Ch 2 Cells Flashcards
Cell Theory
- All living things are composed of cells
- cells are the basic unit of all organisms
- all cells arise from preexisting cells
prokaryotes
have no nucleus or other internal membranes
eukaryotes
have nucleus and are more complex. make up every other form of life except bacteria.
which cells have membrane bound organelles
eukaryotes
which cells have a single, circular chromosome.
prokaryote
which cells have plasmids
prokaryote
which cells have smaller ribosomes
prokaryotes
which cells have larger ribosomes
eukaryotes
which cells have cytoskeletal elements, like microfilaments
eukaryotes
which cells have sizes of 1-10 um
prokaryotes
which cells have tough external cells walls
prokaryotes and eukaryotic plant.protist cells
how old is the earth
4.6 billion years old
theory of endosymbiosis
eukaryotic cells containing organelles like mitochondria and chloroplasts evolved whne free-living prokaryotes took up permanent residence inside other prokaryotic cells. This was the origin of a eukaryotic cell.
chromatin network
a network of DNA wrapped with histones into chromosomes
nucleolus
prominent region inside nucleus of a cell that is not dividing. compnonents of ribosomes are synthesized here.
ribosomes
site of protein synthesis, made of ribosomal RNA and protein. suspended in cytoplasm or bound to ER
Endoplasmic reticulum
system of membrane channels that traverse cytoplasm.
Rough ER
studded with ribosomes. site of protein synthesis AS WELL AS cytoplasmic transport.
Smooth ER
Synthesizes steroid hormones. Connects ER to Golgi. detoxifies cell.
Golgi Apparatus
contains flattened sacs of membranes stacked next to each other and surrounded by vesicles. They modify, store, and package substances produced in the rough ER. also secretes substances to other pats of cell and to cell surface.
lysosome
sac of hydrolytic (digestive) enzymes enclosed by single membrane. principle site of intracellular digestion. breaks down and recycles cell parts, renews cells. aids in apoptosis.
mitochondrion
site of cell respiration. consist of outer double membrane and folded inner membranes called criste.
vacuole
store substances for cell.
vesicle
tiny vacuole.
plastids
only found in algae and plants. 3 types: chloroplasts, leucoplasts, and chromoplasts,
chloroplasts
green, contain chlorophyll, sites of photosynthesis. inner membrane of grana which lie in the stroma.
leucoplasts
plastids that are colorless and store starch.found in roots or tubers.
chromoplasts
plastids that store carotenoid pigments and are responsible for colors of carrots, tomoatoes, and daffodils.
cytoskeleton
network of protein filaments that extends throughout the cytoplasm and gives the cell its shape.
microtubules
thick hollow tubes that make up cilia, flagella, and spindle fibers.
microfilaments
made of protein actin and help support the shape of the cell.
centrioles and centrosomes
only found in animal cells. two centrioles are a right angles to each other and make up one centrosome. made up of microtubules arranged in circle
cilia and flagella
made of microtubules, cilia shorter than flagella
Cytosol
refers to the semiliquid portion of the cytoplasm
cyclosis
process where organelles suspended in the cytosol and get carried around the cell as cytoplasm cycles around the cell.
fluid mosaic
term to describe structure of cell membrane. consists of phospholipid bilayer with molecules of cholesterol embedded within.
solvent
the substance that does the dissolving
solute
substance being dissolved
hypertonic
greater concentration of solute than other solution
hypotonic
lower concentration of solute than other solution
passive transport
movement of molecules down concentration gradient by diffusion or osmosis. never requires energy
simple diffusion
movement of particles from high to low concentrations. this is how alveoli work
facilitated diffusion
relies on special protein membrane channels to assist in transporting substances across membrane
osmosis
diffusion of water across membrane
plasmolysis
cell in hypertonic solution that causes water to leave the cell, causing it to shrink
turgid
water enters a plant cell in a hypotonic solution and cell swells. if animal cell, it would burst.
active transport
movement of molecules against gradient. requires energy (ATP).
exocytosis
active release of molecules from a cell, like synapse of nerve cells.
pinocytosis
cell drinking; uptake of large, dissolved molcules.
phagocytosis
engulfing of large particles or large organisms by pseudopods.
compound microscope
main tool for studying cell structure (cytology)
resolution
image clarity
phase contrast microscope
light microscope that enhances contrast. useful for living unstained cells
transmission electron microscope
useful for study of interior of cells. however, it kills the tissue being studied, elaborate prep, specimens must be thinly sliced, expensive.
scanning electron microscope
useful for study of surface of cells. goves 3D appearance. kills tissue
ultracentrifuge
enables scientists to isolate components of cells in large quantities by cell fractionation. requires blender
freeze fracture
studies details of membrane structure under electron microscope
