pH Flashcards
Why is maintaining pH in body fluids crucial for animals?
Abnormal H+ concentrations can influence protein function, change molecular conformation, and have serious functional consequences.
How does pH vary with temperature in animals?
Neutral pH is higher at low temperatures and lower at high temperatures.
What is the alphastat hypothesis?
It suggests that changes in pH with temperature help maintain a constant state of electrical charge on protein molecules.
What are the main consequences of fluctuations in H+ concentration?
They include altered enzyme activity, disturbed K+ levels, and changes in excitability of nerve and muscle cells
How do respiratory disturbances affect pH balance in animals?
High CO2 levels lead to respiratory acidosis, lowering pH due to increased H2CO3 in body fluids.
What is environmental acidosis, and how does it affect marine life?
Environmental acidosis is the increase in H+ concentration in oceans, weakening shells and coral skeletons and affecting growth and survival.
How do marine animals like corals respond to increased acidity?
Coral growth declines, and diversity drops in areas with increased acidity, as seen near volcanic CO2 seeps.
What is the effect of ocean acidification on bivalve molluscs?
Acidic conditions slow larval growth and shell development, negatively impacting populations.
How do echinoderms like sea urchins respond to pH changes?
Slight pH decreases can block their egg metabolism, affecting development and fitness.
What is the effect of pH changes on fish like walleye pollock?
Increased acidity causes them to use more energy for bicarbonate buffering, potentially harming growth.
What are the three lines of defense against changes in H+ concentration?
Chemical buffer systems, respiratory mechanisms, and excretory mechanisms.
What are the four buffer systems in vertebrates?
The four buffer systems are CO2-HCO3− buffer system, peptide and protein buffer system, hemoglobin buffer system, and phosphate buffer system.
Why is the CO2-HCO3− buffer system effective in the extracellular fluid (ECF)?
It is effective because HCO3− is abundant in the ECF, and both HCO3− and CO2 are closely regulated by the kidneys and respiratory system.
What is the role of hemoglobin (Hb) as a buffer?
Hemoglobin buffers H+ generated from CO2 in transit between tissues and the lungs or gills, binding H+ at systemic capillaries and releasing it at respiratory organs to form CO2.
How does the phosphate buffer system function in the intracellular fluid (ICF)?
It consists of Na2HPO4 and NaH2PO4, which donate or accept H+ to buffer pH changes, primarily in the ICF and urine.