ch 7: prokaryotes and eukaryotes Flashcards
what features do ALL CELLS have?
cell membranes, cytoplasm, genome of DNA, and ribosomes
cell membrane
phospholipid bilayer, surrounds the fluids and other structures that make up the “insides of a cell”
cytoplasm
the insides, which consists of a liquid, water based cytosol containing dissolved molecules
ribosomes
RNA molecules that make proteins using information copied from DNA
features of prokaryotes
- rigid cell wall
- additional outer plasma membrane
- slimy capsule of polysaccharide
- flagellum
- fimbriae
flagellum
whip-like protein complex that allows prokaryotes to move
fimbriae
hair-like projections that allow prokaryotes to stick to surfaces
can prokaryotes exist as free-living single cells?
yes and also in aggregates (chains, clusters or biofilms)
how did eukaryotic cells evolve?
from a prokaryotic ancestor
why do eukaryotes differ from prokaryotes?
the cell membrane from prokaryotes migrated and surrounded different parts of cytoplasm to create organelles
endosymbiosis
mutually beneficial relationship between two organisms where one lives inside the body of another
- some single-celled organisms were engulfed and kept
what was the first proto-organelle to form from cell membrane of prokaryote?
endoplasmic reticulum which later enclosed the DNA to form nucleus
possible paths of evolution to eukaryotic cells
- inside out
- outside in
are prokaryotes or eukaryotes bigger?
eukaryotes (10 to 100um) compared to prokaryotes (1 to 10um)
how does DNA form differ in eukaryotes and prokaryotes?
eukaryotes: DNA in linear chromosomal form
prokaryotes: circular chromosomal form in nucleoid
what are prokaryotes?
archaea and bacteria
- most common cell type
do prokaryotes have membrane-bound compartments?
no, eukaryotes do and they are called organelles
eukaryote types
plant and animal cells
what do plant cells have that animal cells do not?
- cell wall surrounding plasma membrane
- chloroplasts
- large central vacuole
where are ribosomes in prokaryotes?
free floating in cytoplasm
where are ribosomes in eukaryotes?
free floating in cytoplasm or attached to rough ER
functions of cytoskeleton
- supports and maintains cell shapes
- railroad track for organelle and vesicle movement
- anchors the cell and organelles
- make-up cilia and flagella
structural features of cytoskeleton
long spindle-like protein fibers
what do proteins in plasma membranes anchor to?
cytoskeleton and extra cellular matrix
endomembrane system
protein + lipid synthesis +distribution factory in eukaryotes
what are all organelles surrounded by?
plasma membrane which is made of a phospholipid bilayer, proteins and carbs
function of nucleus
contains the genetic information (DNA) of the cell
what is made in the nucleus?
RNA copies of protein-making information
structural features of nucleus
surrounded by double plasma membrane and contains the nucleolus
nuclear envelope
two membranes perforated by nuclear pores that regulate movement of substances
nucleolus
where ribosomes are made
does the nuclear membrane allow everything in?
no, only certain things
what do molecules have to have to enter the nuclear membrane?
specific series of amino acids
endoplasmic reticulum structural features
contains the highest fraction of membranes in a cell and has a continuous membrane with nucleus
Rough ER function
- protein synthesis by ribosomes
- protein folding
- protein glycosylation
smooth ER function
- lipid synthesis and lipid modification
- stores calcium for cell signaling
how is where a protein functions in a cell determined?
whether it is made by a cytoplasmic ribosome or ribosome attached to rough ER
golgi apparatus
series of flattened sacks called cisternae
cis golgi
receives vesicles from Er
trans golgi
sends vesicles of proteins to where they function
is cis or trans golgi closer to cell membrane?
cis
function of golgi apparatus
collects, modifies, sorts and packages proteins and lipids from ER
what do some vesicles mature into?
lysosomes and perixosomes
what happens to the products after the golgi apparatus sorts them?
packed into vesicles and sent to where they function in cell
function of lysosomes
- breaks down unwanted substances like bacteria and worn-out organelles
- hydrolyzes nucleic acids, carbs, proteins, and lipids
structural features of lysosomes
acidic which is necessary for protein folding/function
what environment do lysosomal enzymes need to fold correctly?
in low ph of a lysosomal vesicle
how are proteins denatured?
heat, pH, salt, and solvents
what do central vacuoles do in plant and fungi cells?
store ions and toxic compounds, store anthocyanins in flowers, and contain hydrolases
structural feature of central vacuole
provides structure for plant cells: water enters the vacuole by osmosis
what are cell walls in plants and fungi made of?
cellulose
what do animal cells attach to?
extracellular matrix proteins
function of chloroplast
site of photosynthesiss
structural features of chloroplasts
uses outer, inner, and thylakoid membranes
function of mitochondria
site of chemical reactions of cellular respiration that supply most of the cellular energy
structural features of mitochondria
uses outer and inner membrane
what is in the inner membrane of mitochondria?
matrix
what is in between the inner and outer membrane of mitochondria?
innermembrane space
what is outside the mitochondria?
cytoplasm
structure of peroxisomes
small vesicular organelle that contains enzymes similar to lysosomes
function of peroxisomes
enzymes carry out redox reductions and detoxifies cell of lipids and alcohols
what must be complementary for proteins to bind?
chemical nature of protein must be complementary to chemical nature of what binds to the protein
what is the basis of how a protein function?
change in shape of a protein as it binds or unbinds other molecules
what 4 things are inside the nucleus?
DNA, RNA, proteins and hormones
what do proteins and hormones do?
determine which regions of DNA are used
what can pass through the nucleus pore easily?
small molecules like nucleotides can pass with their concentration gradient
nuclear localizing signal (NLS)
specific series of amino acids required for nucleus entry
nuclear exit signal
different specific series of amino acids required for nucleus exit
what binds to the NLS sequence and what does it do?
special shuttle proteins and they carry the protein through the nucleus pore complex
specifically, what do the shuttle proteins bind to?
protein fingers of the NPC and they are pushed through to the nucleus
where do cytosolic ribosomes go?
cytosol, chloroplasts, mitochondria, peroxisomes, nucleus
where do rough ER ribosomes go?
outside of cell, cell surfaces, cell membrane, lysosomes, back to ER
ER signal sequence
specific series of amino acids that a shuttle binds to, and brings to RER
pathway from ER to outside of cell
- protein enters ER while being synthesized by ribosome and is processed; one or more carb groups are added
- protein exits ER inside a vesicle and travels to cis face of golgi apparatus
- protein enter golgi apparatus and is further modified
- protein exits golgi apparatus in a vesicle and moves to plasma membrane through trans face of golgi
- protein is secreted from cell
process of protein sorting and vesicle transport
- proteins carry distinct tags that serve as zip codes in endomembrane system
- proteins are sorted in the trans-golgi cisternae when they bind to different receptors
- transport vesicles bud off the trans face and travel to their destinations
- transport vesicles attach and fuse at different destinations using cytosolic and membrane proteins to deliver their contents
what type of proteins bind to the localizing sequences in the Golgi?
integral membrane proteins in the plasma membrane of the golgi
how do other proteins create vesicles?
they come to the cluster of receptors bound for a certain location and pinch off the plasma membrane
receptor mediated endocytosis
molecules brought in from extracellular space by binding to receptors proteins in the cell membrane
phagocytosis
entire cells are brought into the cell and disassembled by the lysosome
autophagy
worn out organelles are destroyed in the lysosome
structure of actin filaments
two coiled strands that have plus end and minus end
subunits of actin filaments
actin
functions of actin filaments
- maintain cell shape by resisting tension
- move cells vis muscle contraction or cell crawling
- divide animal cells in two
- move organelles and cytoplasm in plants, fungi, and animals
structure of intermediate filaments
fibers wound into thicker cables
subunits of intermediate filaments
many different proteins such as kertains, lamins, etc
functions of intermediate filaments
-maintain cell shape by resisting tension
- anchor nucleus and other organelles
structure of microtubules
hollow tube with plus and minus end
subunits of microtubules
alpha and beta-tubulin dimers
functions of microtubules
- maintain cell shape by resisting compression
- move cells via flagella or cilia
- move chromosomes during cell division
- assist formation of cell plate during plant cell division
- provide tracks for intracellular transport
what happens when actin and myosin interact?
it causes movement by myosin proteins pulling on actin
what do kinesin and dynein motor proteins do?
move on microtubules
