MCAT prep Biological Science P1

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concept checks from kaplan- biological sciences review book
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Flashcards by sabrinaparker905, updated more than 1 year ago
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Question Answer
check 1.1 Id the components of the Cell Theory 1. 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
Check 1.2 a. components of a light microscope and their functions 1. 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
check 1.2 b. advantages and disadvantages of different kinds of microscopy a. 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
check 1.2 c. autoradiography and centrifugation autoradiography: 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
check 1.3 prokaryotes vs. eukaryotes prokaryotes: 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
check 1.4 organelles: nucleus functions as city hall, contains DNA, has subsection nucleolus where the ribosomal RNA (rRNA) is made
check 1.4 organelles: ribosomes responsible for protein production; 2 types free and bound
check 1.4 organelles: endoplasmic reticulum 2 types: smooth and rough (ribosomes); ER is responsible for the proper production and sorting of materials from cell, shipping center
check 1.4 organelles: Golgi Apparatus repackages certain products; gets stuff from smooth ER, and sends to cell surface
check 1.4 organelles: vesicles and vacuoles (plant) used to transport and store materials that are ingested, secreted, processed, or digested by the cell
check 1.4 organelles: lysosomes garbage dumps of cells, material is brought in by endosomes, break down materials ingested by the cell; autolysis
check 1.4 organelles: mitochondria powerhouse of the cell, inner membrane: ETC
check 1.4 organelles: microbodies catalyze 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
check 1.4 organelles: chloroplasts solar power plants found in photosynthetic organisms (plants and algae)
check 1.4 endosymbiotic theory certain eukaryotic organelles originated from ingested prokaryotes (ex. mitochondria)
check 1.4 organelles: plants vs. animal plants have glycosomes, chloroplasts, cell well (cellulose)
check 1.4 cytoskeleton its 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
check 1.5 hypotonic hypotonic soln: concentration of solutes inside the cell is higher than the surrounding soln; causes the cell to swell - burst
check 1.5 hypertonic hypertonic soln: higher concentration outside the cell, water leaves the cell and it shrivels
check 1.5 isotonic equal concentrations with equal H20 flow
check 1.5 facilitated diffusion/passive transport uses integral membrane proteins to serve as channels for substrates to avoid the hydrophobic region
check 1.5 simple diffusion doesn't need energy, move down concentration gradient
check 1.5 active transport uses energy, goes against the conc. gradient, transports polar molecules or ions
check 1.5 osmosis simple diffusion of water
check 1.6 virus nuclear 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
check 1.6 bacteriophages specifically target bacteria, inject genetic material, has nuclei acid, protein coat, tail sheath, tail fibers
check 1.6 virus is nonliving obligate intracellular parasites- cannot replicate independently
ch. 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
ch. 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
check 2.1 functions of enzymes lower 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
check 2.2 substrate and enzyme specifity enzymes tend to catalyze a single rxn or a class of rxns
check 2.2 lock and key theory enzyme's active site (lock) is already in the appropriate confirmation for the substrate (key) to bind
check 2.2 induced fit theory more 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
check 2.3 role of cofactors and coenzymes in supporting the catalysis of biological rxns cofactors: nonprotein molecules (ie small metal ions and small organic groups) coenzymes: the organic cofactors, a vast majority are vitamins
ch. 2.4 enzyme: substrate concentration add more substrate, rate of rxn increase until we begin to level off and reach a max
check 2.4 enzyme: substrate concentration rxn 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
check 2.4 enzyme: temperature enzyme-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
check 2.4 enzyme: pH in 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
check 2.5 allosteric effects allosteric enzymes alternate tween an active/inactive form, causes conformational shift in the protein, and there are activators and inhibitors
check 2.5 allosteric effects: hemoglobin the binding of one molecule of oxygen to hemoglobin shifts the entire molecule, so there is an increased affinity of the remaining subunits for oxygen
check 2.5 feedback inhibition used 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
check 2.5 competitive inhibition occupancy of the active site, can be overcome by adding more substrate so that the substrate to inhibitor ratio is higher, increase in Km
check 2.5 noncompetitive inhibition inhibitor binding to an allostreric site that changes the enzyme conformation; cannot be overcome by adding substrate, Km unchanges but Vmax lowers
check 2.6 zymogens zymogens: have a catalytic (active) domain and regulatory domain, regulatory domain must be either removed or altered to expose the active site
Ch. 2 post-test positive feedback examples childbirth, and clotting
check 3.1 energy storage molecules that are made or used by cells ATP: adenosine triphosphate- primary NAD+: nicotinamide adenine dinucleotide -- NADH (reduced) FAD: flavin adenine dinucleotide (FADH2)
check 3.1 cellular respiration equation C6H12O6 + O2 --> 6 CO2 + 6 H2O + energy
check 3.2 Glycolysis Glucose + 2 ADP + 2Pi + 2 NAD(+)--> 2 pyruvate + 2 ATP + 2 NADH + 2H(+) + 2 H20
check 3.2 glycolysis and ATP total energy output of 4 ATP but a net output of only 2 ATP cause 2 are used to drive the process
check 3.2 fermentation fermentation reduces pyruvate to either ethanol or lactic acid; NADH is oxidized to NAD +
check 3.2 alcohol fermentation pyruvate (3C) --> CO2 + acetaldehyde (2C) acetaldehyde + NADH + H+ --> ethanol (2C) + NAD +
check 3.2 lactic acid fermentation pyruvate (3C) + NADH + H+ --> Lactic Acid + NAD+
check 3.2 cori cycle lactic acid conversion to pyruvate
check 3.2 cellular respiration overview 36 to 38 ATP per molecule of glucose and its aerobic; has 3 major parts pyruvate decarboxylation, citric acid cycle, electron transport chain
check 3.2 pyruvate decarboxylation 2C are lost as CO2 2 pyruvate (3C) + 2 CoA + 2 NAD+ --> 2 NADH + 2 Acetyl-CoA (2C) + 2 CO2 (1C)
check 3.2 citric acid cycle in/out in words cycle 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
check 3.2 citric acid cycle energy every 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)
check 3.2 citric acid cycle: overall rxn 2 Acetyl-CoA + 6 NAD+ + 2 FAD + 2 GDP + 2 Pi + 4 H20 --> 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP + 4 H+ + 2 CoA
check 3.2 Electron Transport Chain oxidative 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
check 3.2 final electron acceptor O2
check 3.2 poison inhibition of ETC cyanide 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
check 3.2 ATP generation and the proton pump energy 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
check 3.2 proton-motive force electrochemical gradient drives H+ passively back across the inner mitochondrial membrane into the mitochondrial matrix
check 3.2 oxidative phosphorylation H+ ions pass through ATP synthases back into the matrix, the energy released allows for the phophorylation of ADP to ATP
check 3.3 metabolism of fats fatty acids undergo beta oxidation which produces acetyl-CoA (TCA input), can undergo 24 rounds
check 3.3 metabolism of proteins only 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
check 3.2 metabolism of carbs vs. fats vs. proteins all lead to TCA cycle and CO2
ch. 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
ch. 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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