Biology Diffusion, Cells

diffusion

the process by which molecules of a substance move from areas of higher concentrations to lower concentrations

osmosis

the diffusion of water molecules through a selectively permeable membrane

permeable

if a particular substance is able to move across a membrane

active transport

an energy-requiring process that enables material to move across a cell membrane against a concentration gradient

osmotic pressure

tends to move water across membranes from a more dilute solution into a more concentrated solution

exocytosis

taking out of the cell, secretion of material out of the plasma membrane

phagocytosis

large particles are taken into the cell by endocytosis

passive transport

transport across a cell membrane without the need for energy (osmosis, diffusion)

facilitated diffusion

molecules are transported across a cell membrane by a carrier protein

nucleolus

the small dense region in the nucleus where the assembly of ribosomes begins

microtubules

the hollow tubes of protein that help maintain the shape of the cell

chloroplasts

organelles that can use energy from sunlight to create energy-rich food molecules

endocytosis

the process by which material is taken into the cell by infoldings of the cell membrane

organ system

fourth, and highest, level of organization in a multicellular organism

cell

the basic unit of life

cell membrane

thin, double layered sheet around the cell, made of phospholipids

cell wall

strong layer around the cell membrane that protects the cell

nucleus

large structure that contains the cell’s genetic information, controls the cell

cytoplasm

portion of the cell outside the nucleus, made up of cytosol, contains organelles

prokaryote

organism whose cells do not contain a nucleus

eukaryote

organism whose cells contain a nucleus. all contain a nucleus, cell membrane, and cytoplasm with organelles.

organelle

specialized structures within a cell that perform important cell functions

chromatin

granular material within the nucleus, looks like spaghetti

chromosomes

distinct, threadlike structures that contain the genetic information of the cell, DNA, forms an X shape

Robert Hooke

responsible for naming cells

Anton van Leeuwenhoek

was first to view an organism under a microscope

Mattias Schleider

concluded that all plants were made out of cells

Theodore Schwann

concluded taht all animals were made out of cells

Rudolph Virchow

reasoned that all cells come from other pre-existing cells by cell division

cell theory

all living things are made of cells, cells are the basic unit of life, cells come from pre-existing cells

lysosomes

contain digestive enzymes, break down food, bacteria, and worn out cell parts for cells, programmed for cell death (autolysis)

nuclear envelope

surrounds the nucleus, contains nuclear pores for materials to enter and leave

cytoskeleton

helps maintain cell shape, helps move organelles around, microfilaments made of ACTIN, microtubules made of TUBULIN

centrioles

only found in animal cells, made up of a bundle of microtubules, help pull chromosomes parts apart to opposite ends of the cell

mitochondrion

powerhouse of the cell, generate cellular energy (ATP), site of cellular respiration

smooth ER

makes cell products that are used INSIDE the cell and transports out to the golgi, functions in lipid synthesis, attached to the ends of rough ER

rough ER

ribosomes on its surface, makes proteins for EXPORT out of cell, functions in protein synthesis

ribosomes

makes proteins, can be attached to rough ER or free in cytoplasm

golgi apparatus

modifies, sorts, and packages molecules from ER for storage or transport out of cell

celia

are shorter and more numerous on cells that function in moving the cell

flagella

are longer and fewer than cilia, function in moving cells

vacuoles

fluid filled sacks for storage in only plant cells

three modes of passive transport

diffusion, facilitated diffusion, osmosis

three types of solutions

isotonic, hypotonic, hypertonic

isotonic solution

water and dissolved substances diffuse into and out of the cell at the same rate

hypertonic solution

solute concentration is higher outside the cell. water diffuses out of the cell

hypotonic solution

solute concentration is higher inside the cell, water diffuses into thecell

pinocytosis

the process of taking up liquid