Podcast
Questions and Answers
What is the main function of the plasma membrane?
What is the main function of the plasma membrane?
- To provide a rigid structure to the cell
- To produce energy for the cell
- To store genetic information
- To regulate what enters and exits the cell (correct)
What type of macromolecule primarily makes up the plasma membrane?
What type of macromolecule primarily makes up the plasma membrane?
- Carbohydrates
- Lipids (correct)
- Nucleic Acids
- Proteins
Which of the following describes the tails of phospholipids?
Which of the following describes the tails of phospholipids?
- Hydrophilic
- Ionic
- Polar
- Hydrophobic (correct)
What is the function of integral proteins in the cell membrane?
What is the function of integral proteins in the cell membrane?
What is a solution?
What is a solution?
Which of the following describes a selectively permeable membrane?
Which of the following describes a selectively permeable membrane?
In a hypertonic solution, the concentration of solutes is ______ outside the cell than inside the cell.
In a hypertonic solution, the concentration of solutes is ______ outside the cell than inside the cell.
Which type of transport does not require energy?
Which type of transport does not require energy?
What is the movement of molecules from an area of high concentration to an area of low concentration called?
What is the movement of molecules from an area of high concentration to an area of low concentration called?
Which process involves the expulsion of materials from a cell?
Which process involves the expulsion of materials from a cell?
Flashcards
Prokaryotic Cells
Prokaryotic Cells
Cells that lack a defined nucleus, genetic material dispersed in the cytoplasm.
Eukaryotic Cells
Eukaryotic Cells
Cells that have a defined nucleus.
Plasma Membrane
Plasma Membrane
Thin flexible barrier around all cells; allows nutrients in and wastes out.
Homeostasis
Homeostasis
Signup and view all the flashcards
Selective Permeability
Selective Permeability
Signup and view all the flashcards
Lipids
Lipids
Signup and view all the flashcards
Phospholipid Head
Phospholipid Head
Signup and view all the flashcards
Phospholipid Tails
Phospholipid Tails
Signup and view all the flashcards
Integral Membrane Proteins
Integral Membrane Proteins
Signup and view all the flashcards
Exocytosis
Exocytosis
Signup and view all the flashcards
Study Notes
Cell Membrane Structure & Function
- Addresses how substances move into and out of cells
Types of Cells
- There are two types of cells: Prokaryotic and Eukaryotic
Prokaryotic
- These cells lack a defined nucleus
- Dispersed genetic material in the cytoplasm characterizes them
Eukaryotic
- These cells have a defined nucleus
Plant Cell
- Have a cellulose cell wall with chloroplasts and vacuoles
Animal Cell
- These cells have a rigid cell wall, may have flagella
Protist
- Can have a cell wall, but they lack differentiated tissues
Fungal
- Have a chitin cell wall and are heterotrophs
The Cell (Plasma) Membrane
- It is a thin, flexible barrier around all cells
- Allows nutrients to enter and wastes to exit
- Maintains homeostasis within the cell
Homeostasis
- Regulation of conditions to maintain life in balance
Selective Permeability
- Allows some substances to pass through while preventing others
Structure of the Plasma Membrane
General Info
- Most of the molecules in the plasma membrane are lipids
- Lipids are made of glycerol and fatty acids
- If a phosphate group replaces a fatty acid, a phospholipid is formed
- The plasma membrane features a phospholipid bilayer due to water existing both inside and outside of a cell
The Phospholipid Bilayer
- Has a head and two tails
- The phosphate group makes the head polar, attracting it to water
- The fatty acid tails are hydrophobic, repelled by water
Other Components of the Plasma Membrane
Proteins
- Two main types exist in the cell membrane, Integral and Peripheral
Integral proteins
- Extend from the outside to the inside of the membrane
- Used for transport, forming channels and pumps to move materials
Peripheral proteins
- Found on the inside or outside of the cell membrane
- Used as receptors or anchors for the cytoskeleton
- Receive chemical signals like hormones from outside the cell
Carbohydrates
- Important for cellular recognition
- Help the cell to be recognized as a certain type
Cholesterol molecules
-
Prevent fatty acid tails from sticking together
-
The plasma membrane is often referred to as the cell membrane
Cell Transport Definitions
- A solution is a liquid mixture of two or more substances
- A solute is the substance being dissolved in a solution
- A solvent is the substance doing the dissolving
- Concentration is the measurement of the amount of solute
- A permeable membrane allows every substance through
- An impermeable membrane allows nothing through
- A selectively permeable membrane allows some substances through, but not others
Types of Solutions
- Hypertonic solution has a higher concentration of solutes outside the cell than inside, resulting in "above" strength
- Hypotonic solution has a higher concentration of solutes inside the cell compared to outside, leading to "below" strength
- Isotonic solution has the same concentration of solutes inside and outside the cell, resulting in the same strength
How Cells are Effected by Different Solutions
- Water accounts for over 70% of the human body
- Unregulated water levels can lead to cell damage, swelling, blood cell bursting or brain damage
- Cells regulate and maintain their water content through specific processes
Types of Transport
Passive Transport
- Passive transport doesn't require energy to move substances across cell membranes
- Substances move from an area of high concentration to an area of low concentration, following the concentration gradient
Active Transport
- Requires energy (ATP) to move molecules across the cell membrane
- Molecules move from a region of lower concentration to a region of higher concentration, against the concentration gradient
Active Transport Movement
- Molecules or ions move across a cell membrane from a region of low concentration to a region of higher concentration, requiring cellular energy
Passive Transport Types
Hypertonic/Hypotonic Solutions
- Passive transport include Hypertonic & Hypotonic solutions
Facilitated Diffusion
- Diffusion of a solute from high to low concentration through an integral protein (channel or carrier)
Diffusion
- Solute particles move from an area of high concentration to one of low concentration
- Examples include: baking in an oven, nail varnish, food dye and the smell of a fart
Dynamic Equilibrium
- Amount coming in equals the amount coming out, resulting in no net movement
Osmosis
-
Movement of water from hypotonic solution to a hypertonic solution
-
Solutes cannot pass through the membrane due to their size, however water can
-
Small amounts of water pass straight through the membrane, large amounts through aquaporins to areas with higher solute concentration
-
Glucose/ions are too large to go between phospholipids needing integral/transport proteins
-
Very small, unchanged/nonpolar molecules like O2 and CO2 can pass
-
H2O can pass in small amounts, but large amounts need proteins known as aquaporins
Movement of Large Materials through Vesicle Formation
Exocytosis
- The expulsion or secretion of materials from a cell
Endocytosis
- A cell surrounds and takes in material from its environment
How Cells Obtain Materials from Environment
-
Cells get materials they need through the cell membrane (passive/active transport)
-
Once inside, the cell transports those materials to all the different regions
-
Each organelle has a specific structure and function for the cell to maintain homeostasis
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Exploration of cell structure and function, covering both prokaryotic and eukaryotic cells. Includes plant, animal, protist, and fungal cells. Addresses cell membrane structure, function, homeostasis and selective permeability.