Lecture Exam 2
A plant cell placed is distilled water will __________ ; and animal cell placed in distilled water will ____________. a. Become turgid, be normal in shape b. Become turgid, burst c. Burst, burst d. Become flaccid, shrivel
b. Become turgid, burst
A compound composed of carbon, hydrogen and oxygen with the approximate chemical formula (CH2O) includes sugars, straches and cellulose what is this called a. Protein b. Carbohydrates c. Phospholipid d. Cholesterol
b. Carbohydrate - Found on the outside surface of cells and are bound either to protein ( form glycoproteins) or to lipids (form glycolipids) - Form distinctive cellular markers, like a ID badge, allows cells to recognize each other. - Important to immune system, allow immune cells to differentiate between body cells ( don't attack) and foreign cells/tissues ( they attack)
Undergo a subtle change in shape that translocate the solute-binding site across the membrane is called _______________ a. Facilitated Diffusion b. Carrier Proteins c. Channel Proteins d. Aquaporins
b. Carrier Proteins
Facilitated diffusion involves either ___________ proteins or ______________ proteins. a. Connection Proteins ; Carrier Proteins b. Carrier Proteins ; Channel Proteins c. Transport Proteins ; Recognition Proteins d. Connection Proteins ; Channel Proteins
b. Carrier Proteins ; Channel Proteins
Glycoproteins are important for a. Binding hormones b. Cell recognition by the immune system c. Forming ion d. Active transport through the membrane
b. Cell recognition by the immune system
Composed of 4 fused carbon rings, is found alongside phospholipids in the core of the membrane is called a. Phospholipid b. Cholestrol c. Carbonhydrate d. Membrane Protein
b. Cholestrol - tucked between the hydrophobic tails of the membrane phospholipids
Referring to a solution that has a higher concentration of solute ( and therefore a lower concentration of free water) than has the cytosol of a cell a. Isotonic b. Hypertonic c. Movement of water from to the cell d. Hypotonic
b. Hypertonic
Relationship between the cell membrane flexibility and double bonds in the Hydrocarbon chain of phospholipid bilayer
- Cell membrane made up of double layer of these phospholipid molecules - hydrophilic heads will face the water while the hydrophobic tails will be in the center because they face away from water - Phospholipid bilayer makes the membrane very stable which allows flexibility - Hydrogen bond help stabilize the lipid bilayer structure
Groups of molecules which can diffuse either easily or hardly via membrane
1. Diffuse easily - Simple diffusion * Structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide and hydrophobic molescule such as lipid,to pass through the cell membrane down their concentration gradient -Osmosis * nonpolar easily pass through cell membrane -Carbon dioxide 2. Diffuse hardly - Large uncharged polar molecule such as sugar, cannot easily go through the cell membrane - Charged molecules such as ions, are unable to diffuse through a phospholipid bilayer - Hydrogen ions cannot cross a lipid bilayer by free diffusion
What are the subcategories of passive transport?
1. Simple Diffusion 2. Facilitated Diffusion 3. Osmosis
What are the six major functions of membrane proteins
1. Transport 2. Enzymatic Activity 3. Signal Transduction 4. Cell-cell Recognition 5. Intercellular Joining 6. Attachment to the Cytoskeleton and Extracellular Matrix (ECM)
After each molecules, place the two-word term that most specifically describes the process by which it moves through a plasma membrane. 1. Carbon Dioxide:___________ a. Simple Diffusion b. Facilitated Diffusion 2. Ethyl Alcohol: ___________ a. Simple Diffusion b. Facilitated Diffusion 3. Sodium Ion: ___________ a. Simple Diffusion b. Facilitated Diffusion 4. Glucose: ___________ a. Simple Diffusion b. Facilitated Diffusion
1. a. Simple Diffusion 2. a.Simple Diffusion 3. b. Facilitated Diffusion 4. b. Facilitated Diffusion
What is the activation energy in the enzymatic reaction?
Catalysis in the Enzyme's Active Site - The substrate binds to the active site of the enzyme - Active site can lower an activation energy barrier by 1. orienting substrates correctly 2. straining substrate bonds 3. providing a favorable microenvironment 4. covalently bonding to the substrate
Model of cell membrane structure. Membranes are composed of a double layer of phospholipids in which various proteins are embedded. The phospholipid bilayer is a somewhat fluid matrix that allows the movement of proteins within it. What is this.
Fluid Mosaic Model Of Cellular Membrane -Phospholipids are the most abundant lipid in the plasma membrane - Phospholipids are amphipathic molecules, containing hypdrophobic and hydrophilc regions - Plama membrane exhibits selective permeability allowing some substance to cross it more easily than others
The diffusion of a substance across a biological membrane is passive transport because no energy is expended by the cell to make it happen. What are the four that happens.
Simple Diffusion, Carrier Protein, Channel Mediated Facilitated Diffusion, Osmosis
Proteins are the second major component of plasma membranes. There are two main categories of membrane proteins what are they called
Integral and Peripheral 1. Integral - Intergrated into the membrane. -Have at least 1 hydrophobic region that anchors them to the hydrophobic core of the phospholipid bilayer - Protein that extend all the way across the membrane is called transmembrane protein - Some form a channel that allow ions or other small molecules to pass -Embedded in the phospholipid bilayer; may or not extend through both layers 2. Peripheral - Found outside and inside surfaces of membrane attached to integral proteins or to phospholipids. - Do not stick into the hydrophobic core of the membrane and tend to be more loosely attached - On the inner or outer surface of the phospholipid bilayer, but not embedded in its hydrophobic core
The movement of water from/to the cell
Osmosis - Movement of water through a selectively water permeable membrane by simple diffusion or by facilitated diffusion through aquaporins - Water moves down its concentration gradient from a higher concentration of free water molecules to a lower concentration of free water molecule
What are the two principal types of molecules in plasma membranes, and what is the general function of each?
Phospholipids and Lipid. Phospholipid act as a structural component of the plasma membrane whereas lipids are required for energy storage
What allow passage of hydrophilic substances across the membrane a. Transport Proteins b. Aquaporins c. Passive Membrane Transport d. Facilitated Diffusion
a. Transport Proteins
During exocytosis, a membrane enclosed ______________ carrying material to be expelled moves to the cell's surface, where the __________'s membrane fuses with the cell's plasma membrane. a. Vesicle ; Vesicle b. Food vacuole ; Vesicle c. Interstitial fluid ; Adhesive junction d. Tight junction ; Gap junction
a. Vesicles ; Vesicles
Does exocytosis require energy?
Yes, active transport
The movement of materials across a membrane through the use of cellular energy, normally against a concentration gradient what kind of transport is this a. Active Transport b. Passive Transport c. Transport Protein d. Facilitated Diffusion
a. Active Transport
The movement of a substance through a membrane down its concentration gradient is called _____________ a. Diffusion b. Osmosis c. Active Transport Channel d. Tight junctions
a. Diffusion
Which of the following is true? a. Enzymes decrease activation energy requirements b. Heat cannot supply activation energy c. Enzymes slow down the chemical reactions d. Enzymes increase activation energy requirements
a. Enzymes decrease activation energy requirements
The diffusion of molecule across a membrane, assisted by protein pores or carries embedded in the membrane is called a. Facilitated Diffusion b. Simple Diffusion c. Osmosis
a. Facilitated Diffusion
The transport protein speed the passive movement of molecules across the plasma membrane is called ______________________ a. Facilitated Diffusion b. Carrier Proteins c. Channel Proteins d. Aquaporins
a. Facilitated Diffusion
Referring to a solution that has the same concentration of solute (and therefore the same concentration of free water) as has the cytosol of a cell a. Isotonic b. Hypertonic c. Movement of water from to the cell d. Hypotonic
a. Isotonic
Which of the following is not true of endocytosis? a. It is a form of passive transport b. It includes pinocytosis c. It can occur in coated pits d. It is used by Amoeba to feed on Parmecium
a. It is a form of passive transport
Diffusion directly through the phospholipid bilayer is called ____________ diffusion, and molecules that take this route must be soluble in ________or be very small and have no net electrical charge. a. Simple diffusion ; Lipids b. Facilitated diffusion ; Water c. Aquaporins ; Lipids d. Simple diffusion ; Water
a. Simple diffusion ; Lipids
Diffusion directly through the phospholipid bilayer us called ____________ diffusion, and molecules that take route must be soluble in _____________ or be very small and have no net electrical charge. a. Simple, Lipids b. Facilitated, Oils c. Carrier mediated, Lipids d. Active, Fats
a. Simple, Lipids
The hydrophobic regions of an _______________________ consist of one or more stretches of nonpolar amino acids, often coiled into alpha helices a. Peripheral Protein b. Integral Proteins c. Membrane Proteins d. Transmembrane Protein
b. Integral Proteins - Penetrate the hydrophobic core - Span the membrane are called transmembrane proteins
____________ that open or close in response to a stimulus (gated channel) a. Channel Protein b. Ion Channel c. Aquaporins d. Facilitated Diffusion
b. Ion Channel
The movement of materials across a membrane down a gradient of concentration, pressure, or electrical charge without using cellular energy which transport is this a. Active Transport b. Passive Transport c. Transport Protein d. Facilitated Diffusion
b. Passive Transport - No work (energy) to move substances down the concentration gradient - The diffusion of a substance across a biological membrane because no energy is expended by the cell to make it happen 1. simple diffusion 2. carrier and channel mediated facilitated diffusion 3. osmosis
A membrane that is permeable to some substances but not to others is described as being _______________. a. A active transport channel b. Selectively permeable c. A diffusion d. A aquaporins
b. Selectively permeable
The diffusion of water, dissolved gases, or lipid soluble molecules through the phospholipid bilayer of a cellular membrane is called a. Facilitated Diffusion b. Simple Diffusion c. Osmosis
b. Simple Diffusion
The ability of a surrounding solution to cause a cell to gain or lose water is call a. Isotonic b. Tonicity c. Hypertonic d. Hypotonic
b. Tonicity
Facilitated diffusion across a membrane requires _____________ and moves a solute _________________ its concentration gradient. a. Energy and transport proteins, up b. Transport protein, down c. Energy and transport proteins, up d. transport proteins, up (against)
b. Transport protein, down
A chemical reaction, the energy needed to force the electron shells of reactants together, prior to the formation of products what is this called a. Catalyst b. Enzyme c. Activation Energy (EA) d. Active Site
c. Activation Energy (EA) - Every chemical reaction between molecules involves bond breaking and bond forming - Initial energy needed to start a chemical reaction which is also called free energy of activation - Often supplied in the form of thermal energy that the reactant molecules absorb from their surroundings
The sodium concentration in a cell is 10 times less than the concentration in the surrounding fluid. How can the cell move sodium out of the cell? a. Passive Transport b. Facilitated diffusion c. Active Transport d. Receptor mediated endocytosis
c. Active Transport
What are the three types of cell attachment structures in animal cells a. Phagocytosis ; Receptor mediated endocytosis ; Pinocytosis b. Cytosol ; Interstital Fluid ; Endocytosis c. Adhesive junction ; Tight junction ; Gap junction d. Plamaodesmata ; Hypertonic ; Turgoe pressure
c. Adhesive junction ; Tight junction ; Gap junction
Provide corridors that allow a specific molecule or ion to cross the membrane is called __________________ a. Facilitated Diffusion b. Carrier Proteins c. Channel Proteins d. Aquaporins
c. Channel Proteins
Requires that the cell expand energy to move substance across membranes. Occurs when transporting substances against concentration gradients or when moving particles or fluid droplets into or out of the cell. What is this transport call a. Passive Transport b. Active Transport c. Energy Requiring Transport d. Facilitated Diffusion
c. Energy Requiring Transport - energy is spent to move molecules against their gradient *builds potential - Active transport proteins are often referred to as pumps, moving solute uphill *Maintaining gradients, acquiring food, excreting wastes, cell to cell communication - Includes 1. Active Transport 2. Endocytosis - process in which the plasma membrane engulfs extracellular material. Forms membrane bound sacs that enter the cytoplasm and thereby move material into the cell 3. Exocytosis - process which intracellular material is enclosed within a membrane bound sac that moves to the plasma membrane and fuses with it, releasing the material outside the cell
Animal cells are surround by ______________ fluid. This fluid is ______________ to the cytosol. a. Phospholipid ; isotonic b. Plasma ; hypertonic c. Interstitial ; isotonic d. interstitial ; hypotonic
c. Interstitial ; isotonic
Diffusion _________________________. a. Occurs by active transport b. Is always facilitated c. Is increased when temperature increases d. requires aquaporin protein
c. Is increased when temperature increases
The diffusion of water across a differentially permeable membrane, normally down a concentration gradient of free water molecules. Water moves into the solution that has a lower concentration of free water from a solution that has a high concentration of free water is called a. Facilitated Diffusion b. Simple Diffusion c. Osmosis
c. Osmosis
The diffusion of water across a membrane that is selectively permeable to water in response to gradients of concentration, pressure, or temperature is called ____________ a. Diffusion b. Isotonic c. Osmosis d. Channel Protein
c. Osmosis
Substances diffuse down their concentration gradient, the region along which the density of a chemical substance increase or decreases. No work (energy) to move substances down the concentration gradient. Which function is this? a. Selectively Permeable b. Transport Proteins c. Passive Membrane Transport d. Facilitated Diffusion
c. Passive Membrane Transport
Movement of material across a membrane down a gradient of concentration, pressure, or electrical charge without using a cellular energy is called a. Channel Protein b. Carrier Proteins c. Passive Membrane Transport d. Osmosis
c. Passive Membrane Transport - Substances diffuse down their concentration gradient, the region along which the density of a chemical substance increase or decreases - no work energy to move substances down the concentration gradient - The diffusion of a substance across biological membrane because no energy is expended by the cell to make it happen 1. Simple Diffusion 2. Carrier and Channel mediated Facilitated Diffusion 3. Osmosis
Which best describes the structure of a cell membrane? a. Protein between two bilayer of phospholipids b. A bilayer of protein coating a layer of phospholipids c. Protein embedded in a bilayer of phospholipids d. Cholesterol embedded in a bilayer of phospholipids
c. Protein embedded in a bilayer of phospholipids
A protein that regulates the movement of water soluble molecule through the plasma membrane which transport is this a. Active Transport b. Passive Transport c. Transport Protein d. Facilitated Diffusion
c. Transport Protein - Some are called channel protein, have hydrophilic channel that certain molecules or ions can use as a tunnel - Other are called carrier proteins bind to molecules and change shape to shuttle them across the membrane - Channel proteins are called aquaporins facilitate the passage of water - Specific for the substance it moves
Membrane consist of a bilayer of _____________________? a. Plasma Membrane b. Fluid mosaic model c. Phospholipid d. Aquaporins
c. phospholipid
Which of the following cannot enter a cell by simple diffusion a. oxygen b. estrogen c. sugar d. water
c. sugar
The moment of materials across a membrane through the use of cellular energy, normally against a concentration gradient is called _______________ a. Channel protein b. Passive transport c. Energy requiring transport d. Active transport
d. Active transport
A channel protein in the plasma membrane of a cell that is selectively permeable to water is called _________________ a. Selectively permeable b. Channel protein c. Passive transport d. Aquaporins
d. Aquaporins
The movement of a substance through a membrane down its concentration gradient is called _____________. When applied to water, this process is called __________. Channels that are specific for water are called ______________. a. Osmosis, diffusion, carrier b. Diffusion, osmosis, active protein c. Osmosis, diffusion, aquaporins d. Diffusion, osmosis, aquaporins
d. Diffusion, osmosis, aquaporins
The process in which intracellular material is is enclosed within a membrane bound sac that moves to the plasma membrane and fuses with it, releasing the material outside the cell is called __________________ a. Endocytosis b. Pinocytosis c. Phagocytosis d. Exocytosis
d. Exocytosis
The diffusion of molecules across a membrane, assisted by protein pores or carriers embedded in the membrane what kind of transport is this a. Active Transport b. Passive Transport c. Transport Protein d. Facilitated Diffusion
d. Facilitated Diffusion - Transport proteins speed the passive movement of molecules across the plasma membrane - Carrier protein undergo a subtle change in shape that transloacte the solute binding site across the membrane * Channel proteins include 1. aquaporins for facilitated diffusion of water 2. ion channels that open or close in response to a stimulus gated channels
Referring to a solution that has a lower concentration of solute ( and therefore a higher concentration of free water) than has the cytosol of a cell a. Isotonic b. Hypertonic c. Movement of water from to the cell d. Hypotonic
d. Hypotonic
Lipid consisting of glycerol bonded to 2 fatty acids and one phosphate group, which bears another group of atoms. Charged and contains nitrogen. Double layer of phospholipids is a component of all cellular membranes is called ________________ a. Cholesterol b. Membrane Proteins c. Carbohydrate d. Phospholipid
d. Phospholipid - Arranged in a bilayer, make up the basic fabric of the plasma membrane. - Are amphipathic , means have both hydrophilic and hydrophobic regions - Arrange themseleves with their hydrophobic tails facing each other and their hydrophilic heads facing out - Made form a liposome ( hollow droplet of bilayer membrane)
What is the five major categories of protein within the bilayer a. Selective permeable, enzymes, carrier, lipids b. Receptor, enzymes, gap junctions, active transport, aquaporins c. Diffusion, osmosis, active transport channel, gap junctions, selective permeable d. Receptor, recognition, enzymes, attachment, transport
d. Receptor, recognition, enzymes, attachment, transport
The quality of a membrane that allows certain molecules or ions to move through it more readily than others is called a. Transport Protein b. Passive Transport c. Facilitated Diffusion d. Selectively Permeable
d. Selective Permeability of Plasma Membrane - Cell must exchange material with its surroundings, a process controlled by the plasma Membrane - Regulating the cell's molecular traffic - Hydrophobic (non polar) molecules, such as hydrocarbons, can dissolve in the lipid bilayer and pass through the membrane rapidly - Polar molecule, such as sugars, do not cross the membrane easily
A cell must exchange materials with its surrounding, a process controlled by the plasma membrane. Plasma Membranes are ___________ , regulating the cell's molecular traffic. a. Transport Protein b. Passive Membrane Transport c. Facilitated Diffusion d. Selectively Permeable
d. Selectively Permeable
