selectively permeable
some materials can pass through while others can not
diffusion
molecules move from an area of high concentration to an area of low concentration
osmosis
diffusion of water molecules across a selectively permeable membrane, through a aquaporin protein channel
passive transport
the movement of materials across a cell membrane without using energy
HIGH to LOW
active transport
the cell must use energy to transport materials across the cell membrane
LOW to HIGH
ATP -> ADP + Pi
What are the types of passive transport?
simple diffusion, facilitated diffusion, and osmosis
endocytosis
the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell
large materials are taken into the cell
exocytosis
the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell
large materials exit the cell
phagocytosis
the cell engulfs debris, bacteria, or other sizable objects
solute
a substance ex. (sugar or salt) that is dissolved in another substance
solvent
usually a liquid that dissolves another substance ex. water
isotonic
The concentration of water inside the cell is equal to the concentration of water outside the cell. There is an equal amount of water entering and exiting the cell. ex. the cell maintains shape
hypotonic
The concentration of water outside the cell is greater than the water concentration inside the cell. So, water outside the cell moves into the cell. ex. the cell swells possibly explodes
hypertonic
The concentration of water inside the cell is greater than the concentration of water outside the cell. So, water leaves the cell. ex. the cell shrinks
simple diffusion
molecules move from high to low concentration, a form of passive transport
facilitated diffusion
polar solutes (ions, carbohydrates, nucleic acids) move through a
specific protein channel for each particle; a type of passive transport
phospholipids
hydrophilic head
hydrophobic tail
phospholipid bilayer
two layers of phospholipids, with a hydrophobic, or water-hating, interior and a hydrophilic, or water-loving, exterior
fluid mosaic model
term used to describe the cell membrane because it is 1. fluid/movable 2. has many components, primarily phospholipids, proteins, and some cholesterol
surface area to volume ratio
ratio decreases as the size of the shape increases
hydrophilic
a substance that is attracted to water, such as the phosphate group of a phospholipid
hydrophobic
a substance that hates/repels water, such as the fatty acid tails of a phospholipid
cell theory
a scientific theory which describes the properties of cells
A widely accepted explanation of the relationship between cells and living things
cytoskeleton
a network of protein filaments that helps the cell to maintain its shape
cell wall
strong supporting layer around the cell membrane in plants, algae, and some bacteria
prokaryote
A unicellular organism that lacks a nucleus and membrane bound organelles
DNA not in nucleus
eukaryotic
Cell with a nucleus (surrounded by its own membrane) and other internal organelles.
rough endoplasmic reticulum
site of protein synthesis
mitochondria
site of cellular respiration
Produces energy
vacuole
Cell organelle that stores materials such as water, salts, proteins, and carbohydrates
cilia
Hairlike projections that extend from the plasma membrane and are used for locomotion
cell membrane
A thin, flexible barrier around a cell; regulates what enters and leaves the cell
ribosomes
Site of protein synthesis
flagella
whiplike structure used for movement/locomotion
nucleus
A part of the cell containing DNA and RNA and responsible for growth and reproduction
phospholipids
A lipid that contains phosphorus and that is a structural component in cell membranes.
make up cell membranes
Golgi body
modifies and packages proteins and other material to be exported
chloroplast
An organelle found in plant and algae cells where photosynthesis occurs
pseudopodia
A cellular extension of amoeboid cells used in moving and feeding.
False feet
smooth endoplasmic reticulum
That portion of the endoplasmic reticulum that lacks ribosomes.
cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended
eukaryote
A cell with a nucleus
any organism whose cells contain a nucleus and other organelles enclosed within membranes
lysosome
An organelle containing digestive enzymes
Robert Hooke
First to observe "small chambers" in cork and call them cells.
Anton van Leeuwenhoek
first saw living organisms under his microscope
Schwann
concluded that all animals are made of cells
Schleiden
concluded that all plants are made of cells
virchow
proposed that all cells come from other cells