AP Biology - Chapter 6

nucleoid

A dense region of DNA in a prokaryotic cell.

thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.

actin

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.

food vacuole

A membranous sac formed by phagocytosis of microorganisms or particles to be used as food by the cell.

central vacuole

A membranous sac in a mature plant cell with diverse roles in reproduction, growth, and development.

nuclear lamina

A netlike array of protein filaments that maintains the shape of the nucleus.

plasmodesmata

An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells

peroxisomes

Contain oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals

cristae

Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.

centrioles

One of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope; play a role in cell division.

mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

centrosome

Structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. A centrosome has two centrioles.

rough ER

That portion of the endoplasmic reticulum studded with ribosomes, attached to nuclear membrane and synthesizes phospholipids for cell membrane

mitochondrial matrix

The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.

stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

nucleus

The organelle that contains the DNA and controls the processes of the cell

nucleolus

The organelle where ribosomes are made, synthesized and partially assembled, located in the nucleus

extracellular matrix

The substance in which animal tissue cells are embedded, consisting of protein and polysaccharides.

cytoskeleton

a microscopic network of actin filaments and microtubules in the cytoplasm of many living cells that gives the cell shape and coherence

motor proteins

a protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.

chloroplast

a structure in the cells of plants and some other organisms that captures energy from sunlight and uses it to produce food

endoplasmic reticulum

an internal membrane system in which components of cell membrane and some proteins are constructed

nuclear envelope

double membrane perforated with pores that control the flow of materials in and out of the nucleus

tubulin

globular protein subunit forming the hollow cylinder of microtubules

keratin

hard protein material found in the epidermis, hair, and nails

microtubules

hollow tubes of protein about 25 nanometers in diameter, support the cell and moves organelles within the cell, composed of tubulin polymers

chromatin

long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes

endosymbiont theory

mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.

lysosome

organelle filled with enzymes needed to break down certain materials in the cell

ribosomes

organelles made of protein and RNA that direct protein synthesis in the cytoplasm

plastids

organelles that are surrounded by a double membrane and contain their own DNA

phagocytosis

process in which extensions of cytoplasm surround and engulf large particles and take them into the cell

glycoproteins

proteins that have carbohydrates covalently bonded to them

intermediate filaments

range from 7-11nm in diameter, and strengthen the cell and help maintain its shape, stabilize the positions of organelles, and stabilize the position of the cell with respect to surrounding cells through specialized attachment to the cell membrane, composed of keratin subunits

contractile vacuole

saclike organelles that expand to collect excess water and contract to squeeze the water out of the cell

cilia

short, hair-like structures made of microtubules that enable movement of cells or movement of materials outside a cell

vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

grana

stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis

cell wall

strong supporting layer of cellulose or chitin around the cell membrane in plants, algae, and some bacteria

smooth ER

synthesis of lipids, phospholipids and steroid sex hormones-help detoxify drugs and poisons (liver cells) involves adding hydroxyl groups to drugs to make soluble and easier to flush from body

cell fractionation

technique in which cells are broken into pieces and the different cell parts are separated

cytosol

the aqueous part of the cytoplasm within which various particles and organelles are suspended

microfilaments

thinner, solid rods of protein that enable the cell to move or change shape when protein subunits slide past one another, composed of actin subunits

flagella

whiplike tails found in one-celled organisms to aid in movement