Big Idea #2 Essentials Flashcards
3 differences between prokaryotic and eukaryotic cells
-where DNA is stored (p: nucleoid, not membrane enclosed/ e: nucleus, double membrane enclosed) -organelles (p: not present/ e: present) -size (p: smaller/ e:larger)
In animal cells only
-lysosomes- digestive organelle, macromolecules are hydrolyzed -centrosomes/centrioles: used in cell division -flagella: movement
In plant cells only
-chloroplasts -central vacuole: storage, breakdown of waste, hydrolysis of macromolecules -cell wall: protects cell, maintains shape -plasmodesmata: channels through cell walls that connect cytoplasms of adjacent cells
(nucleus) nuclear envelope
double membrane enclosing nucleus, perforated by pores, continuous with ER
(nucleus) nucleolus
nonmembranous structure involved in production of ribosomes
(nucleus) chromatin
material consisting of DNA and proteins
endoplasmic reticulum (ER)
active in membrane synthesis and other synthetic and metabolic processes, detoxifying, has rough and smooth regions.
peroxisome
various specialized metabolic functions, produces hydrogen peroxide as by-product, then converts it to water
microvilli
projections that increase the cell’s surface area
golgi apparatus
active in synthesis, modification, sorting, and secretion of cell products
ribosomes
complexes that make proteins
role of phospholipids in cell membranes
make up cell membranes, hydrophobic tails, hydrophilic heads, double layered to make a bilayer, acts a boundary
role of proteins in cell membranes
transport of substances across cell membrane (transport proteins), response of cell to chemical stimuli (receptor proteins), speed up chemical reactions (enzymatic)
role of carbohydrates in cell membranes
attached to proteins or lipids outside the cell membrane (extracellular), protection/cushioning for cell membrane, cell recognition, attaches cells together
chemical force (ion’s concentration gradient) and electrical force (effect of membrane potential on ion’s movement, inside cell membrane is negative while the outside is positive) acting on an ion
electrochemical gradient
release of free energy, ex: cellular respiration
exergonic reaction
absorbtion of free energy, “uphill”,stores free energy, ex: photosynthesis
endergonic reaction
role of ATP
energy currency of the cell, providing the energy for most of the energy-consuming activities of the cell.
how do enzymes work in reactions
lowering activation energy
factors that influence enzyme activity
-temperature & pH -coenzymes/cofactors -inhibitors
how temperature & pH effect enzyme activity
increasing heat can speed up reactions, over that temperature can cause the protein molecule to denature from disrupting weak bonds. same with pH. there are optimal conditions for enzymes.
how cofactors effect enzyme activity
nonprotein helpers for catalytic activity
how enzyme inhibitors effect enzyme activity
inhibit actions of enzymes
three stages of cell communication
- reception: signaling molecule outside cell binds to a receptor protein 2. transduction: signaling molecule changes receptor protein, initiating transduction. converts signal to a form that can bring about a certain cellular response. 3. response
How G protein coupled receptors receive cell signals and start transduction
G protein coupled receptor -> G protein -> adenylyl cyclase, catalyzes the conversion of ATP to cAMP -> cAMP activates another protein -> response
How receptor tyrosine kinases recieve cell signals and start transduction
react to binding of signaling molecules by forming dimers and then adding phosphate groups the tyrosines on the cytoplasmic part of the other monomer making up the dimer. relay proteins in the cell can be activated by binding to diff. tyrosine phosphates, allowing several pathways to trigger at once.