Renal Physiology: Nutrient Retention Mechanism

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Which of the following is NOT a function of the kidneys?

Regulating salt balance
Regulating pH balance of blood
Regulating water balance
Regulating CO2 levels in the blood (correct)

What is the net effect of H+ secretion into kidney tubules on blood pH?

Increase in blood pH
Indirect effect on HCO3- levels
Decrease in blood pH (correct)
No effect on blood pH

What is the major buffer present in the blood for pH regulation?

H2O
HCO3- (bicarbonate) (correct)
K+ ions
NaCl

Which enzyme catalyzes both intra- and extracellular production of carbonic acid?

Carbonic anhydrase (B) Signup and view all the answers

When arterial pressure is less than 85 mm Hg, which of the following is NOT expected to occur?

Stimulation of thirst by angiotensin (C) Signup and view all the answers

In cardiac muscle, the rapid depolarization phase of an action potential is primarily due to:

Na+ influx through voltage-gated channels (C) Signup and view all the answers

Which of the following best describes the refractory period in cardiac muscle cells?

It prevents tetanic contractions to protect the heart. (C) Signup and view all the answers

Which statement accurately describes a characteristic of cardiac muscle?

Cardiac muscle cells are connected by intercalated discs. (A) Signup and view all the answers

What is the primary function of the atrioventricular (AV) node in the heart's electrical conduction system?

To delay conduction between atria and ventricles to ensure proper filling. (D) Signup and view all the answers

What is the purpose of countercurrent exchange in biological systems?

To create a gradient that amplifies the movement of substances (C) Signup and view all the answers

How do electrochemical gradients serve as sources of potential energy in transport mechanisms?

By actively pumping ions against their concentration gradients (B) Signup and view all the answers

In the context of plant biology, what is the significance of 'genetic redundancy'?

It ensures that plants can survive with mutations in certain genes (D) Signup and view all the answers

How does the action spectrum differ from the absorption spectrum in photosynthesis?

The action spectrum shows light wavelengths absorbed by pigments; the absorption spectrum shows wavelengths promoting photochemical reactions (D) Signup and view all the answers

What is the primary function of photophosphorylation in chloroplasts during photosynthesis?

To convert light energy into chemical energy in the form of ATP (B) Signup and view all the answers

What is the role of phytochrome in plants?

Acting as a sensor of light quantity, quality, and duration (C) Signup and view all the answers

What recurring mechanism involves hormone action at many different levels and the concept of signaling webs?

Signaling webs vs. distinct pathways (B) Signup and view all the answers

How do C4 and CAM plants differ in their carbon fixation pathways?

C4 plants use PEP carboxylase to fix carbon, while CAM plants use RuBisCO (C) Signup and view all the answers

Which plant photoreceptor plays a crucial role in regulating growth by sensing light wavelengths?

Phytochrome (B) Signup and view all the answers

What is the primary function of bioassays when detecting an unknown chemical in plants?

To assess the chemical's effect on plant growth or other biological responses (A) Signup and view all the answers