Metabolic Pathways and Hormonal Regulation

<p>Turns glycolysis off (A)</p> Signup and view all the answers

<p>Phosphorylation can either activate or inhibit enzymes depending on the context (B)</p> Signup and view all the answers

<p>Promotes glycogen storage and suppresses gluconeogenesis (A)</p> Signup and view all the answers

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

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

<p>Turns OFF glycolytic enzyme gene expression (B)</p> Signup and view all the answers

<p>Decreases blood glucose levels (D)</p> Signup and view all the answers

<p>Increased activity of glycogen synthase (A)</p> Signup and view all the answers

<p>It modifies enzyme activity temporarily (D)</p> Signup and view all the answers

<p>Gluconeogenesis is suppressed (B)</p> Signup and view all the answers

<p>The activities of key enzymes (C)</p> Signup and view all the answers

<p>The slowest step that limits reaction speed (D)</p> Signup and view all the answers

<p>They are distinct and thermodynamically favorable. (A)</p> Signup and view all the answers

<p>Phosphorylation of fructose-1,6-bisphosphate (B), Phosphorylation of fructose-6-phosphate (C)</p> Signup and view all the answers

<p>It influences enzyme activity through interaction with substrate molecules. (A), It can both enhance and inhibit enzymatic reactions. (B)</p> Signup and view all the answers

<p>It is coupled to the hydrolysis of ATP. (C)</p> Signup and view all the answers

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

<p>Muscle, liver, and fat cells (D)</p> Signup and view all the answers

<p>To phosphorylate glucose. (B)</p> Signup and view all the answers

<p>Different enzymes are utilized to bypass irreversible steps. (D)</p> Signup and view all the answers

<p>They often represent irreversible steps. (C)</p> Signup and view all the answers

<p>Destruction of pancreatic β-cells due to autoimmune processes (D)</p> Signup and view all the answers

<p>Sedentary lifestyle (B)</p> Signup and view all the answers

<p>90% (B)</p> Signup and view all the answers

<p>South Asian and Black African individuals (A)</p> Signup and view all the answers

<p>Insulin resistance (B)</p> Signup and view all the answers

<p>Increased risk of kidney failure (C)</p> Signup and view all the answers

<p>Study and manipulate metabolic pathways (B)</p> Signup and view all the answers

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

<p>They serve as a primary source of metabolic fuel. (D)</p> Signup and view all the answers

<p>They can turn on/off insulin resistance when necessary. (D)</p> Signup and view all the answers

<p>Cycles of high calorie intake and obesity. (A)</p> Signup and view all the answers

<p>Their flight muscles increase in size significantly. (B)</p> Signup and view all the answers

<p>Birds efficiently mobilize fat deposits during activity. (D)</p> Signup and view all the answers

<p>Irreversible, rate-limiting steps in reactions. (B)</p> Signup and view all the answers

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

<p>High sugar diet. (A)</p> Signup and view all the answers

A key metabolic control process where enzymes are modified by adding or removing phosphate groups in response to hormones like insulin and glucagon.

Insulin promotes glycogen storage by increasing glycogen synthase activity and decreasing glycogen phosphorylase activity.

Glucagon promotes glycogen breakdown by decreasing glycogen synthase activity and increasing glycogen phosphorylase activity.

Enzyme that builds glycogen from glucose.

Enzyme that breaks down glycogen into glucose.

The process of creating glucose from non-carbohydrate sources (like protein).

The breakdown of glucose.

The regulation of the rate and direction of reactions within a metabolic pathway, achieved using phosphorylation and other methods.

Glycolysis breaks down glucose for energy, while gluconeogenesis builds glucose. They're opposing processes, controlled by different hormones.

Insulin promotes glycogen storage and inhibits gluconeogenesis, lowering blood glucose.

Glucagon stimulates glycogen breakdown and gluconeogenesis, raising blood glucose.

Hormones influence enzyme activity (like glycogen synthase, phosphorylase) in glycogen metabolism or gluconeogenesis, shifting the direction of the pathway.

A way to control enzyme activity where adding or removing a molecule reversibly changes the enzyme's form (e.g., phosphorylation/dephosphorylation) and activity.

The slowest step in a reaction that limits the entire reaction's speed.

Biosynthesis and degradation of molecules usually happen through different sets of reactions.

Enzymes decrease activation energy needed for a reaction, making the reaction faster.

The steps in glycolysis that control the overall rate of the pathway, usually involving the irreversible reactions (e.g., Glucose phosphorylation, Fructose-1,6-bisphosphate formation).

An enzyme crucial in glycolysis, catalyzing the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate. A key regulatory point.

A chemical reaction that proceeds in one direction under certain conditions.

A type of enzyme regulation where the activity of an enzyme is modulated by the binding of a molecule at a site distinct from the active site.

Polypeptide hormones that regulate glucose metabolism, often have opposing effects on metabolic processes.

Reactions or steps in a metabolic pathway crucial for regulation in a pathway.

Animals that hibernate store large amounts of fat during autumn to fuel their metabolism over winter. Fat is an energy-rich source and generates metabolic water when broken down.

Hibernating animals like bears can temporarily turn on and off insulin resistance to maintain stable blood sugar levels throughout the year. This is achieved through changes in gene expression.

Migratory birds accumulate large fat deposits to fuel their long flights. This fat is efficiently mobilized during flight, allowing them to travel great distances.

Metabolic pathways have key, irreversible steps that control the direction and speed of the pathway. These steps are often catalyzed by specific enzymes.

Enzymes involved in a metabolic pathway can be regulated reciprocally, where the activity of one enzyme is increased while another is decreased, ensuring efficient control.

Enzymes can be modified by the binding of molecules to their regulatory sites, altering their activity and influencing the pathway's direction.

When metabolic control mechanisms malfunction, it can lead to various diseases. This underlines the importance of understanding metabolic pathways in disease treatment.

Studying animals like hibernating bears and migratory birds provides insights into metabolic control and diabetes. Their unique adaptations can inform research on human diabetes.

A global health crisis affecting millions worldwide, with projected increases in prevalence and associated deaths. Characterized by dysregulation of glucose homeostasis.

An autoimmune disease where the body's immune system destroys pancreatic beta cells, leading to a complete lack of insulin production.

A metabolic disorder characterized by insulin resistance, leading to impaired glucose uptake and utilization. The body may still produce insulin, but it may not function properly.

A condition where cells don't respond normally to insulin, preventing them from taking up glucose from the bloodstream. This leads to elevated blood sugar levels.

Factors that increase the likelihood of developing type 2 diabetes, including obesity, sedentary lifestyle, age, diet, and genetics.

Animal models used to study diabetes and test potential treatments, often involving obese mice with genetic mutations affecting metabolic pathways.

A hormone produced by fat cells that signals satiety (feeling full) to the brain. Mutations in leptin can cause hyperphagia (excessive eating) and hyperglycemia.