AP EXAM 2 Flashcards
What are the 4 general processes carried out by cells?
Cell growth, DNA replication, preparation for division, and cell division
Describe the 3 main components of a cell and their functions.
The cell membrane : surrounds the cell and controls the substances that go into and out of the cell
The nucleus : contains the nucleolus and most of the cells DNA
The cytoplasm : jelly-like fluid inside the cell containing various organelles responsible for different cellular functions
Where are intracellular and extracellular fluids located?
Intracellular is located inside the cells of the body while extracellular fluid is located outside the cells in the spaces between them
Describe the structure of a phospholipid.
Head attracted to water and tail repels water.
How do phospholipids arrange themselves in the plasma membrane? Why?
As a bilayer with heads facing water and tails facing away from water
How is the plasma membrane described according to the fluid mosaic model?
A flexible, fluid mosaic of various components, primarily phospholipids, cholesterol, and proteins, which are embedded within a phospholipid bilayer and can move freely within the membrane plane, allowing for a dynamic and adaptable cell boundary
Describe 5 functions of membrane proteins.
Transporting molecules across the membrane, acting as enzymes, facilitating cell signaling, cell recognition, and anchoring the cell to the extracellular matrix
helps maintain the membranes stucture and fluidity and makes it thicker and less permeable
Cholesterol
cell recognition, cell adhesion, cell signaling, protection, cell membrane stability, energy, blood group determination, immune system assistance
Glycolipids
cell to cell interactions, signaling, immune system, cell shape and integrity, transport, protection
Glycoproteins
channeling or transporting molecules across the membrane
Integral (transmembrane) proteins
support, communication, enzymes, and molecule transfer in the cell
Peripheral proteins
allow the cell to be selectively permeable
Phospholipid bilayer
What is a concentration gradient?
The process of particles, which are sometimes called solutes, moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles
Describe the process of diffusion (simple diffusion). Are molecules moving down or against their concentration gradient? Does this movement require energy? Is a protein needed for diffusion to occur in the cell or does it occur across the lipid bilayer? Which type of molecules are more likely to diffuse across the lipid bilayer?
Passive movement of molecules from an area of higher concentration and an area of low concentration, moving DOWN. Occurs directly across the lipid bilayer of a cell membrane, without the need for a protein transporter, allowing small, non-polar, or lipid-soluble molecules to easily diffuse across the membrane, like oxygen and carbon dioxide
Describe factors that can influence the rate of diffusion.
Concentration gradiant, membrane permeability, temperature, and pressure
What is facilitated diffusion? Does this process require a transport or carrier protein? Does this process require energy? Which type of molecules are more likely to utilize facilitated diffusion?
Passive transport where molecules move across a cell membrane with the help of specific transport proteins (carrier proteins or channel proteins), moving DOWN their concentration gradient. Polar molecules and large ions, which cannot easily pass through the cell membrane on their own, are most likely to utilize facilitated diffusion
What are the 3 types of carrier proteins?
Uniporters, symporters, and antiporters
Describe the process of osmosis. What is the difference between osmotic and hydrostatic pressure?
Osmosis is the passive movement of water molecules across a semi-permeable membrane from a region of high water concentration to a region of low water concentration essentially aiming to equalize the solute concentrations on both sides of the membrane.
What is tonicity?
Relative solute concentration of a solution compared to another solution, particularly in relation to a cell; it determines the direction of water movement across a cell membrane
Hypotonic
A solution with a lower solute concentration than the cell, causing water to move into the cell by osmosis leading to the cell SWELLING AND BURSTING
Hypertonic
A solution with a higher solute concentration than the cell, causing the water to move out of the cell by osmosis, leading to cell SHRINKAGE
How does the primary active transport process work?
Uses ATP to move molecules across a membrane by utilizing specific carrier proteins that change shape to bind and transport the desired molecules
What is the main primary active transport pump in our cells? How does it function?
Moves sodium out of cells and potassium into them