Integrative Tissue Metabolism Quiz

In the well-fed state, high glucose levels trigger insulin release, promoting glucose uptake by insulin-dependent tissues (e.g., muscles, adipose) via GLUT4. The liver independently takes up glucose via GLUT2, and insulin then enhances glycolysis, glycogenesis (glycogen storage), lipogenesis (fat storage), and protein synthesis in the liver. Dietary fats are processed into chylomicrons and transported to tissues. Excess amino acids are converted into fats.

Insulin promotes glucose uptake, glycogen storage, fat synthesis, and protein synthesis, especially in the liver, muscles, and adipose tissue. It promotes energy storage rather than breakdown when sufficient energy is available.

Elevated blood glucose levels trigger insulin release. Insulin activates glucose transport into specific tissues (like muscles and adipose) via GLUT4 receptors. The liver also takes up glucose independently through GLUT2 receptors.

The process of converting glucose into glycogen for storage in the liver and muscles.

The process of synthesizing fats from excess nutrients, primarily glucose, in the liver.

The liver is the central hub for carbohydrate, lipid, and protein metabolism. It stores glycogen, produces glucose, synthesizes fats, and processes amino acids.

Packages of dietary fats transported via the lymphatic system, then the bloodstream to peripheral tissues for storage or use.

The process of producing glucose from non-carbohydrate sources, crucial during fasting states.

The state of the liver when it is actively converting excess glucose and other nutrients into fatty acids for storage.

Insulin stimulates the liver to synthesize fatty acids from excess glucose, promoting fat storage.

The liver takes up glucose via GLUT2, utilizes it for energy, or converts it into glycogen for storage. If energy is abundant, it gets converted into fatty acids for storage.

This enzyme catalyzes the first step in fatty acid synthesis, converting Acetyl-CoA into Malonyl-CoA.

This enzyme plays a key role in converting Acetyl-CoA into fatty acids, using Malonyl-CoA as a building block.

In the well-fed state, the liver's main focus shifts to storage. It takes up glucose, stores it as glycogen, and converts excess glucose into fat.

Excess amino acids can be used for protein synthesis, but also converted into pyruvate and then into Acetyl-CoA, contributing to fatty acid synthesis.

Chylomicrons are packages of dietary fats (triglycerides) that are transported via the lymphatic system and then the bloodstream to tissues for storage or use as energy.

The liver processes dietary fats into chylomicrons, which transport triglycerides to tissues that need them.

Although the liver independently takes up glucose via GLUT2, insulin enhances this uptake and promotes glucose utilization for energy, glycogen synthesis, and fatty acid synthesis.

The liver is the primary source of glucose during fasting, using glycogen stores and then gluconeogenesis.

Amino acids (from muscle), glycerol (from adipose tissue), and lactate (from anaerobic glycolysis) are all used to make glucose during gluconeogenesis.

Fatty acids are mobilized from adipose tissue and used for energy in muscles and ketones in the liver.

The liver uses fatty acids for energy production and to create ketone bodies, which can be used as fuel by the brain and other tissues.

The metabolic state when the body is not receiving enough glucose from food, and must rely on stored energy reserves.

Glucagon, a hormone released during fasting, stimulates the liver to release stored glucose (glycogenolysis), produce new glucose (gluconeogenesis), and break down fat (lipolysis).

The breakdown of stored fat in adipose tissue to release fatty acids into the bloodstream.

A state where glycogen stores are depleted, and the body relies primarily on fat breakdown and gluconeogenesis for energy.

The body shifts from using glucose as the primary energy source to relying on fatty acids and ketone bodies, produced by breaking down stored fat and amino acids.

Glucagon activates processes like glycogenolysis, lipolysis, gluconeogenesis, and ketogenesis, while inhibiting pathways like glycolysis.

In the fasting state, the liver becomes the central hub for fuel regulation, releasing glucose, producing ketones, and breaking down fat.

The process of producing glucose from non-carbohydrate sources, primarily amino acids from muscle, glycerol from fat, and lactate from anaerobic glycolysis. Gluconeogenesis is crucial for maintaining blood glucose levels during prolonged fasting.

Muscle protein breakdown occurs during starvation to provide amino acids for gluconeogenesis. This process initially sustains blood glucose levels, but it slows down after about 7 days.

Glycerol, released from adipose tissue breakdown, serves as a substrate for gluconeogenesis, providing a steady source of glucose production during starvation.

During prolonged starvation, the body starts producing ketone bodies from fat breakdown. These are a major energy source for the brain, helping to spare glucose.

Gluconeogenesis is the primary source of glucose production during starvation. The body uses non-carbohydrate sources, like amino acids, glycerol, and lactate, to make glucose.

Muscle protein degradation slows down after 7 days of starvation. The body prioritizes preserving muscle mass for essential functions.

Glucagon receptors are primarily located on the liver cells. Glucagon, released in response to low blood glucose, binds to these receptors, activating various metabolic processes in the liver, including gluconeogenesis.

Beta-adrenergic receptors are found in the liver and muscle cells. They play a crucial role in regulating metabolism, especially during the fasting state, by responding to adrenaline.

The body mainly relies on pre-existing ATP and creatine phosphate (CP) for the first 3 seconds of intense muscle activity, like weightlifting.

After the initial 3 seconds, the body uses up its CP stores. Once depleted, it relies on anaerobic glycolysis to produce ATP for the next 12 seconds.

This process breaks down glucose without oxygen to quickly produce ATP. It results in lactate as a byproduct.

For longer, sustained activity, the body relies on aerobic metabolism, which uses oxygen to break down glucose and fatty acids for ATP production.

This is the process of using oxygen to generate ATP from glucose, fatty acids, and other energy sources. It provides energy for prolonged, intense activities.

For activities like marathons, muscles primarily obtain ATP through oxidative phosphorylation of acetyl-CoA, which can be produced from both glucose and fatty acids.

This process breaks down fatty acids into acetyl-CoA, which can then be used in oxidative phosphorylation.

This cycle is part of aerobic respiration, where acetyl-CoA is further broken down and electrons are released to drive ATP production.