Untitled Deck Flashcards
What are the upper and lower limits to cell size related to?
Surface area and volume ratios.
What is the structure of a cell membrane primarily composed of?
Phospholipid molecules.
How do phospholipid molecules relate to cell membrane properties?
They allow separation of cell contents from the environment.
What types of substances can cross the cell membrane?
Small nonpolar molecules, water, and certain ions.
What is the difference between permeable, semi-permeable, and selectively permeable?
Permeable allows all substances, semi-permeable allows some, selectively permeable allows specific substances.
What are the roles of fibrous proteins in cell membranes?
Provide structural support and facilitate communication.
What function do pore proteins serve in the cell membrane?
Allow specific molecules to pass through.
What is the function of channel proteins in the cell membrane?
Facilitate the transport of ions and molecules.
What role do glycoproteins play in cell membranes?
Involved in cell recognition and signaling.
What is the significance of cholesterol in cell membranes?
Maintains membrane fluidity and stability.
Define diffusion in the context of cell membranes.
Movement of molecules from high to low concentration.
How is osmosis defined?
Diffusion of water across a membrane.
How does osmosis relate to facilitated diffusion?
Water moves through aquaporins in a facilitated manner.
What are hypertonic, hypotonic, and isotonic solutions?
- Hypertonic: higher solute concentration outside
- Hypotonic: lower solute concentration outside
- Isotonic: equal solute concentration
How do animal and plant cells react in hypertonic solutions?
Animal cells shrivel, plant cells become plasmolyzed.
What is the outcome for animal and plant cells in hypotonic solutions?
Animal cells may burst, plant cells become turgid.
What is the role of transport proteins in diffusion?
Facilitate the movement of substances across the membrane.
Compare active transport and facilitated diffusion.
Active transport requires energy; facilitated diffusion does not.
What determines the direction of substance movement across a membrane?
Concentration gradient.
What is the importance of aquaporins in osmosis?
They facilitate water transport across cell membranes.
What is the difference between passive and active transport?
Passive transport does not require energy; active transport does.
What are the causes of ocean acidification?
Increased CO2 absorption by oceans.
What are the consequences of ocean acidification?
Impacts marine life, particularly calcifying organisms.
What is the pH scale used to measure?
Acidity or alkalinity of a solution.
