ap bio unit 2

organelle

specialized structure within a cell that performs a specific function.

membrane bound organelles

structures within a cell that are enclosed by a lipid membrane and carry out specific functions, like the nucleus, mitochondria, and endoplasmic reticulum.

ribosomes

small cell structures that make proteins by linking amino acids together according to instructions from the cell’s DNA.

smooth er

a membrane-bound organelle that helps make lipids, detoxify chemicals, and store calcium in the cell.

rough er

membrane-bound organelle studded with ribosomes that helps make and transport proteins.

golgi complex(apparatus)

a membrane-bound organelle that modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.

mitochondria

membrane-bound organelles that produce energy for the cell by converting glucose and oxygen into ATP through cellular respiration.

mitochondria matrix

the innermost compartment of the mitochondrion, containing enzymes, DNA, and ribosomes, where the Krebs cycle (citric acid cycle) takes place.

mitochondria inner membrane

the folded membrane inside the mitochondrion that contains proteins for the electron transport chain and ATP production.

lysosomes

membrane-bound organelles that contain digestive enzymes to break down waste, damaged cell parts, and foreign materials.

vacuole

a membrane-bound organelle that stores water, nutrients, and waste products, and helps maintain cell pressure and structure.

peroxisomes

small membrane-bound organelles that break down fatty acids and detoxify harmful substances, producing and using hydrogen peroxide in the process.

chloroplast

membrane-bound organelles in plant cells that capture sunlight and convert it into chemical energy through photosynthesis.

thylakoids

flattened, membrane-bound sacs inside chloroplasts where the light-dependent reactions of photosynthesis occur.

chloroplast electron transport chain

a series of proteins in the thylakoid membrane that transfer electrons from water to NADP⁺, creating a proton gradient used to produce ATP and NADPH during photosynthesis.

stroma

the fluid-filled space inside a chloroplast that surrounds the thylakoids and contains enzymes for the Calvin cycle, where sugars are synthesized.

cytoskeleton

a network of protein fibers in a cell that provides structure, shape, and helps with movement and transport within the cell.

cytoplasm

the jelly-like substance inside a cell that surrounds organelles and allows materials to move within the cell.

cell membrane

a thin, flexible barrier that surrounds the cell, controlling what enters and leaves and helping maintain the cell’s environment.

cell wall

a rigid outer layer found in plant, fungal, and bacterial cells that provides structure, support, and protection.

nucleus

a membrane-bound organelle that stores the cell’s DNA and controls its growth, metabolism, and reproduction.

nucleolus

a dense structure inside the nucleus where ribosomal RNA (rRNA) is made and ribosome assembly begins.

nuclear membrane

a double-layered membrane that surrounds the nucleus, controlling the movement of materials in and out.

surface area to volume ratio

the comparison of a cell’s outer surface area to its internal volume, which affects how efficiently the cell can exchange materials with its environment.

phospholipids

molecules with a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails that make up the main structure of cell membranes.

membrane bound proteins

proteins embedded in or attached to a cell membrane that help with transport, communication, and signaling.

transport proteins

membrane proteins that help move substances, like ions or molecules, across a cell membrane.

active transport

the movement of molecules across a cell membrane using energy, usually from low concentration to high concentration.

passive transport

the movement of molecules across a cell membrane without using energy, which includes diffusion (molecules moving from high to low concentration) and facilitated diffusion (molecules moving through a transport protein from high to low concentration).

facilitated diffusion

the passive movement of molecules across a cell membrane through a transport protein, from an area of high concentration to low concentration.

tonicity

the ability of a solution to change the shape or volume of a cell by affecting the movement of water across its membrane.

osomoregulation

the process by which organisms regulate the balance of water and solutes in their bodies to maintain proper cell and body function.

osmosis

the passive movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

glycoproteins

proteins with sugar chains attached that are found on the cell membrane and help with cell recognition, signaling, and adhesion.

glycolipids

lipids with sugar chains attached that are found on the cell membrane and help with cell recognition and communication.

selective permeability

the property of a cell membrane that allows certain substances to pass through while blocking others.

water potential

a measure of the potential energy of water in a system, indicating the direction water will flow, typically from areas of high water potential to low water potential.

endocytosis

the process by which a cell takes in large molecules or particles by engulfing them in a portion of its cell membrane, forming a vesicle.

exocytosis

the process by which a cell releases substances, such as proteins or waste, by enclosing them in a vesicle that fuses with the cell membrane.

cell compartmentalization

the organization of a cell into separate membrane-bound areas (organelles), each with specific functions, allowing the cell to carry out multiple processes efficiently.

endosymbiosis

the theory that certain organelles, like mitochondria and chloroplasts, originated as free-living bacteria that were engulfed by a larger cell and formed a mutually beneficial relationship.