Cells, Tissues, Organs
What are the four main types of cells?
Epithelial, Nervous, Muscle, and Blood
What are the main components of the plasma membrane?
phospholipids, lipid bilayer, cholesterol, carbohydrates, and proteins
What is the primary distinguishing factor between active transport and passive diffusion?
Active transport moves substances against their electrochemical gradient and requires metabolic energy (ATP)
If a selectively permeable membrane separates two solutions, osmosis will occur as water moves:
From an area of lower osmolarity to an area of higher osmolarity
What is the fundamental difference between a graded membrane potential and an action potential?
Graded potentials fade over distance and time, whereas action potentials are all-or-none and propagate without fading
What are the four main types of tissues?
Epithelial tissue, Connective tissue, Nervous tissue, and muscle tissue
What are the main plasma membrane proteins?
channels, carrier, docking, receptors, and glycoproteins
What modifications would increase the rate of simple diffusion of a lipophilic drug across a cellular membrane?
Increasing the concentration gradient of the drug across the membrane
Why is maintaining the tonicity of bodily fluids within a strict homeostatic range critical for survival?/ what happens to the cell if it is not maintained
Severe deviations cause cells to swell and lyse, or shrink and disrupt metabolic machinery
During synaptic transmission at a chemical synapse, what directly triggers the exocytosis of neurotransmitter vesicles into the synaptic cleft?
The influx of Ca2+ through voltage-gated calcium channels in the presynaptic terminal in response to an action potential
What are some basic cell function?
control exchange of materials between cell and its surrounding environment, sensing and responding to changes in surrounding environment, synthesize building blocks, proliferation/cell proliferation
Which specialized cell junction has small connecting tunnels formed by connexons?
Gap junctions
Glucose is large and polar, preventing it from passing directly through the lipid bilayer. When it enters a cell down its concentration gradient without using ATP, it utilizes:
Facilitated diffusion via a carrier protein
What is the difference between osmotic pressure and hydrostatic pressure?
Osmotic pressure is the force required for the osmotic movement of water, while hydrostatic pressure is the pressure exerted by a fluid at rest due to the force of gravity or pumping
The resting membrane potential of a typical neuron is closest to the equilibrium potential of which ion, and why?
K+, because leaky potassium channels allow K+ to diffuse out of the cell down its concentration gradient at rest
When comparing the fluid compartments of the body, what is the difference between the composition of the intracellular fluid (ICF) versus the extracellular fluid (ECF)?
The ICF is rich in potassium ions and proteins, while the ECF features high concentrations of sodium and chloride ions
How do voltage-gated ion channels differ functionally from chemically-gated (ligand-gated) ion channels?
Voltage-gated channels open in response to changes in the membrane potential, while chemically-gated channels open when a specific molecule binds to the receptor
Thinking about Fick's Law, what happens to the rate of diffusion as the molecular weight increases?
rate of diffusion decreases
A red blood cell is placed into a solution, causing the cell to lose water and crenate (shrink). The solution is best described as:
Hypertonic relative to the intracellular fluid
A neuron with one axon and one dendrite extending directly from opposite sides of the cell body is structurally classified as
Bipolar neuron
What are the homeostatic control mechanisms?
Receptor, control center, effector
During a cell transmembrane receptor signaling cascade, what is the specific role of a kinase?
To synthesize cyclic AMP (cAMP) directly from membrane phospholipids
What is the difference between membrane pores and gated channels?
membrane poles are always open
gated channels only open to a stimulus
What happens to cell volume if the cell is placed in a hypertonic solution?
Cells Shrink
During the depolarization phase of an action potential, which ion movement is primarily responsible for changing the membrane potential from negative to positive?
Na+ rushing into the cell through voltage-gated Na+ channels