unit 4 vocab.

function of a microscope

to observe objects at a magnified, normally cellular, level

cell stain

used to make normally transparent cells visible under a microscope

cell theory

1. all living things are made up of cells

2. cells are the basic units of structure and function in living things

3. new cells are produced from existing cells

prokaryote

cells that don’t enclose DNA in nucleus. older, smaller, and simpler cells. unicellular.

eukaryote

cells that enclose their DNA in a nucleus. newer, larger, and more complex cells. can be multi- or unicellular. contain membrane-bound organelles.

archaea

a prokaryotic group of microorganisms that are similar to bacteria. capable of living in extreme conditions

eukaryotic cell types

animal cells, plant cells, fungi cells, and many other unicellular organisms

protists

eukaryotic single-celled organisms that don’t fit into the plant/animal/fungi category

plant cell

common eukaryotic cell type. uniquely contains a cell wall, chloroplast, and a central vacuole.

animal cell

common eukaryotic cell type. uniquely contains centrioles and lysosomes.

fungi

eukaryotic organisms, including mushrooms, mold, and yeast

fluid-mosaic model

used to describe the nature of membranes in cells because of the constant motion of the bilayer and the pattern or “mosaic” of lipids and proteins that are always changing.

cell membrane

selectively permeable membrane that supports, shapes, and protects the cell. contains phospholipids, and various proteins and carbs.

lipid bilayer

double-layered sheet that forms a flexible but strong barrier between a cell and it’s surroundings

selectively permeable

allows some substances to pass across while others cannot

mitochondria

the powerhouse of the cell. its purpose is cellular respiration (the process of converting glucose or sugar molecules into usable energy). have an inner and outer membrane and folds inside called cristae (increase surface area → increased respiration). have their own DNA and carry out their own replication

lysosomes

a type of vesicle that buds from the golgi apparatus and is surrounded with a membrane as they contain a digestive enzyme. the enzyme is used to break down macromolecules and the cells own material to return them to the cytoplasm to be used again. responsible for destroying old organelles. “waste management”. ONLY FOUND IN ANIMAL CELLS

nucleus

carrier of genetic material, controls reproduction of the cell, all cell activities, directs protein synthesis by sending out messages to ribosomes. surrounded by a double membrane that is dotted with thousands of pores.

golgi apparatus

modifies, sorts, and transports proteins that have arrived from the ER. appears as a stack of thin membranes.

vesicles

small, spherical sacs surrounded by a single membrane. classified based on their contents (e.g. transport, lysosomes, peroxisomes, etc.). transports proteins throughout the protein synthesis process

ribosomes

made up of a large and small subunit. can be free floating or attached to the ER. cell’s most numerous organelle. composed of protein and RNA. site of all protein synthesis.

cell wall

supporting structure found in plant and fungi cells. lies outside the plasma membrane. provides support and protection to the cell. composed of mostly cellulose. ONLY FOUND IN PLANT/FUNGI CELLS

centriole

short cylinders perpendicular to one another. found near the nuclear membrane. organize the microtubules during cell division to form a framework for separating chromosomes. ONLY FOUND IN ANIMAL CELLS

endoplasmic reticulum (ER)

internal membrane system of the cell (“intracellular highway”). rough ER has ribosomes attached, where newly produced proteins will be inserted for to make them functional. smooth ER has no ribosomes, rather makes lipids for membranes.

active transport

the movement of materials from areas of low concentration to high, which requires energy.

passive transport

the movement of materials from areas of high concentration to low, which requires no energy.

concentration gradient

the difference in the concentration of molecules across a distance

sodium-potassium pump

embedded in a cell’s membrane and help small molecules and ions move through during active transport

diffusion

the spreading out of molecules from a region of high concentration to a region of low. depends on size and shape of the molecule (small, non-polar can diffuse across the membrane, water, proteins and ions need channels)

facilitated diffusion

type of diffusion/passive transport used for molecules that are charged or too large thus don’t pass through the membrane. proteins are used to pass them through (pump and channel proteins)

endocytosis

the process of taking material into the cell by creating pockets in the membrane that close onto themselves and break off into the cell, creating vesicles (pinocytosis = drinking, phagocytosis = eating)

exocystosis

the release of large molecules by which a vesicle fuses with the membrane and releases its contents out

osmosis

type of passive transport. the movement of water across a membrane from high to low concentration

hypertonic

the concentration of solute molecules outside the cell is higher than the concentration inside. water will diffuse out (shrinkage)

hypotonic

the concentration of solute molecules outside the cell is lower than the concentration inside. water will diffuse in (swelling)

isotonic

the concentration of solute molecules outside the cell is equal to the concentration inside. water will diffuse in both directions and at an equal rate.

aquaporins

protein channels for water

neuron

cells of the nervous system, which make up nerves. transit chemical and electrical information in order to communicate. three types: sensory, motor, interneuron

motor neuron

type of neuron that carries impulses from the spinal cord and brain to the muscles and glands.

sensory neuron

carry impulses from the sensory organs to the spinal cord and brain

brain

complex organ made up of two types of cells: neurons and glial cells. interprets, processes, responds to, and stores information. divided into three parts: cerebrum, cerebellum, and brainstem

spinal cord

long, thin bundle of nerves that extends from the medulla of the brainstem and down the vertebral column. made up of gray and white matter. connects the sensory neurons of the PNS to the brain.