Bio Exam 2 Specific Flashcards
Differences between Eukaryotes and Prokaryotes
Eukaryotes:
- larger
- DNA in nucleus
- organelles
Prokaryotes:
- smaller
- no organelles
Similarities between Eukaryotes and Prokaryotes
Cytoplasm
Plasma Membrane
Endomembrane System
Nuclear Envelope (double layrered)
Endoplasmic Reticulum (Rough and Smooth)
Golgi Apparatus
Vesicles (pouches of plasma membrane)
Chromatin v Chromsome
Chromatin: loosely wound DNA
Chromosome: tightly wound
Job of nucleus
house and copy DNA
3 types of cytoskeleton
Microtubules
Intermediate Filaments
Microfilaments
Microtubules
made of Tubullin
- hollow
- movement and support (tracks for motor proteins)
- can originate from centrosome
- cilia and flagella, separation of DNA
- arranged in cricles of 9 triplets or doublets
Intermediate Filaments
made of Keratin
- twisted fibrous proteins
- many originate from centrosome, built from centrioles
- anchor and structure
Microfilaments
made of Actin protein
- muscle contractions
- cytoplasmic streaming
- cell shape
Cisternea
flattened membrane vesicles found in the ER
Plasmodesmata
cytosol, water, ions
4 types of junctions
1) Tight junctions: no leaks
2) Desmosome: velcro (strong–> high mechanical stress)
3) Gap junction: channel (quick movement from one cell to another–> rapid signaling)
4) Plasmodesmata: plant cell wall channels
6 fucntions of membrane proteins
transport channels
receptors fro signaling molecules
cytoskeleton
enzymatic activity
intercellular attachment
cell - cell recognition
Amphipathic
partially hydrophobic, partially hydrophilic
cholestorol
reduces membrane fluidity but at low temps stops it from freezing solid
Active Transport
REQUIRES ENEGY!
- primary
- secondary (cotransport)
- vesicular
Vesicular Transport
Exocytosis (exit the cell)
Endocytosis (into the cell)
- receptor mediated
-pinocytosis (cell drinking)
- Phagocytosis (cell eating)
Passive Transport
NO ENERGY NEEDED!
Diffusion
- simple
- osmosis (water)
- facilitated –> aquaporins, channel mediated, carrier mediated
Diffusion
substances moves until they are equally and randomly distributed
Simple diffusion
solute moves from high to low
Tonicity
ability of a solution to alter cells water volume
Active Transport
moves molecules against their concentration gradient
Co-transport
uses stored energy from active transport
building a concentration gradient in order to do other work
Vesicular (bulk) Transport
molecules moved in tiny containers called vesicles
endocytosis (inside the cell)
exocytosis (outside the cell)
electrogenic pump
voltage differences on either side of the cell membrane, ex. 3Na + and 2K +
Local signalling
- gap junctions
- cell - cell recognition
- paracrine = local regulator
- synaptic
Long distance signaling
- endocrine
- nervous tissue
3 stages of cell signaling
Reception
Transduction
Response
Reception
recognize the signaling molecule
Transduction
convert original signal into form that can trigger cellular response. often involves relay molecules
Response
finally triggers specific activity
ligand
signaling molecule, binds specifically to another molecule
G protein coupled receptor
- utilizes transmembrane receptor
- binds GTP (energy shuttle molecule) to a G protein
- activates another enzyme
Ligand gated ion channel
- channel only opens to specific ligand binds
- allows movement of molecules that may trigger intracellular response
Intracellular Receptors
diffuse straight through the membrane
Protein Kinase
transfer phosphate group –> phosphorylate –> activate
Protein Phosphate
remove a phosphate –> deactivate
chemical energy
potential energy is available in chemical reaction
Thermal energy
kinetic energy associated with random movements if atoms or molecules
Anabolic
or endergonic reactions: build up
positive change in G
lessens entropy locally
Catabolic
or exergonic: tears down
negative change in G
spontaneous: does not require energy from outside to start reaction so can happen whenever
increases entropy
change in G
final G - initial G
Energy Coupling
using an exergonic reaction to drive an endergonic one
Phosphorylation
transferring a phosphate group
competition inhibition
active site is filled by “mimic” so normal substrate cant gain access
non competitive inhibition
bind to a different part of the enzyme, causes enough of a change that active site isn’t accessible to normal substrate
Allosteric Inhibition
stabilizes in inactive form
Allosteric Regulation
activator molecule binds and stabilizes in active form
Cooperativity
when actual binding influences further binding in other active sites
