Biology Chapter 5 Flashcards

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Questions and Answers

What happens when phospholipids are placed in water?

A phospholipid bilayer is formed.

What are integral proteins?

Partially in or fully span the bilayer.

What are peripheral proteins?

Located on the inner or outer surface of the bilayer.

What is the phospholipid bilayer?

Quite flexible and not rigid. Signup and view all the answers

What is the function of transporters in membrane proteins?

Allow only certain substances to pass in and out of the cell. Signup and view all the answers

What is the role of enzymes in membrane proteins?

Speed up chemical reactions. Signup and view all the answers

What do attachment proteins do?

Connect to ECM, cytoskeleton, etc. Signup and view all the answers

What is the purpose of cell-cell recognition proteins?

Act as an ID badge. Signup and view all the answers

What do intercellular joining proteins do?

Attach to other cells. Signup and view all the answers

What is signal transduction in membrane proteins?

Respond to environment. Signup and view all the answers

What is passive transport?

Requires no energy; occurs naturally. Signup and view all the answers

What is active transport?

Requires energy; doesn't occur naturally. Signup and view all the answers

What is simple diffusion?

Movement of substances from high to low concentration. Signup and view all the answers

What is facilitated diffusion?

Same as simple diffusion except a protein helper is required. Signup and view all the answers

What are channel proteins?

Same as a pore, 'a tunnel'. Signup and view all the answers

What are ion channels?

Part of channel proteins; a pore that allows ions to pass through. Signup and view all the answers

What do carrier proteins do?

Protein binds to a specific substance and helps it through the membrane. Signup and view all the answers

What is osmosis?

The diffusion of water across a semi-permeable membrane. Signup and view all the answers

What is a solution?

A mixture of a solvent and another substance. Signup and view all the answers

What is a solute?

The substance that is dissolved in the solvent. Signup and view all the answers

What is hypertonic?

Higher concentration of solute in a solution. Signup and view all the answers

What is hypotonic?

Lower concentration of solute in a solution. Signup and view all the answers

What is isotonic?

Same concentration of solute. Signup and view all the answers

What happens when an animal cell is placed in a hypertonic solution?

Water will diffuse out. The cell will probably die. Signup and view all the answers

What is crenation?

Water diffusing out of an animal cell. Signup and view all the answers

What happens when a plant cell is placed in a hypertonic solution?

Water will diffuse out of the cell. Vacuole and cytoplasm will shrink. Signup and view all the answers

What is plasmolysis?

The cell membrane will pull away from the cell wall. Signup and view all the answers

What happens when an animal cell is placed in a hypotonic solution?

Water will diffuse into the cell. The cell will swell and burst. Signup and view all the answers

What is hemolysis?

When an animal cell is placed in a hypotonic solution, the cell bursts. Signup and view all the answers

What happens when a plant cell is placed in a hypotonic solution?

Water diffuses into the cell, causing it to expand. Signup and view all the answers

What is turgor pressure?

Causes plant cells to be firm. Signup and view all the answers

What happens when a cell is placed in an isotonic solution?

Water molecules enter and exit the cell at a constant rate. Signup and view all the answers

What is the sodium potassium pump?

Pumps 3 sodium ions (Na+) out of the cell and 2 potassium ions (K+) into the cell. Signup and view all the answers

What is coupled transport?

Simultaneous transport of two substances across the cell membrane. Signup and view all the answers

Study Notes

Phospholipids and Membrane Structure

When phospholipids are placed in water, they form a bilayer with hydrophilic heads in contact with water and hydrophobic tails facing inward.
Membrane flexibility varies: saturated fats make membranes less flexible, while unsaturated fats increase flexibility. Cholesterol reduces overall membrane flexibility.

Membrane Proteins

Integral Proteins: Span the phospholipid bilayer, either partially or fully embedded.
Peripheral Proteins: Located on the inner or outer surface of the bilayer and do not penetrate the membrane.

Functions of Membrane Proteins

Transporters: Control the passage of specific substances in and out of cells, allowing selective movement.
Enzymes: Speed up chemical reactions at the membrane surface.
Attachment: Connect cells to the extracellular matrix (ECM) and cytoskeleton, stabilizing the cell structure.
Cell-Cell Recognition: Serve as identification tags for cells, facilitating cell communication.
Intercellular Joining: Enable attachments between neighboring cells.
Signal Transduction: Relay signals from the environment to the cell's interior, triggering responses.

Transport Mechanisms

Passive Transport: Moves substances naturally from high to low concentration without using cellular energy. Types include:
- Simple Diffusion: Direct movement through the membrane; spontaneous and energy-free.
- Facilitated Diffusion: Requires a protein to assist substances in crossing the membrane.
- Osmosis: Specific diffusion of water across a semi-permeable membrane from high to low water concentration.
Active Transport: Requires energy to move substances against their concentration gradient, from low to high concentration.

Types of Proteins in Facilitated Diffusion

Channel Proteins: Create a pore or tunnel for substances to pass through.
Ion Channels: Specialized channels for ions, which can open and close to regulate ion passage.
Carrier Proteins: Bind to specific substances (e.g., sugars and amino acids) to transport them across the membrane.

Solutions and Concentration Types

Solution: A mixture of a solvent and solute.
Solute: The substance that dissolves in a solvent.
Hypertonic: Higher solute concentration leading to lower water concentration.
Hypotonic: Lower solute concentration resulting in higher water concentration.
Isotonic: Equal concentration of solutes in comparison to another solution.

Cell Behavior in Different Solutions

Hypertonic Solutions:
- Animal cells lose water, resulting in crenation; cells may die.
- Plant cells undergo plasmolysis where the membrane pulls away from the cell wall.
Hypotonic Solutions:
- Animal cells take in water, swell, and may experience hemolysis (bursting).
- Plant cells swell and maintain turgor pressure, becoming firm due to water pressure in the vacuole.
Isotonic Solutions: Water moves in and out at a constant rate; animal cells remain normal while plant cells become limp.

Sodium-Potassium Pump and Coupled Transport

Sodium-Potassium Pump: Actively transports 3 sodium ions out of the cell and 2 potassium ions into the cell, maintaining low sodium and high potassium concentrations inside.
Coupled Transport: Simultaneously transports two different substances across the membrane, utilizing energy to move one substance out while bringing another in.

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Description

Test your knowledge on the cellular structures presented in Chapter 5. These flashcards cover important concepts such as phospholipids and the roles of integral and peripheral proteins in the cell membrane. Perfect for students looking to reinforce their understanding of cell biology.