Cellular level of organization

What is the primary function of the cell membrane?

A protective barrier that regulates entry and exit of substances.

What is the role of the nucleus in a cell?

The control center of the cell, containing DNA and coordinating activities like growth and reproduction.

What do mitochondria do?

Known as the 'powerhouse of the cell,' they generate ATP through cellular respiration, supplying energy for cellular functions.

What is the amphipathic nature of phospholipids?

Hydrophilic (polar) heads face the water inside and outside the cell, while hydrophobic (nonpolar) tails align inward to form a bilayer.

What percentage of membrane lipids does cholesterol constitute and what is its function?

makes up ~20% of membrane lipids and regulates membrane fluidity.

What is the role of glycolipids in the cell membrane?

contribute to cell recognition and signaling, and help form the glycocalyx.

What are integral proteins?

Proteins that span the entire membrane and function as channels or transporters.

Describe the function of peripheral proteins in the cell membrane.

loosely attached to the membrane and serve as enzymes or structural components.

What are the two types of transport mechanisms across the membrane?

Passive transport (e.g., facilitated diffusion) and active transport (e.g., sodium-potassium pump).

What is osmosis?

The movement of water across a selectively permeable membrane from high to low water concentration.

What is the purpose of tight junctions in epithelial cells?

seal adjacent cells and regulate permeability.

What do adherens junctions provide?

Strong mechanical attachments between cells that maintain tissue integrity.

What is the function of gap junctions?

enable rapid communication between cells, allowing coordinated activities.

What is the composition of synovial membranes?

connective tissue and secrete synovial fluid for joint lubrication.

What is the endothelium?

A specialized epithelial tissue derived from mesoderm found in the circulatory system.

What role do glycoproteins play in the cell membrane?

essential for cell recognition and signaling.

What is the primary function of the cell membrane?

A protective barrier that regulates entry and exit of substances.

What is the role of the nucleus in a cell?

The control center of the cell, containing DNA and coordinating activities like growth and reproduction.

What do mitochondria do?

Known as the 'powerhouse of the cell,' they generate ATP through cellular respiration, supplying energy for cellular functions.

What is the amphipathic nature of phospholipids?

Hydrophilic (polar) heads face the water inside and outside the cell, while hydrophobic (nonpolar) tails align inward to form a bilayer.

What percentage of membrane lipids does cholesterol constitute and what is its function?

makes up ~20% of membrane lipids and regulates membrane fluidity.

What is the role of glycolipids in the cell membrane?

contribute to cell recognition and signaling, and help form the glycocalyx.

What are integral proteins?

Proteins that span the entire membrane and function as channels or transporters.

Describe the function of peripheral proteins in the cell membrane.

loosely attached to the membrane and serve as enzymes or structural components.

What are the two types of transport mechanisms across the membrane?

Passive transport (e.g., facilitated diffusion) and active transport (e.g., sodium-potassium pump).

What is osmosis?

The movement of water across a selectively permeable membrane from high to low water concentration.

What is the purpose of tight junctions in epithelial cells?

seal adjacent cells and regulate permeability.

What do adherens junctions provide?

Strong mechanical attachments between cells that maintain tissue integrity.

What is the function of gap junctions?

enable rapid communication between cells, allowing coordinated activities.

What is the composition of synovial membranes?

connective tissue and secrete synovial fluid for joint lubrication.

What is the endothelium?

A specialized epithelial tissue derived from mesoderm found in the circulatory system.

What role do glycoproteins play in the cell membrane?

Essential for cell recognition and signaling.

What is facilitated diffusion?

A passive transport mechanism that uses carrier proteins to move molecules across the membrane.

What is the sodium-potassium pump?

An active transport mechanism that moves sodium out of the cell and potassium into the cell against their concentration gradients.

Define selective permeability.

The ability of the cell membrane to allow certain substances to pass while blocking others.

What is the function of the cytoplasm?

The gel-like substance within the cell membrane that holds organelles and facilitates metabolic processes.

What is the significance of the cytoskeleton?

Provides structural support, maintains cell shape, and aids in cell movement and division.

Explain the role of ribosomes in a cell.

sites of protein synthesis, translating mRNA into amino acid chains.

What are lysosomes?

Organelles containing enzymes that digest cellular waste and materials.

What is the function of the endoplasmic reticulum (ER)?

synthesizes proteins and lipids; rough ER has ribosomes, while smooth ER does not.

What is the role of the Golgi apparatus?

To modify, sort, and package proteins and lipids for secretion or use within the cell.

Describe the function of vesicles.

Small membrane-bound structures that transport materials within the cell.

What is the purpose of peroxisomes?

Organelles that contain enzymes for oxidation reactions and break down fatty acids and amino acids.

What are centrioles?

Cylindrical structures that play a role in cell division by facilitating the organization of the mitotic spindle.

What encompasses the term 'cell signaling'?

The process by which cells communicate with each other through chemical signals.

Define apoptosis.

The programmed cell death that occurs in multicellular organisms.

What is the extracellular matrix?

A network of proteins and carbohydrates that provide structural and biochemical support to surrounding cells.

What is endocytosis?

The process by which cells internalize substances by engulfing them in a membrane-bound vesicle.

What is exocytosis?

The process of releasing substances from a cell through vesicles that fuse with the plasma membrane.

What are the functions of cell junctions?

To provide adhesion between cells, allow communication, and control permeability.

What is the role of cholesterol in maintaining membrane stability?

helps to stabilize membrane fluidity across temperature variations.

What are integrins?

Transmembrane proteins that facilitate cell-extracellular matrix adhesion.

What is the importance of protein glycosylation?

vital for protein folding, stability, and cell-cell recognition.

What is the function of transport proteins?

They assist in moving substances across the cell membrane.

What are amphiphilic molecules?

Molecules that contain both hydrophilic and hydrophobic parts, like phospholipids.

How do cells respond to environmental changes?

By signaling pathways that adjust cellular functions and gene expression.

What is the role of antigen-presenting cells?

They process and present antigens to T cells, initiating an immune response.

What are cytokines?

Signaling proteins that mediate and regulate immunity, inflammation, and hematopoiesis.

What is the function of the plasma membrane?

To protect the cell from its external environment and to regulate what enters and exits the cell.

Explain the function of tight junctions in more detail.

They prevent the leakage of materials between cells and maintain the distinct environments of different tissues.

What is the role of the cytoplasmic membrane in prokaryotes?

To serve as a barrier and site for metabolic activities, since prokaryotes lack membrane-bound organelles.

Define the term 'signal transduction'.

The process by which a cell translates an external signal into a functional response.

What is the function of nuclear pores?

They regulate the exchange of materials (like RNA and proteins) between the nucleus and the cytoplasm.

What is the purpose of phospholipid bilayers?

To create a barrier that separates the inside of the cell from the outside environment.

What is a cell's resting membrane potential?

The electrical potential difference across the plasma membrane when a cell is at rest.

What are stem cells?

Undifferentiated cells with the ability to develop into various cell types.

What is the difference between prokaryotic and eukaryotic cells?

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

What is facilitated diffusion's distinguishing feature?

It does not require energy, as substances move down their concentration gradient.

What is membrane potential?

The difference in electric charge inside and outside of a cell's membrane.

How do mutations affect cell function?

disrupt normal cell functions, potentially leading to diseases like cancer.

What are the effects of high salt concentrations on cells?

It can lead to osmotic stress, causing cell shrinkage or damage.

What is autophagy?

The process by which cells degrade and recycle their own components.

What is the importance of cell communication?

It allows cells to coordinate their functions and respond to changes in their environment.