Ch 4 and Ch 5 Flashcards
microscopy
the only reason we can look at cell structure today
light microscope
light passes through the specimen and lens that refracts an image
needed components of microscopy
magnification, resolution, and contrast
electron microscope
focuses beam of electrons on specimen; better resolution
transmission electron microscope
inject a dye and electrons shoot through the specimen
scanning electron microscope
put gold on top of cell and shoot electrons to see topography of the cell
cell fractionation
place broken-up cells in a centrifuge and different organelles will make layers; used to study organelles
cytoplasm
suspends components of the cell
cell size limits
an upper limit exists because a certain surface area is required in order for diffusion to occur fast enough; a lower limit exists because there must be space for enough enzymes and DNA
plasma membrane
a selective barrier allows passage of necessary molecule transfers; also important in cell to cell signalling
nucleus
where genes, DNA, and rRNA are kept
nuclear envelope
double membrane that are structured by protein filaments but allow items to pass through pores; rRNA move from here to the ER
nucleolus
inside the nucleus, holds rRNA and directs messenger RNA
ribosomes
cell components that carry out protein synthesis, are “free” in the cytoplasm or “bound” to the Rough ER
endomembrane system
the organelles with inner cell membranes
vesicles
sacs made of membrane that transfer membrane segments and hold small things
endoplasmic reticulum
(endomem); connected to the nuclear envelope; smooth ER and rough ER
rough ER
(endomem); forms proteins meant to be excreted, packages in vesicles
smooth ER
(endomem); carries out metabolic processes and synthesis of lipids
golgi apparatus
(endomem); receives packages from ER and modifies them; receives, sorts, and ships items to the correct parts of the cell
lysosome
(endomem); hold enzymes that digest compounds in the cell
autophagy
when the lysosome uses enzymes to recycle organic compounds in the cell
vacuoles
(endomem); have membranes derived from the ER and Golgi, transport products
mitochondria
cellular respiration and creates ATP
chloropasts
photosynthesis for the energy of the cell
endosymbiont theory
a eukaryotic cell was once using other cells to create energy for it, but one day it used phagocytosis to engulf these prokaryotes as organelles
cytoskeleton
network of fibers in and outside of the cell that provide means for support and motility
motility of cytoskeleton
cytoskeleton attaches motor proteins and cilia and flagella are parts of cytoskeleton that move the cell around
types of cytoskeleton fibres
microtubules (thick), intermediate filaments, microfilaments (thin)
microtubules
thick fibre that shapes and supports the cell while also providing tracks for organelles to move
centrioles and centrosomes
places from where filaments and tubules attach, important in cellular reproduction
microfilaments and intermediate filaments
provide tension in structure; intermediate filaments are more permanent
extra cellular matrix
provides the support that cell wall does for plants, for animal cells; glycoproteins and glycolipids, as well as collagen connect to cytoskeleton and provide connection between outer membrane and the cell
“glyco”
means there is a carbohydrate attached
the phospholipid bilayer
amphipathic; proteins float freely while other lipids attach to the membrane; the two layers shift laterally so the membrane remains fluid
membrane fluidity
fluid when layers can shift laterally; cholestrol and other specialized lipids prevent the settling and solidifying of the two layers even as temperatures change
integral proteins
penetrate hydrophobic parts of the lipid bilayer; usually totally transmembrane; allows hydrophillic substances to pass
water’s polarity
water is polar and dissolves other polar molecules
peripheral proteins
appendages to the membrane that are attached to the extracellular matrix, but also functional
selective permeability of the cell membrane
hydrophobic molecules (nonpolar) can dissolve and pass through the lipid bilayer; hydrophillic (polar) can’t dissolve and must be transported
transport proteins
allow hydrophillic substances (polar) to pass through the membrane; channel proteins or carrier proteins
channel proteins
transport proteins that make a pathway for substances to pass through
carrier proteins
attach to a substance, change it’s properties and shape, transports across the membrane, then detaches
diffusion
passive transport; a substance tending to spread out; moves from high concentration to low; only if membrane allows it to pass
osmosis
passive transport; the diffusion of water across a membrane that tries to reach equilibrium of solute concentration if the solute can’t pass through the membrane
hypertonic
outside liquid has higher concentration of solute; cell’s water is squeezed out
hypotonic
inner cell has higher concentration of solute; cell intakes water
isotonic
the solute’s concentration is equivalent and the cell is in equillibrium
plant cells is hypotonic solutions
won’t burst because the cell wall prevents too much water from rushing into the cell
turgor
a plant cell is more turgid when there is more water filling the cell wal
active transport
uses energy like ATP to power a protein to move a solute against its gradient
ion pumps
are electrically and chemically influenced to move an ion; they diffuse with the gradient electrochemically as long as a stimulus opens their gates
electrogenic pump
an ion pump that goes against the concentration gradient; transports 3 positive ions for every 2 negative ions, so creates membrane potential
cotransport
pumps an ion one way; then when the ion diffuses back the other way, the ion brings something else with it
exocytosis
a vacuole membrane fuses with the outer membrane and releases its contents
phagocytosis
engulfs a particle and creates a vacuole with the membrane
pinocytosis
a small vesicle collects extracellular fluid and transports those solutes
