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MCAT prep Biological Science P1
Fichas del conjunto (69)
- 1check 1.1 Id the components of the Cell Theory1. all living things are made of cells
2. cell is the basic functional unit of life
3. cells only arise from pre-existing cells
4. cells carry genetic info in the form of DNA - 2Check 1.2 a. components of a light microscope and their functions1. diaphragm: controls the amount of light passing through the specimen
2. coarse adjustment knob: roughly focuses the image by moving the stage
3. fine adjustment knob: finely focuses the image - 3check 1.2 b. advantages and disadvantages of different kinds of microscopya. compound light microscope- most common, used for nonliving specimens
b. phase contrast microscope: for living organisms, uses differences in refractive indices
c. electron microscope: most powerful microscope- down to the atomic level, uses a beam of electrons, in picometers - 4check 1.2 c. autoradiography and centrifugationautoradiography: uses radioactive decay to follow biochm. processes that occur in the cell, exposed to an essential cmpd that include radioactive atoms, the cells are incubated, fixed, covered with photographic film and kept in the dark, image on the film shows the distribution of radioactive material within the cell
centrifugation: spinning at very rapid speeds, it increases the force put on the material in the test tubes and separates stuff by gravity - 5check 1.3 prokaryotes vs. eukaryotesprokaryotes: bacteria, cell wall in all, no nucleus, ribosomes (30S and 50S), no membrane bound organelles, unicellular
eukaryotes: protists, fungi, plants, animals, cell in some stuff, nucleus, ribosomes (40S, 60S), membrane bound organelles, uni or multicellular - 6check 1.4 organelles: nucleusfunctions as city hall, contains DNA, has subsection nucleolus where the ribosomal RNA (rRNA) is made
- 7check 1.4 organelles: ribosomesresponsible for protein production; 2 types free and bound
- 8check 1.4 organelles: endoplasmic reticulum2 types: smooth and rough (ribosomes); ER is responsible for the proper production and sorting of materials from cell, shipping center
- 9check 1.4 organelles: Golgi Apparatusrepackages certain products; gets stuff from smooth ER, and sends to cell surface
- 10check 1.4 organelles: vesicles and vacuoles (plant)used to transport and store materials that are ingested, secreted, processed, or digested by the cell
- 11check 1.4 organelles: lysosomesgarbage dumps of cells, material is brought in by endosomes, break down materials ingested by the cell; autolysis
- 12check 1.4 organelles: mitochondriapowerhouse of the cell, inner membrane: ETC
- 13check 1.4 organelles: microbodiescatalyze specific types of rxn by sequestering the necessary enzymes and substrates
peroxisomes: create hydrogen peroxide within a cell, break down fats, detoxifaction catalysis in liver
glyoxysomes: important in germinating plants; convert fats to fuel - 14check 1.4 organelles: chloroplastssolar power plants found in photosynthetic organisms (plants and algae)
- 15check 1.4 endosymbiotic theorycertain eukaryotic organelles originated from ingested prokaryotes (ex. mitochondria)
- 16check 1.4 organelles: plants vs. animalplants have glycosomes, chloroplasts, cell well (cellulose)
- 17check 1.4 cytoskeletonits the highway system of our cell, transport system and structural strength
3 cmpts: microfilaments, microtubules, and intermediate filaments
microfilaments: actin and myosin- muscular contraction, movement of materials within cell membrane
microtubules are hollow and polymers of tubulin proteins, involved in chromosomal separation, structural basis for cilia and flagella
intermediate filaments help maintain the overall integrity of the cytoskeleton - 18check 1.5 hypotonichypotonic soln: concentration of solutes inside the cell is higher than the surrounding soln; causes the cell to swell - burst
- 19check 1.5 hypertonichypertonic soln: higher concentration outside the cell, water leaves the cell and it shrivels
- 20check 1.5 isotonicequal concentrations with equal H20 flow
- 21check 1.5 facilitated diffusion/passive transportuses integral membrane proteins to serve as channels for substrates to avoid the hydrophobic region
- 22check 1.5 simple diffusiondoesn't need energy, move down concentration gradient
- 23check 1.5 active transportuses energy, goes against the conc. gradient, transports polar molecules or ions
- 24check 1.5 osmosissimple diffusion of water
- 25check 1.6 virusnuclear info may be circular or linear, single or double stranded, DNA or RNA, hijacks a cell machinery, virus will replicate and turn out new copies of itself known as virions
- 26check 1.6 bacteriophagesspecifically target bacteria, inject genetic material, has nuclei acid, protein coat, tail sheath, tail fibers
- 27check 1.6 virus is nonlivingobligate intracellular parasites- cannot replicate independently
- 28ch. 1 post-test 5. which of the following types of nucleic acid will never be found in a virus?In a virus, nucleic acid can be either linear or circular and is found in 4 varieties: 1 strand DNA/RNA, 2x DNA/RNA
- 29ch. 1 post-test 8. Which of the following is NOT a function of the smooth endoplasmic reticulum?the smooth ER is involved in transport of materials throughout the cell, in lipid synthesis, and in the detoxification of drugs and poisons. Proteins can cross into smooth ER, where they are secreted into cytroplasmic vesicles and transported to the Golgi apparatus. Protein syn. is not a function of the smooth ER but rather of the ribosomes associated with the rough ER
- 30check 2.1 functions of enzymeslower activation energy of a rxn, do not affect the overall delta G or delta H, are not changed or consumed in the course of the rxn
- 31check 2.2 substrate and enzyme specifityenzymes tend to catalyze a single rxn or a class of rxns
- 32check 2.2 lock and key theoryenzyme's active site (lock) is already in the appropriate confirmation for the substrate (key) to bind
- 33check 2.2 induced fit theorymore scientifically accepted; substrate and enzyme active site don't seem to fit together, once the substrate is present and ready to interact with the active site, molecules find the induced form or transition state. shape of the active site becomes complementary only after the substrate binds the enzyme
- 34check 2.3 role of cofactors and coenzymes in supporting the catalysis of biological rxnscofactors: nonprotein molecules (ie small metal ions and small organic groups)
coenzymes: the organic cofactors, a vast majority are vitamins - 35ch. 2.4 enzyme: substrate concentrationadd more substrate, rate of rxn increase until we begin to level off and reach a max
- 36check 2.4 enzyme: substrate concentrationrxn rate= .5Vmax, Km= [S], when [S] is less than Km, changes in [S] will greatly affect the rxn rate, at high [S], it exceeds Km and approaches Vmax
- 37check 2.4 enzyme: temperatureenzyme-catalyzed rxns tend to double in rate for every 10 C increase until the best temp is reached for the human body it is 37 C
- 38check 2.4 enzyme: pHin human blood, optimal pH is 7.4, pH of 7.3 is acidosis; pepsin-stomach has max activity around pH 2, pancreatic enzymes (small instestine) work best around pH 8.5
- 39check 2.5 allosteric effectsallosteric enzymes alternate tween an active/inactive form, causes conformational shift in the protein, and there are activators and inhibitors
- 40check 2.5 allosteric effects: hemoglobinthe binding of one molecule of oxygen to hemoglobin shifts the entire molecule, so there is an increased affinity of the remaining subunits for oxygen
- 41check 2.5 feedback inhibitionused in hormone inhibition; the product of a rxn may bind to an enzyme or enzymes that acted earlier in its biosynthetic pathway, thereby making the enzyme unavailable for other substrates to use
- 42check 2.5 competitive inhibitionoccupancy of the active site, can be overcome by adding more substrate so that the substrate to inhibitor ratio is higher, increase in Km
- 43check 2.5 noncompetitive inhibitioninhibitor binding to an allostreric site that changes the enzyme conformation; cannot be overcome by adding substrate, Km unchanges but Vmax lowers
- 44check 2.6 zymogenszymogens: have a catalytic (active) domain and regulatory domain, regulatory domain must be either removed or altered to expose the active site
- 45Ch. 2 post-test positive feedback exampleschildbirth, and clotting
- 46check 3.1 energy storage molecules that are made or used by cellsATP: adenosine triphosphate- primary
NAD+: nicotinamide adenine dinucleotide -- NADH (reduced)
FAD: flavin adenine dinucleotide (FADH2) - 47check 3.1 cellular respiration equationC6H12O6 + O2 --> 6 CO2 + 6 H2O + energy
- 48check 3.2 GlycolysisGlucose + 2 ADP + 2Pi + 2 NAD(+)--> 2 pyruvate + 2 ATP + 2 NADH + 2H(+) + 2 H20
- 49check 3.2 glycolysis and ATPtotal energy output of 4 ATP but a net output of only 2 ATP cause 2 are used to drive the process
- 50check 3.2 fermentationfermentation reduces pyruvate to either ethanol or lactic acid; NADH is oxidized to NAD +
- 51check 3.2 alcohol fermentationpyruvate (3C) --> CO2 + acetaldehyde (2C)
acetaldehyde + NADH + H+ --> ethanol (2C) + NAD + - 52check 3.2 lactic acid fermentationpyruvate (3C) + NADH + H+ --> Lactic Acid + NAD+
- 53check 3.2 cori cyclelactic acid conversion to pyruvate
- 54check 3.2 cellular respiration overview36 to 38 ATP per molecule of glucose and its aerobic; has 3 major parts pyruvate decarboxylation, citric acid cycle, electron transport chain
- 55check 3.2 pyruvate decarboxylation2C are lost as CO2
2 pyruvate (3C) + 2 CoA + 2 NAD+ --> 2 NADH + 2 Acetyl-CoA (2C) + 2 CO2 (1C) - 56check 3.2 citric acid cycle in/out in wordscycle starts with the combination of acetyl-CoA (2C) and oxaloacetate (4C) to generate citrate (6C), 8 rxns, 2 CO2 molecules released, and oxaloacetate is regenerated
- 57check 3.2 citric acid cycle energyevery turn of the cycle makes 1 ATP generate high-energy electrons that are carried by NADH and FADH2;
for each molecule of acetyl-CoA that enters the cycle, 3 NADH and 1 FADH2 are produced (x2 to get total for 1 glucose) - 58check 3.2 citric acid cycle: overall rxn2 Acetyl-CoA + 6 NAD+ + 2 FAD + 2 GDP + 2 Pi + 4 H20 --> 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP + 4 H+ + 2 CoA
- 59check 3.2 Electron Transport Chainoxidative phosphorylation is the process by which electron from NADH and FADH2 are passed along an assembly line of carriers that release free energy with each transfer: carriers are cytochromes
- 60check 3.2 final electron acceptorO2
- 61check 3.2 poison inhibition of ETCcyanide blocks the final transfer of e- to O2; DNP (dinitrophenol) destroys the mitochondrion's ability to generate a useful H+ gradient that's necessary for effective ATP generation
- 62check 3.2 ATP generation and the proton pumpenergy production relies on coupling the energy drops to the phosphorylation of ADP; H+ gradient across the inner mitochondrial membrane links the oxidation of NADH and FADH2 to ADP phosphorylation; H+ accumulates in the mitochondrial matrix
- 63check 3.2 proton-motive forceelectrochemical gradient drives H+ passively back across the inner mitochondrial membrane into the mitochondrial matrix
- 64check 3.2 oxidative phosphorylationH+ ions pass through ATP synthases back into the matrix, the energy released allows for the phophorylation of ADP to ATP
- 65check 3.3 metabolism of fatsfatty acids undergo beta oxidation which produces acetyl-CoA (TCA input), can undergo 24 rounds
- 66check 3.3 metabolism of proteinsonly used when carbs are insufficient, transaminases remove the amine moiety from amino acids and create alpha-keto acids, these acids can be converted into acetyl-CoA or intermediates of TCA cycle
- 67check 3.2 metabolism of carbs vs. fats vs. proteinsall lead to TCA cycle and CO2
- 68ch. 3 post-test 12. what is the total amount of ATP yielded by the catabolism of 1 glucose molecules via Krebs cycle?24 ATPs
Total ATP made/acetyl-CoA molecule: 3x3 (from NADH) + 2 (FADH2) + 1 (GTP)= 12 X2(times around) = 24 - 69ch. 3 post-test Given the triglyceride breakdown process, why does it generally take a long time to lose pounds of fat while dieting?There is a great amount of energy stored in triglycerides, which make up a large % of fat tissue. in order to lose a fat molecule or a pound of fat you must use up all energy in the fat without storing more fat, so much energy in the fat that the process of fat loss takes a long time
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- concept checks from kaplan- biological sciences review book
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- sabrinaparker905
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