prokaryotes vs eukaryotes Flashcards
cell theory
cells are fundamental unit of life
all living organisms are composed of cells
all cells come from preexisting cells
microscopy
watching and learning about cells by lookng at their movement
light microscopy
fluorescent microscopy
electron microscopy
difference between the three microscopy methods
light microscopy - you can basically just see the cell
fluorescent microscopy - bright/neon
electron microscopy - must be fixed –> cells must be killed
kill and spill
way to investigate cells outside of microscopy
- cell fractionation
- centrifugation
cell fractionation
blow up cells and separate major organelles and structure from one another
centrifugation
spin lysate at increasing speeds to separate out the alrger, then progressively smaller fragments
life is segmented into what three main domains
archaea
eukaryotic
bacteria
prokaryotes characteristsics
don’t have membrane bound organelles
no nucleus
they have ribosomes, plasma membrane, and nucleoid
peptidoglycan cell wall
cell wall that bacterial cells have
made out of plasma membrane with peptidoglycan on top of it
peptidoglycan is made up of peptides holding two carbohydrates
- NAM and NAG carbohydrates interlinked and bound by oligosaccharides
different cell wall architecture between two types of bacteria
gram-positive
gram - negative
gram-positive cell wall
purple stained cell
made up of layers of peptidoglycan
only rely n the layers of peptidoglycan
gram-negative
one layer of peptidoglycan
two double membranes
have lipopolysaccharides
different bacteria shapes
cocci-round
bacilli-rod shaped
spiral
antibiotic drugs/ how they work
example
destroy cell wall to kill bacteria
ex: penicillin binds to protein and inhibits its function
ways to kill bacteria
cell wall synthesis
dna replication
translation
folic acid metabolism
bacterial flagella –> what they do how they move
flagella allows identification of bacterial cell type
flagella made up of flagellin
counterclockwise movement of flagella allows them to move forward
clockwise makes them tumble
pili
short, hollow tread-like structure on bacterial cell
allows bacteria to adhere to one another and to each other
also allows for bacterial conjugation
bacterial conjugation
bacterial sex
one bacteria has a specific plasmid
the bacteria with the plasmid contacts the other bacteria with pilus
dna polymerase reads the dna and replicates the plasmid
both bacteria now have the plasmid
allows them to learn how to protect themselves from antibiotics
plasmid
smaller than chromosomal dna but carries many genes
circular
Why do we breathe in oxygen and respire carbon dioxide
Oxygen acts as a terminal electron acceptor of oxidative phosphorylation and the carbon dioxide is a waste product in pyruvate oxidation and the TCA cycle
Limits to cellular size
why are cells so small
Smaller cells allow for faster diffusion of gasses
Closer the mitochondria is to the surface, the faster that diffusion will occur
Get nutrients in and waste products out → easier with smaller cells
Why are we not made up of three giant cells
Cells must be small so diffusion of nutrients and waste products can occur efficiently
Unicellular organisms
Single cells
Limited capabilities
Every function must be done by one cell
Multicellular organisms
Can be larger in size because many cells are working for one organism
More specialized functions
All life shares:
Dna is the genetic material of life
Cells are surrounded by a membrane
Have ribosomes that perform translation
Similar metabolism
Similar chemical composition
4 major differences between prokaryotes and eukaryotes
Eukaryotes can be both unicellular and multicellular but tend to be multicellular → prokaryotes are unicellular
Eukaryotes have a nucleus and other organelles that are surrounded by plasma membrane
Eukaryotes are 10 to 100 times larger
Eukaryotes have cytoplasm complexity
- have many Organelles
Nucleus
have a Double membrane called Nuclear envelope
Contain nucleolus, nuclear pore, nuclear lamina, etc
Nucleolus
Site for assembling ribosomes
chromosomes
Large dna molecules attached to proteins that regulate their expression
Compacting or relaxing dna to change how accessible they are
Lamin
Packaging material
part of the cytoskeleton of the cell
Made of many proteins
Role is to protect dna
nuclear pores
regulate what comes in and out of the nucleus
Nuclear pore checks to make sure pre-mrna is processed into mature rna before it is sent to the cytoplasm
exportins
proteins responsible for allowing mrna to leave
how do we get things inside the nucleus
they must have some sort of id
nuclear localization sequence of proteins
embedded in organelles
“postal code” recognized by protein called importin that allow things to enter nucleus
integral membrane proteins
proteins that are a part of the endomembrane system
list:
- rough er
- smooth er
- golgi apparatus
-lysosomes
what two things make up endoplasmic reticulum
rough er
- plasma membrane that is flattened out but with ribosomes on it
smooth er
- flattened out plasma membrane without any ribosomes on it
golgi apparatus structure
stack of plasma membrane discs that are adjacent to one another
lysosomes structure
bubbles of fat
sacs
in order for proteins to be secreted out of the cell or to stay in the plasma membrane to go into any of these organelles, you need a ____
signaling peptide
s.p. must be at the n-terminus(first sequence to be read)
in order to remain in endomembrane system. proteins need
a retention sequence
Suppose you wish to determine the identity of a mitochondrial import peptide sequence that is part of a protein, which is encoded by the nuclear genome, that functions in the electron transport chain. You suspect the sequence is MAMAMAMA. What would be best to do to establish the identity of the sequence
show the MAMAMAMA sequence is necessary for import by deleting it from the protein and measuring import of the protein into the mitochondria
show the sequence is sufficient for import by adding it to an enzyme in glycolysis and measuring import of the protein into the mitochondria
the mcdb1a protein is synthesized by both muscle and liver cells. in liver cells, mcdb1a protein is found free floating around the cytoplasm; in contrast, it is never found free in the cytoplasm of muscle cells but is always sent to the nucleus. what must be true about the MCDB1A mRNA?
muscle MCDB1a mRNA is likely larger than liver MCDB1A mRNA due to the NLS sequence
nuclear lamina
support nucleus inside of the membrane (skeleton of nucleus)
3 types of lamin in humans but they are only made up of 2 separate genes (A,B,C)
splicing allows for the different types of lamin
progeria
medical condition caused by mutations in lamin
premature aging due to abnormal nucleus shape
endomembrane system
composed of the endoplasmic reticulum, golgi complex, vesicles/lysosomes, and vacuoles
dense network of closed membrane tubules, closed vesicles, and closed sacs
bubbles of fat that are flattened or pinched into different shapes/organelles
single phospholipid bilayer membrane
there is a constant movement in the system
endomembrane system function
sequester
- lock molecules/particles into the cisternal space of the vesicles or sacs
transport
- transport sequestered molecules around or out of the cell
chemical modification
-chemically modify sequestered molecules
endocytosis vs exocytosis
exocytosis
release of cargo outside of the cell
contents of the vesicle are released by the fusion of plasma membrane of vesicle and of the cell
endocytosis
indagination
eating molecules outside the cell to bring them in
lysosome
vesicle with digestive enzymes that can break down molecules that are ingested
proteases break down proteins
nucleases that break down nucleic acids
glycosylases that break down carbohydrates
what family does lysosome and its digestive enzymes belong to
hydrolases
they use water to break the macromolecules down into monomeric units
vesicles
bubble of fat made up of one phospholipid bilayer
circular, small mobile, single-membrane organelle that moves things around throughout the cell
little sacs
vesicles are pinched out from plasma membrane, carrying contents in it when indagination occurs
to restore the portion of the plasma membrane lost from this, the vesicle fuses to the membrane and releases its contents during exocytosis
rough er
has ribosomes attached to its surface
synthesizes proteins with signaling peptides
proteins with signaling peptides is detected by proteins that dock it into the er. then the ribosome takes the protein and secretes it into the er
protein goes through rough er, smooth er, golgi, and outside the cell
make all secreted proteins
smooth er
lacks ribosomes
ribosomes font dock into er
synthesize lipids, metabolize carbs, detox drugs and poison, store Ca2+
Ca2+ is a signaling molecule for several different mechanisms
calcium is stored in smooth er
golgi body
same as others, bubble made out of fat but it has been flattened into tubes called cisternae
moves and transports things through cisternae
cisternae
makes up golgi body
two faces
cis face (points towards nucleus)
receives things into the cell
trans face (pointing to outside of the cell)
ships out the cell
molecules move from cis to trans and are chemically modified
insulin
protein that your pancreas secretes to let your body know there is sugar in your blood
vacuole
store toxic waste materials
store food, nutrients, ions, metabolites
mitochondria
about the size of a bacterial cell
produces ATP
regulates Ca2+ in the cytosol
regulates programmed cell death
grow and divide via binary fission
have their own chromosome
the number of mitochondria depend on the cell
why?
if you have a cell that does a lot of work, you will have a lot of mitochondria in one cell
what does the mitochondria having its own chromosome mean
encodes ribosomal rna, trna, atp synthase, etc proteins
retrograde transport
when proteins move from nucleus to mitochondria
require mitochondrial localization sequence to occur
plastids
family of organelles that are double membrane
main function is to synthesize sugars (chloroplasts)
store pigments and starches (chromoplasts, leucoplast)
chloroplasts
presents in plants and protists
thylakoid membranes stack to form grana/granum
contain light harvesting pigments called chlorophyll
to synthesize sugars two reactions occur in chloroplasts
what occurs in chloroplasts
photosynthesis
two reactions of photosynthesis
light reactions
calvin cycle
light reactions - photosynthesis
occurs in membranes of chloroplast thylakoids
harvest energy of sun
use energy holding hydrogen and oxygen together in a water molecule to produce ATP
pass down high energy electrons using sunlight, which excites the electrons in the chlorophyll
electrons make their way down an atp synthase to produce atp
nadp+ is the electron acceptor, nadph is the electron carrier
calvin cycle
happen in stroma (liquid around thylakoids)
takes co2 from the air and creates glucose
reduces CO2 to sucrose
