Biology 131
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108 terms
Terms | Definitions |
|---|---|
 Endo-membrane system | seperate structural and functional regions |
| Endo-membrane system | synthesizes proteins and lipids |
| Endo-membrane system | packaging and transport system |
| Endo-membrane system | sequestors toxic chemicals |
| Endoplasmic Reticulum | -membrane surrounding a lumen -rough ER -smooth ER -rough ER and smooth ER often continuous |
| Rough ER | -contains many ribosomes for protein synthesis -proteins are chemically modifies in lumen |
| Smooth ER | produces lipids and breaks down toxins |
| Golgi Complex | membranous sacs without ribosomes |
| Golgi Complex | chemical modification and packaging |
| Golgi Complex | regulates movement of many proteins |
| Golgi Complex | endocytosis of external susbstances |
| Lysosomes | membrane bound vesicle -contains hydrolytic enzymes -digestion and protection |
| Lysosomes | low pH phagocytosis |
| Prokaryotic cells | -bacteria and archaea -DNA -Cytoplasm -Plasma membrane -Rigid Cell wall |
| Cytoplasm | location of most metabolic activity |
| Plasma membrane | little or no internal membrane structure |
| Eukaryotic Cells | -membrane-bound nucleus -internal organelles -protists, fungi, animals, and plants |
| Nucleus | -contains chromatin -chromosomes -nuclear envelope |
| Chromatin | mixture of DNA and protein |
| Chromosomes | one DNA molecule and associated proteins |
| Nuclear Envelope | nuclear pores open between both layers |
| DNA | codes for genetic traits |
| Cytoplasm | ions and organic molecules in aqueous solution |
| Plasma membrane | lipid bilayer surrounding the cell |
| Cell | -highly organized, water-based compartment -filled with concentrated chemicals -bounded by a thin flexible "membrane" |
| The Cell Theory | -all organisms are composed of cells -the cell is the smallest "living" unit -all cells arise from pre-existing cells |
| Mitochondria | Two membranes -inner one is folded into cristae -surrounds matrix main function is ATP production -"powerhouse" of the cell -site of cellular respiration -breakdown of organic molecules to produce energy -requires oxygen |
| Structures of plant cells | chloroplasts central vacuoles cell walls |
| Which organelle is the site of most of the cells protein synthesis? | cytoplasmic ribosomes |
| In which organelle are steroid hormones synthesized? | the smooth ER |
| How many membranes surround a chloroplast from a plant cell? | 2 |
| Which type of cytoskeletal protein is responsible for the movement of chromosomes during cell division? | microtubules |
| DNA strands can be visualized using which instrument? | electron microscope |
| The organelles and biomolecules present in homogenized cells can be separated by centrifugation. Which of the following would be found at the top of a centrifugation gradient? | ATP molecules |
| Which organelle is found only in plants? | glyoxysomes |
| The endomembrane system contains what? | the golgi apparatus and ER |
| The presence of _______ means that substances must pass through, rather than between, the epithelial cells that form the lining of the small intestine. | tight junctions |
| Nucleic acids are not found in... | plant vacuoles |
| The proteins that make up the cytoskeleton of bacteria are similar to ______ in eukaryotic cells. | actin |
| Which protein powers the movement of both cilia and vesicles within a cell? | dynein |
| Which organelle is involved in energy conversions? | chloroplasts |
| Some proteins that are on the surface of mammalian cells contain carbohydrates. These proteins are synthesized by ______ and the sugars added in the _______. | the rough ER and golgi apparatus |
| Plastids | present in nearly all plant cells |
| Microtubules | directly involved with the movement of organelles within a cell |
| A universal feature of receptors is that they | undergo structural (shape) changes when the signal molecule is bound. |
| In facilitated diffusion, | specific integral membrane proteins mediate transport. |
| cAMP is referred to as a | second messenger |
| Which of the following molecules do you think would diffuse across a phospholipid bilayer fastest, assuming that there are no proteins associated with the bilayer? [Hint: Keep in mind the nature of the interior of the bilayer.] | NH3 |
| Hormones are chemical signals that | travel through circulatory systems. |
| The phosphorylation of proteins by ATP | is catalyzed by enzymes known as "protein kinases." |
| Caffeine | binds to receptors in the brain |
| The sodium-potassium pump (or Na+-K+ pump) | results in the formation of Na+ concentration gradient across the plasma membrane. |
| What would happen if a suspension of red blood cells in an isotonic NaCl solution was suddenly diluted with pure water by a factor of 10? | The cells would swell and lyse (burst). |
| Osmosis | the movement of water across membranes. |
| Phospholipids spontaneously form bilayer structures, but oils form small droplets. Why do oils not form bilayers? | Oils do not have the polar head group that phospholipids have. |
| In addition to the bilayer lipids and proteins, membranes may contain _______ in the form of _______ and _______. | carbohydrates; glycoproteins; glycolipids |
| Adenylyl cyclase | makes cAMP from ATP with the liberation of pyrophosphate (PPi). |
| Which step of the signal transduction cascade that results in glucose release during the "fight-or-flight" response does not directly involve a nucleotide? | Epinephrine binding to its receptor |
| Suppose the concentration of epinephrine in the blood stream of an animal drops. The cyclic AMP concentration in liver cells would be expected to _______ because _______ activity would _______. | decrease; adenylyl cyclase; decrease |
| In animals, cell recognition | involves proteins in plasma membranes. |
| Receptor-mediated endocytosis | results in the formation of clathrin-coated vesicles. |
| Chemical signal transduction pathways | involve binding of the signal molecule to receptors. |
| The mitochondrial ATP synthase | makes ATP at the expense of the proton gradient established by electron transport. |
| Reagents, such as dinitrophenol, increase the permeability of the mitochondrial inner membrane to protons. The addition of dinitrophenol to a suspension of animal cells should over the short term | inhibit mitochondrial ATP synthesis. |
| The ultimate source of energy for ATP synthesis in chloroplasts is | light |
| The major product of photosynthesis that is exported from the leaves to the rest of the plant is | sucrose. |
| In photosynthesis, NADPH is used for the | reduction of 3-phosphoglycerate (3PG). |
| Glycolysis | is an oxidation-reduction process. |
| The immediate source of energy for ATP synthesis in chloroplasts is | the electrochemical proton gradient. |
| Fermentation | results in the formation of lactic acid or ethanol. |
| The end products of glycolysis are | pyruvate, ATP, and NADH. |
| photosystem | a complex of pigments, proteins, and a reaction center chlorophyll |
| releases less energy than glycolysis | citric acid cycle |
| In green plant photosynthesis, water is | oxidized to oxygen gas (O2) in the light |
| The mitochondrial electron transport chain | oxidizes the intermediate electron carriers, NADH and FADH2. |
| Endergonic reactions are A) nonspontaneous B) spontaneous | nonspontaneous |
| absorption spectrum | A graph of light absorption versus wavelength of light; shows how much light is absorbed at each wavelength. |
| action spectrum | A graph of a biological process versus light wavelength; shows which wavelengths are involved in the process. |
| aerobic | presence of oxygen; requiring oxygen. (Contrast with anaerobic.) |
| anaerobic | Occurring without the use of molecular oxygen, O2. (Contrast with aerobic.) |
| carbon-fixation reactions | The phase of photosynthesis in which chemical energy captured in the light reactions is used to drive the reduction of CO2 to form carbohydrates |
| The catabolic pathways by which electrons are removed from various molecules and passed through intermediate electron carriers to O2, generating H2O and releasing energy. | cellular respiration |
| In photosynthetic light reactions, the flow of electrons that produces ATP but no NADPH or O2 | cyclic electron transport |
| The anaerobic degradation of a substance such as glucose to smaller molecules such as lactic acid or alcohol with the extraction of energy. | fermentation |
| The biochemical synthesis of glucose from other substances, such as amino acids, lactate, and glycerol | gluconeogenesis |
| An organism that requires preformed organic molecules as food | heterotroph |
| ATP formation in the mitochondrion, associated with flow of electrons through the respiratory chain. | oxidative phosphorylation |
| A quantum of visible radiation; a "packet" of light energy. | photon |
| Regulation of the activity of a protein (usually an enzyme) by the binding of an effector molecule to a site other than the active site. | allosteric regulation |
| A transport protein in plant and animal cell membranes through which water passes in osmosis. | aquaporin |
| autocrine | A chemical signal that binds to and affects the cell that makes it |
| A compound formed from ATP that acts as a second messenger. | cAMP (cyclic AMP) |
| A process by which liquids or solid particles are taken up by a cell through invagination of the plasma membrane | endocytosis |
| A process by which a vesicle within a cell fuses with the plasma membrane and releases its contents to the outside | exocytosis |
| Passive movement through a membrane involving a specific carrier protein; does not proceed against a concentration gradient. | facilitated diffusion |
| A lipid to which sugars are attached. | glycolipid |
| A protein in which sugars are attached | glycoprotein |
| Any molecule that binds to a receptor site of another (usually larger) molecule | ligand |
| Pertaining to a chemical signal, such as a hormone, that acts locally, near the site of its secretion | paracrine |
| Diffusion across a membrane; may or may not require a channel or carrier protein | passive transport |
| Endocytosis by a cell of another cell or large particle. | phagocytosis |
| Endocytosis by a cell of liquid containing dissolved substances. | pinocytosis |
| The hydrostatic pressure of an enclosed solution in excess of the surrounding atmospheric pressure | pressure potential |
| An enzyme that catalyzes the addition of a phosphate group from ATP to a target protein. | protein kinase |
| Allowing certain substances to pass through while other substances are excluded; a characteristic of membranes | selectively permeable |
| Cell that is responsive to a particular type of physical or chemical stimulation. | sensory receptor cell |
| The series of biochemical steps whereby a stimulus to a cell (such as a hormone or neurotransmitter binding to a receptor) is translated into a response of the cell. | signal transduction pathway |
| An integral membrane protein that spans the phospholipid bilayer. | transmembrane protein |
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