Honors Biology - Unit 4 ✅

Aquaporin

Protein channels that assist water in diffusing rapidly across the cell membrane.

Cholesterol

Type of steroid that is found in animal cell membranes to help keep phospholipids spaced out.

Concentration Gradient

The difference in the concentration of a substance between two areas. Particles tend to follow a natural pattern moving from high to low concentration.

Diffusion

The net movement of particles down a concentration gradient from a region of higher concentration to a region of lower concentration.

Endocytosis

The process by which cells take in substances from outside of the cell by engulfing them in a vesicle.

Exocytosis

The process by which a cell transports secretory products through the cytoplasm to the plasma membrane.

Facilitated Diffusion

A method of passive transport of specific particles (polar or charged substances) moving down the concentration gradient (high to low) across the cell membrane via through protein channels or carrier proteins.

Hydrophilic

Attracted to water (easily mixes with water)

Hydrophobic

Tending to repel or fail to mix with water.

Hypertonic

Having a higher concentration of solutes in solution (compared to a cell)

Hypotonic

Having a lower concentration of solutes (more dilute) in a solution (compared to a cell)

Homeostasis

The tendency to maintain a stable, relatively constant internal environment.

Isotonic

The solution has an equal concentration on both sides of the membrane.

Insoluble

Unable to dissolve in a particular solvent (for example, oil in water).

Soluble

Able to dissolve in a particular solvent.

Integral Protein

A protein that spans the cell membrane and helps transport or communicate.

Nonpolar molecule

Electrons are shared equally between atoms in a molecule, leading to the neutrality of the molecule (no charge).

Polar molecule

Electrons are shared unequally between atoms within a molecule, leading to slight charges forming on opposite poles of the molecule.

Osmosis

The diffusion of water across a selectively permeable membrane.

Passive Transport

The movement of ions and other atomic or molecular substances across cell membranes without need of energy input.

Peripheral Protein

A protein attached to the surface of the membrane; used for signaling or support.

Permeability

The quality of a membrane that allows substances to pass through it.

Phagocytosis

The engulfment of larger food particles ("cell eating")

Phospholipid

Major component of the cell membrane; structurally similar to fats, BUT they only have 2 fatty acids (hydrophobic) attached to a phosphate head (hydrophilic) that includes a glycerol molecule bonded to a phosphate group.

Phospholipid Bilayer

A two-layered arrangement of phospholipid molecules that form a cell membrane; the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward.

Pinocytosis

Engulfment of a liquid (or solutes) by a cell ("cell drinking")

Semipermeable

Allowing certain substances to pass through it but not others, especially allowing the passage of a solvent but not of certain solutes.

Solute

The minor component in a solution, dissolved in the solvent.

Solvent

The liquid in which a solute is dissolved to form a solution.

Tonicity

The ability of a solution to cause a cell within it to gain or lose water.

Transport Proteins

Proteins involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane.

Turgidity (Tugor pressure)

The force within plant cells that pushes the plasma membrane against the cell wall. Helps the plant to be more rigid/stable so it can stay upright.

Active transport

A cell must expend energy (ATP) in order to move solutes against its concentration gradient (low to high) with the aid of a transport protein.

Channel protein

Creates a hydrophilic channel that some molecules and ions use as a tunnel to pass through the membrane (typically high to low concentration)

Carrier protein

Binds its passenger (i.e. glucose), changes shape, and releases its passenger on the other side

All of them

What type of cells have a cell membrane?

E

Which letter in the diagram represents a PROTEIN?

Osmosis

Which method of transport is being illustrated?

Isotonic

What type of solution is the FAR LEFT cell in?

Pinocytosis

What specific method of transport involved cell “drinking”?

Phosphate head

Which part of the phospholipid is hydrophilic?

Hypotonic

What type of solution is the MIDDLE cell in?

Diffusion

What method of transport is being illustrated?

Facilitated diffusion

What method of transport is being illustrated?

J

Which letter in the diagram represents a PROTEIN CHANNEL?

Active transport

What method of transport is being illustrated?

Hypertonic

Saltwater is ___________ to freshwater.

Hypertonic

Your cells are __________ to pool water.

Endocytosis

Which method of transport is being illustrated?

Phagocytosis

What method of transport involved the cell “eating”?

Hypertonic

What type of solution is the FAR RIGHT cell in?

A

Which letter in the diagram represents a CARBOHYDRATE?

Lipid tail

Which part of the phospholipid is hydrophobic?

F

Which letter in the diagram represents the PHOSPHOLIPID BILAYER?

Equilibrium

When all solutes are evenly distributed, ______ has been reached.

A

Which letter in the diagram represents a PHOSPHOLIPID?

False

True or False: Particle movement is non-random in diffusion.

I

Which letter in the diagram represents a CHOLESTEROL molecule?

d. All of them

Which of the following is a component found in the cell membrane?

a. Phospholipid

b. Protein

c. Carbohydrate

d. All of them

a. Active transport

Which of the following DOES NOT move from high to low concentration?

a. Active transport

b. Osmosis

c. Facilitated diffusion

d. Diffusion

d. All of them

Which of the following is a function of the cell membrane?

a. Regulates what enters/exits

b. Support and protection

c. Helps maintain homeostasis

d. All of them

Cell membrane

The cell structure that regulates the passage of materials into and out of the cell is the _____.

Carbohydrates

Which organic compound attached at the cell surface helps individual cells identify one another?

b. Cellulose

Which one of the following components is not found in the cell

membrane?

a. transport proteins

b. Cellulose

c. Carbohydrates

d. Lipids

Receptor proteins

These membrane proteins recognize and bind to substances at

the cell surface, forming a method of communication.

High; low

In the absence of other forces, materials will tend to move from areas of ____ concentration to areas of ____ concentration.

Cell wall

Lipid bilayer membranes are found in all of the following cell structures except for the _____.

Enzymes

Some membrane proteins are ____ that speed up certain chemical reactions in the cell.

Fluid mosaic

The _____ model of membrane structure describes the constant

movement of lipids and proteins within the membrane.

Plasmolysis

This condition might occur if too much water leaves the cell and the cell membrane collapses.

Contractile vacuoles

Freshwater protists use _____ to pump excess water out of their

cells.

Polar substances

All of the following can diffuse directly across the lipid bilayer

except for _____.

Energy

The movement of materials against the concentration gradient would require ____.

a. Oxygen

Which one of the following can move across a membrane without the help of a transport protein?

a. Oxygen

b. Water

c. Ions

d. Proteins

Vacuoles

During endocytosis, infoldings of the membrane break loose to form _____.

Ion channels

Charged atoms such as Na+, K+, Cl- , and Ca+2 cross membranes through _____.

Circulatory System

Carries water in plasma (liquid portion of your blood).

Endocrine System

Sends signals to kidneys to control water levels.

Urinary System

Controls water levels in blood plasma.

Nervous System

Detects changes in the amount of water in the body.

Positive Feedback

Moving AWAY from homeostasis; when a change in a system in AMPLIFIED (snowball effect).

Negative Feedback

RETURNING to homeostasis; a system responds to change, and the system returns to the original state or decreases the rate of change.

1. Thin - to easily allow for movement of materials

2. Flexible - to allow for ease of movement and conforming to different spaces

What are two helpful characteristic of cell membranes?

1. Regulates what enters and exits the cell

2. Provides protection and support for the cell

What are the two main functions of the cell membrane?

Proteins and phospholipids

What’s the primary membrane composition?

Carbohydrates and cholesterol

What’s the secondary membrane composition?

Channel protein

A type of transport protein that forms a pore or tunnel through the cell membrane, allowing specific ions or small molecules to passively diffuse (without energy) across the membrane, typically down their concentration gradient.

Protein pump

A type of transport protein that uses energy (usually from ATP) to move ions or molecules against their concentration gradient (from low concentration to high concentration). This process is known as active transport.

Marker protein with carbon chain

A glycoprotein—a protein with an attached carbohydrate chain (the "carbon chain")—that extends from the cell's surface. These proteins act as cell-recognition markers (like ID tags) that help the immune system and other cells identify the cell as belonging to the organism. They are crucial for cell-to-cell communication.