Eukaryotic Cells Flashcards
3 principles of cell theory
all living organisms composed of 1 or more cells
cell is the most basic unit of life
all cells arise from preexisting living cells
major differences between prokaryotes and eukaryotes
pro - no membrane boudn organelles, no histones, no post transcription modification of mrna , smaller ribosomes, pertidoglycan cells walls, binary fission
euk - mitosis, cells walls of chitin or cellulose if present
difference between prokaryote and eukaryotic flagella
pro - made of flagellin and rotate around
euk - 9+2 microtubule configuration and have a whip like action
describe the structure of the nucleus
outer nuclear envelope has pores that RNA (not dna!!!!) can exit
nucleolus is where rRNA is transcribed
where would you expect to find lots of mitochondria
muscles where energy is required because it generates most of the cells atp via aerobic respiration
how do mitochondria replicate
have their own circular dna and ribosomes
where would you expect to find lysosomes
in cells that are about to undergo apoptosis because they break down macromolecules with hydrolytic enzymes
what are peroxisomes
self replicatign cytosolic vesicles involved in lipid and protein storage
produce hydrogen peroxide to inactivate toxic substances
what does the rough ER do
has a bunch of protein manufacturing ribosomes
once to proteins are made they will be sent to to the golgi and then the final destination outside of the cell
some functions of the smooth ER
lipid and steroid catabolism and metabolism
carb metabolism
drug detox
what does golgi apparatus do
processes and packages macromolecules
where would you expect to find lots of golgi and rough ER
secretion cells like pituitary cells
5 membrane bound organelles you must know
nucleus - contains dna mitochondria - produce energy lysosomes - digest ER rough - protein translation ER smooth - protein metabolism golgi - packaging
what are the 3 structures in cytoskeleton small to largest
microfilaments (actin) – intermediate filament – microtubule
microfilaments are used for
cytokinesis
work with myosin during muscle contraction
what are microtubules used for
intracellular transport
cilia and flagella
mitotic spindle in mitosis and meiosis
the cellular structures of a mitotic spindle
pair of centrioles in the centrosome (microtubule organizing center) has growing polar microtubles as they get closer to the chromosome becomes kinetochore microtubules. the point it attaches to the chromosome is the kinetochore
how does cholesterol modulate membrane fluidity
at low temps prevents solidification by disrupting close packing of phospholipids
at high temps reduces phospholipid movement
macromolecules permeability in regards to plasma membrane
if large too big to cross
gases permeability in plasma membrane
small non polar = cross
hydrophobic molecules permeability in plasma membran
can cross if small due to hydrophobic interior
polar molecules permeability in plasma membrane
large - cant cross
small - hard to cross bc of polarity
amino acids and charged ions permeability in plasma membrane
charged = cant cross
3 types of endocytosis done by the plasma membrane
phagocytosis - eat the particle
pinocytosis - drink the particle
receptor mediated - has to bind to receptor
how does exocytosis occur
golgi apparatus produces secretory vesicles
difference between tight junction, desmosomes, gap junction
tight - water tight seal between cells prevents passage of molecules
desmosome - attach to cytoskeleton of each cell but dont prevent fluid from circulating
gap - tunnels connecting cells crucial for communication
what can pass through a semi permeable membrane for the purposes of the mcat
small
non polar
lipid soluble
water
describe passive diffusion
no energy
NON MEMBRANE PROTEINS
allows passage of permeable molecules down their concentration gradient
what is facilitated diffusion
still no energy but there is a carrier protein so impermeable solutes can pass through based on their concentration gradient
what is primary active transport
impermeable solute moved against concentration gradient where ATP is used directly to transport the solute in question
explain the NA K pump ***
Na binds to protein
ATP phosphorylation changes protein conformation
expels 3 Na to extracellular fluid , K binds
K binding releases phosphate group which restores protein conformation
2 K released in cytoplasm
what is secondary active transport
electrochemical gradient of one solute drives the transport of another molecule against its concentration gradient
3 classes of membrane receptors (proteins that allow cells to communicate with environment)
enzyme linked
ligand gated ion channel
g protein coupled receptors
explain cell signalling
plasma membrane has receptor proteins that are activated by a signal molecule trigger an internal cell signalling pathway mediated by secondary messengers where the signal becomes amplified and results in a cellular response
what is the extracellular matrix
extracellular part of animal tissue that provides structural support to cells
has adhesive proteins which help cells stick together
