Exam 4 - Ch. 23 Metabolism and Nutrition Objectives

Describe the source of intestinal gas

Intestinal gas, or flatus, is generated by bacterial activities in the colon when indigestible carbohydrates stimulate bacterial gas production

Where does most nutrient absorption occur?

in the small intestine, primarily in the jejunum

Outline the steps involved in digestion, and list the nutrients used by the body.

ingestion, propulsion, mechanical breakdown, chemical digestion, absorption, and elimination. There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water

Summarize the main features of protein metabolism

cycle of breaking down proteins, synthesizing new ones and removing nitrogenous waste products that result from these reactions.

Explain when glycolysis is important in cellular metabolism.

glucose is the main source of fuel for tissues in the body.

Explain the role of glycogen in cellular metabolism.

glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells

_______________ - formation of glycogen from glucose _______________ - breakdown of glycogen to glucose _______________ - Formation of glucose from non-carbohydrate sources like protein and fat.

glycogenesis glycogenolysis gluconeogenesis

Describe the fate of fatty acids in lipid metabolism

Fatty acids are oxidized to acetyl CoA for energy production in the form of NADH

list the products of glycolysis.

2 ATP, 2 NADH, 2 pyruvate

What molecule forms the common substrate for the citric acid cycle?

2-carbon molecule of acetate

Which molecule is a key reactant in both ATP production from fatty acids and lipogenesis?

Acetyl-CoA is a reactant molecule in ATP production and in the synthesis of most types of lipids

Compare catabolism and anabolism

Catabolism is the breakdown of large molecules into smaller ones, whereas anabolism is buildup of large molecules from smaller building blocks.

What does the liver do with the chylomicrons it receives?

Chylomicron remnants deliver dietary cholesterol to the liver. It is then incorporated into very low-density lipoproteins (VLDL), which are secreted in plasma

Identify the fates of fatty acids

Fatty acids may become a source of energy or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol, and steroids

Summarize the important events and products of glycolysis

Glucose enters the cytoplasm. Glucose reacts with ATP. ATP gives off energy and then has to change back to ADP. Glucose changes into G3P. Then NAD+ gains an electron and hydrogen and changes into NADH. NADH is sent to the Electron Transport Chain. At the same time ADP is changed into ATP. ATP is used throughout the cell. Then G3P is changed into pyruvic acid. The pyruvic acid is sent to the Krebs cycle.

Compare glycogenesis and glycogenolysis.

Glycogenesis is the formation of glycogen from glucose. Glycogenolysis is the breakdown of glycogen to glucose.

Describe the roles of LDLs and HDLs.

HDL helps rid your body of excess cholesterol so it's less likely to end up in your arteries. LDL is called "bad cholesterol" because it takes cholesterol to your arteries, where it may collect in artery walls

What is glycogen?

It is a stored formed of glucose/energy manufactured by the liver

What two coenzymes transfer hydrogen atoms to the electron transport system?

NAD and FAD

What are the products of the electron transport chain? chapter 23.4

NAD+, FAD, water and protons

Most of the absorbed nutrients enter into which blood vessel?

Nutrients absorbed in the small intestine travel mainly to the liver through the HEPATIC PORTAL VEIN

Define nutrition

Taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them

Describe the importance of the electron transport chain.

The ETC is the most important stage of cellular respiration from an energy point of view because it produces the most ATP.

Briefly describe the citric acid cycle, and explain its role.

The citric acid cycle is the final common oxidative pathway for carbohydrates, fats and amino acids. It is the most important metabolic pathway for the energy supply to the body. TCA is the most important central pathway connecting almost all the individual metabolic pathways.

Why is digestion important?

To break food particles down into smaller, absorbable components.

Why do cells make new compounds?

To maintain and repair structures, to support growth, and to build up nutrient reserves

Describe the role of the nutrient pool in cellular metabolism.

contains all organic building blocks that a cell needs to provide energy and create new cellular components. The nutrient pool is a source of substrates (nutrients) for catabolism and anabolism, e.g., glucose, fatty acids, amino acids.

Identify when most of the CO2 is released during the complete catabolism of glucose.

during the citric acid cycle (Kreb's cycle)

Identify the two classes of vitamins

fat soluble and water soluble

What is the role of the liver in protein metabolism?

formation of plasma proteins, amino acid interconversion, deamination of amino acids and urea synthesis (for ammonia excretion).

Describe the role of CCK (cholecystokinin) release and its effects on proteins

mediates digestion in the small intestine by inhibiting gastric emptying. increases the release of fluid and enzymes from the pancreas to break down fats, proteins and carbohydrates.

________________ - the chemical processes that occur within a living organism in order to maintain life. ________________ - the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism. ________________ - the synthesis (building) of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism.

metabolism catabolism anabolism

What is the difference between a micelle and a chylomicron?

micelles are globules of lipid molecules that are arranged in a spherical form in an aqueous solution while chylomicrons are lipoproteins that consist of a core made from triglycerides and cholesterols and a coat made from phospholipids and apolipoproteins

Explain why carbohydrates are preferred over proteins and lipids as an energy source.

most frequently used as an energy source, as they are fast-acting and turn into energy as soon as they are ingested. This energy powers the brain and body. The energy that powers the brain and body is generated when carbohydrates are broken down

Describe the importance of the citric acid cycle.

the most important metabolic pathway for the energy supply to the body. TCA is the most important central pathway connecting almost all the individual metabolic pathways.

Define oxidative phosphorylation.

the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers

Explain the process of metabolic turnover.

the process in which cells continuously replace their cellular components

List the reactants required and products generated by mitochondria.

the reactants required by mitochondria are continuous supply of 2-carbon substrates and O2's the mitochondria products are CO2, H2O and ATP

If vitamins do not provide a source of energy, what is their role in nutrition?

vitamins are required for the release of energy from protein, fat and carbohydrates.