Human Physiology Week 3 - Metabolism (Transcripts)
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Questions and Answers

What is the primary function of ATP in the body?

  • To serve as the universal currency of energy. (correct)
  • To act as a chemical messenger.
  • To build muscle tissue.
  • To store long-term energy.

    • Which pathway is primarily used for quick, instantaneous energy needs?

  • Aerobic metabolism.
  • Adenylate kinase pathway. (correct)
  • Glycolytic pathway.
  • Creatine phosphate pathway.

    • For activities lasting up to ten seconds, which method is most effective for ATP production?

  • Adenylate kinase pathway.
  • Creatine phosphate pathway. (correct)
  • Glycolytic pathway.
  • Aerobic metabolism.

    • Which pathway is commonly used to produce ATP during exercises up to about two minutes in duration?

    <p>Glycolytic pathway.</p> Signup and view all the answers

    What is the common intermediate produced in aerobic metabolism for energy production?

    <p>Acetyl-CoA.</p> Signup and view all the answers

    What is produced when phosphocreatine is combined with ADP?

    <p>Creatine and ATP</p> Signup and view all the answers

    Which process occurs in the absence of oxygen?

    <p>Glycolysis</p> Signup and view all the answers

    What is the end product of glycolysis?

    <p>Pyruvate and ATP</p> Signup and view all the answers

    What is the primary function of the aerobic pathway?

    <p>Generate large amounts of ATP</p> Signup and view all the answers

    Which molecule is essential for the initiation of the aerobic pathway?

    <p>Acetyl-CoA</p> Signup and view all the answers

    Where does glycolysis take place within the cell?

    <p>Cytoplasm</p> Signup and view all the answers

    Which of the following can be converted into Acetyl-CoA for ATP generation?

    <p>Fatty acids</p> Signup and view all the answers

    What is the primary storage form of glucose in the body?

    <p>Glycogen</p> Signup and view all the answers

    How much energy does one gram of fat provide compared to carbohydrates?

    <p>Nine calories</p> Signup and view all the answers

    How long could 10 kilograms of excess fat theoretically provide ATP for a starving person?

    <p>40 days</p> Signup and view all the answers

    Which statement is true regarding muscle energy during exercise?

    <p>Fat is available for muscle contraction during exercise.</p> Signup and view all the answers

    What is the total amount of glycogen stored in the liver approximately?

    <p>100 grams</p> Signup and view all the answers

    Which macronutrient provides the least amount of energy per gram?

    <p>Carbohydrates</p> Signup and view all the answers

    Approximately how many grams of glucose can the body utilize at once for energy?

    <p>20 grams</p> Signup and view all the answers

    What is a likely consequence of having excess body fat?

    <p>Increased reserve of energy for survival.</p> Signup and view all the answers

    Which process is primarily used for the breakdown of liver glycogen?

    <p>Glycogenolysis</p> Signup and view all the answers

    What is the primary process for breaking down glycogen into glucose?

    <p>Glycogenolysis</p> Signup and view all the answers

    What promotes the uptake of glucose into muscle and adipose tissue?

    <p>Insulin</p> Signup and view all the answers

    What does gluconeogenesis refer to?

    <p>The formation of new glucose</p> Signup and view all the answers

    What is the main issue in Type 1 diabetes?

    <p>Insufficient insulin production</p> Signup and view all the answers

    What leads to sweet-smelling urine in diabetes?

    <p>Excessive glucose in urine</p> Signup and view all the answers

    What is the typical condition of insulin levels in Type 2 diabetes?

    <p>High insulin levels are ineffective</p> Signup and view all the answers

    What measurement indicates a normal fasting blood glucose level?

    <p>Under 100 mg/dL</p> Signup and view all the answers

    Which hormone is primarily responsible for increasing glucose production in the liver during exercise?

    <p>Glucagon</p> Signup and view all the answers

    What is the primary reason for elevated blood glucose levels in Type 2 diabetes?

    <p>Inadequate insulin response in target tissues</p> Signup and view all the answers

    Study Notes

    ATP Production and Pathways

    • ATP (adenosine triphosphate) serves as the universal energy currency in the body, powering cellular functions like muscle contraction and nerve signaling.
    • Continuous ATP production is essential due to constant ATP usage.
    • Four main pathways generate ATP based on energy needs:
      • Adenylate Kinase Pathway: Converts ADP to ATP for immediate energy bursts.
      • Creatine Phosphate Pathway: Provides energy for short bursts (up to 10 seconds), crucial for activities like sprints.
      • Glycolytic Pathway: Uses glucose/glycogen to produce ATP quickly for activities lasting about 2 minutes.
      • Aerobic Metabolism: Involves oxidative phosphorylation and electron transport chain, utilizing glucose/glycogen or fatty acids to produce large amounts of ATP.

    Anaerobic and Aerobic Pathways

    • Anaerobic Pathways: Function without oxygen.
      • Creatine Phosphate Reaction: ADP receives a phosphate from creatine phosphate, producing ATP and creatine.
      • Glycolysis: Breaks down glucose/glycogen into pyruvate, generating 2-3 ATP molecules in the cytoplasm.
    • Aerobic Pathway: Requires oxygen and takes place in mitochondria.
      • Converts pyruvate or fatty acids to acetyl-CoA, followed by the Krebs cycle and electron transport chain, producing a significant amount of ATP.

    Energy Storage in the Body

    • The body has limited immediate glucose reserves (about 20 grams) that support roughly one hour of energy.
    • Glycogen: Stored primarily in the liver (100 grams) and muscles (200 grams), serves as a critical reservoir of glucose.
    • Fat Storage: More energy-dense than carbohydrates; about 250 grams of fat can provide approximately 2,000 calories, while 500 grams of glucose would equal the same caloric energy.
    • Carbohydrates and proteins yield about 4 calories per gram, while fats provide around 9 calories per gram.

    Glucose Metabolism and Regulation

    • Glucose in the bloodstream originates from dietary intake and liver glycogen stores.
    • Glycogenolysis: Breakdown of glycogen to glucose in the liver.
    • Gluconeogenesis: Formation of new glucose from non-carbohydrate sources (e.g., proteins).
    • Insulin promotes glucose uptake in muscles and adipose tissues, while epinephrine stimulates glucose production in the liver during exercise.

    Diabetes and Metabolic Diseases

    • Type 2 Diabetes Mellitus: Common metabolic disease characterized by high blood glucose levels. Excess glucose in urine gives it a sweet taste.
    • Type 1 Diabetes Mellitus: Often occurs in early life due to autoimmune destruction of insulin-producing cells in the pancreas, resulting in insufficient insulin production.
    • In Type 2 diabetes, insulin is present, but the body's response to it is impaired, often due to less sensitive insulin receptors or reduced receptor numbers, leading to elevated blood glucose levels.### Understanding Type 2 Diabetes Mellitus
    • Normal fasting blood glucose level is under 100 mg/dL; levels above indicate potential diabetes.
    • Type 2 diabetes can cause fasting blood glucose levels to rise significantly, often exceeding 200 or even 300 mg/dL.
    • Excess glucose persists in the bloodstream, affecting various body cells, including blood vessel linings.

    Effects of Elevated Glucose

    • High glucose levels cause glycosylation, triggering biochemical changes in cell membranes of blood vessels and red blood cells.
    • Chronic excess glucose leads to vascular damage and increased inflammation, setting the stage for atherosclerosis.
    • Atherosclerosis results in blood vessels becoming sticky and bumpy, increasing risks of heart attacks (myocardial infarction) and strokes.

    Complications Associated with Type 2 Diabetes

    • Vascular damage from diabetes can restrict blood flow, leading to peripheral neuropathy and retinal neuropathy, potentially causing blindness.
    • Diabetes is correlated with various morbidities due to the vascular changes caused by prolonged high glucose levels.

    Symptoms and Early Indicators

    • Key signs of diabetes include polyuria (excessive urination) and polydipsia (excessive thirst).
    • Polyuria occurs because glucose in urine attracts extra water, leading to increased urination and subsequent thirst.

    Diagnostic Testing

    • Fasting glucose levels are essential for diagnosing Type 2 diabetes and for ongoing management.
    • HbA1C test measures glycosylated hemoglobin, reflecting average blood glucose levels over the past 4 to 6 weeks.
    • Higher HbA1C levels indicate more prolonged high glucose exposure, while lower levels suggest better glucose control.

    Pre-diabetes

    • Defined as fasting blood glucose levels between 100 mg/dL and 125 mg/dL, indicating a risk of progressing to Type 2 diabetes.
    • Impaired glucose tolerance may be observed, where blood glucose spikes after meals despite normal fasting levels.
    • This state signals increasing insulin resistance, suggesting the need for lifestyle changes, including improved diet and increased physical activity.

    Importance of Lifestyle Intervention

    • Early intervention during the pre-diabetic stage can delay or potentially reverse the onset of Type 2 diabetes.
    • Emphasis on a healthy lifestyle is crucial for preventing the progression of glucose intolerance to diabetes.

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