Cell E2 Review

What are the major steps in glycolysis?

1) glucose and atp make 2, G3P molecules, 2) these are oxidized and 2 ATP/NADH is made, 3) these molecules are then converted to 2 pyruvate, 2 more ATP made for a net of 2 ATP

What are the two major types of fermentation, what are the products?

lactate (= 2 lactate, 2 NAD+) and alcohol (2 ethanol, 2 CO2, 2 NAD+), they both yeild 2 ATP but only from glycolysis

all details about pyruvate oxidation

reactants are 2 pyruvate, 2 coA, 2 NAD+, products are 2 acetyl-coA, 2 NADH, no ATP generated, happens in mitochondrial matrix, sends the 2 acetyl-coA into CAC

all details of citric acid cycle

reactants are acetyl-coA, water, NAD/FAD, ADP, products are CO2, ATP, NADH, FADH2 and regenerates oxaloacetate, per 2 turns (for 2 pyruvate) yields 4 CO2, 6 NADH, 2 FADH2, 2 ATP, happens in mitochondrial matrix

What is the structure of the mitochondria and what happens where?

has inner and outer mems, outer for permeability with proteins, intermembrane space, inner mem has infoldings called crista/cristae, intercristial space is where protons accumulate in ETC, has matrix in the middle which is semifluid, has enzymes/ribosomes/DNA here

What do NADH, ADP, AMP, ATP, CoA, and AcetylcoA have to do with regulating the citric acid cycle?

ATP and NADH are products so these would inhibit the CAC, AMP/ADP/Acetyl coA and coA are reactants so these would probably promote the CAC

relate the lipid content of the inner mitochondrial membrane to its fluidity and the impact on diffusion of the respiratory complexes

the inner mitochondrial membrane has a high ratio of unsaturated fats to saturated fats, and basically no cholesterol so its fluidity is high and the mobility of the complexes is high

How many ATP are generated from each NADH and FADH2, use that to calculate energy yield from aerobic respiration?

NADH generates 3 and FADH2 generates 2, 8 from glycolysis (2 atp 2 NADH (3 each)), 6 from pyruvate oxidation (2 NADH), 24 from CAC (2 ATP, 6 NADH (18 atp) 2 NADH (4 ATP) = 38 theoretically

coenzyme A (coA)

it binds to a pyruvate and in this process releases CO2 (1 carbon), making acetyl-coA which is 2 carbons and coA

Acetyl coA

what is entered into CAC, this is 2 carbons from pyruvate and coenzyme A

oxaloacetate

this is what binds with acetyl coA in CAC, it ends up getting regenerated in this cycle

ribulose 1-5 biphosphate

this is a 5 carbon sugar group, primary carbon dioxide acceptor in calvin cycle, rubisco catalyzes reaction between this and co2 which splits the 6 carbon sugar into 2 molecules of 3 pga

rubisco

catalyzes reaction between CO2 and ribulose 1-5 biphosphate which makes 2 molecules of 3 PGA

photosystem

a protein complex found in thylakoids, captures light energy and moves electrons through light dependent reactions of photosynthesis

microtubule organizing center

acts as the main site for microtubule nucleation, stabilization, growth, specilized structure in eukaryotes, regulates cell shape, intracellular transport

What are the roles of various microtubule associated proteins?

usually for stablizing or severing

What are Rho GTPases and how are they inactivated/activated?

proteins that are activated when bound to GTP and inactive when bound to GDP, they help regulate the cytoskeleton, cell polarity, migration

What are the major steps in photosynthesis and what happens in each?

1) light dependent reactions which absorb light, water molecules split releasing oxygen (from excited e), electrons move through ETC to create ATP and NADPH 2) calvin cycle where carbon dioxide is turned into sugar

What are the products and reactants in the two major steps in photosynthesis?

1) reactants are water and sunlight, products are ATP, oxygen, NADPH 2) input is CO2, ATP, NADPH products are glucose/sugar, NAD, ADP

How does the adsorption spectrum of chlorophyll relate to the visible light spectrum and to the colors of light absorbed for photosynthesis versus reflected by green plants?

light travels as photons absorbed by pigments, energy is transfered to electron as photoexitation, different pigments absorb different wavelengths of light, chlorophyll a and b in most plants have a wide range of absorbance

What happens in the calvin cycle (3 stages), what is the main product and what are major reactants?

1) carbon fixation, CO2 and RuBP are combined to make citrate a 6 C sugar which is quickly broken into 2 molecules of 3 PGA (by rubisco), 2) then reduction which makes 6 G3P and uses 6 ATP, 6 NADPH, 1 of the G3P then goes to make glucose or sugar while the other 5 3) regenerate RuBP using 3 more ATP

What is dynamic instability? How does it work?

the quick switching between growth and shrinkage at ends of microtubules depending on environment

What are some of the structures that microfilaments form?

microvilli (increase surface area of cell with finger like protrusions), cell cortex (gel like network of actin filaments below membrane, supports cell shape and mechanics), stress fibers (contractile bundles of actin and myosin help cell adhere to surfaces and maintain tension), contractile rings (help pinch during cytokineses), lamellipodium and filipodium

How much ATP and NADPH are needed to fix one CO2? To produce one glyceraldehyde-3-phosphate?

to fix 1 CO2 would be 3 ATP and 2 NADPH, but to produce one neg G3P would be 9 ATP and 6 NADPH

How have some plants adapted to reduce rubisco’s oxygenase activity, what are the advantages and disadvantages

typically involves boosting/storing CO2 levels sometimes by making it into an acid

What is the role of GTP binding to tubulin for microtubule stability?

GTP binding promotes MT assembly and stability, GDP triggers depolymerization and weakens the contacts

Difference between lumen/stroma and matrix/intercristial space

lumen and stroma in chloroplast, lumen is inside thylakoids, stroma is outside of thylakoids, matrix and intercristial space are in mitochondria, matrix is all the way inside while intercristial space is in between membranes

properties of microtubules, microfilaments, and intermediate filaments

MTs: tubulin, polarity, uses GTP, largest, MFs: actin, polarity, smallest, uses ATP, IFs: middle, different subunits, no substrate, no polarity

functions of microtubules

cell shape and structural support, cell polarity, tracks for motility of organelles, mitotic spindle, flagella and cilia motility

functions of microfilaments

cell structure (edge), cell attachment and locomotion, muscle contraction, cleavage furrow in cytokinesis, cytoplasmic streaming, cell crawling

functions of intermediate filaments

structural support, bears tension yet flexible, nuclear laminate and scaffolding, hair

how do cells crawl over substrates?

they use lamellipodia and filopodia (actin/MF), extension of leading edge, attachment, tension generated and pulls forward, trailing edge released

What are cell adhesion molecules and what are their roles?

proteins on cell surface that helps cells stick to each other or to the ECM

What is the extracellular matrix and what is its role?

network of proteins, enzymes and sugars that support cells in tissues, helps cells attach, communicate, grow, and move

What molecules comprise the ECM, what are their properties how do they work?

there are structural proteins such as elastin and collagen which give it strength and flexibility, there are proteoglycans which are protein/sugar complexes that provide the matrix in which the structural molecules are in, also adhesive glycoproteins such as laminins, fibronectins that allow cells to attach to ecm (binding w integrin)

How is DNA packaging regulated, how can histones be modified?

methylation of histones which can be repressive or activation, acetylation which promotes decondensation (increases gene expression)

lamellipodia and filopodia

lamellipodia is a thin sheet of cytosol while filopodia is finger like projections

Arp 2/3

a complex of proteins to nucleate and build branched networks of actin filaments

What is the epithelial to mesenchymal transition and how is it related to cancer?

a process where stationary, polarized epithelial cells lose their cell adhesion and structural polarity and transform into mobile/invasive mesenchymal like cells, cancer cells undergo EMT and will begin metastasis

what is the nuclear matrix, what is the function?

maintains the shape of nucleus and provides an organizing skeleton for the chromatin fibers

cadherin

used in adhesive junctions, helps cells stick together and maintain tissues (needs calcium)

b-catenin

binds to cadherin, role in cell adhesion

claudin

used in tight junctions, thought to interlock together to form a tight seal

connexin

used in gap junctions, hollow channels that allow ions and small molecules but not larger molecules

collagen

in ECM, most abundant protein, forms fibers with high strength, one of the structural proteins

elastin

in ECM as structural protein, stretchable elastic fibers

proteoglycans

protein + GAG chains forming the adhesive glycoproteins

fibronectin

can bind to macromolecules in ECM and cell surfaces, associate with cell surfaces , bind to integrins

laminin

for structural support and maintains tissue organization and regulates movement of molecules into cells, binds to integrin

integrin

these integrate the cytoskeleton with the ECM, bind to fibronectin and laminin (in ECM)