Biology Ch 5

Transport proteins allow the movement of ions and small molecules across plasma membranes. Identify the type of transport protein from each example as uniporter, symporter, or antiporter.

A protein moves one Cl− out of the cell and one HCO−3 into the cell. -antiporter A protein allows Ca2+ to flow into a mitochondrion when bound by a ligand. -uniporter A protein moves one H+ ion and one K+ ion out of the cell. -symporter

Select the statements that accurately describe endocytosis.

- the cell expends energy to transport materials into the cytosol - the cell membrane engulfs a particle into the cytoplasm and forms a vesicle around it

Which statements describe examples of facilitated diffusion?

-A kidney cells absorbs water molecules down their concentration gradient using membrane protein. - A neuron allows potassium ions to leave the cell down their concentration gradient using a membrane channel - An inner ear hair cell allows potassium ions to flow down their concentration gradient using a membrane pump and cellular energy

Select the descriptions that apply to the sodium‑potassium pump.

-Adenosine triphosphate (ATP) is necessary for the pump's function. -The pump moves potassium ions into the cell and sodium ions out of the cell.

Select the statement that describes an electrochemical gradient.

sum of the differences in charge and chemical concentration of ions across a membrane

The sodium-potassium pump, also known as the Na+/K+ ATPase, is shown in this animation. The movement of ions through this membrane protein is an example of...

active transport.

Which statements are properties of protein‑facilitated active transport?

-Substances cross the plasma membrane by being pumped through a protein using ATP -Substances can be moved across the plasma membrane against a concentration gradient.

What does the fluid mosaic model describe about the structure of plasma membranes?

-proteins and other membrane components are embedded in the membrane -phospholipids in the membrane are not covalently bonded to each other

Properties of integral membrane proteins and those that are properties of the peripheral membrane proteins

Integral membrane proteins -reach through all of part of the membrane -can move literally side ways in the hydrophobic part of the membrane -acts as tunnels through the cell membrane Peripheral membrane proteins -attach at the cell membrane surface

the movement of water through a semipermeable membrane

Osmosis

Two forms of endocytosis are pinocytosis and phagocytosis. The following statements are characteristics of either pinocytosis or phagocytosis. Match each description to the appropriate category.

Pinocytosis: - extracellular fluid is engulfed - tiny vesicles are formed -it it referred to as cellular drinking Phagocytosis: - large particles are engulfed - large vesicles are formed - pseudopodia are used

Which choice describes diffusion?

The movement of a substance down a concentration gradient from an area of high concentration to an area of low concentration.

Which statement describes the fluid mosaic model?

a phospholipid bilayer with various molecules embedded within and floating between the layers.

Facilitated diffusion is a protein‑facilitated movement of solutes across a membrane from an area of higher concentration to an area of lower concentration. Which of the terms best describes facilitated diffusion?

passive transport

Which molecules are the main components of the plasma membrane?

proteins and lipids