plasma membrane

Question 1

Semipermeability (Selective Permeability)

Answer 1

The membrane lets some things in and out but blocks others.

Question 2

Sensitivity

Answer 2

The cell’s ability to sense and respond to its surroundings.

Question 3

Dynamic equilibrium

Answer 3

Balanced movement, even though things keep moving.

Question 4

Net movement

Answer 4

Overall direction molecules move—like more people leaving than entering.

Question 5

Concentration gradient

Answer 5

Molecules move from crowded areas to less crowded ones.

Question 6

Lipid

Answer 6

Fats that make up the cell membrane’s protective barrier

Question 7

Carbohydrate

Answer 7

Sugars that help cells recognize each other.

Question 8

Protein

Answer 8

Tiny machines in the cell that do different jobs.

Question 9

Membrane transport

Answer 9

How stuff gets in and out of the cell.

Question 10

Glycocalyx

Answer 10

A sugary coating that protects and helps cells communicate.

Question 11

Diffusion

Answer 11

Molecules spreading out from crowded to less crowded areas.

Question 12

Facilitated diffusion

Answer 12

Diffusion with a little help from a protein.

Question 13

Osmosis

Answer 13

Water moving to balance concentrations.

Question 14

Active transport

Answer 14

The cell uses energy to move stuff against the flow

Question 15

Hypertonic

Answer 15

Cell shrinks because it loses water.

Question 16

Hypotonic

Answer 16

Cell swells because it gains water.

Question 17

Isotonic

Answer 17

No change—water levels are balanced.

Question 18

Plasma Membrane Structure: Phospholipids

Answer 18

Phospholipids have a hydrophilic head and hydrophobic tail. They form the bilayer of the membrane

Question 19

Plasma Membrane Structure: Cholesterol

Answer 19

Cholesterol affects membrane fluidity—more cholesterol makes the membrane more fluid.

Question 20

Plasma Membrane Structure: Proteins

Answer 20

Transmembrane proteins span the membrane; peripheral proteins are loosely attached. Both have specific roles in cell function.

Question 21

Plasma Membrane Structure: Carbohydrates

Answer 21

Carbohydrates play a role in cell recognition and protection, forming structures like the glycocalyx.

Question 22

Fluid Mosaic Model

Answer 22

The membrane is fluid with proteins moving within the lipid bilayer, resembling a mosaic.

Question 23

Membrane Functions: Selective Permeability

Answer 23

The membrane controls what enters and exits the cell, allowing only certain substances through.

Question 24

Membrane Functions: Communication and Sensitivity

Answer 24

Proteins and carbohydrates help the cell interact with its environment, detecting and responding to changes.

Question 25

Membrane Functions: Protection and Adhesion

Answer 25

The membrane protects the cell and allows it to stick to other cells or surfaces.

Question 26

Membrane Transport: Simple Diffusion

Answer 26

Small, nonpolar molecules move directly across the membrane from high to low concentration.

Question 27

Membrane Transport: Facilitated Diffusion

Answer 27

Molecules move across the membrane with the help of proteins, such as channels or carriers.

Question 28

Membrane Transport: Osmosis

Answer 28

Water moves across the membrane through aquaporins, following the concentration gradient.

Question 29

Active Transport: Primary Active Transport

Answer 29

ATP is used to move molecules against their concentration gradient (e.g., sodium-potassium pump).

Question 30

Active Transport: Secondary Active Transport

Answer 30

Uses the energy from one gradient to drive the movement of another molecule.

Question 31

Bulk Transport: Exocytosis

Answer 31

Large molecules are moved out of the cell via vesicles.

Question 32

Bulk Transport: Endocytosis

Answer 32

Large molecules are brought into the cell via vesicles (includes phagocytosis).

Question 33

Membrane Protein Functions: Receptors

Answer 33

Receptors receive signals from the environment and trigger cellular responses.

Question 34

Receptors receive signals from the environment and trigger cellular responses.

Answer 34

Channels, carriers, and pumps help move substances in and out of the cell.

Question 35

Membrane Protein Functions: Cell Identity and Adhesion

Answer 35

Membrane Protein Functions: Cell Identity and Adhesion

Question 36

Key Processes: Concentration Gradients

Answer 36

Substances move from high to low concentration in passive transport; low to high in active transport.

Question 37

Key Processes: ATP and Energy Use

Answer 37

ATP is used in active transport to move substances against their concentration gradient.

Question 38

Key Processes: Tonicity and Osmosis

Answer 38

Understand how hypertonic, hypotonic, and isotonic solutions affect cells through osmosis.