BIOCHEM LEC Flashcards
Regulation of water balance
a. Hypothalamic mechanisms
b. Antidiuretic Hormone
c. Retention or excretion by the Kidneys
which involves the inability to concentrate urine or adjust
to subtle changes in extracellular fluid osmolarity, results from the unresponsiveness of renal tubular osmoreceptors to ADH
Nephrogenic Diabetes Insipidus
angle between two hydrogen atoms to the oxygen in H2O
105 degree
molecule with electrical charge distributed asymmetrically about its structure
DIPOLE
Slightly Positive Side of H2O
Hydrogen
Slightly Negative Side of H2O
Oxygen
Bicarbonate and other buffers normally maintain the pH of extracellular fluid between ____ and ___
7.35, 7.45
Blood pH below 7.35
Acidosis
blood pH above 7.45
Alkalosis
Suspected disturbances of acid-base balance are verified by measuring the pH of __________________
arterial blood
Water’s strong dipole is responsible for its high _____________________
dielectric constant
the _______ the dielectric constant, the ________ the force of attraction between charged and polar species
Higher, Weaker
enables water to dissolve many
organic biomolecules that contain functional groups
hydrogen bonding
chemical species that forms bonds with electrophiles by donating an electron pair
Nucleophile
electron rich molecules
nucleophile
electron poor molecules
electrophile
Nucleophilic attack by water typically results in the cleavage of the amide, glycoside, or ester bonds that hold biopolymers together
Hydrolysis
catalyze the hydrolysis of proteins into their component amino acids
Protease
catalyze the hydrolysis of the phosphoester bonds in DNA and RNA
nuclease
strongest force that holds molecules together
Covalent Bonds
contributes to stability & functional competence of molecules
Non- covalent Bonds
most biomolecules are ______________
Amphipathic
possess both charged or polar region and hydrophobic or non polar region
Amphipathic
refers to the tendency of nonpolar
compounds to self-associate in an aqueous environment
hydrophobic interactions
minimizes the disruption of energetically favorable interactions between and is therefore driven by
the surrounding water molecules
self-association
interactions between oppositely charged groups within or between biomolecules
Electrostatic Interactions
arise from attractions between transient
dipoles generated by the rapid movement of electrons in all
neutral atoms
Van der Waals Forces
PRoton Donors
Acids
Proton acceptors
Bases
_________ pH= high concentration of H+
Low
_________ pH= low concentration of H+
High
Normal Values for pH in blood
7.35- 7.45
Normal Values for PaCO2 in blood
35-45mmHg
Normal Values for PaO2 in blood
80-100mmHg
Normal Values for HCO3 in blood
22-26mEq/L
Oxygen saturation
95-100%
low pH, High paCO2, High H2CO3, N HCO3
Respiratory Acidosis
high pH, low paCO2, low H2CO3, N HCO3
Respiratory Alkalosis
low pH, N paCO2, N H2CO3, low HCO3
Metabolic Acidosis
high pH, N paCO2, N H2CO3, high HCO3
Metabolic Alkalosis
Biologic systems are essentially _____________ and use chemical
energy to power living processes
Isothermic
is that portion of the total energy change in a system that is available for doing work
ΔG or Free Energy
states that the total energy of a system, including its surroundings, remains constant.
First Law of Thermodynamics
states that the total
entropy of a system must increase if a process is to occur
spontaneously
Second law of Thermodynamics
is the extent of disorder or randomness of the system and becomes maximum as equilibrium is
approached
Entropy
If ΔG is negative, the reaction proceeds spontaneously with
loss of free energy
Exergonic
if ΔG is positive, the reaction proceeds only if free energy can be gained
Endergonic
the breakdown or oxidation of fuel molecules
Catabolism
the synthetic reactions that buildup substances
Anabolism
both catabolism and anabolism
Metabolism
organisms utilize simple exergonic processes; for example, the
energy of sunlight (green plants), the reaction Fe2+ → Fe3+ (some bacteria)
Autotrophic
organisms obtain free energy by coupling their metabolism to the
breakdown of complex organic molecules in their environment
heterotrophic
is the greatest quantitativesource of ~ in aerobic organisms. ATP is generated in themitochondrial matrix as O2
is reduced to H2O by electrons passing down the respiratory chain
Oxidative Phosphorylation
A net formation of two ~ results from the formation of lactate from one molecule of glucose, generated
in two reactions catalyzed by phosphoglycerate kinase and
pyruvate kinase, respectively
Glycolysis
One ~ is generated directly in the
cycle at the succinate thiokinase step
The citric acid cycle
act as storage forms of group transfer potential
Phosphagens
defined as the removal of eectrons
Oxidation
is defined as the gain of eectrons
reduction
Enzymes invoved in oxidation and reduction are called
oxidoreductases
Classifications of oxidoreductases
- Oxidases
- Dehydrogenases
- Hydroperoxidases
- Oxygenases
catayze the remova of hydrogen from a substrate
using oxygen as a hydrogen acceptor.* They form water or
hydrogen peroxide as a reaction product
Oxidases
is a hemoprotein widey distributed in
many tissues, having the typica heme prosthetic group present in myogobin, hemogobin, and other cytochromes
Cytochrome oxidase
The action of the enzyme Cytochrome oxidase is blocked by
Carbon Monoxide, cyanide, and hydrogen sulfide
contain flavin mononucleotide (FMN)or flavin adenine dinucleotide (FAD) as prosthetic groups.
Flavoprotein
play an important roe in protecting the body against the harmful effects of reactive oxygen species (ROS)
Hydroperoxidases
are iron-containing hemoproteins in which
the iron atom oscillates between Fe3+ and Fe2+ during oxidation and reduction.
Cytochromes
are highy reactive oxygen-containingmoecues such as peroxides, which are formed during norma
metaboism, but can be damaging if they accumuate.
Reactive Oxygen Species
have a variety of functions in metaboism;
oxidases and dehydrogenases pay major roes in respiration;
Oxidoreductases
protect the body against damage by free
radicas; and oxygenases mediate the hydroxyation of drugs
and steroids.
hydroperoxidase