AP BIO Unit-2

Cell

A group of organelles and molecules working together to perform a specific task and help maintain homeostasis in an organism.

Prokaryotes

Single-celled organisms without a nucleus or membrane-bound organelles, including bacteria and archaea.

Eukaryotes

Organisms that can be single-celled or multicellular, containing a nucleus and membrane-bound organelles, such as plants, animals, fungi, and protists.

Surface to Volume Ratio

The relationship that limits cell size; as a cell grows, its volume increases faster than its surface area.

Metabolic Requirements

The needs of a cell that set an upper limit on its size, making it difficult to move materials in and out efficiently as size increases.

Membrane-bound Organelles

Organelles that have their own membrane, allowing for compartmentalization and specialization within the cell.

Non-membrane Bound Organelles

Organelles that do not have their own membrane, such as ribosomes and the cytoskeleton.

Endosymbiotic Theory

The theory that eukaryotic cells evolved from prokaryotic cells that ingested mitochondria and chloroplast-like proto-prokaryotes.

Plasma Membrane

A phospholipid bilayer that regulates what enters and exits the cell and protects the cell's interior.

Ribosomes

Organelles that synthesize proteins by reading messenger RNA, found either free-floating in the cytoplasm or attached to the rough endoplasmic reticulum.

Cytoplasm

The liquid within a cell that helps maintain shape and is the site of metabolic reactions.

Cytoskeleton

A network of fibers that helps maintain cell shape, supports organelles, and facilitates movement within the cell.

Centrioles

Organelles that help form spindle fibers during cell division, aiding in the separation of chromosomes.

Flagella

Long, whip-like structures that aid in cell movement, moving in a propeller-like motion.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Lysosomes

Organelles containing hydrolytic enzymes that break down waste materials and cellular debris.

Vacuoles

Storage organelles that hold fluids, biomolecules, and waste products; larger in plant cells to maintain turgor pressure.

Mitochondria

Organelles responsible for ATP production through cellular respiration, featuring a double membrane for compartmentalization.

Chloroplasts

Organelles in plant cells that conduct photosynthesis, containing thylakoid membranes to increase surface area for reactions.

Selectively Permeable

A property of the plasma membrane that allows certain substances to pass while blocking others.

Passive Transport

The movement of substances across a cell membrane without energy input, following the concentration gradient.

Osmosis

The diffusion of water across a selectively permeable membrane, moving from areas of low solute concentration to high.

Isotonic Solution

A solution where solute and water concentrations are equal, resulting in no net movement of water.

Hypotonic Solution

A solution with a lower concentration of solute than inside the cell, causing water to move into the cell and potentially leading to swelling.

Hypertonic Solution

A solution with a higher concentration of solute than inside the cell, causing water to move out and leading to cell shrinkage.

Facilitated Transport

The process of moving substances across a membrane via specific proteins, without energy, following the concentration gradient.