution. A pH of 7 is neutral. Solutions with a pH below 7 are acidic, and solutions with a pH above 7 are alkaline (basic).

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Acid-Base Balance

The process of maintaining a stable pH in the body fluids.

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Normal pH of Arterial Blood

The normal pH of arterial blood is 7.4.

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Alkalosis

A condition where the pH of arterial blood is higher than 7.45.

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Acidosis

A condition where the pH of arterial blood is lower than 7.35.

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Kidney's Role in Acid-Base Balance

The kidneys play a crucial role in maintaining acid-base balance by filtering waste products and regulating the levels of bicarbonate (HCO3-) ions in the blood.

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Nephron

The functional unit of the kidney. A long, twisted tube responsible for filtering waste and regulating blood volume and composition.

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Renal Tubule

The second part of a nephron, where filtered substances are reabsorbed back into the blood and other substances are secreted into the tubule for elimination.

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Glomerulus

A ball of capillaries within the renal corpuscle where filtration occurs.

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Bowman's Capsule

A cup-shaped structure surrounding the glomerulus, capturing filtered fluid from the blood.

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Proximal Convoluted Tubule (PCT)

The first part of the renal tubule, responsible for reabsorbing most of the filtered water, glucose, and amino acids.

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Distal Convoluted Tubule (DCT)

The final part of the renal tubule, responsible for fine-tuning electrolyte and fluid balance.

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Nephron Loop (Loop of Henle)

A hairpin-shaped structure in the nephron, critical for regulating water and electrolyte balance.

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Collecting Duct

The final segment of the nephron, collecting urine from multiple nephrons and carrying it to the renal pelvis.

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Cortical Nephron

Shorter nephrons primarily located in the cortex of the kidney.

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Juxtamedullary Nephron

Longer nephrons with loops extending deep into the medulla of the kidney.

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Vasa Recta

Specialized blood vessels surrounding the nephron loop, crucial for maintaining the concentration gradient in the medulla.

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Study Notes

Anabolism and Catabolism

  • Anabolism is the synthesis of large molecules from smaller ones. An example is the synthesis of proteins from amino acids.
  • Catabolism is the hydrolysis of complex structures into simpler ones. An example is the breakdown of proteins into amino acids. Hydrolysis breaks down polymers. This process shares the same root as the word "catastrophic".

Cellular Respiration

  • Cellular respiration is the catabolic breakdown of food that captures energy from food to form ATP.
  • The goal of cellular respiration is to trap chemical energy in ATP.
  • Energy can be stored in glycogen and fats for later use.
  • Phosphorylation is when enzymes shift high-energy phosphate groups from ATP to other molecules.
  • Phosphorylated molecules become activated to perform cellular functions. This is a quick way to create ATP.

Three Stages in Processing Nutrients

  • Stage 1: Digestion, absorption and transport to tissues.
  • Stage 2: Cellular processing (in cytoplasm)
    • Synthesis of lipids, proteins, and glycogen
    • Catabolism (glycolysis) into pyruvic acid and acetyl CoA
  • Stage 3: Oxidative breakdown of intermediates into CO2, water and ATP.
  • This process occurs in mitochondria.
  • Cellular respiration consists of glycolysis of stage 2 and all of stage 3.

Oxidation-Reduction (Redox) Reactions

  • Oxidation reactions involve the gain of oxygen or loss of hydrogen atoms (and their electrons).
  • In a redox reaction, oxidized substances lose electrons and energy.
  • Reduced substances gain electrons and energy.
  • Redox reactions are catalyzed by enzymes that usually require a B vitamin coenzyme.

ATP Synthesis

  • Two mechanisms are used to make ATP from captured energy during cellular respiration:
      1. Substrate-level phosphorylation involves high-energy phosphate groups being directly transferred from phosphorylated substrates to ADP. An example is the phosphagen system in skeletal muscle.
      1. Oxidative phosphorylation is a more complex process that produces most ATP. Chemiosmosis couples the movement of substances across membranes to chemical reactions. Energy released from oxidizing food is used to pump H+ across the inner mitochondrial membrane, creating a steep H+ concentration gradient. Electrons transfer through transport proteins to create a proton gradient. ATP synthase uses the energy of the protons to bind phosphate groups to ADP.

Oxidation of Glucose

  • Glucose is oxidized via the following reaction: C6H12O6 + 6O2 → 6H2O + CO2 + 32ATP + heat
  • Complete glucose catabolism requires three pathways:
      1. Glycolysis: glucose splitting in half
      1. Krebs cycle (Citric acid cycle): making several intermediates.
      1. Electron transport chain and oxidative phosphorylation.

Glycogenesis, Glycogenolysis, and Gluconeogenesis

  • Glycogenesis: stores glucose by making glycogen to store glucose when levels are high
  • Glycogenolysis: breakdown of glycogen to glucose monomers when blood glucose levels are low
  • Gluconeogenesis: forming new glucose from noncarbohydrate sources such as fats and proteins when blood glucose levels drop.

Lipid Metabolism

  • Lipids provide a greater energy yield than either glucose or protein.
  • Fat catabolism yields 9 kcal per gram of carbohydrate or protein.
  • Only triglycerides are routinely oxidized for energy. -Glycerol breakdown: treat as glucose -Fatty acid breakdown: fatty acids undergo Beta oxidation in mitochondria
  • Ketogenesis in liver converts accumulated acetyl CoA to ketone bodies (ketones) if carbohydrate intake is inadequate. The buildup of ketones can cause metabolic acidosis.

Water, Electrolyte, and Acid-Base Balance

  • Body Water Content:
    • Infants have more water than adult males and females (who tend to have higher fat content and less skeletal muscle mass.)
    • Water is less prevalent in adipose tissue.
    • The average water content declines to ~45% in old age.
  • Body Fluid Compartments:
    • Intracellular fluid (ICF): ~25L, 40% of body weight
    • Interstitial fluid (IF): ~12L, 80% of ECF
    • Plasma: ~3L, 20% of ECF,
  • Electrolytes: dissociate into ions in water, examples include inorganic salts, acids, bases, and some proteins. They conduct current and have greater osmotic power, and ability to cause fluid shifts.
  • Water intake and output must equal each other.
  • ECF osmolality is maintained near 280-300 mOsm.

Disorders of Water Balance

  • Dehydration: ECF water loss due to hemorrhage, burns, vomiting, diarrhea, etc. -Signs and symptoms of dehydration include "cottony" oral mucosa, thirst, dry flushed skin, and oliguria. -Results can include weight loss, fever, mental confusion, hypovolemic shock, and electrolyte loss.
  • Hypotonic hydration: ECF osmolality decreases,causing osmosis of water into the tissues' cells. -Signs can include severe metabolic disturbances, nausea, vomiting, muscular cramping, and cerebral edema.
  • Edema: Atypical accumulation of interstitial fluid causing tissue swelling. This can impair tissue function by increasing the distance for oxygen and nutrient diffusion into cells.

Renal Clearance

  • Volume of plasma that the kidneys can clear of a given substance in a given time, used to determine GFR
  • Inulin can be used to measure GFR, as it is freely filtered and not reabsorbed or secreted. GFR is approximately 125 ml/min.

Urine

  • Urine is the filtrate of blood minus useful substances, representing about 1 percent of the original filtrate. It contains metabolic wastes and unneeded substances.
  • Other normal solutes found in urine include Na+, K+, PO43−, and SO42− Ca2+, Mg2+ and HCO3−
  • Abnormally high concentrations of any constituent, or abnormal components such as blood proteins, WBCs, and bile pigments, could indicate a pathology problem.
  • Normal urine has a slightly acidic pH (range 4.5-8.0) and a slightly aromatic odor .
  • Cloudiness or abnormal color may indicate an infection or other relevant problem.
  • Specific gravity is between 1.001 to 1.035.

Regulation of Water Intake

  • Thirst mechanism is driven by the hypothalamic thirst center..
  • Osmoreceptors in the hypothalamus detect changes in ECF osmolality, and are triggered when plasma osmolality rises 1-2%, or in cases of decrease in blood volume or pressure , triggered by Angiotensin II or a decrease in blood volume or pressure.

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Description

Test your knowledge on cellular respiration and the processes involved in oxidative phosphorylation. This quiz covers crucial topics such as ATP yield, the electron transport chain, and the functions of different cell types in the kidneys. Understand the biochemical pathways that contribute to energy production in cells.

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