cells

What are cells?

Cells are structural and functional units of organisms, including humans.

Why are cells important?

They perform general housekeeping functions necessary to sustain life.

What are the general functions of cells?

Covering, lining, storage, movement, connection, defense, communication, and reproduction.

What is the cell theory?

All living organisms are composed of one or more cells, cells are basic units of structure and function in all living organisms, all cells arise from pre-existing cells through division.

What are organelles?

Complex, organized structures with unique shapes that perform different functions for the cell.

What are the three main components of cells?

Plasma membrane, cytoplasm, and nucleus.

What is the plasma membrane?

The thin outer border of the cell that regulates the passage of substances between the internal and external environments.

What describes the structure of the plasma membrane?

Fluid mosaic model; a fluid phospholipid layer with embedded proteins, carbohydrates, and cholesterol.

How does diffusion differ from osmosis?

Diffusion is the movement of molecules down their concentration gradient, while osmosis specifically involves the movement of water.

What is active transport?

The movement of molecules against their concentration gradient through integral proteins using energy.

What is phagocytosis?

'Cell eating' - the process by which large molecules, invaders, or bacteria are engulfed through the cell membrane.

What is the function of ribosomes?

Ribosomes are protein producers, either free-floating or membrane-bound.

What is the function of the Golgi apparatus?

To sort, process, and package products from the rough endoplasmic reticulum.

What is the main function of the mitochondria?

Produces energy for cellular functions by transferring energy from chemical bonds to ATP.

What is the function of peroxisomes?

Degrade harmful substances, including hydrogen peroxide, and break down fatty acid molecules.

What is the cytoskeleton?

A network composed of protein subunits that provides structure, shape, and coordinates cellular movement.

What is the nucleus's role in the cell?

It acts as the control center, housing genetic material that directs cellular activities.

What are chromosomes?

Organized levels of genetic material, visible during cell division, with humans having 46 chromosomes.

What is the cell life cycle composed of?

The cell life cycle encompasses interphase and mitotic phase.

What is cytokinesis?

The division of the cytoplasm and organelles, marking the final step of cell division.

What are telomeres?

Telomeres are repetitive sequences at the ends of chromosomes that limit the number of times a cell can divide.

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

The ER synthesizes proteins (rough ER) and lipids (smooth ER), and transports them throughout the cell.

What is the function of lysosomes?

Lysosomes are organelles that contain enzymes for degrading waste materials and cellular debris.

How do cells communicate with each other?

Cells communicate through signaling molecules that bind to receptors on target cells.

What is a stem cell?

Stem cells are undifferentiated cells with the ability to develop into various cell types.

What is apoptosis?

Apoptosis is the programmed cell death process, essential for development and homeostasis.

What is the purpose of the cell membrane's permeability?

The cell membrane's permeability regulates the entry and exit of substances, maintaining homeostasis.

What are the two types of cell division?

Mitosis, which produces identical daughter cells, and meiosis, which reduces the chromosome number for gamete formation.

What is the role of chloroplasts in plant cells?

Chloroplasts are responsible for photosynthesis, converting sunlight into chemical energy.

What is a virus?

A virus is a microscopic infectious agent that can only replicate inside a living host cell.

What are multicellular organisms?

Multicellular organisms are living beings made up of multiple cells that work together for survival.

What is the function of the nucleus in a cell?

The nucleus acts as the control center of the cell, housing DNA and regulating gene expression.

What is the significance of the plasma membrane's fluid mosaic model?

The fluid mosaic model explains the dynamic nature of the plasma membrane, consisting of a flexible lipid bilayer with embedded proteins.

What organelle is known as the powerhouse of the cell?

The mitochondria are known as the powerhouse of the cell, producing ATP through cellular respiration.

What is the primary role of ribosomes in the cell?

Ribosomes are responsible for synthesizing proteins by translating messenger RNA.

How do osmosis and diffusion relate to processes of cell transport?

Both osmosis and diffusion are passive transport mechanisms, allowing substances to move across membranes without energy.

What are microtubules, and what is their function?

Microtubules are part of the cytoskeleton that provide structure, shape, and assist in cell division and transport.

How do cells maintain homeostasis?

Cells maintain homeostasis by regulating their internal environment and responding to external changes.

What role do enzymes play within the cell?

Enzymes act as catalysts to speed up biochemical reactions within the cell, aiding in metabolism.

What is the function of cholesterol in the plasma membrane?

Cholesterol helps to stabilize the fluidity of the plasma membrane, allowing for flexibility across temperature changes.

What is the difference between eukaryotic and prokaryotic cells?

Eukaryotic cells have a defined nucleus and membrane-bound organelles, while prokaryotic cells lack a nucleus and are usually smaller and simpler.