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Biology Test #2
| Question | Answer |
|---|---|
| What do plant cells in a hypotonic environment do? | become turgid (normal) |
| Ligands | 1. any molecule that binds specifically to a receptor site of another molecule 2. It causes a receptor protein to undergo a change in shape |
| Hormone | 1. Multi-cellular organism, one of many types of secreted chemicals that are formed in specialized cells 2. travel in body fluid 3. act on specific target cells in other parts of the body to change their functioning |
| Local Regulators | Secreted molecule that influences cells near where its secreted |
| Signal Transduction Pathway | Series of steps linking a mechanical or chemical stimulus to a specific cellular response |
| Electrogenic Pump | ion transport protein that generates voltage across a membrane |
| What do Human cells do in a hypotonic Environment? | Swell, and possibly lyse |
| Receptor-Mediated Endocytosis | 1. Movement of specific molecules into a cell by inward budding of membrane vesicles 2. enables a cell to acquire a bulk quantities of specific substances |
| Pinocytosis | 1. type of endocytosis in which the cell ingests extracellular fluid and dissolved solutes 2. cellular drinking |
| Phagocytosis | 1. Type of endocytosis 2. Large particulate substances are taken up by the cell 3. carried out by protists and certain immune cells of animals 4. cellular eating |
| Endocytosis | energy in |
| Exocytosis | Energy out |
| ATP | Energy |
| Proton Pump | actively transports hydrogen ions out of the cell |
| Active Transport | Movement of a substance across a cell membrane, with an expenditure of energy against its concentration gradient |
| Gated Channels | Trans-membrane protein channel that opens or closes in response to a particular stimulus |
| What do Human cells do in an isotonic environment? | they're normal |
| Ion Channel | Trans-membrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient |
| Facilitated Diffusion | 1. Spontaneous passage of molecules or ions across a biological membrane with the assistance of specific trans-membrane transport proteins 2. requires special protein, for way of passage |
| Plasmolysis | 1.Cytoplasm in walled cells shrivels and plasma membrane pulls away from the cell wall 2. happens when cell loses water to hypertonic environment. |
| Osmoregulation | Control of water balance |
| Hypotonic environment | 1.When surrounding a cell, will cause the cell to take up water. 2. Swell, and maybe lyse (burst) |
| Hypertonic Environment | 1. When surrounding cell, will cause the cell to lose water 2. shrivel |
| Isotonic | 1. remains the same 2. no effect of the passage of water into or out of the cell |
| Plasma Membrane | boundary that separates the living cell from its surroundings |
| Tonicity | ability of a solution surrounding a cell to cause that cell to gain or lose water |
| Osmosis | Diffusion of water across a selectively permeable membrane, from a concentration of low solutes to a concentration of high solutes |
| Passive Transport | diffusion of a substance across a biological membrane with no expenditure of energy |
| Concentration Gradient | region along which the density of a chemical substance increases or decreases |
| Diffusion | 1. movement of molecules of any substance so that they spread out evenly into the available space 2. high to low |
| What do plant cells do in an isotonic environment? | become flaccid |
| Aquaporins | channel protein in the plasmam membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis |
| Channel Protein | Only allow charged, polar, and large ions through |
| Transport Protein | Transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane |
| Glycoprotein | Protein with one or more carbohydrates covalently bonded to it |
| Glycolipid | Lipid covalently attached to a carbohydrate |
| What do human cells do in a hypertonic environment? | shrivel |
| Peripheral Proteins | 1. side proteins 2. appendages loosely bound to the surface of the membrane |
| What do plant cells do in a hypertonic environment? | they plasmolyze |
| Integral Proteins | penetrate hydrophobic core of lipid bilayer |
| Fluid Mosaic Model | envisions membrane as mosaic of proteins molecules drifting laterally in a fluid bilayer of phospholipids |
| Ampipathic | has both a hydrophobic and hydrophilic region |
| Selective Permeability | allow some substances to cross more easily than others |
| Scaffolding protein | large relay proteins to which several other relay proteins are simultaneously attached |
| Diacylglycerol | Produced by cleavage of a certain kind of phospholipid in the plasma membrane |
| Inositol Triphosphate | 1. produced by clevage of a certain kind of phospholipid in the plasma membrane 2. stimulates release of calcium from estrogen receptor |
| Ligand-gated ion channel | membrane receptor containing a region that can act as a gate when the receptor changes it |
| Adenylyl Clycase | converts ATP to cylic AMP in response to an extracelluar signal |
| Cylic AMP or cAMP | enzyme embedded in the plasma membrane |
| Second Messanger | 1. small 2. water soluable 3. can readily spread throughout cell by diffusion 4. relays a signal to a cells interior in response to a signaling molecule bound by a signal receptor protein. |
| Protein Phosphates | enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase |
| Protein Kinase | an enzyme that transfers phosphate groups from ATP to a protein |
| Receptor Tyrosine Kinases | 1. membrane receptors that attach phosphates to tyrosines 2. can trigger many pathways |
| G protein | Protein that binds the energy-rich molecule GTP |
| G Protein-coupled receptor | 1. plasma membrane receptor that works with help of a G protein 2. have 7 aplha helices spanning the membrane |
| Whatre the 2 types of integral proteins? | Channel and carrier proteins |
| Polar molecules are... | hydrophillic |
| Non polar molecules are... | Hydrophobic |
| How does a phospholipid differ from a triglyceride? Which one is amphipathic? (how do you know?) Think in terms of BOTH structure AND function. | Phospholipids have 2 tails, they also have hyrophillic head and hydrophobic tails (ampipathic). They are also usually charged. Triglycerides have 3 fatty acid tails, and are completely hydrophobic. |
| What would happen to a membrane if its phospholipid tails were to become longer? Would you expect an organism with long, saturated tails to live at high temperatures or low temperatures? Explain your answer. | They would become more rigid, you would expect them to live at higher temperatures |
| Describe the phospholipids you would predict to find in an organism adapted to live at very low temperatures. Explain your answer. | You would expect short fatty acid tails, to keep the plant more fluid. |
| What is the difference between an integral and a peripheral membrane protein? | integral protein (transmembrane) penetrates the lipid bilayer,the peripheral protein is loosely bound to the surface of a membrane, or part of an integral protein, not embedded in the lipid bilayer. |
| What factors influence if and how a solute will cross a membrane? | Charge and size of molecule |
| What are the properties of solutes that can cross a membrane by simple diffusion? | Non polar, hydrophobic, and small molecules |
| Can O2 do simple diffusion UP its concentration gradient? Explain your answer | no, simple diffusion moves down the concentration gradient. for something to move up the concentration gradient it would take energy (active transport) |
| What is the difference between simple and facilitated diffusion? | simple diffusion can go straight through the membrane, facilitated diffusion needs a type of protein |
| What is active transport? How is it different than facilitated diffusion? Does it share any similarities with facilitated diffusion? | Active transport is the movement of solutes up its concentration gradient with the input of energy. Differs from facilitated because, facilitated doesnt need energy. They share the use of a protein |
| What is osmosis? | Movement of water across a semi permeable membrane from an area of low solute concentration to an area of high solute concentration. |
| What will happen to a cell placed in a hypertonic solution? | it will shrivel, because more solutes are outside the cell. |
| What will happen to a cell placed in a hypotonic solution? What about if that cell is a plant cell or a bacterial cell? | A human cell placed in a hypotonic environment will swell, and possibly lyse. However if the cell is a plant or bacterial cell it was become turgid |
| Compared to your cells, an isotonic IV saline solution has a solute concentration that is ________________. [higher, lower, the same as] | The same As |
| What would happen if you used an IV saline solution that was hypertonic relative to cells? | The cells would shrivel, cause the patient to become dehydrated |
| Which type of transport is used to transport LDL into cells from the circulation? | Endocytosis |
| How does insulin get secreted from the pancreatic cells that make it? Why can't insulin be exported by say simple diffusion? | exocytosis, it cant be by simple diffusion because its too big |
| Microtubules are made of ____________. (fill in the blank) What are some important functions of microtubules in cells? | made of protein/amino acids. main functions, maintenance of cell shape, cell motility, chromosome movements in cell division, and organelle movement |
| Microtubules | hollow rod composed of tubulin proteins that make up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella |
| Describe the structure and some of the functions of microfilaments. | two intertwined strands of actin, each a polymer of actin subunits Tubulin polymers, made of actin. Main functions: maintenance of cell shape, changes in cell, muscle contraction, cytoplasmic streaming, cell motility, cell division. |
| Microfilaments | cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making part of the cytoskeleton and acting alone or with myosin to cause cell contraction (actin filament) |
| any chemo drugs mess with dividing cells by messing with chr movement during cell division. What structure must they inhibit? | Microfilaments |
| Ate cake, high blood sugar. How can glucose enter a cell? | Facilitated diffusion |
| Can ions cross a membrane by simple diffusion? | no, because they are charged |
| If INTRACELLULAR solute concentration is high, which way will water flow by osmosis? | Into the cell |
| When a cell is in a hypertonic solution, water will move | out of the cell |
| What is osmosis? | movement of water to a higher solute concentration |
| What two things does a cell need in order to respond to a signaling molecule in its environment? | a receptor and a transduction pathway |
| How does a signal molecule reach its target in the process of local signaling? | by diffusion |
| Is hormonal signaling local or long distance? How do you know? Why wouldnÕt it ÒworkÓ for a hormone to signal via local signaling? | long distance, because, they're excreted into the blodd stream |
| List the general steps/components required for a cell to respond to signal (start with the signaling molecule). | 1. binding of signal receptor 2. dimerization 3. auto-phosphorylation 4. phosphorylation of other molecules 5. transduction pathway (kinase cascade) 6. cellular response |
| So what is the response to epinephrine? To insulin? To estrogen? | 1.response to epinephrine- break down of glycogen to release energy, opens up channels 2.response to insulin- when a signal binds to the receptor it tells the cell to put protein channels in membrane |
| Do cells with (only) an insulin receptor respond to estrogen? Explain your answer. | No, because receptors are VERY specific |
| Why can estrogen have an intracellular receptor but the insulin receptor has to be a membrane receptor? | because estrogen is a steroid, which is a lipid, which is a cholesterol, which is hydrophobic, so it can pass by simple diffusion. It has to have a receptor because its too large to enter the cell |
| What happens when the signal binds to an ion channel receptor? | the Ion channel opens |
| Describe the three main parts of a tyrosine kinase receptor listed below (e.g. what each part does, whether youÕd predict it to be hydrophobic or hydrophilic, etc.) - the extracellular part - the within the membrane part - the intracellular part | extracellular- hydrophillic, receptor within the membrane- hydrophobic intracellular- hydrophillic, kinase |
| What do kinases do? And what happens to their substrates (targets) as a result? | it transfers a phosphorus group from one molecule to another |
| What happens to a protein kinase receptor when the signal molecule binds to the receptor? (be as specific as you can- there are some steps that we talked about) | signal binds to receptor, it dimerizes, auto-phosphorylation takes place and then becomes a kinase |
| What is a Òkinase cascadeÓ? Does it happen BEFORE the signal binds the receptor, AFTER the signal binds the receptor, BEFORE the cell responds &/or AFTER the cell responds? (circle the correct options) | Kinase cascade is process of phosphorylating many things. It happens after the signal binds to the receptor, but before the cellular response |
| What is signal amplification? Why does this process help explain why hormones can act at such low concentrations? | low concentration of signal yields high cellular response, because one signal creates many cellular responses |
| Why are some responses much faster than others? What is the common feature for a fast response? a slow response? If you see that the signal transduction pathway involves events in the nucleus, would you predict a faster or a slower response? Why? | slow- when you have to make proteins Fast- when theyre already there they just have to be activated. if it involves the nucleus, it will be slow because DNA needs to make the things needed |
| How is a signal molecule reaching the nearby cells (figure 15.1a)? | Diffusion |
| What kind of cell is likely being used in figure 11.5? | epithelial |
| Why can the signaling molecule in figure 11.8 enter the cell? | its a lipid |
| Does insulin enter target cells? | no, its binds to a receptor on the surface of cells |
| When glucose enters (after the insulin signal)- how does it enter? | facilitated diffusion |
| In us (humans), what molecule stores sugar? | glycogen |
| What cells contribute to the increase in blood sugar resulting from the breakdown of glycogen? | liver |
| Glycogen is stored in... | muscle and liver |
| Which type of transport protein binds its solute as the solute is moving down its concentration gradient? | Channel protein |
| which type of transport protein binds its solute as it moves the solute up its concentration gradient? | carrier protein |
| Why do people with type 1 diabetes have high blood sugar? | no insulin to create glucose transporters |
| Based on their insulin levels, what you PREDICT the blood sugar levels to be in people with Type II diabetes? Why is this not the case (Remember we came up with several hypotheses, and how one could test them)? | You would expect blood sugar levels to be low, but it isnt because the insulin receptor is dysfunctional. |
| What is the treatment for type 1 diabetes, and why does it have to be delivered by injection? | Injectable insulin, because insulin is a protein and if taken by mouth it will be digested and then amino acids wont be able to bind to the receptor |
| How does Precose work to help manage blood sugar levels in people with Type 2 diabetes? Be as specific as you can. | Precose is a competitive inhibitor for the enzyme, stopping the digestion of carbs, and if carbs cant be broken down then glucose levels cant raise any further than they are already |
| Compare and contrast how Alli works with how Precose works. | Both are competitive inhibitors, Alli is a competitive inhibitor of lipase, and precose is a competitive inhibitor for carbs, both block digestion |
| Considering the three main steps of signal transduction pathways, which step is no longer working in people with Type 1 diabetes? | Reception is no longer working |
| Estrogen is a | lipid, cholesterol, and can cross by simple diffusion |
| Do you absolutely NEED a membrane receptor for estrogen? | no, there is a membrane receptor, but it doesnt need it, it can cross by simple diffusion |
| In a cell not being acted on by estrogen, where would you find the ER | cytoplasm |
| Which of the following is a non-steroid hormone? | insulin |
| Structure of insulin? | protein |
| The insulin receptor is a protein kinase receptor | in the cell membrane |
| What portion of the receptor does insulin bind to? | extracellular region |
| When insulin binds the receptor | the receptor becomes phosphorylated on the intracellular portion |
| Glucose enters the cell by | Facilitated diffusion |
Created by:
tomtom90
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