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Stack #4539795
bio exam 2
| Term | Definition |
|---|---|
| The plasma membrane defines | the cell, outlines its borders |
| The plasma membrane is a flexible... | selecivley perimiable membrane |
| The fluid mosaic model describes | plasma membrane as a mosaic of components—including phospholipids, cholesterol, proteins, and carbohydrates |
| Phospholipids form | the primary membrane fabric, making them the most abundant component/lipid |
| amphipathic | "dual loving" |
| phospholipids consist of | a three-carbon glycerol backbone two fatty acids attached to carbons 1 & 2 a phosphate-containing group attached to carbon 3 |
| Membranes are primarily stabilized by | weak hydrophobic interactions |
| As temperatures decrease, membranes composed largely of saturated fatty acids with their straight tails, compress, making the membrane | dense and more ridged |
| Membranes high in unsaturated fatty acids remain relativity more fluid due to the presences of a | double bond in their fatty acids resulting in a “kink” in their structure |
| Cholesterol, which lies alongside the phospholipids, tends to | dampen temperature effects on the membrane |
| At lower temperatures, cholesterol prevents | phospholipids from packing too closely together, helping the membrane to remain fluid |
| he plasma membrane consists of proteins—often | clustered together— embedded within the bilayer |
| Peripheral proteins: | found on the inner or outer surface; not embedded within the phospholipids |
| Integral proteins (integrins) are embedded | within the phospholipid layer(s); may or may not penetrate through both layers |
| both peripheral and integral proteins, may serve as | enzymes |
| Carbohydrates are the third major component of a | plasmamembrane |
| Carbohydrates on the exterior surface of the membrane can covalently bond to | lipids or proteins |
| Glycoprotein and glycolipid patterns on the cells' surfaces give many viruses an opportunity for | infection |
| Diffusion is the | passive movement of molecules down their concentration gradient, from an area of higher concentration to an area of lower concentration |
| Passive transport: is the | movement of a substance, down its concentration gradient, across a biological membrane without the use of cellular energy |
| At dynamic equilibrium, there is | no longer a concentration gradient and no net movement across the membrane |
| Osmosis is a | specific type of passive diffusion involving the movement of water molecules across a semi-permeable membrane |
| Tonicity described how the concentration of solute (that can not cross the membrane) in the | extracellular solution can cause a cell to gain or lose water through osmosis |
| Osmoregulation: is a | mechanism living organism possess to control its osmolarity and water balance |
| a Paramecium, which is hypertonic to its environment, has a | ontractile vacuole that pumps out excess water from the cell |
| Facilitated Diffusion is the | diffusion of molecules across a membrane with the help of membrane proteins |
| The integral proteins involved in facilitated transport are known as | transport proteins |
| Transport proteins allow hydrophilic substances (Ions: Na+, K+, Ca+2, and Cl-), simple sugars and amino acids to | cross the membrane that would otherwise be hinder |
| Channels proteins: have a | ydrophilic channel through their core that provides a hydrated opening through the membrane layers |
| Aquaporins: allow the | diffusion of water at a very high rate |
| arrier proteins: binds to a substance | which triggers a conformational change |
| Active transport: the | ovement of a substances against its concentration gradients; the cell must use energy typically in the form of ATP hydrolysis |
| large molecules (such as polysaccharides and proteins) can’t move across the membrane and therefore | move via bulk transport using vesicles |
| Endocytosis is the process by which a cell engulfs | macromolecules by forming vesicles from its plasma membrane |
| Phagocytosis: is the process | hich a cell takes in large particles by surrounding the particle using its membrane and engulfs it |
| Pinocytosis: the cell membrane invaginates | in extracellular fluid containing molecules dissolved in droplets then pinches off making a vesticle |
| king in extracellular fluid containing molecules dissolved in droplets then pinches off | vesticles |
| In exocytosis, transport vesicles containing substances migrate to the | plasma membrane and release their contents to the cell's exterior |
| Which direction of move would you observe if the membrane was permeable to sucrose and glucose, but not fructose? | glucose out of the cell and fructose into the cell |
Created by:
ecoesfeldd