Chapter 22

Which pathway is the opposite of Lipogensis?

Beta-oxidation

Lipolysis:

Breakdown of triglycerides using lipases.

Catabolic metabolism of carbohydrates proteins lipids in FASTED-state

Carbohydrates-Glycogen polymers broken down (glycogenolysis) to glucose in liver and kidney or to glucose 6-phosphate for use in glycolysis. Proteins- Broken down into amino acids then deaminated in liver for ATP production or used to make glucose. Lipids- Triglycerides broken down into fatty acids and glycerol. Fatty acids used for ATP production through aerobic pathways (beta oxidation)

Glycogenolysis:

breakdown of stores from the liver to produce glucose.

Intermediate for Glycolysis:

Fatty acids & amino acids

What happens after you eat a sugary snack?

* Blood glucose become high, * Pancreas releases insulin, * Insulin binds to receptors on target cells, * Cells take in glucose, * Blood glucose returns to normal

Type II Diabetes

* Target cells do not respond normally to insulin * known as insulin-resistant diabetes. Accounts for 90% of all cases of diabetes Insulin resistance Therapy Exercise and weight loss Drugs

Pathways for Aerobic and Anaerobic metabolism of glucose, & compare the energy yields of the two pathways:

*Aerobic- Makes 30-32 ATP molecules Glycolysis: breakdown of glucose Citric acid (Krebs) cycle Electron transport chain Requires oxygen *Anaerobic-Oxygen not available Only 2 ATP molecules produced

What hormone stimulates the breakdown of polymerized glucose?

Glucagon

Glucose is stored in the body as?

Glycogen

Control pathway that influence hunger and satiety:

Hypothalamus contains two control centers; the Feeding center & Satiety center Neural input from the cerebral cortex Neural input from the limbic system Neuropeptide hormones from the GI tract Adipocytokines from adipose tissue

Role of Insulin & glucagon in control of metabolism.

Insulin dominated metabolic state- Fed state * Glucagon dominated metabolic state- Fasting state (Gluconeogenesis, Glycogenolysis, & Ketogenesis.)

Intermediate for Pyruvate processing Acetyl-CoA:

Lactate & amino acids

What cells in the body respond to glucagon by breaking down glycogen & releasing glucose?

Liver cells

Hallmarks of hypercortisolism

-Adrenal tumor that autonomously secretes cortisol -Pituitary tumor that autonomously secretes ACTH -Cushing's disease -Iatrogenic (physician-caused) hypercortisolism -Cushing's syndrome

Hallmarks of hypocortisolism

-Hyposecretion of all adrenal steroid hormones -Addison's disease

Synthesis, storage, and secretion of thyroid horomones

Synthesis- takes place in the thyroid follicles Storage- Center of thyroid follicle filled with colloid, holds supply of hormone Secretion- of thyroxine and triiodothyronine by the thyroid gland are stimulated by the hypothalamic hormone thyrotropin-releasing hormone and the anterior pituitary hormone thyrotropin.

What happens when blood glucose levels are high?

The pancreas releases insulin

What is the best example of negative feedback?

Thyroid hormone (TH) secreted into the bloodstream causes increased cellular metabolism & increased body temp. & increased TH levels inhibit TH release.

Glucose remains in the bloodstream as a result of:

Type 1 and Type 2 Diabetes mellitus

Pyruvate conversion to Lactate occurs:

in Cytoplasm

What happens to excess glucose in the body?

it undergoes Lipogensis

Glycolysis:

metabolic pathway that breaks down glucose into 2 pyruvate molecules. * occurs in the Ctyoplasm

Glycogensis:

process in which excess glucose is linked together & stored as glycogen in muscle & liver.

Gluconeogensis:

production of glucose from smaller products like lactate & amino acids * occurs in the Cytoplasm

Excess glucose can be found in the urine:

When the transport maximum for reabsorption in the kidneys tubules is exceeded, as a result of Type 1 or Type 2 diabetes.

Hallmarks of hyperthyroidism

thyroid gland secretes too much hormone -Increases oxygen consumption and metabolic heat production -Increase protein catabolism and may cause muscle weakness -Hyperexcitable reflexes and psychological disturbances -Influence -adrenergic receptors in the heart

Intermediate for the Citric Acid cycle:

Fatty acids & amino acids

Body cells that respond to insulin include:

Liver cells, & most other cells of the body.

Explain why cortisol is essential for life?

Controls your blood glucose levels to maintain life.

Ch. 23

Endocrine control of growth & Metabolism.

A liver cell responds to insulin by?

taking in glucose & converting it to glycogen.

When blood glucose levels are low:

the pancreas releases glucagon, which eventually causes blood glucose levels to increase.

Insulin is produced by what cells of the Pancreas:

Beta cells

What is the products of Glycolysis?

2 pyruvate, 2 ATP, and 2 NADH

Factors that influence normal growth

1.Growth hormone and other hormones 2.An adequate diet 3.Absence of chronic stress 4.Genetics

Possible fates of ingested nutrients and indicate which is most common for each class of biomolecules:

=Fates: energy, synthesis (creating basic components needed for growth/ maintenance of cells), or storage =Free fatty acids from fats can be used as an energy source or stored as fat =glucose is used mostly for energy or storage =Amino acids are used for protein synthesis

Roles of ADP & ATP in biological energy transfer and storage:

ATP provides most of the cellular energy that drives metabolic processes by transferring energy between reactions (anabolism and catabolism) ATP releases energy when it breaks down to ADP

Carbohydrates:

Absorbed as Glucose, Gatalose, and Fructose. * During Fasted-state glycogen is broken down by the liver * Excess is stored as fat in adipose tissue

Proteins:

Absorbed as amino acids & small peptides. * in fasted state amino acids can be used for gluconeogenesis, * Immediately used for synthesis of proteins, * Excess is stored as fat in adipose tissue

Fats (lipids):

Absorbed as fatty acids, Monoglycerides, & cholesterol. * in Fasted-state, Beta-oxidation occurs to provide intermediated for the citric acid cycle * Cholesterol is used for steroid hormone synthesis * Excess is stored as fat in adipose tissue

Factors that affect metabolic rate:

Age & sex, Amount of lean muscle mass, Activity level, Diet & diet-induced thermogenesis, Hormones, Genetics.

Fed (absorptive) state:

Anabolic pathways synthesize larger molecules from smaller ones *the time right after a meal when the body is absorbing macronutrients * Triglycerides are stored as fats in adipose tissue * Amino acids used by tissues for protein synthesis * Glucose is immediately used for energy through AEROBIC pathways

Physiological functions of CRH & ACTH

Association between stress and the immune function appears to be mediated through CRH and ACTH The CRH family includes CRH and brain neuropeptide urocortin CRH -Decreases food intake -Association with signals that mark the onset of labor -Links to several mood disorders

Anabolic metabolism of carbohydrates proteins lipids in the FED-state

Carbohydrates-Used immediately for energy through aerobic pathways(glycolysis/ citric acid cycle) Used for lipoprotein synthesis in liver. Stored as glycogen in liver and muscles (glycogenesis) and then excess is converted to fat and stores in adipose tissue. Proteins-Most amino acids go to tissue or protein synthesis. If needed for energy, amino acids converted in liver to intermediates for aerobic metabolism. Excess converted to fat and stored in the adipose tissue. Lipids- Stored as triglycerides primarily in the liver and adipose tissue (lipogenesis). Cholesterol used for steroid synthesis or as a membrane component. Fatty acids used for lipoprotein and eicosanoid synthesis.

Fasted (post absorptive) state:

Catabolic pathways break large molecules into smaller ones. * Time between 2 meals when body is performing catabolic reactions in order to maintain blood glucose levels. * Glycogen is broken down by skeletal muscles and liver * Amino acids deaminated for ATP production

Regulatory significance of glycogen/glucose push-pull control:

Endocrine pancreas secretes hormones insulin by beta cells and glucagon by alpha cells in the islets of Langerhans Metabolism is controlled primarily by the ratio of these hormones In the fed state, insulin dominates In the fasting state, glucagon dominates

During AEROBIC metabolism of glucose, most ATP is produced during which group of chemical reactions?

Electron transport (yielding 26-28 molecules of ATP per molecule of glucose)

Why is glucose present in the Urine of people with Diabetes Mellitus?

Insulin target cells are unable to take in the glucose from the blood, resulting in Hyperglycemia & saturation of kindey glucose transporters.

How does binding of insulin to its receptors cause glucose uptake from the bloodstream?

It causes insertion of GLUT4 transporters in the membrane.

Chapter 22:

Metabolism & Energy Balance

Citric Acid cycle occurs:

Mitochondria

Electron transport chain occurs:

Mitochondria

Pyruvate processing to Acetyl-CoA occrus:

Mitochondria

Type I Diabetes

No insulin is produced, glucose levels remain higher than normal, caused by antibodies & leukocytes which destroy beta cells (insulin) * characterized by insulin deficiency from beta cells destruction. Genetic predisposition Often developed in childhood Without insulin cells go into fasted-state metabolism Protein, fat breakdown Hyperglycemia Excessive eating, glucose in urine, excessive urination and thirst Metabolic acidosis

Hallmarks of hypothyroidism

affects the same systems -Slows metabolic rate and oxygen consumption -Decreases protein synthesis -Myxedema (puffy appearance) -Nervous system changes in adults include slowed reflexes, slow speech and thought processes, and feelings of fatigue -Cretinism in infancy -The primary cardiovascular change is bradycardia (slow heart rate)