CH1 Cellular Biology and Membrane Transport in Disease Mechanisms ai

What is the significance of cells in the context of disease?

All body functions depend on the integrity of the cells, making understanding cellular biology essential for understanding disease.

What is cellular crosstalk?

Cellular crosstalk refers to the communication between cells, which is fundamental to cellular biology.

What are solutes?

Dissolved substances in a solution.

What are electrolytes and how are they measured?

Electrolytes are ions such as cations (+) and anions (-) measured in milliequivalents per liter (mEq/L) or milligrams per deciliter (mg/dl).

What are nonelectrolytes?

Substances like glucose, urea, and creatinine that do not dissociate when placed in solution.

What is passive transport?

A process where water and small, electrically uncharged molecules move through pores without requiring energy.

What is diffusion in the context of passive transport?

The movement of a solute from an area of greater concentration to an area of lesser concentration.

What is facilitated diffusion?

A type of passive mediated transport where a protein transporter moves solute molecules through cellular membranes without expending metabolic energy.

What is filtration in membrane transport?

The movement of water and solutes through a membrane due to greater hydrostatic pressure on one side than the other.

What is osmosis?

The movement of water down a concentration gradient.

What is osmotic pressure?

The amount of hydrostatic pressure required to oppose the osmotic movement of water.

What is oncotic pressure?

The overall osmotic effect of colloids, such as plasma proteins.

What is tonicity?

The effective osmolality of a solution.

What is the normal osmolality range in humans?

Normal osmolality is 285 to 294 mOsm/kg.

What defines an isotonic solution?

A solution with the same osmolality or concentration of particles (285 mOsm/kg) as the intracellular fluid (ICF) or extracellular fluid (ECF).

What is a hypertonic solution?

A solution with a concentration of more than 294 mOsm/kg.

What is a hypotonic solution?

A solution with a concentration of less than 285 mOsm/kg, which is more dilute than body fluids.

What is mediated transport?

Transport that can be passive or active, involving the movement of one or more molecules across membranes.

What is active transport?

The movement of larger molecules and molecular complexes into the cell, requiring energy and moving against a concentration gradient.

What is the potassium-sodium pump?

An example of an active transport pump that moves potassium and sodium ions across the cell membrane.

What is endocytosis?

An internalizing process where a section of the plasma membrane enfolds substances from outside the cell, forming a vesicle.

What is pinocytosis?

The ingestion of extracellular fluid (ECF) and its contents by the cell.

What is phagocytosis?

The process where large molecular substances are engulfed by the plasma membrane and enter the cell for isolation and destruction.

What is required for active transport in cells?

Active transport requires receptors that recognize and bind specific molecules, energy expenditure, a hydrostatic pressure gradient, and does not involve pores in the cell membrane.

How does the plasma membrane influence the movement of oxygen (O2), carbon dioxide (CO2), and sodium ions (Na+)?

The inner hydrophobic portions of the plasma membrane lipid bilayer allow CO2 and O2 to cross while Na+ ions cross via mediated transport.

What is a false statement regarding glucose, oxygen, and cellular respiration?

Cellular respiration largely occurs in the rough endoplasmic reticulum.

What is the role of oxygen in cellular respiration?

Oxygen must be present for cellular respiration to take place.

What is produced during cellular respiration?

The ATP produced from cellular respiration is used to power the cell's activities, and carbon dioxide is a by-product.

What impact does a lack of glucose have on the sodium-potassium pump?

The sodium-potassium pump would not function effectively due to a lack of ATP, which is derived from glucose.

What is the primary function of the sodium-potassium pump?

The sodium-potassium pump maintains the electrochemical gradient across the cell membrane by moving sodium out and potassium into the cell.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a defined nucleus and organelles.

What is the significance of the hydrophilic and hydrophobic regions of the plasma membrane?

The hydrophilic regions interact with the aqueous environment, while the hydrophobic regions create a barrier that regulates the movement of substances.

How does glucose enter the cell?

Glucose enters the cell primarily through facilitated diffusion or active transport mechanisms.

What is the relationship between glucose and ATP production?

Glucose is broken down during cellular respiration to release energy that is used to synthesize ATP.

What happens if glucose cannot enter the cell?

If glucose cannot enter the cell, ATP production will decrease, affecting cellular functions.

What is the by-product of cellular respiration?

Carbon dioxide is the primary by-product of cellular respiration.

What are the two main types of cellular transport?

The two main types of cellular transport are passive transport and active transport.

What role does ATP play in active transport?

ATP provides the energy necessary for active transport processes to move substances against their concentration gradient.

What is the function of the rough endoplasmic reticulum?

The rough endoplasmic reticulum is involved in protein synthesis and processing.

What is the role of receptors in active transport?

Receptors in active transport recognize and bind to specific molecules, facilitating their transport across the membrane.

What is the difference between facilitated diffusion and active transport?

Facilitated diffusion does not require energy and moves substances down their concentration gradient, while active transport requires energy to move substances against their gradient.

What is the importance of the sodium-potassium pump in maintaining cellular homeostasis?

The sodium-potassium pump is crucial for maintaining the electrochemical gradient, which is essential for nerve impulse transmission and muscle contraction.

What are the main differences between eukaryotes and prokaryotes?

Eukaryotes have complex cellular organization, membrane-bound organelles, and a well-defined nucleus, while prokaryotes have an indistinct nucleus with a single circular chromosome.

What types of organisms are classified as eukaryotes?

Higher animals, plants, fungi, and protozoa.

List the three general components of a eukaryotic cell.

Plasma membrane, cytoplasm, intracellular organelles.

What is the function of the nucleus in a eukaryotic cell?

The nucleus controls cell division and genetic information, and contains DNA for replication, repair, and transcription.

What is the role of ribosomes in eukaryotic cells?

Ribosomes synthesize proteins and can be free or attached to the endoplasmic reticulum.

Describe the structure and function of the Golgi complex.

The Golgi complex consists of flattened, smooth membranes and secretory vesicles; it processes, secretes, and releases substances, especially proteins.

What are lysosomes and their primary functions?

Lysosomes are saclike structures that originate from the Golgi apparatus, functioning as an intracellular digestion system with about 40 digestive enzymes.

What is the role of peroxisomes in eukaryotic cells?

Peroxisomes detoxify compounds and fatty acids, break down substances into harmless products, and synthesize specialized phospholipids for nerve cell myelination.

How are mitochondria structured and what is their primary function?

Mitochondria are surrounded by a double membrane with increased inner surface area from cristae; they are responsible for cellular respiration and energy production.

What are the main functions of the cytoplasm in a eukaryotic cell?

The cytoplasm is involved in synthesis and transport, waste elimination, metabolic processes, maintenance, motility, and storage.

What is the structure of the endoplasmic reticulum and its function?

The endoplasmic reticulum is a network of tubular or saclike channels, with smooth and rough types; it serves as the site of protein synthesis and senses cellular stress.

What are the components of the cytoplasmic matrix?

The cytoplasmic matrix includes cytosol and cytoplasmic organelles.

What is the structure and function of centrioles?

Centrioles are cylindrical structures involved in cell division and organizing microtubules.

What is the role of microfilaments and microtubules in a cell?

Microfilaments and microtubules provide structural support and facilitate movement within the cell.

What is the significance of the nuclear envelope?

The nuclear envelope surrounds the nucleus, providing a barrier that regulates the passage of molecules in and out of the nucleus.

What is the function of the nucleolus?

The nucleolus is involved in ribosome synthesis and assembly.

What are vaults in the context of eukaryotic cells?

Vaults are ribonucleoproteins shaped like octagonal barrels, involved in transport and cellular processes.

What is the function of smooth endoplasmic reticulum?

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

What is the role of exocytosis in cellular function?

Exocytosis is the process by which cells release substances, such as proteins, into the extracellular space.

What are the primary components of chromatin?

Chromatin consists of DNA and histone proteins, playing a crucial role in DNA replication and gene expression.

What is the significance of histone proteins in the nucleus?

Histone proteins help package and organize DNA into a compact structure, facilitating gene regulation.

What is the primary function of hydrolases found in lysosomes?

Hydrolases are digestive enzymes that break down macromolecules within the lysosome.

What is the cytosol and its primary functions?

The cytosol is the gelatinous, semiliquid portion of the cytoplasm, making up 55% of the total cell volume. Its functions include intermediary metabolism, ribosomal protein synthesis, and storage.

What role does the cytoskeleton play in a eukaryotic cell?

The cytoskeleton acts as the 'bones and muscles' of the cell, maintaining its shape and internal organization, permitting movement of substances within the cell, and facilitating external projections.

What are the main components of the plasma membrane?

The plasma membrane is composed of a bilayer of amphipathic lipids and proteins, which are not uniformly distributed.

What are lipid rafts and their significance in the plasma membrane?

Lipid rafts are microdomains within the plasma membrane that segregate signaling mechanisms and molecules, controlling cytoskeleton remodeling events.

What types of proteins are found in the plasma membrane and their functions?

Plasma membrane proteins include integral, peripheral, and transmembrane proteins, which function as receptors, transporters, enzymes, surface markers, adhesion molecules, and catalysts.

What is a proteolytic cascade?

A proteolytic cascade is a tightly orchestrated sequence of events that leads to the breakdown of proteins, including major cascades like caspase-mediated apoptosis, blood coagulation, matrix metalloproteinase, and complement cascades.

What are cellular receptors and their role in the cell?

Cellular receptors are protein molecules on the plasma membrane, cytoplasm, or nucleus that bind with ligands. They determine ligand binding and the cell's response to that binding.

How does the ligand-receptor complex function in cellular signaling?

The ligand-receptor complex initiates interactions that cause adenylyl cyclase to transform ATP into messenger molecules, stimulating specific cellular responses.

What is the composition of the plasma membrane?

The plasma membrane is primarily composed of amphipathic molecules, which include hydrophilic and hydrophobic regions.

What is the significance of caveolae in the plasma membrane?

Caveolae are small invaginations in the plasma membrane that play a role in signaling and endocytosis.

What is the permeability of the plasma membrane to water-soluble and lipid-soluble molecules?

The plasma membrane is permeable to water-soluble molecules but impermeable to lipid-soluble molecules.

What is the function of microtubules in the cytoskeleton?

Microtubules provide strength and structural support to the cell.

What are the functions of integral and peripheral proteins in the plasma membrane?

Integral proteins are embedded in the membrane and often function as transporters or receptors, while peripheral proteins are attached to the membrane surface and may serve as enzymes or structural components.

What is mechanotransduction in the context of the cytoskeleton?

Mechanotransduction refers to the process by which cells convert mechanical stimuli into biochemical signals, facilitated by the cytoskeleton.

What is the role of centrioles in a eukaryotic cell?

Centrioles are involved in cell division and help organize the microtubules during mitosis.

What is the function of actin microfilaments in the cytoskeleton?

Actin microfilaments are involved in cell movement, shape maintenance, and muscle contraction.

What is the role of ribosomal protein synthesis in the cytosol?

Ribosomal protein synthesis in the cytosol is crucial for producing proteins that are essential for various cellular functions.

What is the importance of cell-to-cell recognition provided by the plasma membrane?

Cell-to-cell recognition is vital for immune response, tissue formation, and communication between cells.

What are the primary functions of the plasma membrane?

The plasma membrane controls the composition of the enclosed space, provides selective transport, facilitates cell-to-cell recognition, and contributes to cellular mobility and shape.

What is the significance of the solid-gel phase and fluid-liquid crystalline phase in the plasma membrane?

These phases describe the physical states of the lipid bilayer, affecting membrane fluidity and the behavior of embedded proteins.

What are the potential treatment options for bacterial infections that minimize harm to other cells?

Antibiotics are often used to treat bacterial infections while minimizing harm to other cells, as they target specific bacterial processes.

What is the role of cellular communication in the body?

Maintains homeostasis, regulates growth and division, and coordinates functions.

What are the types of signaling involved in cellular communication?

Contact-dependent signaling, paracrine signaling, autocrine signaling, hormonal signaling, neurohormonal signaling, and neurotransmitters.

What are neurotransmitters and how do they function?

Neurotransmitters act on the cells that produce and secrete them, act on nearby cells that take them up and destroy them, are produced by neurosecretory neurons, and diffuse across the synaptic cleft to act on postsynaptic receptors.

What are the four essential components of a signaling pathway?

1) The initial signal, 2) the receptor that binds the signal, 3) the signaling molecule(s) that transmit the message, and 4) the effector(s) that result in cellular change.

How does the type of signal affect receptor location?

Hydrophobic signals like estrogen can pass through the plasma membrane and have intracellular receptors, while hydrophilic signals like insulin require integral membrane proteins with extracellular signal-binding domains.

What happens when a signaling molecule binds to its receptor?

The receptor changes its shape or conformation, which may open an ion channel or change the organization of receptor domains.

What is the function of activated signaling molecules?

They influence effectors that cause short-term or long-term cellular changes.

What are examples of short-term cellular changes?

Stimulating cellular movement or changing the activation state of an enzyme.

What typically results in long-term cellular changes?

Changes in DNA transcription, such as activating the cell cycle to begin cellular replication.

What is a protein kinase cascade?

A mechanism for multi-protein signal transduction where a protein kinase adds a phosphate group to specific amino acid residues of proteins using ATP.

What determines where a kinase will phosphorylate another protein?

The amino acids surrounding the phosphorylation site create a specific binding site for the kinase.

What is the significance of the size and composition of the initial signal in a signaling pathway?

It determines whether the receptor signal-binding domain is intracellular or extracellular.

What is the role of phospholipids in cell membranes?

Phospholipids are essential for forming new cell membranes.

What is the function of a filtration system that removes organisms under 0.1 um in diameter?

It rids the body of small organisms.

What is the effect of a drug that prevents duplication of long strands of DNA?

It inhibits DNA replication.