Chapter 3 Wk 2 Flashcards
Are the hydrophilic heads of the phospholipid bilayer polar or non polar?
Polar.
They are able to interact with the polar molecules of the water inside and out of the cell.
Are the hydrophobic tails of the phospholipid bilayer polar?
No
What is DIFFUSION?
The movement of chemicals from higher solute concentration to lower solute concentration.
It is a product of the constant random motion of all atoms.
What is a measure of a fluid’s resistance to flow?
VISCOSITY
More viscosity = slower flow rate
Less viscosity = faster flow rate
The diffusion of water across a semi permeable membrane is called?
OSMOSIS
Selectively (or semi) permeable membrane means that the membrane allows water but not all the solutes dissolved in the water to diffuse through it.
What are the characteristic functions of a cell?
- Cell metabolism and energy use
- Synthesis of molecules
- Communication
What does “cell metabolism and energy use” mean?
CELL METABOLISM is the metabolic reactions (or chemical reactions) that occur within cells. These reactions are collectively known as cell metabolism.
The ENERGY released by some metabolic reactions fuels cellular activities, such as the synthesis of molecules and muscle contraction. During some metabolic reactions energy is released as heat, helping regulate body temps.
What does “synthesis of molecules” involve in relation to the characteristic function of a cell?
The different cells of the body synthesize various types of molecules, including proteins, nucleic acids, and lipids.
The structural and functional characteristics of cells are determined by the types of molecules they produce.
What does “communication” mean in respect to the characteristic functions of a cell?
Cells produce and respond to chemical and electrical signals that allow them to communicate with one another.
Ex: Nerve cells produce chemical signals by which they communicate with muscle cells, and muscle cells respond by contracting or relaxing.
What is the fluid-mosaic model?
It suggests that the plasma membrane is neither rigid nor static in structure but is highly flexible and can change its shape and composition through time.
The lipid bilayer functions as a dense liquid in which other molecules, such as proteins, are suspended.
What are some functions of MARKER PROTEINS within a cell?
They can function as marker molecules, attachment proteins, transport proteins, receptor proteins, or enzymes.
What are MARKER MOLECULES?
Cell surface molecules allow cells to identify other cells or other molecules.
They are either GLYCOPROTEINS or GLYCOLIPIDS.
What is a glycoprotein?
A protein with attached carbohydrates.
What is a glycolipid?
A lipid with attached carbohydrates.
What is an INTEGRAL membrane protein?
A protein molecule that penetrates deeply into the lipid bilayer.
What is a PERIPHERAL membrane protein?
Proteins that are attached to either the inner or the outer surfaces of the lipid bilayer.
What is an ATTACHMENT protein?
An integral protein that allow cells to attach to other cells or to extracellular molecules.
Many attach to intracellular molecules as well.
What is a TRANSPORT protein?
Integral proteins that allow ions or molecules to move from one side of the plasma membrane to the other.
These proteins have 3 characteristics:
- SPECIFICITY
- COMPETITION
- SATURATION
Ex: ATP powered pumps, Carrier proteins, Channel proteins
SPECIFICITY
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COMPETITION
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SATURATION
L
What is a LEAK ION CHANNEL?
AKA Nongated ion channel.
They are always open and are responsible for the plasma membrane’s permeability to ions when the plasma membrane is at rest.
What is a GATED ION CHANNEL?
They can be opened or closed.
What is a LIGAND-GATED ION CHANNEL?
A gated ion channel that opens or closes in response to chemical signals (called LIGANDS).
The ligands, or small molecules, bind to the proteins or glycoproteins.
What is a VOLTAGE-GATED ION CHANNEL?
An ion channel that opens or closes when there is a change in the membrane potential.
Functions of MEMBRANE PROTEINS:
Marker molecules Attachment proteins Transport proteins Enzymes Receptors
A complex of DNA and protein, which consists of many different genes is called a:
Chromosome.
What do we call the system of microfilaments, actin (intermediate filaments), and microtubles that give the cell shape, allow movement, and the routing of molecules and organelles within the cell?
CYTOSKELETON
Functions of CYTOPLASMIC membrane proteins:
Allows cells to identify other cells or molecules
Catalyze chemical reactions
Serve as a binding site for chemical signals
Anchor one cell to another
Allow for molecules and ions to pass through the cell membrane.
CENTROSOME
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CENTRIOLES
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