enzymes and energy, cell respiration and metabolism

what is the effect of temperature and pH in an enzyme action

• inc. temperature will increase the rate of non-enzyme-catalyzed reactions

• temperature of 0 degrees C = reaction rate immeasurable slow; as temp is raised, reaction rate inc. but only up to a point

• a few degrees above body temp (37 degrees C) the reaction rate reaches a plateau

• similar relationship is seen with pH values

what are cofactors

a non-protein molecule bounded to an enzyme for activity; inorganic metal ions

what are coenzymes

organic molecules, derived from water soluble vitamins such as niacin and riboflavin, that are needed for the function of particular enzymes

what occurs in oxidation reduction

• coupled reaction; an atom/molecule can’t become oxidized unless it donates electrons to another, which therefore becomes reduced

• when an atom/molecule gains electrons → reduced

• when an atom/molecule loses electrons → oxidized

• GER LEO

what is metabolism

reactions in the body that involve energy transformation

what is catabolism

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

what is anabolism

reaction that requires the input of energy and include the synthesis of large energy-storage molecules

aerobic cell respiration function

cell recieves oxygen and releases carbon dioxide

what is glycolsis

a metabolic pathway in which glucose is converted into molecules of pyruvic acid, or pyruvate

formula of glycolysis

glucose + 2 nicotinamide adenine dinuclotide (NAD) + 2 ADP + 2Pi = 2 pyruvic acid + 2 NADH + 2 ATP

what is NAD

abbreviation of nicotinamide adenine dinucleotide; important coenzyme found in cells; plays key roles as a carrier of electrons in the transfer of reduction potential

what is FAD

abbrev. of flavin adenine dinucleotide; the precursor molecule to FADH2

the metabolic pathway by which glucose is converted to lactic acid is frequently referred to by physiologist as

anaerobic respiration

what is lactic acid

the waste product from skeletal muscles; occurs when there is no oxygen, so pyruvate is not metabolized by cellular respiration

what is fermentation

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

what is ischemia

• refers to inadequate blood flow to an organ; rate of oxygen delivery is insufficient to maintain aerobic respiration

• can be caused by atherosclerosis, if there is inadequate blood flow to the heart; severe pain in the chest and left arm area

  • pain is associated w/ increased blood levels of lactic acid which are produced by the ischemic heart muscle

• seen in heart infarction

what is glycogenesis

the formation of glycogen from glucose; found in liver

what is glycogenolysis

• the conversion of glycogen to glucose 6-phosphate

• found in the liver and skeletal muscles

what is gluconeogenesis

• the conversion of noncarbohydrate molecules through pyruvic acid to glucose

• found in liver

cori cycle location

the cycle between muscle and liver

structure of mitochondria

• smooth outer membrane, surrounding a very convoluted inner membrane

• the convolutions form recognizable structures called cristae

• the outer and inner membranes create two compartments: the inter-membrane space (between the membranes) and the matrix (the very interior of the mitochrondria)

step 1 of electron transport chain

NADH and FADH2 bring high energy electrons (e-) and protons (H+) to the cristae from either glycolysis or the krebs cycle

step 2 of electron transport chain

the high energy electrons are passed to proton pumps and electron acceptors in the cristae

step 3 of electron transport chain

high energy electrons provide energy so the proton pumps can pump protons (H+) from the matrix to the outer compartment

step 4 of electron transport chain

as electrons pass through the electron transport chain, they lose energy. As they pass the last proton pump, they are now low in energy and are sent back to the matrix

step 5 of electron transport chain

• oxygen is the final electron acceptor. for aerobic respiration to continue, all protons and low energy electrons must be removed.

• when oxygen is present, it is reduced to water by adding protons and electrons. this removes the electrons and protons and also provides a constant source of NAD+ and FAD

step 6 of electron transport chain

the NAD+ and FAD produced in the 1st steps diffuse back to the sites of glycolysis and krebs cycle to help keep those processes going

step 1 of chemiosmosis

NADH and FADH2 bring high energy electrons and H+ from glycolysis and Krebs cycle

step 2 of chemiosmosis

high energy electrons provide energy for the proton pump to pump protons (H+) out to the outer compartment

step 3 of chemiosmosis

a high concentration of protons accumulates in outer compartment. the protons this can diffuse back to the lower concentration in the matrix

step 4 of chemiosmosis

passage of protons through the enzyme ATP synthase provides energy to create ATP

where do all cells in the body get their energy source from

blood

blood contains many energy sources which are from where

• glucose and ketone bodies that come from the liver

• fatty acids from adipose tissue

• lactic acid and amino acids from muscles

the brain’s major energy source comes from

blood glucose, which is supplied by the liver during fasting conditions