module 1 studyguide cell respiration and metabolism

Metabolism

All of the reactions in the body that involve energy.

Is the complete set of chemical reactions that occur in living cells. These processes are the basis of life, allowing cells to grow and reproduce, maintain their structures, and respond to their environments.

Catabolism

release energy, usually by the breakdown of larger organic molecules into smaller molecules

the ones that break down glucose, fatty acids, and amino acids serve as the primary sources of energy for the synthesis of ATP

Anabolism

require the input of energy and include the synthesis of large energy-storage molecules, including glycogen, fat, and protein

Aerobic cell respiration

Requires oxygen in order to generate energy (ATP).

Preferred method of pyruvate breakdown from glycolysis and requires that pyruvate enter hte mitochondrion to be fully oxidized by Krebs cycle.

Anaerobic respiration

Metabolic pathway by which glucose is converted to lactic acid

Cannot receive oxygen

undergoes fermentation

Glycolysis

Metabolic pathway by which glucose, a six-carbon sugar, is converted into molecules of pyruvic acid, or pyruvate.

Glucose + 2NAD + 2ADP + 2Pi = 2 pyruvic acid + 2NADH + 2ATP

NAD

Nicotinamide adenine dinucleotide

Coenzyme found in cells.

Roles: carrier of electrons in the transfer of reduction potential.

FAD

Flavin adenine dinucleotide

Precursor molecule to FADH2. Upon bonding to two hydrogen atoms, FAD is then changed to FADH2 and is turned into an energy-carrying molecule

Fermentation

Process of energy production in a cell under anaerobic conditions (with no oxygen required).

Ischemia

Refers to inadequate blood flow to an organ, such that the rate of oxygen delivery is insufficient to maintain aerobic respiration.

Glycogenesis

Formation of glycogen from glucose.

Cells cannot accumulate very many separate glucose molecules, instead, many organs, particularly the liver, skeletal muscles, and heart, store carbohydrates in the form of glycogen.

(Liver uptakes the extra glycogen, Glycogen is storage in the liver. Process is called ““)

Glycogenolysis

The enzyme glycogen phosphorylase catalyzes the breakdown of glycogen to glucose 1-phosphate.

The glucose 1-phosphate is then converted to glucose 6-phosphate.

The conversion of glycogen to glucose 6-phosphate is called ““.

It is stored in the liver and muscles.

Gluconeogenesis

The conversion of noncarbonhydrate molecules (not just lactic acid but also amino acids and glycerol) through pyruvic acid to glucose is an extremely important process.

Is in the liver.

Cori cycle

During exercise, some of the lactic acid produced by skeletal muscles may transformed through gluconeogenesis in the liver to blood glucose. This new glucose can serve as an energy source during exercise and can be used after exercise to help replenish the depleted muscle glycogen. Two-way traffic between skeletal muscles and the liver is called the Cori cycle. Through the Cori cycle, gluconeogenesis in the liver allows depleted skeletal muscle glycogen to be stored within 48 hours.

(When you work out, your muscles release lactic acid. The lactic acid is transported by blood to liver, liver uptakes lactic acid.)

Mitochondria structure

Smooth outer membrane, surrounding a convoluted inner membrane. The convolutions form recognizable structures called cristae. The two membranes have very different properties.

Together they make two compartments, intermembrane space (compartment between the membranes) and the matrix (very interior of mitochondria).

Electron transport chain steps

and chemiosmosis steps

1. FAD and NAD are coenzymes which reduces electrons and hydrogen ions in the cytoplasm of the cell.

2. These two coenzymes carry/transport hydrogen ions and electrons through teh matrix part of the mitochondria.

3. They release electrons which pass through cristae membrane.

4. Then the coenzymes release the hydrogen ions which move from matrix part to the outer compartment of the mitochondria.

5. After a while, the concentration of hydrogen ions inc in outer compartment called chemiosmosis (osmotic pressure is high). Then the hydrogen ions come back down conc gradient into the matrix which passes through ATP synthase channels. Due to this, 2 things happen: hydrogen ions combines with oxygen molecules to form H2O and ADP combining with P to create ATP.

Why do we use different energy sources?

If all cells used the same energy sources, like glucose, this source would quickly be depleted and cellular starvation would occur.

Uses of different energy sources

the blood

contains a variety of energy sources from which to draw: glucose and ketone bodies that come from the liver, fatty acids from adipose tissue, and lactic acid and amino acids from muscles

Uses of different energy sources

the brain

uses blood glucose as its major energy source. Under fasting conditions, blood glucose is supplied primarily by the liver through glycogenolysis and gluconeogenesis