MCAT bio
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119 terms
Terms | Definitions |
|---|---|
 Cell Theory | 1. All living things are composed of cells 2. The cell is the basic functional unit of life 3. Cells arise only from preexisting cells 4. Cells carry genetic info in the form of DNA |
| Magnification | Increase in apparent size of an object |
| Resolution | Ability to differentiate two closely placed objects |
| Components of Compound Light Microscope | 1. Diaphragm 2. Coarse Adjustment Knob 3. Fine Adjustment Knob |
| Diaphragm | Controls the amount of light passing through the specimen which is important for image control |
| Coarse Adjustment Knob | Focuses the image |
| Fine Adjustment Knob | Finely focuses the image |
| Hematoxylin | Dye that will show nucleic acids within the cell by binding to their negatively charged sugar-phosphate backbone moieties |
| Electron Microscope | Most powerful microscope that allows us to image down to the atomic level |
| techniques for examining the organism | Microscopy, autoradiography, and centrifugation |
| Centrifugation | Spinning down test tubes at high speeds to fractionate cells based on density |
| Prokaryotes | -Simplest of all organisms -Include all bacteria -Cell wall does not enclose any membrane-bound organelles -Genetic material is contained in a single circular molecule of DNA reproduction |
| Bacteria | -Rod-shaped or spherical -Contain a cell membrane and cytoplasm |
| Flagella | Gives cell motility |
| Chromosomes | Linear strands of genetic material encoded in DNA |
| Cytoskeleton | Made of 3 types of proteins: actin filaments, intermediate filaments and microtubules |
| Cell membrane (city wall) | Made of a phospholipid bilayer that encloses the cell and selectively chooses what to let in and out |
| Fluid mosaic model | The phospholipid bilayer is studded with proteins and lipid rafts that can control the movement of solutes in and out of the cell |
| Cholesterol | Help with membrane fluidity and generate steroid hormones |
| Transport proteins (border agents) | Allow protein molecules and ions move in and out of the cell |
| Cell adhesion molecules | Proteins that allow cells to recognize each other and contribute to proper cell differentiation and development |
| Nucleus (city hall and public library) | **commonly tested on MCAT -Control center of the cell |
| Nuclear membrane or envelope | Double membrane that maintains a nuclear environment separate and distinct from the cytoplasm |
| Nuclear pores | Allow for selective two-way exchange of material into and out of the nucleus |
| Genes | Coding regions of genetic material |
| Histones | Organizing proteins that wind linear DNA |
| Chromosomes | Wound linear strands of DNA |
| Nucleolus | Subsection of the nucleus where the ribosomal RNA is synthesized |
| Ribosomes (factories) | -Responsible for protein production -Can be free or bound |
| Endoplasmic reticulum (shipping department) | -Responsible for proper production and sorting of materials from the cell -Two types: smooth and rough |
| Smooth ER | -Lipid synthesis and detoxification of drugs and poisons |
| Rough ER | -Involved in production of protein products |
| Golgi Apparatus | -membrane-bound sacs -receives materials from the ER and then repackages them (in secretory vesicles) to send to the cell surface |
| Exocytosis | Process in which contents are released to a cell's exterior |
| Vesicles and vacuoles | Used to transport and store materials that are ingested, secreted, processed or digested by the cell |
| Lysosomes (garbage dumps) | Take material brought in by endosomes that have hydrolytic enzymes that break down materials ingested by the cell |
| Mitochondria (power plant) | -Supplies energy; contains molecules and enzymes necessary for the electron transport chain |
| Cristae | -in-foldings or highly convoluted structures that increase the surface area for the electron transport chain enzymes to sit within |
| Peroxisomes | Creates hydrogen peroxide within a cell and are used to break down fats into usable molecules |
| Glyoxysomes | Important in germinating plants; convert fats to usable fuel (sugars) until the plant can make its own energy via photosynthesis |
| Chloroplasts | Contain chlorophyll and are responsible for the generation of energy using water, carbon dioxide and sunlight |
| Cell wall | -In eukaryotes, cells surrounded by cell wall for defense and increased stability -In plant cells, cell wall composed of cellulose |
| Osmosis | specific kind of simple diffusion that concerns water; water will move from a region of lower solute concentration to one of high solute concentration |
| Hypotonic | when concentration of solutes inside the cell is higher than the surrounding solution--> swell |
| Hypertonic | when concentration of solutes inside the cell is lower than the surrounding solution--> shrink |
| Isotonic | when solutions inside and outside are equimolar |
| Facilitated Diffusion (Passive transport) | simple diffusion for molecules that need help |
| Active Transport | net movement of a solute against its concentration gradient; requires energy |
| Endocytosis | process whereby the cellular membrane invaginates and engulfs material into the cell |
| Pinocytosis | endocytosis of fluids and small particles |
| Phagocytosis | ingestion of large molecules |
| Viruses | Acellular structures composed of nucleic acids surrounded by a protein coat |
| Endothermic reaction | one that requires energy input |
| Exothermic reaction | one in which energy is given off |
| Enzymes | -Lower activation energy of a reaction -Increase the rate of the reaction -Do not affect the overall delta G of the reaction -Are not changed or consumed in the course of the reaction |
| Chymotrypsin | Cleaves peptide bonds around the amino acids phenylalanine, tryptophan, and tyrosine in a variety of polypeptides |
| Substrate | Molecule upon which an enzyme acts |
| Enzyme-substrate complex | Complex between the enzyme and substrate |
| Active site | Location within the enzyme where the substrate is held during the chemical reaction |
| 2 theories on how enzymes and substrates interact | 1. The lock and key theory 2. Induced fit theory |
| Lock and key theory | the enzyme's active site (lock) is already in the appropriate confirmation for the substrate (key) to bind |
| Induced fit theory (stress ball) | enzyme fits the substrate |
| cofactors | nonprotein molecules that many enzymes require |
| apoenzymes | enzymes without their cofactors |
| holoenzymes | enzymes containing cofactors |
| 2 types of cofactors | -small metal ions -small organic groups |
| Coenzymes | organic cofactors |
| Saturation | Point in which the substrate-enzyme reaction has reached maximum velocity |
| Effects of temperature (Siamese cats) | Enzyme-catalyzed reactions double in rate for every 10 degree increase in temperature until optimum temperature is reached |
| Effects of pH | Enzymes function properly when this is optimal |
| Allosteric enzymes | enzymes that have multiple binding sites and alternate between an active and an inactive form |
| Allosteric sites | the active site is present as well as at least one other site that can regulate the availability of the active site |
| 3 types of reversible inhibition | 1. competitive 2. noncompetitive 3. uncompetitive |
| Competitive inhibition | involves occupancy of the active site |
| Noncompetitive inhibition | inhibitor binding to an allosteric site instead of the active site, which induces a change in enzyme conformation |
| Zymogens | any inactive enzyme precursor that is converted into an active enzyme |
| CoQ10 | a vitamin that is found in the inner mitochondrial membrane of the cell and helps make ATP |
| Autotrophs | organisms that are capable of using the sun's energy to create organic molecules that can store that energy in their bonds |
| Heterotrophic organisms | Derive their energy by breaking down the organic molecules made by plants and harnessing the power held in the bonds of the molecules |
| ATP, NAD+, FAD | These molecules serve as high-energy electron shuttles between the cytoplasm and mitochondria |
| NAD+ and FAD | These coenzymes are capable of accepting high-energy electrons during glucose oxidation |
| Reduction | When NAD+ and FAD accept hydride ions during glycolysis and the Krebs cycle |
| Oxidation | When hydride electrons are removed to produce ATP |
| Glycolysis | Series of reactions that break down glucose into two smaller organic molecules; anaerobic |
| 3 key phases in cellular respiration | 1. pyruvate decarboxylation 2. citric acid cycle 3. electron transport chain |
| 3 major complexes of ETC | 1. NADH dehydrogenase (complex I) 2. b-c1 complex (complex III) 3. cytochome oxidase (complex IV) |
| oxygen | final electron acceptor in the electron transport chain, resulting in the formation of a water molecule |
| cyanide | molecule that blocks the final transfer of electrons to O2 |
| dinitrophenol (DNP) | molecule that destroys the mitochondrion's ability to generate a useful proton gradient that is necessary for effective ATP generation |
| 2 sources of energy in glucose catabolism | 1. substrate-level phosphorylation 2. oxidative phosphorylation |
| 36 ATP | Eukaryotic ATP production per glucose molecule |
| 38 ATP | Prokaryotic ATP production per glucose molecule |
| Carbohydrates | sugar polymers that can be broken down during digestion and then stored in the liver for later use in a polysaccharide form |
| Fats | stored in adipose tissue in the form of triglycerides |
| Proteins | polypeptides that are used as energy sources when carbohydrates are insufficient |
| Cell division | Process whereby a cell replicates its DNA, doubles its organelles and cytoplasm and then splits into 2 daughter cells |
| Binary Fission | seen in bacteria, this is a type of asexual production in which a single DNA molecule attaches itself to the cell membrane and duplicates itself to while the cell itself grows in size; the cell then invaginates or pinches inward to create two identical daughter cells; results in two cells of equal size |
| Autosomal cells | Contain diploid (2n) number of chromosomes |
| Haploid cells | Germ cells that contain the n number of chromosomes |
| Interphase | Consists of the G1, S, G2 and M phases |
| G1 phase (presynthetic gap) | during this phase, cells will create organelles for energy and protein production while also doubling in size |
| Restriction point | to pass this, certain criteria must be met for the cell to pass and enter the synthetic phase |
| S phase | during this phase, we replicate, or synthesize, the genetic material in the cell so that each daughter cell will have identical copies |
| G2 phase (postsynthetic gap) | final stage before cell division; quality control; make sure that there are enough organelles and cytoplasm to make two new daughter cells |
| Mitosis | divided into 4 phases: prophase, metaphase, anaphase, and telophase |
| Cytokinesis | the splitting of the cytoplasm and organelles into the daughter cells |
| Prophase | chromosomes condense, spindles form; nuclear envelope dissolves, allowing spindle fibers to enter the nucleus; kinetochores appear at the chromosome centromere |
| Metaphase | chromosomes align at the equatorial plate, which is equidistant to the two poles of the spindle fibers |
| Anaphase | sister chromatids separate |
| Telophase | new nuclear membranes form |
| Centrioles | paired cylindrical organelles outside of the nucleus in the centrosome and are responsible for the correct division of the DNA |
| Spindle fibers | made from microtubules; radiates outward from centrioles |
| Asexual reproduction | production of offspring from the genetic material of a single parent |
| Budding | equal replication followed by unequal cytokinesis |
| Regeneration | process in which an entire body part can be regrown |
| Parthenogenesis | process by whereby an adult organism develops from an unfertilized egg |
| Extraction | lab technique used to separate a mixture of compounds based on their relative solubilities in two immiscible solvents while taking advantage of the acid/base properties of function groups on the molecules |
| Chromatography | lab technique used to separate compounds based on their relative polarities and may show up as thin-layer, column, or gas chromatography |
| optical activity | in order for this to happen, a compound must contain a chiral carbon |
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