Cell Physiology

Eukaryotic cells are distinguished from prokaryotic cells by the presence of __________.

a membrane-delimited nucleus.

All cells within the human body, except for __________ and __________, contain a nucleus.

mature human red blood cells; cells within the lens of the eye.

The cytoplasm is an aqueous solution containing numerous __________, __________, cytoskeletal elements, and organelles.

organic molecules; ions

Many organelles in eukaryotic cells are __________ compartments that carry out specific cellular functions.

membrane-enclosed

The primary function of the cytoskeleton is __________ and __________.

cell shape; movement

The __________ is responsible for genome storage and DNA and RNA synthesis in eukaryotic cells.

nucleus

Mitochondria synthesize __________ by oxidative phosphorylation and store __________.

ATP; Ca2+

The rough endoplasmic reticulum is involved in the translation of mRNA into __________ proteins or proteins for __________ out of the cell.

membrane-associated; secretion

The Golgi apparatus is responsible for the __________, __________, and __________ of proteins and lipids.

modification; sorting; packaging

Lysosomes are involved in __________ degradation in the cell.

intracellular

The plasma membrane separates intracellular contents from the __________ environment.

extracellular

Membrane transport proteins are involved in the __________ transport of molecules into and out of the cell.

selective

An important function of the plasma membrane is __________ through the use of cell surface antigens.

cell recognition

The lipid bilayer of the plasma membrane is approximately __________ thick.

5 nm

Phospholipids are __________ molecules with a charged head and two hydrophobic fatty acyl chains.

amphipathic

Cholesterol serves to stabilize the plasma membrane at a normal body temperature of __________°C.

37

Glycolipids consist of two fatty acyl chains linked to polar head groups that consist of __________.

carbohydrates

The majority of membrane transport proteins are classified as __________, lipid-anchored, or peripheral.

integral

Integral membrane proteins can span the membrane and are termed __________ proteins.

transmembrane

Aquaporins facilitate the __________ movement of water across the membrane.

passive

The two main mechanisms of endocytosis are __________ and __________.

pinocytosis; phagocytosis

Receptor-mediated endocytosis allows for the uptake of __________ molecules into the cell.

specific

Exocytosis can be either __________ or __________.

constitutive; regulated

The transport of glucose via SGLT-1 and SGLT-2 in epithelial cells is an example of __________ transport.

secondary active

Osmosis is the movement of water across membranes driven by __________ pressure differences.

osmotic

Tonicity refers to the effect of a solution on the __________ of a cell.

volume

A solution that does not change the volume of a cell is termed __________.

isotonic

Oncotic pressure is generated by __________ molecules, especially proteins, in a solution.

large

The specific gravity of urine is often used in clinical settings to assess the __________ ability of the kidneys.

concentrating

The major classes of plasma membrane transporters include water channels, ion channels, solute carriers, and __________ transporters.

ATP-dependent

Osmolarity refers to the osmotic pressure generated by solute molecules in __________ of solvent.

1 L

Active transport requires __________ input to move molecules against their electrochemical gradient.

energy

The elastance of a solute refers to the ability of the solute to exert __________ pressure across a membrane.

osmotic

The Nernst equation is used to calculate __________ equilibrium potential for ions across membranes.

equilibrium

The process of __________ occurs when a piece of the plasma membrane pinches off and internalizes materials.

endocytosis

The main routes for water movement into and out of the cell are through __________, or aquaporins.

water channels

Cell communication is facilitated by the use of __________ and receptors on the plasma membrane.

neurotransmitters

The membrane potential is affected by the concentrations of __________ inside and outside the cell.

ions

Solute carriers can be classified based on whether they transport solutes in the same direction (symport) or in opposite directions (antiport).

The __________ is an example of a P-type ATPase that regulates Na+ and K+ gradients in the cell.

Na+,K+-ATPase

Lipid rafts are important for segregating signaling __________ in the plasma membrane.

molecules

Aquaglyceroporins provide pathways for water and __________ to cross the membrane.

glycerol

G protein-coupled receptors typically span the membrane with __________ α-helical domains.

seven

Na+, K+-pump is essential for establishing __________ gradients essential for cell function.

ion

A protein can be covalently attached to the membrane via a __________ anchor.

lipid

Cell adhesion molecules help to organize __________ between cells.

tissues

What is the function of ribosomes in eukaryotic cells?

Ribosomes are responsible for synthesizing proteins by translating mRNA.

Which organelle is known as the "powerhouse of the cell"?

Mitochondria are known as the "powerhouse of the cell" due to their role in ATP production.

What is the primary role of the smooth endoplasmic reticulum?

The smooth endoplasmic reticulum is involved in lipid synthesis and detoxification.

How do lysosomes maintain cellular integrity?

Lysosomes degrade waste materials and cellular debris, maintaining cellular integrity.

What role do cell surface receptors play in cellular communication?

Cell surface receptors bind to signaling molecules and initiate cellular responses.

What is homeostasis in the context of cellular transport?

Homeostasis refers to the maintenance of stable internal conditions within a cell.

What is the difference between passive and active transport?

Passive transport occurs without energy, while active transport requires energy input to move molecules.

What is the role of the cytoskeleton in cells?

The cytoskeleton provides structural support, aids in cell shape, and facilitates cell movement.

What are gap junctions and their function?

Gap junctions are intercellular channels that allow direct communication between neighboring cells.

What is the significance of enzyme structure in cellular processes?

The structure of enzymes determines their specificity and efficiency in facilitating biochemical reactions.