Midterm 3 Flashcards
Cell Biology 1
Resolution
the ability to observe two adjacent objects as distinct from one another
Contrast
how different one structure looks from another
Transmission Electron Microscopy
protein of interest is labeled with antibodies which are attached to gold particle - a beam of electrons is show through the sample
Scanning Electron Microscopy
sample is coated with a heavy metal - surface is scanned and a 3D image is made
Subcellular Fractionation - contents can be analyzed via
western blotting or immunoprecipitation
Point of Western Blot
Detection of a specific protein
Point of Immunoprecipitation
Allows for isolation of a protein in a mixture
Process of Western Blot
Separate cellular contents via centrifugation or chromatography. Put everything in a gel and do electrophoresis with a membrane on top. The proteins will transfer to the membrane. The membrane is washed/incubated with antibodies that specifically bind to the proteins of interest. Wash off the excess antibodies and develop the film. The thickness of the band tells how high the concentration of proteins is in the sample.
Organelles of Prokaryotes
Ribosomes, cytoplasm, pili/flagella, glycocalyx, cell wall, plasma membrane, and nucleoid
Ribosome
polypeptide synthesis
Cytoplasm
site of metabolism
Pili
allow bacteria to attach to surfaces and each other
Flagella
allow bacteria to move
Glycocalyx
outer gelatinous covering
Cell wall
support and protection
Plasma membrane
encloses cytoplasm, controls movement of substances into and out of cell
Nucleoid
site where DNA is found
Nucleus
most genetic material is expressed and organized here (eukaryotes)
Nuclear envelope
double membrane enclosing nucleus
Nucleolus
site of ribosome subunit assembly
Chromatin
complex of protein and DNA
Lysosome
site of macromolecule degradation
Site of cell signaling
plasma membrane
Cytosol
site of metabolic pathways
Golgi
modification, sorting, and secretion of lipids and proteins
Peroxisome
hydrogen peroxide and other toxins are broken down by these
Cytoskeleton
protein filaments that provide shape and aid in movement
Smooth ER
detoxification, lipid synthesis
Rough ER
protein sorting and secretion
Centrosome
site where microtubules grow and centrioles are found
Nuclear pore
passageway for molecules in and out of the nucleus
Proteome
entire set of proteins expressed by a cell, tissue, or organism
Three types of protein filaments that make up the cytoskeleton
Microtubules, Intermediate filaments, actin filaments
Microtubules
long and hollow, dynamic instability
Intermediate filaments
medium in size, twisted and ropelike in structure
Actin filaments
long and thin fibers
Three parts of motor proteins
Head, hinge, and tail
Three types of motor protein movement
Motor protein moves, filament moves, filament bends
Motor protein moves
walks from - to + and the tail carries the cargo
Filament moves
to left (toward -) and motor proteins are fixed
Filament bends
via actions of motor proteins
Flagella
long and occur singularly or in pairs, 9 + 2 array
Cilia
short and cover part of or the entire cell, 9 + 2 array
Endomembrane system
network of membranes that enclose the nucleus, ER, Golgi, lysosomes, vacuoles, and plasma membrane
How does the endomembrane system pass materials?
membranes are connected directly or via vesicles
Secretory pathway
cargo is moved from ER lumen to vesicles, then travels through the Golgi (cis-medial-trans), then leaves Golgi to plasma membrane to be released from the cell
Pulse-chase proves
secretory pathway
Central vacuoles
in plants for storage
Contractile vacuoles
in protists to expel excess water
Phagocytic vacuoles
in protists and WBC for degradation
Semiautonomous organelles are
mitochondria and chloroplasts
How do semiautonomous organelles reproduce?
bindary fission
How did semiautonomous organelles show up?
endosymbiosis
Fluid mosaic model shows
a membrane composed of lipids, proteins, and carbohydrates
How does the length of phospholipid tails affect fluidity?
Shorter tails are less likely to interact and make the membrane more fluid
How do double bonds affect fluidity?
They create kinks in the tails and phospholipids can’t pack as tightly, leading to more fluidity
How does cholesterol affect fluidity?
It stabilizes the membrane, which makes it less fluid
Lipids are synthesized by which organelles and systems?
Cytosol and endomembrane system
What is glycosylation?
the attachment of a carbohydrate to a protein or lipid
Glycosylation plays a role in
cell surface recognition
N-linked glycosylation
attachment of a carbohydrate to the N of asparagine side chain - this is initiated in ER
O-linked glycosylation
addition of sugars to O atom of serine or threoline - occurs only in Golgi
Types of passive transport
simple diffusion and facilitated diffusion
Simple diffusion
no transport proteins or energy is needed
Facilitated diffusion
transport proteins are needed but energy is not
Active transport requires
energy as it works against a gradient
Rate of diffusion of different substances
ions, charged polar molecules, large < polar organic molecules < gasses, small/uncharged
Isotonic
water and solute concentrations are equal on two sides of a membrane
Hypertonic
the side of the membrane in which the
Osmosis
movement of water
Crenation
cell shrinks in a hypertonic solution because water is leaving
Osmotic lysis
cell swells and bursts in hypotonic solution
Channels
form open passageways for direct diffusion across a membrane
Transporters
result in a conformational change to move across a membrane
Types of transporters
uniporter, symporter, antiporter
Primary active transport
needs an input of energy and is energetically unfavorable
Secondary active transport
uses a pre-existing gradient to move substances
Na/K - ATPase
transports sodium and potassium against gradients using energy from ATP hydroylsis
Electrogenic pump
exports 1 net positive charge
Exocytosis
materials in the cell are packaged into vesicles and excreted into the extracellular membrane
Endocytosis
plasma membrane invaginates to form a vesicle that brings stuff into the cell
Three types of endocytosis
receptor-mediated, pinocytosis, and phagocytosis
Pinocytosis
extracellular fluid is taken into the cell
Phagocytosis
a large thing is engulfed by the cell
When G is negative
the reaction is exergonic and spontaneous
When G is negative
the reaction is exergonic and spontaneous
Ribozyme
RNA molecule with catalytic properties
How do enzymes help lower the activation energy/overcome it?
Position reactants together to facilitate bonding, change the local environment
Competitive inhibitors
bind to the active site and inhibit the ability of the substrate to bind, increases KM
Noncompetitive inhibitors
bind to allosteric site, cause conformational change that inhibits the active site, brings Vmax down
Some other potential requirements of enzymes
prosthetic groups, cofactors, and coenzymes
Catabolic pathway
breaks molecules down, exergonic, and recycles cellular building blocks
How is ATP produced?
catabolic pathway
Anabolic pathway
molecules are synthesized, endergonic
ATP can be made via two ways
substrate-level phosphorylation and chemiosmosis
Substrate-level phosphorylation
an enzyme transfers phosphate from a molecule to ATP
Chemiosmosis
energy stored in an ion electrochemical gradient is used to make ATP from ADP and inorganic P
NADH is
a chemical intermediate
How is NADH made?
when electrons are removed from organic molecules
Oxidation of NADH results in
energy used to make ATP
Molecules that receive electrons from oxidized NADH
become energized and can participate in reactions woohoo
Proteasome
breaks down proteins using proteases which cleave bonds between amino acids
Ubiquitin
tags a target protein to proteasome which breaks it down
