Mastering Biology 5

Active transport by the sodium-potassium pump follows this cycle

1. Three Na+ ions from the cytosol bind to the pump. 2. The binding of Na+ stimulates the phosphorylation of the pump protein by ATP. 3. Phosphorylation causes a conformational change in the pump that moves the three Na+ ions against their concentration gradient and releases them outside the cell. 4. The release of the Na+ ions permits two K+ ions from outside the cell to bind to the pump, and the phosphate group is released. 5. Release of the phosphate group causes another conformational change in the pump. 6. The conformational change in the pump moves the two K+ ions against their concentration gradient and releases them into the cytosol

Drag the labels onto the table to indicate when each statement is true. Labels can be used once, more than once, or not at all. 1. Orange dye moves independently of purple dye 2. Concentration gradients exist that drive diffusion of both dyes 3. There is a net movement of orange dye from side A to side B 4. Purple dye moves only from side B to side A 5. There is no net movement of purple dye

1. always 2. only before equilibrium is reached 3. only before equilibrium is reached 4. never 5. only at equilibrium

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans? Hydrophobic nature Permeability Solubility in water Amphipathic nature

Amphipathic Nature

Calcium ions that act as second messengers are stored in _____. peroxisomes lysosomes chloroplasts endoplasmic reticula mitochondria

ER

Sort the phrases into the appropriate bins depending on whether they describe exocytosis, endocytosis, or both. A: secretes large molecules out of the cell B: requires fusion of vesicles with the plasma membrane C: increases the surface area of the plasma membrane D: forms vesicles from inward folding of the plasma membrane E: decreases the surface of area of the plasma membrane F: Requires cellular energy G: transported substances never physically cross the membrane

Exocytosis: A, B, C Endocytosis: D, E Both: F, G

Which of the following particles could diffuse easily through a cell membrane? Glucose Oxygen (O2) Hydrogen ion (H+) Sodium ion (Na+)

Oxygen

A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? Solution A: 1.4% (m/v) starch Solution B: 7.62% (m/v) starch

Solution A

A semipermeable membrane is placed between the following solutions. Which solution will increase in volume? Solution C: 9% (m/v) NaCl Solution D: 12.4% (m/v) NaCl

Solution D

Which of the following factors does not affect membrane permeability? A: The amount of cholesterol in the membrane B: Temperature C: The saturation of hydrocarbon tails in membrane phospholipids D: The polarity of membrane phospholipids

The polarity of membrane phospholipids

True or false? Osmosis is a type of diffusion.

True

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

True

A protein kinase activating many other protein kinases is an example of _____. amplification deactivation mutualism a cellular response sensitization

amplification

Which of these acts as a second messenger? G protein G-protein-linked receptor protein kinase adenylyl kinase cyclic AMP

cyclic AMP

Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor? glucose glycerol cellulose estrogen starch

estrogen

Endocytosis moves materials _____ a cell via _____. into ... facilitated diffusion into ... a transport protein into ... membranous vesicles out of ... membranous vesicles out of ... diffusion

into ... membranous vesicles

Thyroid hormones bind to _____ receptors. G-protein-linked intracellular steroid tyrosine-kinase plasma membrane ion-channel

intracellular

A signal molecule is also known as a(n) _____. initiator receptor protein key ligand

ligand

Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism? Select all that apply. ions proteins oxygen sucrose carbon dioxide water lipids

oxygen, carbon dioxide, water, lipids

A white blood cell engulfing a bacterium is an example of _____. phagocytosis exocytosis pinocytosis receptor-mediated endocytosis facilitated diffusion

phagocytosis

What is the function of cholesterol in the plasma membrane?

stabilization of phospholipids

Pinocytosis

the cell is engulfing the extracellular fluid

Which of the following statements correctly describe(s) the driving forces for diffusion of Na+ and K+ ions through their respective channels? Select all that apply. A: The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. B: The diffusion of Na+ ions into the cell is impeded by the electrical gradient across the plasma membrane. C: The diffusion of K+ ions out of the cell is impeded by the K+ concentration gradient across the plasma membrane. D: The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. E: The electrochemical gradient is larger for Na+ than for K+.

A, D, E

A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. Solution A: 3.21% (m/v) NaCl Solution B: 1.65% (m/v) glucose Solution C: distilled H2O Solution D: 6.97% (m/v) glucose Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl

Crenation: A, D, E Hemolysis: B, C Neither:

What role does a transcription factor play in a signal transduction pathway? A: By binding to a plasma membrane receptor it initiates a cascade. B: It relays a signal from the cytoplasm to the plasma membrane. C: It activates relay proteins. By binding to DNA it triggers the transcription of a specific gene. D: By binding to DNA it triggers the transcription of a specific gene E: It is a plasma membrane protein that binds signal molecules.

D: by binding to DNA it triggers the transcription of a specific gene

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell? Osmotic Isotonic Hypertonic Hypotonic

Hypotonic

How can a lipid be distinguished from a sugar? Lipids are mostly saturated. A lipid dissolves in water. A lipid is made up of only hydrocarbons. Lipids are mostly nonpolar.

Lipids are mostly non polar

Sort the phrases into the appropriate bins depending on whether they are true only for channels, true only for carrier proteins, or true for both channels and carriers. A: provide a continuous path across a membrane B: allow water molecules and small ions to flow quickly across the membrane C: transport primarily small polar organic molecules D: undergo a change in shape to transport solutes across the membrane E: are integral membrane proteins F: transport solutes down a concentration or electrochemical gradient G: provide a hydrophilic path across the membrane

Only Channels: A, B Only Carriers: C, D Both: E, F, G,

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm. Phospholipase C ... IP3 .... Ca2+ Adenylyl cyclase ... IP3 .... Ca2+ Phospholipase C ... cyclic AMP ... Ca2+ Adenylyl cyclase ... cyclic AMP ... Ca2+ Protein kinase ... PIP2 ... Na+

Phospholipase C ... IP3 .... Ca2+

A signal transduction pathway is initiated when a _____ binds to a receptor. G protein tyrosine kinase calmodulin signal molecule cyclic AMP

signal molecule

A signal transduction pathway is initiated when a _____ binds to a receptor. calmodulin signal molecule cyclic AMP tyrosine kinase G protein

signal molecule

A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off. carbohydrate protein steroid nucleic acid ion

steroid

In this animation, which of the following, when activated by a signal transduction pathway, moved from the cytoplasm to the nucleus of a cell? relay protein DNA plasma membrane receptor protein signal molecule transcription factor

transcription factor

Which of these is the second of the three stages of cell signaling? gene activation reception binding of a neurotransmitter to a plasma membrane receptor transduction cell response

transduction