Biology Chapter 4: Membrane Structure and Function

Which passage functions do not require energy?

1. Diffusion 2. Facilitated Transport

What is the requirement for endocytosis?

Vesicle formation

What is the requirement for exocytosis?

Vesicle fuses with plasma membrane

What is cytolysis?

When a hypotonic solution causes a cell to burst (Only animal cells)

What is equilibrium?

When concentration is the same throughout a cell

What is plasmolysis?

When water moves down its gradient out of the cell. (Only in plants) Causes cell to shrivel up

What is Plasmolysis?

When water moves down its gradient out of the cell. Can cause the cell to shrivel up (Only in plants)

What are the two types of Bulk Transport?

1. Endocytosis 2. Exocytosis (Both require ATP)

What are the two other names for Facilitated Transport?

1. Facilitated Diffusion 2. Passive-Mediated Transport

Name the two types of channel proteins

1. Integral proteins 2. Peripheral Proteins

List examples of diffusion

1. Lipid soluble Molecules 2. Gases

Explain the process of Receptor-Mediated Endocytosis

1. Molecule binds to specific receptor protein on cell membrane 2. Coated pit pinches in 3. Coated vesicle is formed 4. Coated vesicle attaches to lysosome to digest material

Name the three types of endocytosis

1. Pinocytosis 2. Phagocytosis 3. Receptor-Mediated Endocytosis

Explain the Process of Cell Signaling

1. Receptor: Binds to a signaling molecule and becomes activated-initiates cell transduction pathway 2. Transduction Pathway: Series of relay proteins that ends when a protein is activated 3. Response: Targeted proteins bring about responses

Explain process of Transduction Pathway caused by cell signaling

1. Signal molecule attaches to receptor 2. Signal gets passed from protein to protein 3. Signal reaches a target protein 4. Target protein, a response is triggered

List examples of facilitated transport

1. Some sugars 2. Some amino acids

List the targeted proteins used in cell signaling

1. Structural Protein 2. Gene Regulation 3. Enzyme

Which targeted proteins cause which reactions in cell signaling?

1. Structural protein: Altered shape/movement of cell 2. Gene Regulation: Altered gene expression 3. Enzyme: Altered metabolism or function of the cell

Explain the process of endocytosis

1. Substances contact membrane 2. Membrane forms a pouch 3. Pouch pinches off to form vesicle 4. Vesicle travels to lysosome to help break down food

List examples of active transport

1. Sugars 2. Amino Acids 3. Ions

Explain the process of phagocytosis

1.Cell membrane (pseudopod when process is in ameoboid cell) reach out and engulf particle 2. Cell membrane pinches in 3. Vesicle is formed 4. Vesicle fuses with lysosome 5. Digestive enzymes in lysosome break down particle -Can be observed

What does it mean for a cell membrane to be a Fluid-Mosaic Model?

Consistency of membrane is solid enough to form a boundary, but flexible and permeable like a fluid. It is mosaic because it is made of many different proteins.

What does an integral protein do?

Determines specific function

What is osmosis?

Diffusion of water across a semi-permeable membrane. (Same as diffusion just without the water moving)

What is ATP?

Energy molecule

List the responses caused by cell signaling

1. Altered shape or movement of cell 2. Altered metabolism or function of cell 3. Altered gene expression and amount of cell protein (More/less protein being made

What is the requirement for active transport?

1. Carrier plus energy

Explain the process of Pinocytosis

1. Cell membrane surrounds drop of fluid with dissolved solutes 2. Cell membrane pinches in 3. Vesicle is formed around the particle

What is required for facilitated transport?

1. Channels or Carrier 2. Concentration Gradient

What is Pinocytosis?

-Also known as "cellular drinking" -Ingestion of liquid into cell by the budding of small vesicles from the cell membrane

What is phagocytosis?

-Also known as "cellular eating" -When a large particle (like a food particle or another cell) is taken in.

Definition of Concentration

-Amount of atoms in one area -Equals diffusion

Definition of Concentration Gradient

-Area where their concentration is high to an area where concentration is low

Facilitated Transport

-Carrier proteins move substances down with concentration Gradient Reversible if gradient changes direction

Hypertonic Solution

-Causes cell to shrivel up -More water on the inside -Water moves OUT of cell (Down the concentration gradient) through diffusion -More dissolved particles outside the cell (Concentration is greater outside the cell) -(Think hyper=more. There are more dissolved particles outside of cell). -Water moves out of the cell into the solute

Isotonic Solution

-Concentration dissolved substances is same as inside cell. -Implies that water is the same concentration as inside cell. -Water moves in and out of cell at same rate -Result: No visible change in cell

Hypotonic Solution

-Concentration of dissolved substance is higher inside the cell (Think hypo=less. Less dissolved particles outside of cell) -More water on the outside (Water concentration is higher outside the cell). -Water moves down its gradient (into the cell) -Result: In plants-cell wall becomes turgid. In animals-cells can burst (Known as cytolysis) -Water moves out of solution and into cell

Glycoproteins

-Have carbohydrate chains attached -Used for cell recognition

Cholesterol

-In animals -Stiffens and strengthens membrane -Regulates fluidity

What is Bulk Transport?

-Movement of molecules in or out of cell.

What is endocytosis?

-Moving particles into cell that are too large to passively cross the cell membrane (When cell goes out and brings something back in).

Peripheral Proteins

-On one side or the other of the membrane -Anchored by the cytoskeleton -Provide structure

Channel Proteins

-Pass molecules through -Contain channel down the middle -Can be gated

Carrier Proteins

-Pass molecules through by combining with it -Shape-specific (Molecules must be a certain shape to pass through)

Active Transport

-Requires energy -Uses ATP to pump molecules against/up concentration gradient -Moves molecules from area of low concentration of solute to area of high concentration

What is passive transport?

-Requires no energy to move substances across membrane (Requires no ATP). -Its atoms, molecules, and small particles are in constant motion (Brownian Motion) -Can move in any direction -Usually move from areas of higher concentration to areas of lower concentration

What is Receptor-Mediated Endocytosis?

-Selective process of importing materials into cell -Uses receptor proteins to help carry large particles across cell membrane -Uses a receptor protein shaped so that only a specific molecule can bind to it

Integral Proteins

-Span entire membrane -Protrude on one side or the other -Float around

Which passage functions requires energy?

1. Active Transport 2. Exocytosis 3. Endocytosis

What does cytolysis do to a cell?

Animals: It causes the cell to burst because animal cells do not have the cell wall to add extra support from the added pressure. Plants: Adds osmotic pressure to cell wall, which provides the plant with support and helps it stand up better.

What does plasmolysis do to plants?

Causes cell to lose water. -Makes cell shrivel up. (In plants)

Selectively Permeable

Certain substances can move across plasma membrane while others cannot

What is the requirement for diffusion?

Concentration gradient

Which solution causes a plant cell's central vacuole to lose water and the cytoplasm to shrink?

Hypertonic Solution

Which solution can cause an animal cell to shrivel up?

Hypertonic solution

Which solution can cause an animal cell to burst?

Hypotonic solution

Which solution fills a plant cell's vacuole with water?

Hypotonic solution

Where are the receptors for Receptor-Mediated Endocytosis located?

In coated pits on the plasma membrane. -The cytosolic surface of the coated pits are covered by coat proteins

Which solution causes no movement of water in both a plant and animal cell?

Isotonic Solution

List examples of endocytosis

Macromolecules

List examples of exocytosis

Macromolecules

What material makes up the cell membrane?

Phospholipids

Purpose of Phagocytosis

Protects the body by ingesting harmful particles, bacteria, waste, and dead or dying cells. -Examples of particles ingested: food particles or another cell -Is non-specific (meaning it does not taken in certain materials, it just takes in whatever particle is there).

Definition of Transduction Pathway

Series of relay proteins that ends when a protein is activated

What does a peripheral protein do?

Structural, stabilizes, and shapes the membrane signaling pathways

Growth Factor

Tells a cell to divide

What happens to the cell wall of a plant cell when there is a hypotonic solution present?

The cell wall becomes turgid

Which process is happening when a plant begins to wilt?

The plant is going through plasmolysis.

What are enzymatic protiens?

They carry out metabolic reactions directly.

What is the purpose of Receptor-Mediated Endocytosis?

To pick up certain substances needed by the cell

Which direction does active transport move?

Toward higher concentration

Which direction does endocytosis move?

Toward inside

Which direction does diffusion move?

Toward lower concentration

Which direction does facilitated transport move?

Toward lower concentration

Which direction does exocytosis move?

Toward outside

Purpose of Pinocytosis

Used by blood cells. cells that line the kidney tubules or the intestinal wall, plant cells, and -Can only be observed with electron microscope -Non-Specific