AP Biology Unit 2

cell wall

rigid cell covering made of various molecules that protects the cell, provides structural support, and gives shape to the cell

central vacuole

large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation

chloroplast

plant cell organelle that carries out photosynthesis

chromatin

protein-DNA complex that serves as the building material of chromosomes

chromosome

structure within the nucleus that is made up of chromatin that contains DNA, the hereditary material

cytoplasm

entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

cytoskeleton

network of protein fibers that collectively maintain the shape of the cell, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell, and enable unicellular organisms to move independently

cytosol

gel-like material of the cytoplasm in which cell structures are suspended

endomembrane system

group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins

endoplasmic reticulum (ER)

series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids

eukaryotic cell

cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs

extracellular matrix

material (primarily collagen, glycoproteins, and proteoglycans) secreted from animal cells that provides mechanical protection and anchoring for the cells in the tissue

Golgi apparatus

eukaryotic organelle made up of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution

lysosome

organelle in an animal cell that functions as the cell's digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

mitochondria

cellular organelles responsible for carrying out cellular respiration, resulting in the production of ATP, the cell's main energy-carrying molecule

nuclear envelope

double-membrane structure that constitutes the outermost portion of the nucleus

nucleoid

central part of a prokaryotic cell in which the chromosome is found

nucleolus

darkly staining body within the nucleus that is responsible for assembling the subunits of the ribosomes

nucleus

cell organelle that houses the cell's DNA and directs the synthesis of ribosomes and proteins

organelle

compartment or sac within a cell

peroxisome

small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

plasma membrane

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, that separates the internal content of the cell from its surrounding environment

prokaryote

unicellular organism that lacks a nucleus or any other membrane-bound organelle

ribosome

cellular structure that carries out protein synthesis

rough endoplasmic reticulum (RER)

region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis

smooth endoplasmic reticulum (SER)

region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutants), and stores calcium ions

vacuole

membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport

vesicle

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus

cell wall

rigid cell covering made of various molecules that protects the cell, provides structural support, and gives shape to the cell

central vacuole

large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation

centrosome

region in animal cells made of two centrioles

chlorophyll

green pigment that captures the light energy that drives the light reactions of photosynthesis

chloroplast

plant cell organelle that carries out photosynthesis

chromatin

protein-DNA complex that serves as the building material of chromosomes

chromosome

structure within the nucleus that is made up of chromatin that contains DNA, the hereditary material

cytoplasm

entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

cytosol

gel-like material of the cytoplasm in which cell structures are suspended

endomembrane system

group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins

endoplasmic reticulum (ER)

series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids

eukaryotic cell

cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs

Golgi apparatus

eukaryotic organelle made up of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution

lysosome

organelle in an animal cell that functions as the cell's digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

mitochondria

cellular organelles responsible for carrying out cellular respiration, resulting in the production of ATP, the cell's main energy-carrying molecule

nuclear envelope

double-membrane structure that constitutes the outermost portion of the nucleus

nucleoid

central part of a prokaryotic cell in which the chromosome is found

nucleolus

darkly staining body within the nucleus that is responsible for assembling the subunits of the ribosomes

nucleus

cell organelle that houses the cell's DNA and directs the synthesis of ribosomes and proteins

organelle

compartment or sac within a cell

peroxisome

small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

plasma membrane

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, that separates the internal content of the cell from its surrounding environment

prokaryote

unicellular organism that lacks a nucleus or any other membrane-bound organelle

ribosome

cellular structure that carries out protein synthesis

rough endoplasmic reticulum (RER)

region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis

smooth endoplasmic reticulum (SER)

region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutants), and stores calcium ions

vacuole

membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport

vesicle

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus

active transport

method of transporting material that requires energy

amphiphilic

molecule possessing a polar or charged area and a nonpolar or uncharged area capable of interacting with both hydrophilic and hydrophobic environments

aquaporin

channel protein that allows water through the membrane at a very high rate

carrier protein

membrane protein that moves a substance across the plasma membrane by changing its own shape

channel protein

membrane protein that allows a substance to pass through its hollow core across the plasma membrane

concentration gradient

area of high concentration adjacent to an area of low concentration

diffusion

passive process of transport of low-molecular weight material according to its concentration gradient

electrochemical gradient

gradient produced by the combined forces of an electrical gradient and a chemical gradient

electrogenic pump

pump that creates a charge imbalance

endocytosis

type of active transport that moves substances, including fluids and particles, into a cell

exocytosis

process of passing bulk material out of a cell

facilitated transport

process by which material moves down a concentration gradient (from high to low concentration) using integral membrane proteins

fluid mosaic model

describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids (sugar chains attached to proteins or lipids, respectively), resulting in a fluid character (fluidity)

glycolipid

combination of carbohydrates and lipids

glycoprotein

combination of carbohydrates and proteins

hydrophilic

molecule with the ability to bond with water; "water-loving"

hydrophobic

molecule that does not have the ability to bond with water; "water-hating"

hypertonic

situation in which extracellular fluid has a higher osmolarity than the fluid inside the cell, resulting in water moving out of the cell

hypotonic

situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell

integral protein

protein integrated into the membrane structure that interacts extensively with the hydrocarbon chains of membrane lipids and often spans the membrane; these proteins can be removed only by the disruption of the membrane by detergents

isotonic

situation in which the extracellular fluid has the same osmolarity as the fluid inside the cell, resulting in no net movement of water into or out of the cell

osmolarity

total amount of solutes dissolved in a specific amount of solution

osmosis

transport of water through a semipermeable membrane according to the concentration gradient of water across the membrane that results from the presence of solute that cannot pass through the membrane

passive transport

method of transporting material through a membrane that does not require energy

peripheral protein

protein found at the surface of a plasma membrane either on its exterior or interior side

pinocytosis

a variation of endocytosis that imports macromolecules that the cell needs from the extracellular fluid

plasmolysis

detaching of the cell membrane from the cell wall and constriction of the cell membrane when a plant cell is in a hypertonic solution

primary active transport

active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane

pump

active transport mechanism that works against electrochemical gradients

receptor-mediated endocytosis

variation of endocytosis that involves the use of specific binding proteins in the plasma membrane for specific molecules or particles

secondary active transport

movement of material that is due to the electrochemical gradient established by primary active transport

selectively permeable

characteristic of a membrane that allows some substances through but not others

solute

substance dissolved in a liquid to form a solution

tonicity

amount of solute in a solution

transport protein

membrane protein that facilitates passage of a substance across a membrane by binding it

cotransport

active transport that uses energy from an electrochemical gradient to transport two different ions across the cell membrane through a protein

symport

type of cotransport in which two different ions are transported in the same direction

antiport

type of cotransport in which two different ions are transported in the opposite directions