Gap Finder - Movement Processes

Polar molecules must use protein ____ to enter the cell. What kind of diffusion is this?

channels Facilitated Diffusion

Movement is often driven by ___ ___.

concentration gradients

Phagocytosis

process in which extensions of cytoplasm surround and engulf very large particles and take them into the cell

2 Requirements for Osmosis

- Water & a Selectively Permeable Membrane - no water? no osmosis - no selectively permeable membrane? no osmosis

Rehydration

- increased fluid intake will reduce extracellular tonicity until your ECF and ICF are isotonic again

What easily diffuses across a cell membrane? (3)

- many nonpolars - O2 and CO2 - lipid solubles

Active Transport (3)

- movement against/up a concentration gradient - requires energy - Pump (Na+/K+ pump)

Osmosis

- passive! - Diffusion of water through a selectively permeable membrane - critical for maintain intracellular water content

Facilitated Diffusion (3)

- still Passive! - use of channel proteins to move across PM ex. Glucose must bind to a channel protein to be moved across the PM

Water Intoxication (2)

- too much liquid too quickly can lead to ECF becoming hypotonic to your cells - cells swell and can lyse

Endocytosis

A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane.

sodium-potassium pump (2)

A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients. - requires ATP!

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Which of the following is an example of phagocytosis? - A white blood cell engulfs a bacterium and breaks it down to get rid of it. - A cell membrane folds inward and forms a vesicle around a bit of extracellular fluid and pulls the fluid inside. - Oxygen enters a red blood cell. - A vesicle containing a protein moves to the cell membrane, fuses with it, and releases the protein to the outside.

A white blood cell engulfs a bacterium and breaks it down to get rid of it.

What affects the rate of diffusion? (4)

Concentration gradient - steeper/faster Temperature - hotter/faster (the particles have more energy thus move around faster) Size of molecule - smaller/faster Diffusion distance - shorter/faster

Which of the following is an example of facilitated diffusion? - Diffusion of nonpolar molecules directly through the membrane - Diffusion of polar molecules through a carrier protein - Moving polar molecules through a carrier protein from low to high concentration - Diffusion of gases like O2 and CO2 directly through the membrane

Diffusion of polar molecules through a carrier protein

Which of the following is correct about diffusion rate? - Diffusion rate is faster for larger molecules. - Diffusion rate is faster when there is a greater concentration gradient. - Temperature has no effect on diffusion rate. - Diffusion rate is slower for smaller molecules.

Diffusion rate is faster when there is a greater concentration gradient.

Which of the following is the main difference between endocytosis and exocytosis? - Endocytosis moves materials into a cell, whereas exocytosis expels materials from the cell. - Endocytosis moves solids and exocytosis moves liquids. - Endocytosis always requires the item being moved to bind to a receptor while exocytosis does not need a receptor. - Endocytosis is cell eating and exocytosis is phagocytosis.

Endocytosis moves materials into a cell, whereas exocytosis expels materials from the cell.

In which organelle are the vesicles that will undergo exocytosis produced? - Lysosomes - The Nucleus - Golgi Apparatus - Phagosomes

Golgi Apparatus - Among its several duties, the Golgi apparatus processes materials and packages them into a vesicle for transport out of the cell.

What does equilibrium tell us about a concentration gradient?

If equilibrium is reached, there is no concentration gradient. equilibrium = equal distance between molecules

Potassium is often more concentrated (inside OR outside) the cell.

Inside!

3 Relative Terms Used to Compare Solutions w/ Solutes that Can't Pass Through the Membrane

Isotonic - same solute concentration; no net movement as water moves across membrane Hypertonic - higher solute concentration Hypotonic - lower solute concentration

What is most likely to happen to a phagosome brought into a cell by phagocytosis? - It breaks up into small vesicles for exocytosis. - Lysosomes will fuse with it to digest its contents. - It gradually decomposes on its own. - It fuses with the nucleus for processing.

Lysosomes will fuse with it to digest its contents.

Water entering a tea bag is osmosis. Is the dissolved tea leaving the bag considered osmosis as well? Why?

NO- It's just simple diffusion. Osmosis is ONLY the diffusion of WATER through a selectively permeable membrane.

Is movement UP/AGAINST a concentration gradient passive?

NO- it's active transport which requires energy

What uses channel proteins? (4)

Na+ K+ glucose polar molecules

Which of the following is not a passive process? - Oxygen diffusion - Na+/K+ pump - Facilitated diffusion of glucose - Osmosis

Na+/K+ pump

Sodium is often more concentrated (inside OR outside) the cell.

Outside!

Which of the following uses extensions of the membrane called pseudopodia to form a membrane sac around the object to be transported into the cell? - Pinocytosis - Receptor-mediated endocytosis - Facilitated diffusion - Phagocytosis

Phagocytosis - Phagocytosis uses pseudopodia (false feet) to surround an object to be brought into the cell. The membrane sac produced is called a phagosome.

Pearson explanation of Sodium-Potassium Pump!

The sodium/potassium pump is an active process which uses a transport protein to move ions both in and out of the cell. It also does not use invagination of part of the membrane during its function, as the forms of endocytosis do.

Which of the following statements about diffusion is incorrect? - Simple diffusion moves substances down their concentration gradient, whereas facilitated diffusion moves substances up their concentration gradient. - Simple diffusion allows molecules to pass directly through the phospholipid portion of the membrane, whereas facilitated diffusion allows other molecules to pass through the membrane via protein channels. - Both simple and facilitated diffusion are passive processes. - Both processes can allow molecules to move in either direction, based on the current concentration gradients.

Simple diffusion moves substances down their concentration gradient, whereas facilitated diffusion moves substances up their concentration gradient.

Which of the following is not a form of endocytosis? - Sodium/potassium pump - Receptor-mediated - Phagocytosis - Pinocytosis

Sodium/potassium pump

Which of the following is responsible for producing the "water gradient" that drives osmosis? - The semipermeable membrane - Solute molecules - Adenosine Triphosphate (ATP) - Carrier proteins

Solute molecules

receptor-mediated endocytosis

The uptake of specific molecules based on a cell's receptor proteins

Which statement about molecules at equilibrium is incorrect? - They stop moving once equilibrium is reached. - The molecules are spaced out about evenly - All molecules experience about the same number of collisions. - There is no concentration gradient.

They stop moving once equilibrium is reached.

By osmosis, water moves from a Hypotonic solution to a Hypertonic solution. T/F

True! The Hypotonic solution has less solute, MORE water. The Hypertonic solution has more solute, LESS water.

Which of the following is necessary for diffusion to occur? - temperatures above 20 degrees Celsius - a membrane - a channel protein - a concentration gradient

a concentration gradient

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Which of the following is not required for osmosis? - Concentration gradient - Semipermeable membrane - Water - Cell

cell - Water and a semipermeable membrane are the things required for osmosis. For there to be net movement of water during osmosis, a concentration gradient would also be necessary. Not all instances of osmosis occur across living cell membranes.

Molecules stop moving intermittently. T/F

false Molecules are constantly moving

Concentration gradients typically move from areas of low to high concentration. T/F

false! move from high to low concentration

During dehydration, the extracellular fluid becomes ___ to your intracellular fluid.

hypertonic This will draw water out of your cells, causing them to shrink. You will swell.

passive transport (2)

molecules spontaneously move down their concentration gradient; requires no energy - simple diffusion, facilitated diffusion, osmosis

Can diffusion occur without a concentration gradient?

no!

Does movement down a concentration gradient require energy?

no! It's passive

Simple Diffusion - active or passive?

passive

Is external respiration passive or active?

passive!

The movement of water molecules is changed from Simple Diffusion to Osmosis simply by adding a _____

selectively permeable membrane

Solution (3)

solute(s) dissolved in a solvent - our body fluids are solutions! - Salt (solute) + Water (solvent) = Salt Water (solution)

For osmosis, what variable of solute matters? Why?

the amount of solute present - the more solute, the less room for water - We need to know which side of the selectively permeable membrane has the most water because water will move from there (high concentration) to the other side (low concentration)

Brownian Motion

the chaotic movement of colloidal particles, caused by collision with particles of the solvent in which they are dispersed

In the body, the solvent is always ___

water

Polar molecules are ___ soluble.

water

When does a concentration gradient occur?

when concentration differs in adjacent areas

Can simple diffusion occur without a selectively permeable membrane?

yes!