AP Biology- Chapter 6 and 7 (organelles)

Centrosome

A "microtubule-organizing center"; In many cells, microtubules grow out from a _______ near the nucleus; In animal cells, the __________ has a pair of centrioles, each with nine triplets of microtubules arranged in a ring

Nuclear Envelope

A double membrane that encloses the nucleus, perforated with pores that regulate traffic with the cytoplasm; continuous with the with the endoplasmic recticulum in eukaryotic cells

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Vesicles

A membranous sac in the cytoplasm of a eukaryotic cell; , Small membrane sacs that specialize in moving products into, out of, and within a cell; travel along the monorails formed by the cytoskeleton

Lysosomes

A membranous sac of hydrolytic enzymes that can digest macromolecules, _______ enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids, __________ enzymes work best in the acidic environment inside the _________, fuses with the food vacuole to digest the molecules, uses enzymes to break down materials

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement; A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions; organizes the cell's structures and activities, anchoring many organelles

Nucleolus

A nonmembraneous structure involved in production of ribosomes; a nucleus has one or more _______

Plasma Membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cell that controls the movement of materials in and out of the cell through active or passive transport through active or passive transport

Rough Endoplasmic Reticulum

A system of internal membranes within the cytoplasm dotted with bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates). Functions: distributes transport vesicles (proteins surrounded by membranes) synthesizes secretory proteins, chemically modifies proteins made by the ribosomes attached to its surface, which are then use in the cell membrane or for transport outside the cell, and is a membrane factory for the cell.

Microfilaments

Also known as actin filaments, they are two intertwined strands of actin, each a polymer of actin subunits; Functions: maintenance of cell shape (tension-bearing elements), changes in cell shape, cytoplasmic streaming, cell motility (as in pseudopodia, cell division (cleavage furrow formation), forms a cortex

Endosymbiont Theory

An early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host. The host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion. At least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts

Cell wall

An extracellular structure that distinguishes plant cells from animal cells; Also found in Prokaryotes, fungi, and some protists; Functions: protects the plant cell, maintains its shape, and prevents excessive uptake of water; Structure: made of cellulose fibers embedded in other polysaccharides and protein; Has multiple layers: Primary cell wall (relatively thin and flexible), Middle lamella (thin layer between primary walls of adjacent cells), Secondary cell wall (only in some cells added between the plasma membrane and the primary cell wall)

Golgi Apparatus

An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum; buds off lysosomes and vesicles; the "post office" of the cell. Made of flattened membranous sacs called cisternae.

Extracellular Matrix (ECM)

Animal cells lack cell walls but are covered by an elaborate _________; made up of glycoproteins such as collagen, proteoglycans, and fibronectic; ______ proteins bind to receptor proteins in the plasma membrane; Functions: support, adhesion, movement, regulation

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates; found in plant cells; single-membrane. Food _______ are formed by phagocytosis; contractile _______, found in many freshwater protists, pump excess water out of cells; central _______, found in many mature plant cells, hold organic compounds and water

Ribosomes

Composed of RNA and protein. Site of protein synthesis. Some scattered in cytosol(free), others attached to ER(bound)

Nucleus

Control center of the cell; An organelle bounded by a double membrane (double lipid bilayer) called the nuclear envelope. The nucleus contains the genome and is the site of replication and transcription; Contains DNA; , A cell structure that contains nucleic acids, the chemical instructions that direct all the cell's activities.

Intermediate Filaments

Fibrous proteins supercoiled into thicker cables; Function: maintenance of cell shape (tension-bearing elements), anchorage if nucleus and certain other organelles, formation of nuclear lamina

Desmosomes

Found in animals; Fasten cells together into strong sheets; anchoring

Tight Junctions

Found in animals; Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

Gap Junctions

Found in animals; Provide cytoplasmic channels between adjacent cells

Chloroplasts

Found in plants and algae; are the sites of photosynthesis; an organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water; contains chlorophyll whcih gives plants their green pigment; Structure includes: thylakoids, membranous sacs, stacked to form a granum and stroma, the internal fluid. One of the group of plant organelles, called plastids.

Plasmodesmata

Found in plants; Cytoplasmic channels through cell walls that connect the cytoplasms of adjacent cells; Channels that perforate plant cell walls; Through ______, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell

Microtubules

Hollow tubes with walls consisting of 13 columns of tubulin molecules; Functions in: maintenance of cell shape, cell motility, chromosome movements in cell division, organelle movements; tubulin polymers

Smooth Endoplasmic Reticulum

Lacks ribosomes. Functions: synthesize lipids, metabolize carbohydrates, detoxify drugs and poisons, store calcium ions, is an enzyme warehouse

Chromatin

Material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes

Flagellum

Motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane

Cell Junctions

Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact; plasmodesmata, tight junctions, desmosomes, gap junctions

Mitochondria

Organelle in nearly all eukaryotic cells where cellular respiration occurs and most ATP is generated; some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix; cristae present a large surface area for enzymes that synthesize ATP; double-membrane- a smooth outer membrane and an inner membrane(two compartments: intermembrane space and the mitochondrial matrix) folded into cristae; contains free ribosomes and circular DNA molecules; grows and reproduces somewhat independently of their cells;

Microvilli

Projections that increase the cell's surface area

Endomembrane system

Regulates protein traffic and performs metabolic functions in the cell. Components: nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, plasma membrane

Peroxisomes

Specialized metabolic compartments bounded by a single membrane; catalyze the production and breakdown of hydrogen peroxide and convert it to water; breaks down lipids and toxic substances; How _________ are related to other organelles is still unknown; abundant in the liver and kidney where they neutralize free radicals and detoxify alcohol and other drugs. Also break down fatty acids which mitochondria uses for energy;