Looks like no one added any tags here yet for you.
why are cells so small
cell surface to volume ratio
why is cell surface to volume ratio important
plasma membrane surrounding cell must provide sufficient surface area for exchange of oxygen, nutrients, and wastes relative to the volume of the cell
nucleus structure
surrounded by nuclear envelope, double membrane with pores, most DNA located in the nucleus
nucleus function
double membrane with pores regulates movement of materials between nucleus and cytoplasm
nucleolus structure
dense structure inside nucleus
nucleolus function
synthesizes rRNA & combines it with proteins to make ribosomal subunits
ribosome structure
composed of protein and RNA
ribosome function
making protein
two different types of ribosomes
free and bound
free ribosomes
produce proteins to be used within the cytosol
bound ribosomes
attached to ER or near nucleus, make proteins that will be included with membranes, packed into organelles, or exported from the cell
what does the endomembrane system consist of
nuclear envelope, ER, golgi apparatus, lysosomes, vesicles, vacuoles, plasma membrane
what is the endomembrane system
The endomembrane system is a network of membranes that function to modify, transport, and package proteins and lipids in the cell
endoplasmic reticulum location
continuous within the nuclear envelope
smooth ER function
multifunctional, has enzymes involved in phospholipid/steroid synthesis, carbohydrate metabolism, and drug detoxification. works on storage and release of calcium ions during muscle contractions
smooth ER structure
no ribosomes on outside surface
rough ER structure
ribosomes on outside surface
rough ER function
manufactures proteins intended for secretion, manufactures membranes
Golgi apparatus function
shipping and receiving
Golgi apparatus structure
stack of flattened sacs
lysosomes function
in animal cells only, digests food and takes apart damaged parts of cell
what is phagocytosis
when lysosomes digest food and pass products into the cytosol
what is autophagy
when damaged organelles fuse to lysosome, enzymes dismantle the membrane bound material, organic monomers are returned to cytosol for reuse
lysosome structure
membrane- enclosed sacs containing hydrolytic enzymes that digest macromolecules
different functions of vacuoles
food, contractile vacuole (pump excess water out of freshwater protists), storage vacuole (in only plants), large central vacuole (in only plants)
storage vacuoles function
store organic compounds/inorganic ions for the cell, may contain dangerous metabolic by products, poisonous or unpalatable compounds for protection from predators
large central vacuole function
encloses a solution called cell sap, a plant increases in size as a vacuole absorbs water and expands, can fill 80 percent or more of a cell
endosymbiont theory
mitochndeia and chloroplasts originated as prokaryotic cells engulfed by an ancestral eukaryotic cell
evidence of endosymbiont theory- both organelles____
surrounded by double membrane, grow and reproduce independently within the cel, contain some DNA and ribosomes, synthesize some of their own proteins
mitochondria structure
double membrane- narrow inner membrane space exists between the two layers, smooth outer membrane, inner membrane folded for cristae, respiratory enzymes embedded in membrane
mitochondria function
chemical energy conversion, provides ATP for the cellc, folding in membrane increases surface area for enzymatic reaction
mitochondrial matrix
inside inner membrane, contains respiratory enzymes, mitochondrial DNA, and ribosomes
chloroplast structure
two membranes separated by thin inner membrane space, thylakoids, storm, amylopasts, chromoplasts
thylakoids
inside inner membrane, flattened sacs, the stacks of sacs called grana, photosynthetic enzymes embedded
stroma
fluid surrounding thylakoids, contain chloroplast DNA, ribosomes, and enzymes
amyloplasts
store starch
chromoplasts
contain pigments for fruits and flowers
cytoskeleton structure
network of protein fibers
cytoskeleton function
give mechanical support, cell movement
3 types of protein fibers
microtubules, microfilaments, intermediate filaments
what proteins produce cellular movements
motor proteins
microtubules
hollow rods, provide supporting framework for the cell, separate chromosomes during cell division
motor proteins
powered by ATP hydrolysis, transports organelles, responsible for muscle contraction, responsible for cell division
cilia and flagella
universal structure, may be used to move through aqueous media, stationary cells use to move fluid past the cell
cell wall of plants
protects the cell from damage and maintains shape, some cells add a secondary cell wall between the plasma membrane and primary wall for more protection and support (wood)
extracellular matrix
attached to outside of animal cells, mechanical signaling pathway between firbronectins/integrins of ECM and microfilaments of cytoplasm
plant junction
plasmodesmata- channel in plant cell wall that connects plasma membrane of bordering cells, small solutes, water, some proteins, and RNA can move cell to cell
3 animal cell junctions
tight, desmosomes, gap
tight junctions
hold adjacent cell membranes tightly together
desmosomes
anchoring junctions hold cells in strong sheets
gap junctions
communicating junctions for exchange of ions and small molecules between cells