Unit 3: The Cell (Bio. 1)


control center of the cell and contains the cells DNA


strands of DNA located in the nucleus- in eukaryotes. Prokaryotes don't have a nucleus so it is floating in a pocket in the cytoplasm.

nuclear pores

holes in the nuclear membrane that allow substances to pass through


found in the nucleus; makes ribosomes


pair of small cylindrical structures used during cell division and animal cells


clear gel-like fluid in cells, suspends organelles, and site of many chemical reactions


a.k.a. "suicide sacs" - called suicide sacs because because they will kill their cell if the cell becomes too damaged to repair thus protecting nearby cells from damage; sac containing digestive enzymes; digest worn out organelles and food; helps destroy

Cell wall

Rigid structure located outside the plasma membrane that provides protection and support. plants, fungi, and some bacteria


contains green pigment(chlorophyll). Captures light energy and converts it to chemical energy. found in plants and algae


power house". Highly folded inner membrane. Transforms energy from food sources. ALL eukaryotes have them


membrane-bound compartment that temporarily stores food, water, enzymes, etc.;
animal cells? many small ones
plant cells? one large one called the central vacuole

rough endoplasmic reticulum

Folded membranes studded with ribosomes. Involved in the synthesis and transport of proteins.

smooth endoplasmic reticulum

Folded membranes without ribosomes attached. Make lipid components of cell membrane.


support structure for the cell made of microtubules and microfilaments. found in animal cells(not on the diagrams)


makes proteins- can be free (in cytoplasm) or bound (attached to rough ER)


Short hair-like structures on outside of the cell used in locomotion and feeding. Some animal cells, bacteria cells, protists


long whip-like projection used in locomotion

nuclear envelope

double- layered membrane that separates the nucleus from the cytolasm.

golgi apparatus

Stack of flattened membrane- bound sacs. Modifies materials; packages and secretes.

plasma membrane

flexible boundary composed of a phospholipid bilayer that allows materials to exit and enter cell


a small specialized structure within a cell that performs specific functions

Anton van Leeuwenhoek

invented the light microscope

Robert Hooke

used a compound light microscope to study cork cells; named cells; "father of microbiology

Matthias Schleiden

observed a variety of plants (botany); concluded that all plants are made of cells

Theodor Schwann

made observations on animals (zoology); concluded that all animals are made of cells

Rudolf Virchow

concluded that new cells can be produced only from the division of existing cells; contradicted the cell idea that life arises from nonliving matter


cells with no membrane- bound organelles; no nucleus


cells that contain membrane- bound organelles; have a nucleus

semi- permeable

selectively permeable; some things pass freely, while others cannot


particles move from an area of high concentration to an area of low concentration

passive transport

the cell uses no energy to move particles across the cell membrane

active transport

movement of molecules across the membrane against the concentration gradient and requires energy from the cell

concentration gradient

uneven distribution of molecules

channel proteins

channels (tunnels) made of protein that are always open to allow molecules to pass through

carrier proteins

carry" molecules across the cell membrane by changing shape when molecules attach to them

facilitated diffusion

process of diffusion in which molecules pass across the membrane through the cell membrane channels


the facilitated diffusion of water across a semi- permeable membrane


a water channel protein in a cell

hypotonic solution

the concentration of solutes is lower in the solution outside the cell than the concentration inside the cell

turgor pressure

positive internal pressure in a cell resulting from osmotic pressure

hypertonic solution

the concentration of solutes outside the cell is higher than the concentration inside the cell


plasma membrane rips away from the cell wall

isotonic solution

the concentration of solutes in the solution is equal to the concentration of solutes inside the cell

small molecules

protein pumps- small molecules and ions are carried across the membrane by proteins that act like pumps

large molecules

changing shape of membrane (bulk transport)

Cell theory

1. All organisms are composed of one or more cells
2. The cell is the basic unit of life
3. All cells come from preexisting cells

bulk transport

process in which molecules cross the cell membrane


process by which a cell surrounds surrounds and takes in material from its environment


cell drinking/ taking in a liquid


cell eating/ taking in a solid


expulsion or secretion of materials from a cell