Lecture 8 Flashcards
Mitochondria
Site of cellular respiration
What is cellular respiration
A metabolic process that uses O2 to make ATP (E) for cell functions from food
Mitochondria is or is not in the endomembrane system
Is not
Which cells have more mitochondria
Muscle tissues (require high amounts of energy)
Cytoskeleton is
Network of protein fibers that give shape/structure to cells
Up to 1/3 of cell’s protein content is used for
Cytoskeleton
3 types of protein rods (cytoskeleton)
- Microtubules (largest in diameter)
- Microfilaments (smallest)
- Intermediate filaments (medium)
Microtubules look like
Thick hallow protein tubes
What has this function? Gives cell shape and support
Microtubules
What enables cells to change shape (can extend/contract, very dynamic)
Microtubules
What is involved in communication into/out of cell by interacting with plasma membrane prots
Microtubules
What serves as tracks along which organelles (vesicles) can move (with motor proteins)
Microtubules
What do microtubules form
Flagella, cilia and centrosomes
What is a flagella
Has undulating motion that generates force, cells have one of a few
What is cilia (ex trachea or fallopian tubes)
Work like oars, occur in large numbers
Centrosomes are composed of
2 centrioles
What is a centrosome
Responsible for moving chromosomes and pulling cell apart during divison
Function of microfilaments
Help support cell’s shape, involved in cell motility (muscle contraction (actin filaments))
Intermediate filaments function
Maintenance of cell shape
Three types of cell junctions
- Tight junction
- Desmosome
- Gap/communication junction
Which junction prevents leakages of fluid across layer of cells by forming seals around and makes us water tight (junctions between skin cells)
Tight junctions
Which junction attaches cells to e/o and to ECM so that they remain part of tissues, linked to cytoskeleton, don’t stop passage of materials between cells
Desmosome
Which junction are channels connecting cytoplasm of adjacent cells allowing for communication (ex pancreas cells communicate so secrete insulin at same time)
Communicating junctions
Where is the extracellular Matrix
Outside of cell membrane
Holds cells together, contributes to structural support, provides info cues that determine cell activity
ECM
Composition of ECM
-fluid (ECF)
-proteins and carbohydrates in this fluid
What is the extracellular fluid
Surrounds cell, ~33% of body’s total water content (mostly water)
What does the ECF contain
Mostly water, ions (mostly Na and Cl), nutrients (from blood vessels), wastes, hormones, …
Intracellular fluid (ICF) major cation :
Potassium and magnesium
ECF major cation :
Sodium
What helps anchor cells to their environment, coordinate behaviour of cells that compose same tissue and organ?
ECM
What affects gene expression in nucleus-> prot synthesis-> cell function
ECM (occurs through physical/chemical communication pathways between ECM and cytoskeleton)
What transmits signals between ECM/cytoskeleton -> integrate changes inside/outside cell
Integrins (proteins)
By communicating w cell through integrins, ECM regulates
Cell’s function, structure/behavior
What physically separates inside and outside of cell
Plasma membrane
What creates compartments within cell (organelles/vesicles)
Cell membrane
Components of cell membranes
-Lipids (phospholipids/cholesterol)
-proteins
-carbohydrates (glycolipids/glycoproteins)
What is physical barrier between ECM and cytoplasm
Plasma membrane
The cell membrane is most permeable to
Small molecules (o2 co2 h2o) and hydrophobic lipid soluble substances
Selectively permeable membrane acts as barrier to
Most hydrophilic substances -> pass under specific circumstances
What might transport hydrophilic molecules if they’re stopped from crossing the membrane
Membrane transport proteins
PM contains protein receptors that
Communicate info into cell
Glycolipids and glycoproteins are involved in
Cell to cell recognition and communication between cells and ECM to maintain homeostasis
What allows separation between inside and outside cell in membranes
Hydrophobic interior of bilayer
Membranes are fluid -> phospholipids can
Turn on axis or upside down, move lateral over surface of membrane
Increasing nb of saturated FA will ____ membrane fluidity
Decrease
Increasing nb if unsat FA will_____ membrane fluidity
Increase
Cholesterol in membranes help
Maintain integrity of membranes (prevents phospholipids from moving apart too much and forming clumps
What is necessary to : keeping things inside while transporting others across membrane, allowing cell to change shape and allow membrane molecules (proteins receptors, enzymes) to move laterally to have appropriate enviro to function)
Membrane fluidity
Cell membrane proteins functions
- Transport
- Enzymatic activities
- Signal transduction
- Cell-cell recognition
- Intercellular joining
- Attachment to cytoskeleton/ECM
6 functions of membrane proteins
- Receptor
- Enzyme
- Channel
- Gated channel
- Cell-identity marker
- Cell adhesion molecule
