epitope
the antigen's binding site -- used in process of finding a protein in a cell
How do we find a protein in the cell?
an antibody is used to bind to a specific antigen's epitope. A secondary antibody tagged w/a fluorescent cmpd is added and binds to primary antibody. The image can be seen w/a fluorescent microscope.
Cell theory: what is it and who discovered it
all life comes from preexisting life -- discovered by Louis Pasteur .
Why are cells so small?
Large SA:V ratio allows for quicker rate of diffusion for monitoring what goes in and out of a cell. We want to bring in nutrients and release waste
Unicellular
a single cell, like bacteria. Bc they're single cells, they can develop into biofilm or communities like coral
Multicellular
many cells, like humans. Carry out different functions
What are the 3 major domains of life?
Bacteria, Archaea, Eukarya BA= prokaryotes E=eukaryotes (fungi, protists, plants, animals)
What is the cell wall in prokaryotes made of?
peptidoglycan
How many membranes do prokaryotes have?
some have 2 membranes: the outer and inner
What is the inner membrane in a prokaryotic cell called?
periplasmic space
Where is DNA stored for a prokaryotic cell?
the nucleoid contained in the cytoplasm
What is the flagella?
a tail that allows the cell to swim. Can make bacteria spin: clockwise is a forward motion while counterclockwise is TUMBLING
What is the pili?
It's used for sex amongst bacteria; allows adhesion to other bacteria or surfaces. It builds bridges between inferiors and exchange cytoplasmic material
What is another word for bacterial sex?
conjugation
bacterial sex
the pili connects them together
plasmids that enclose circular DNA are transferred through the pili during replication
Who discovered penicillin and how?
Alexander Fleming; grew penicillin mold and saw that bacteria couldn't grow near it. Discovered it killed bacterial cells and prokaryotes b/c they tend to have a cell wall
pencillin
it links peptides to sugars
What is the nucleolus?
a part of the nucleus with ribosomal genes. It's where ribosomes are made and assembled
What is the double membrane of the nucleus called and what supports it?
The nuclear envelope; it is supported by the lamina ['laminates"=support] and is contiguous of the ER. Holds different proteins and keeps nucleus from being compressed
What is the function of nuclear pores?
to regulate what comes in and out of a cell
What does a mutation in lamin-A cause?
early aging due to a collapsed nucleus
Describe the nuclear pore complex
it forms channels to allow passage of macromolecules and is important for trafficking. ' it is inside the nuclear envelope
mRNAs binded to proteins go out while nuclear proteins go in. They must have a NLS attached in order to be recognized by the pores
cytosol
Where are proteins sythesized?
What protein recognizes a NLS?
an importin protein
NLS are ______ for import of protein into nucleus and __________ to direct a normally cytoplasmic protein into the nucleus
necessary; sufficient
What is C-myc?
a transcription factor; binds to DNA & turns on transcription of genes associated with replication.
if turned back on unnecessarily it leads to cancer due to overexposure
What size are mitochondria?
about the size of a bacterial cell
What are the 3 functions of mitochondria?
produce energy, ATP
regulate calcium levels
regulate signals that mediate cell death
how do mitochondria grow and divide?
binary fission; pinching off in the middle
describe the structure of mitochondria
it has an inner and outer membrane
the outer is smooth and semipermeable
the inner has a lot of folds (cristae)
it has a matrix inside & mitochondrial localization sequence
what is the matrix?
the matrix is the inner part of the mitochondria. It holds rna, trna, ATP synthases, and the electron transport chain.
a mutation in NADH leads to this
blindness
how is the pH gradient created and what is its purpose
it is part of the electron transport chain; hydrogen is pumped out to create a gradient across the inner membrane and then hydrogen flows in to create ATP.
it is more acidic bc of the hydrogen drive
it is a source of energy
what are plastids?
plants; they have a double membrane
serve for photosynthesis and storage
what is the third membrane of the cytoplasm? Function?
the thylakoid; has proteins to bind chlorophyll & light pigments for photosynthesis
what is the middle of the cytoplasm called? What is its function?
the stroma; holds DNA & ribosomes
what are the 2 reactions of chloroplasts?
light --> takes energy from the sun to make O2, ATP, NADPH
dark --> use ATP and NADPH to make CO2 which is then sugar
endosymbiosis
the belief that mitochondria & chloroplast originated when large eukaryotes ate small prokaryotes
Peroxisomes
squared granular or crystalline arrays of enzymes that catalase to destroy toxic peroxides
Chromoplasts
pigment storage
attract insects for pollinating
Plant vacuole (3 functions)
store toxic waste materials, food & nutrients
provide TURGOR aka stiffness for structure
can contain hydrolytic enzymes
leucoplasts- what and found where?
store starch, lipids or proteins found in roots/nonphotosynthetic tissue
amyloplasts
store starch in potatoes
diabetes: 2 types
high blood sugar, weakness, lethargy, and weight loss
Type 1: juvenile--lack of insulin. The own immune system attacks beta cells of pancreas
Type II: lack of insulin responsiveness
insulin: what and discovered by who
peptide hormone secreted into blood by beta cells in pancreas
binds to cell surface of muscle & fat cells : signals to import and store glucose
discovered by Banting and Best
Endomembrane system
network of closed membrane tubules, closed vesicles, and closed sacs
divides cytoplasm in 2 (inside and outside membrane sacs)
3 Functions of Endomembrane System (STC)
Sequestration: of molecules/particles into cysternal space of vesicles Transport: of sequestered molecules/particles from place to place w/in cytoplasm or to nucleus Chemical modification
What makes up the endomembrane system?
Rough ER
Smooth ER
Golgi Complex
Vesicles
Rough ER
has ribosomes attached
is where integral membrane proteins & proteins that are secreted are made
they're then translocated across the membrane into cysternal space
Smooth ER
lipid synthesis
detoxification of hydrophobic toxins
Golgi complex (post office)
modifies carbs/proteins and ships them to the cell surface
Vesicles
lysosomes, peroxisomes, secretory ; move to cell surface
Secretory pathway
rough ER --> golgi --> vesicles
Integral Membrane proteins
secreted proteins with signal sequence at N-terminus
direct ribosome to rough ER signal removed in lumen of ER
Golgi apparatus
has a cis/trans region
vesicles from ER fuse with the cis region
pinch off and fuse with medial and trans region
pinch off trans and fuse with plasma membrane
proteins inside vesicle secreted outside cell
proteins in vesicle membrane inserted in plasma membrane
lysosomes
pinched off the golgi
cells recycling center
has digestive enzymes break down old cellular materials
digest ingested bacteria
Tay-Sachs Disease
lysosomal storage disease
mutation in gene for hexose-aminidase A prevents lysosomes from breaking down certain membrane glycolipids
leads to blindness, dementia, death
Phagocytosis
when macrofuge ingests bacteria
the phagosome fuses with lysosome to kill bacteria
Randy Schekman (schek, shake)
isolated yeast cells that had secretion defects
called them sec genes encode membrane proteins that are involved in membrane traffic
The eukaryotic cytoskeleton's 3 different skeletal fibers
Microfilaments
Intermediate Filaments
Microtubules
Microfilaments
made up of actin monomer
polarization on plus end
depolarization on minus end
assembled by noncovalent bonds at the end of filaments
partakes in treadmilling
Intermediate filaments
build similar cable like filaments
very stable NOT DYNAMIC
Cell shape of microfilaments
Stress fibers: bundled actin, maintain skin cell shape attach to focal adhesion -Microvili: project from cell surface most found in intestine
actin join integrin
Movement of Eukaryotic Cytoskeleton
DUE TO MICROFILAMENTS proven bc of amoeba experiment where Cytochalisin B blocks formation of microfilaments leading to movement
An example of intermediates
nuclear lamins
support nucleus, attachment points for DNA keratin filaments
support skin, hair
Microtubules
made of alpha beat tubulin dimers
both ends have different properties
Two functions of microtubules
Dynamic instablity: switching b/w growth and shortening ends
Treadmilling
Function of microtubules in animals
centrioles surrounded by pericentriolar matrix
centriole = set of 9 triplet microtubules
Dynein motor proteins
help move the cilia and flagella
negative directed
make microtubules slide past each other
Type of microtubules vesicles use to move
dynein and kinesin motors
How microtubules move
using the cilia or flagella!
Lipid rafts
-high in cholesterol --> less fluidity
more rigid
3 types of molecule transportation
Passive diffusion
Carrier mediated diffusion
Active transport
Passive diffusion
no ATP required
from high concentration to low
Type of molecules that can't diffuse passively
most water soluble
any with a positive or negative charge ex. sugars, AA, proteins
How do molecules that can't diffuse passively get across the membrane?
channel proteins ex. Ion channels
Carrier mediated diffusion
ex. glucose carrier protein NO ENERGY REQUIRED
Active transport
needs energy and ion gradient
moves molecules against their concentration gradient
Uniporter
active transport: moves one substance in one direction
Symporter
active transport: two substances in same direction
Antiporter
active transport: two substances moving in opposite directions
Types of gated ion channel
ligand binding and voltage
Endocytosis & exocytosis
moving complex molecules into cells fusion of membrane vesicle to plasma membrane
3 types of endocytosis
Phagocytosis: large particles and small cells engulfed inside vesicles
Pinocytosis: cell drinking; taking up water into vesicles
Receptor mediated endocytosis: specialized form--takes in certain kinds of macromolecules into cells
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