A tour of the cell Flashcards
What is the cell theory?
- organisms are composed of one or more cells
- cell is the basic unit of structure and organization in organisms
- All cells come from preexisting cells
PROKARYOTIC…
- usually single-celled
- No nucleus or membrane-bound organelles
- Metabolism through aerobic and anaerobic means
- Genetic material localized–NUCLEOID
- Most cells have peptidoglycan which makes up cell walls
- Circular DNA, one form of RNA polymerase
- No cytoskeleton
What is peptidoglycan? Function?
It makes up cell walls and is mainly found in prokaryotes such as bacteria. Protects bacteria from environment stress.
pro means?
before
eu- means
after
Eukaryotic cells have…
- Nuclear membrane encolsed DNA
- Organelle have membranes
- RNA and protein synthesized in two different locations
- Linear DNA molecules with non-coding introns
- More than one RNA polymerase
why does a cell go through mitosis?
because it is becoming too large and more inefficient
Cells are compartmentalized to…
increase SA to Volume ration
specialized reaction withing and localized reactions when needed
smaller cells are more efficient and each organelle increases SA
Why are small compartments important?
The isolated areas of the cell, allow for various conditions for different reasons aka Ph, the concentration of solute differences
Each smaller structure can be…
specialized can carry out specific functions
this can increase complexity and provide surfaces for reactions
Plasma membrane consist of
lipid bilayer
proteins
- channels, transport, pumps, and receptors
Cytoplasm
area between the outer membrane and nuclear membrane including organelles
Cytosol
Liquid/ gel material containing water, gazes, and macromolecules
Nuclear Envelope
is a double membrane system contains a double phospholipid bilayer
contains pores that regulate the entrance and exit of ions and small proteins(proteins guide things into pores)
also contains a large number of proteins
Nuclear Lamina
protein network that hold and reinforce structures together
made of intermediate filaments and regulates access to DNA,
Involved in RNA transciption, nuclear and chromatic organization, cell cycle regulation, cell development, differentiation, nuclear migration and apoptosis
one difference in enzyme can cause premature death of cell
Ribosomes
Smallest and most numerous organelle and are reusable
two types free and bound
catalyzes formation of peptide bonds using RNA molecules
What is the composition of a ribosome? And where is it synthesized?
60% rRNA
40% proteins
Synthesized in nucleolus
Two parts of a ribosome?
Large subunit and small subunit
Free ribosomes
create protein for that cells usw
Bound ribosomes
bound to Er or nuclear membrane
Er contain mainly what proteins
secretory protains – make proteins that leave cell
Nucleus contains what volume of the total cell
6-10%
What surrounds the nucleus and what is continuous with the nucleus
nuclear envelope surrounds and ER is continuous
Chromosome
one single DNA molecule associated with proteins
organized DNA
Chromatin
DNA molecules and histone proteins
condenses to form chromosomes
Nucleolus
genes for rRNA that will be assembled into ribosomal subunits
may have more than one in cell
endomembrane system
interior network of membrane that assemble lipids and produce and modify proteins
What is apart of the endomembrane system
nuclear envelope, ER, Golgi, lysosome, vacuole
what volume of the cell does the endomembrane system take up
50%
ER
network of tubes and sacs that are continuous with nuclear membrane
most extensive membrane system
two types
- rough
- smooth
rough ER
- studded with proteins and ribosomes
produces secretory proteins
signal sequence on polypeptide instructs ribosomes to attach to ER (docking site)
transmembrane proteins
proteins that are made here are often used in lumen
Sooth ER
lipid production, CH2O metabolism, storage of ions(CA+), detoxification of drugs/alcohol
proteins in membrane or within lumen catalyze reactions
what can be synthesized in both types of ER
phospholipids
Golgi Bodies function
Process, Package, Sort!
describe the structure of Golgi
individual layers with constant motion of vesicles
each layer has different chemicals and the amount of layers depends on the cell
How many Golgi are in a cell
only 1
Cis face is what
the closest part to the nucelaus and is where the material enters
Trans Face
closest to the membrane cell and exit of everything in vesicles
What is found in lumen of the Golgi
enzymes that catalyze the addition or removal of parts
What types of vesicles can the golgi form?
secretory and lysosomal vesicles
Lysosomes are different in what way?
they are single membrane bound organelle
Lysosomes function
Cell recycler
contains 40 different hydrolytic enzymes responsible for the digestion of macromolecules, autolysis, intracellular digestion
dead cells no longer able to maintain H+ gradient so oganelle breaks down releasing contents
What makes lysosomes
Golgi and ER
What disease is caused by faulty lysosomes
tay-sachs
faulty enzyme in lysosomes responsible for lipid breakdown
pre-mature death
Phagocytosis
Lysosomes play an important role in phagocytosis. When macrophages phagocytose foreign particles, they contain them within a phagosome. The phagosome will then bind with a lysosome to form a phagolysosome. These enzymes are critical in oxygen-independent killing mechanisms.
Autophagy
is a catabolic process in eukaryotic cells that delivers cytoplasmic components and organelles to the lysosomes for digestion. Lysosomes are specialized organelles that break up macromolecules, allowing the cell to reuse the materials.
Vacuoles
storage of water, ion, pigments
How are vaculoles different that vesicles formed by Golgi and ER
they are larger
Where is the plant central vacuole enclosed in
tonoplast ( and provides cell with hydrostatic pressure
Plants holding water in vacuoles is important because
keeps plants upright and erect
how many membranes does a chloroplast have
three
the stroma of a chloroplast is analygous to the
matrix
Similar to the mitochondria
the chloroplast is semi-autonomous
Cytoskeleton consists of
protein fibers that support and give shape to a cell
three types of fibers
microtubules
intermediate filaments
microfilaments
Three fibers and their size
microtubules - thickest
intermediate filaments- medium size
microfilaments - thinnest
peroxisomes function
contains catalase that breaks down H2O2 formed during metabolism of alcohols
self-replicating
makes and hydrolyses peroxide
Mitochondria origin
usually maternal (comes from mother) but sometimes can be paternal
mitochondira function
production of atp
double membrane
have their own DNA
divide on their own
have ribsomes that produce enzyme for atp production
what theory is there related to mitochondria
endosymbiont theory
what is the endosymbiont theory?
that some of the organelles in eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are the same size as prokaryotic cells and divide by binary fission. Mitochondria and chloroplasts have their own DNA which is circular, not linear
what is the intermembrane space?
space between inner and outer membrane in mitochondria
Motor proteins
kinesin goes right
dynein goes left
hydolyse ATP to change protein
Microtubules loook like
tunnel- hoolow walls
microtubules consist of what
tubulin
a dimer consisting of alpha and b tubulin
Microfilaments look like
rope bc of two intertwined strings
Microfilaments are made of
actin
Intermediate filaments look like
one think coil made up of hundreds of smaller coils
Intermediate filaments are made up of
several different proteins such as keratin
centrosome is the
microtubule organizing center ONLY FOUND IN ANIMALS
by controlling the number location and orientation of microtubules
describe what stops polymerization
Cholchicine
what prevents depolymerization
taxol
in the cenrtosome what side does the polymerization go
the positive side away from the centrosome
Cilia and Flagella structure
9 to 2 structure
dynein walks microtubukes past one another
What anchors flagella/cillia
basal body
muscles are composed of ..
microfilaments
what provided structure to long cells
intermediate fillaments
what enables cell movements in phagocytosis and cytokinesis
microfilaments
what is found in desmosomes
desmosomes are used in cell to cell contact
intermediate filaments
what gives the nucleus its shape
intermidiate filaments
what allows cell to cell junction in plants
plamodesmata
what allows cell to cell junction in animals
tight junctions
desmosomes
gap junctions
tight junctions prevents
leakage between cells
desmosomes
mechanically attach cells to each other
anchoring sited for intermediate filamets
gap junctions
communication pathway between cells only small things can get through
what is analygous to plasmodemata
gap junctions
tight junctions, desmosomes, and gO JUNCTIONS have what in common
can only be found in eukaryote cells
plant cells walls
prevent cells from bursting
what are plant cell walls made of
cellulose
due to plasmodesmata
everything must cross membrane at least once
plant cell secretion forms
pectin
pectin acts as
adhesivse in miffle lamella
plants without secondary cell walls are
herbs
plants with secondary wall are
woody
new plants can be bendy bc
they have yet to develope second wall yet
Extracellular matrix
intricate network of proteins and polysaccharides that are organized into a meshwork on the outside of cells
what two things provide structure and strength in the ECM
proteins like collegen and elastin
