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Biology Exam 2
| Question | Answer |
|---|---|
| Define Biological Membranes | -Regulates cell transport and signaling -Composed of a bilayer with proteins |
| Types of Membrane Protein | Peripheral, lipid linked, and integral |
| Integral (Transmembrane) | -Have one or more regions physically embedded in the phospholipid bilayer |
| Lipid Linked | -Lipid-molecule is covalently attached to an amino acid side chain within the protein |
| Phospholipids | -Noncovalently bound either to integral membrane proteins that project out from the membrane, or to polar head groups of phospholipids |
| Lipid Rafts | -a group of lipids floating together as a unit -high concentration of cholesterol -unique set of membrane proteins |
| Factors affecting fluidity | -lengths of phospholipid tails -double bonds -cholesterol -temperature |
| Passive Transport | -requires no energy input |
| active transport | -the movement of material through a cell membrane using energy -two types: primary and secondary transport -against its gradient from low to high -EX: movement of CA2+ ions |
| Primary Transport | EX: Sodium potassium pump |
| Secondary Transport | EX: Sodium glucose pump |
| Endocytosis | -three types -receptor, pinocytosis, and phagocytosis -EX: Immune system -Plasma membrane folds inwards to form a vesicle that brings substance into the cell |
| Isotonic | -equal solute on both sides of the membrane |
| Symporter | -two or more ions or molecules that transport things in the same direction |
| Antiporter | -two or more ions or molecules transported in opposite direction |
| Pinocytosis | -membrane vesicles form from the plasma membrane to allow cells to internalize the extracellular fluid |
| Phagocytosis | -membrane vesicle forms to engulf a larger particle |
| Transmembrane gradient | -Concentration of a solute is higher on one side of a membrane than the other |
| Exocytosis | -material inside the cell packaged into vesicles and excreted into the extracellular medium -EX: Digestive enzymes |
| Uniport | -single molecule or ion |
| electrochemical gradient | -both electrical and chemical gradient -formation of a gradient requires an input of energy |
| Metabolism | -the sum total of all chemical reactions that occur within an organism |
| Kientic energy | -associated with movement |
| potential energy | -due to structure or location |
| 5 types of energy | -light -heat -mechanical -chemical potential -electrical/ion gradient |
| Two laws of thermodynamics | 1. energy cannot be created or destroyed 2. the transfer of energy increases the entropy |
| Gibbs free energy | -amount of energy available to do work -HGST |
| Anabolic | -requires energy input from intermediates to drive reactions -Biosynthetic reactions |
| Catabolic Reactions | -breakdown of reactants -used for recycling building blocks -used for energy to drive endergonic -Energy stored in intermediates such as ATP and NADH -used for energy to drive endergonic reactions -EX: breakdown of glucose: ATP is produced |
| Regulation of Metabolic Pathways | -gene regulation -cellular regulation -biochemical regulation -rate-limiting |
| 3 stages of cell signaling | -receptor activation -signal transductions -cellular response |
| types of cell surface receptors | -enzyme-linked receptors -g-protein coupled receptors -ligan-gated ion channels |
| intracellular receptors | -cytosol and nucleus -turns on the transcript of certain genes -estrogen receptor -inside the cell |
| 3 parts of signal transduction pathway | 1. relay proteins activate a protein kinase cascade 2. protein kinase cascade phosphorylates intracellular proteins such as transcription factors 3. phosphorylates transcription factors stimulate gene transcription |
| g-protein | -ligands bind to the surface of the first messenger -leads to the productions of the second messenger -they relay signal on the inside of the cell -EX: cAMP |
| Cyclic AMP (cAMP) | -Singal Amplification -Speed |
| cAMP production steps | 1. cAMP is stimulated 2. cAMP activates the protein kinase A (PKA) 3. cAMP binds to active cites of PKA, which releases the subunits of PKA 4. Cellular Response |
| hormonal signaling | -a type of long-distance signaling where an endocrine excretes hormone sin a blood vessel to travel to a target cell |
| Apoptosis | -programmed cell death -keeps the proper number of cells and tissues -sculpts tissues and organs -eliminates cell that has become worn out by infections of bacteria |
| Aerobic respiration | - A chemical process in which oxygen is used to make energy from carbohydrates (sugars). |
| Anaerobic respiration | -lacks oxygen -two strategies -uses substance other than 02 as final electron acceptor -produces atp only via substrate-level phosphorylation called fermentation -nitrate -also makes atp via chemiosmosis |
| Oxidation Phosphorylation | -high energy electrons removed from NADH and FADH2 to makes ATP -typically requires oxygen -Oxidative process involves electron transport chain -Phosphorylation occurs by ATP synthase |
| Citric Acid cycle | -acetyl is removed from acetyl CoA and attached to oxaloacetate to form citrate -series of organic molecules regenerated in each cycle -regulated by the availability of substrates and by feedback inhibition |
| Rate Limiting steps | 1. citrate synthase 2. isocitrate dehydrogenase 3. a-ketoglutarate |
| breakdown of a pyruvate | -broken down by dehydrogenase -molecule of CO2 removed from each pyruvate -transported into the mitochondria matrix -remaining portion attaches to CoA to make acetyl CoA |
| Glycolysis | -break down of glucose into pyruvates -occurs with or without oxygen -ten steps in three phased: energy investment, cleavage, and energy liberation |
| Enzymes | -lower the activation energy or chemical reactions -speeds up the reaction rate -a spontaneous reaction |
| exergonic | -spontaneous -less than zero -energy is released |
| endergonic | -not spontaneous -positive energy changed -requires addition of energy to drive reaction |
| Competitive Inhibition | -molecule binds to active site -inhibits ability of substrate to bind |
| Noncompetitive inhibition | -inhibitor binds to allosteric site, not active site |
| Irreversible inhibition | -usually bind covalently to an enzyme to inhibit its function -not common way for cells to control enzyme function |
| Simple Diffusion | -moves across a membrane by passing directly through the phospholipid bilayer -EX: oxygen and carbon |
| facilitated diffusion | -a solute through a membrane with the aid of a transport protein -sodium ions |
| Function of electrochemical gradients | -transport of ions and molecules -production of energy -osmotic regulation -neuronal signaling -muscle contraction -bacterial swimming |
| Types of proteins that carry out membrane transport | -Transporters -Carrier |
| Conformational change | -transport solute across the membrane |
| Direct Intercellular signaling | -cell junctions allow signaling molecules to pass from one cell to another |
| Contact-dependent signaling | -molecules bound to the surface of cells serve as signals to cells coming in contact with them |
| Autocrine signaling | -cells secrete signaling molecules that bind to their own cell surface and similar neighboring cells |
| Paracrine signaling | -cell secretes a signaling molecule that does not affect the cell -influences nearby cells |
| Receptor Activation | - signaling molecule binds to receptor |
| Singal transduction | -activated receptor stimulates a sequence of changes |
| Cellular response | -changed enzyme activity -change function of structural proteins -change gene expression |
| Ligand | -signaling molecule that binds noncovalent to receptor with high specificity |
| Enzyme-linked receptors | -Extracellular domain binds ligand -intracellular domain becomes functional catalyst -most are protein kinases -becomes active when signaling molecule is bound -found in plasma membrane -EGF receptor |
| G-protein coupled receptors | -receptors has transmembrane segment -activated receptor bind to g protein -releases GDP and binds GTP instead -GTP causes g protein to dissociate - a subunit and b/y dimer interact with other protein in a signaling pathway -in plasma membrane |
| Ligand-gated ion channels | -ligand binding causes ion channels to open and ions to flow through the membrane -transmit synaptic signals between neurons and muscles or between two neurons -EX: acetylcholine receptor -opens the ion channel found in plasma membrane |
| Singal Transduction Pathway | -relay proteins activate a protein kinase cascade -protein kinase cascade phosphorylates intracellular proteins such as transcriptions factors -phosphorylated transcription factors stimulate gene transcription |
| Apoptosis through signal transduction- intrinsic pathway | -mitochondrial pathways is stimulated by DNA damage that could cause cancer -Mitochondria release cytochrome c into the cytosol; forms apoptosome -apoptosome initiates the activation of caspases |
| Apoptosis through signal transduction – extrinsic pathway | -The extrinsic pathway begins with activation of death receptors -Signaling molecule is a trimer -Death-inducing signaling complex forms -The initiator procaspase is cleaved and initiator caspase is released and activates the executioner pr |
| crenation | -shrinkage of a cell in a hypertonic solution |
| Osmotic | -swelling and bursting of a cell in a hypotonic solution |
| Osmosis | -water diffuses through a membrane from an area with more water to an area with less water |
| Plasmolysis | -plasma membrane pulls away from the cell wall (when water exits the cell) |
| Fluidity | -individual molecules remain in close association but can readily move within a membrane -membranes are semifluid -can rotate freely and move laterally -can flip-flop |
| Flippase | -requires atp to transport lipids between leaflets |
| Four Factors affecting the ability of solutes | 1. size 2. polarity 3. charge 4. concentration |
| Electrogenic Pump | -exports one net positive charge -ion plumps play a primary role in the formation and maintenance of ion electrochemical gradients |
| Transport of Ions and molecules | -symporters and antiporters use H+ and Na+ gradients to take up nutrients and export waste products |
| Production of energy intermediates | -In the mitochondria and chloroplasts, H+ gradients are use to synthesize ATP |
| osmotic regulation | - Animal cells control their internal volume by regulating ion gradients between the cytosol and extracellular fluid |
| neuronal signaling | -Na+ and K+ gradients are involved in conducting action potentials -the signals transmitted by neurons |
| muscle contraction | -Ca2+ gradients regulate the ability of muscle fibers to contract |
| bacterial swimming | -H+ gradients drive the rotation of bacterial flagella |
| High permeability | -Gases -CO2, N2, )2, Ethanol -Very small, uncharged molecules |
| moderate permeability | -Water -H20 and H2NCON -Urea |
| low permeability | -Polar organic molecules -Sugars |
| very low permeability | -Ions -Animo acids, atp, proteins, Na+, K+, and CI- -Charged polar molecules and macro-molecules |
| Membrane Structure | -phospholipids are amphipathic molecules that -Hydrophobic faces inwards -Hydrophilic faces outwards |
| Proteins that uses ATP for energy | 1. metabolic enzymes 2. transporters 3. motor proteins 4.chaperones 5. DNA modifying enzymes 6. tRNA synthetases 7. Protein Kinases |
| Substrates | -reactants that bind to active sites -lock and key metaphor -induced fit phenomenon -high specificity |
| Prosthetic groups | -small molecules permanently attached to the enzyme |
| Cofactor | -usually inorganic ion that temporarily binds to enzyme |
| Coenzyme | -organic molecule that participates in reaction but is left uncharged afterward |
| Biochemical regulation | -feedback inhibition -products inhibits early |
| Gene Regulation | -turn genes on or off |
| Cellular Regulation | -cell-signaling pathways like hormones |
| Half-life | -time it takes for 50% of the molecules to be broken down and recycled |
| Proteasome | -breaks down proteins using protease enzymes |
| Ubiquitin | -tags target proteins to the proteasome to be broken down or recycled -degraded improperly folded proteins -rapidly degrade proteins to respond to changing cell conditions -recycle amino acids for new proteins |
| Lysosome | -contain hydrolases to break down proteins, carbohydrates, nucleic acids, and lipids -digest substance taken up by endocytosis -Autophagy |
| Cellular Respiration | -primary aim to make atp aerobic respiration uses oxygen -process by which living cells obtain energy from organic molecules and release waste products |
| Glucose Metabolism | -glucose is broken down -some energy is lost as heat but much is used to make 3 energy intermediates: ATP, NADPH, and FADH2 |
| Four metabolic pathways | 1. glycolysis 2. breakdown of pyruvate 3. citric acid cycle 4. oxidative phosphorylation |
| Energy Investment | -ATP is hydrolyzed or broken down to create fructose |
| Cleavage | -carbon molecule is broken down |
| Energy Liberation | - two glyceraldehyde molecules broken down into two pyruvate molecules -Produces 2 NADH and 4 ATP |
| Chemiosmosis | -chemical synthesis of A T P as a result of pushing H+ across a membrane -protons can only pass through ATP synthase |
| Electron Transport Chain in Oxidation | ETC = Protein complexes and small organic molecules embedded in the inner mitochondrial membrane Electrons originally found in N A D H or F A D H2 are transferred to components of the E T C |
| Fermentation | -breakdown of organic molecules without net oxidation -fermentation produces far less ATP than oxidative phosphorylation |
Created by:
maddie_5
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