A&P Chapters 3-4 Cellular Form/Function, Genetics Flashcards
Describe the 5 Components of Modern Cell Theory
- All organisms are composed of cells and the products of those cells
- The cell is the simplest structural and functional unit of life
- An organism’s structure and function is due to the characteristics of its component cells
- Cells are only derived from other cells
- Since all cells in an organism share a common ancestry, they all share some similarity in composition and metabolism
Everything in the body is a cell or made from a cell.
What is the common size of a cell? Why is it important that the cell not get too large?
The typical size of a cell is 10-15 microns.
It is important that a cell not get too large because it cannot coordinate the exchange of nutrients and waste properly. The cell cannot diffuse nutrients and waste out quickly enough.
What are the 3 components that 99.9% of cells have?
Cell Membrane, Organelles, Cytoplasm
Describe the cell membrane
Completely envolopes the cell and regulates what comes in and what goes out of the cell.
The cell membrane is made of a phospholipid bilayer with many proteins, glycoproteins, glycolipids and other structures embedded in the membrane.
The cell membrane is a double layer of phospholipids, the phospholipid bilayer. 98% of the membrane is phospholipid.
The heads of the phospholipids are hydrophilic, they are polar and contain a phosphate group. They face the extracellular and intracellular side.
The hydrophobic fatty acid tails are buried in the middle of the membrane.
The other 2% of the membrane is a variety of protiens and other structures. These protiens regulate the movement of molecules across the membrane.
Many biological molecules are not able to pass freely across the membrane. They need protieins to transport them.
Cytoplasm is…
The intracellular environment consisting of cytosol and cytoskeleton.
Why is cytoskeleton important?
It gives and manages the shape of a cell. The cytoskeleton also provides for the transportation of materials in a cell.
Organelles do what?
Carry out specialized tasks and metabolic processes.
List some membrane protiens
Receptors, Enzymes, Channel Proteins, Cell Identity Proteins, Cell-adhesion molecule.
Receptors…
Bind to chemical messengers such as hormones sent by other cells.
Enzymes…
Break down a chemical messenger and terminates it’s effect.
Ion Channel Proteins…
Are constantly open and allow ions to pass into and out of the cell.
Gated Ion Channel Proteins…
Open and closes to allow ions through only a certain times.
Cell-Identity Markers…
Are glycoproteins acting as a cell identity marker distinguishing the body’s own cells from foreign cells.
Cell-Adhesion Molecules…
Bind one cell to another.
Osmosis is…
The diffusion of water down its concentration gradient. Water moves to the side of the membrane with the higher solute concentration to reach equilibrium.
Water is free to move across cell membranes and will move from an area of LOW solute concentration to an area of HIGH solute concentration.
What can pass freely through cell membranes? What cannot?
Water, Oxygen, CO2, steroids and some small uncharged molecules can pass freely.
Proteins, fatty acids, large molecules and ions cannot pass freely across the membrane.
Define Crenation
The process in which a red blood cell in a hypertonic solution becomes shrunken and spiky.
Define Lysis
The destruction of a cell, when it gains too much water and bursts.
A solution is a combination of…
A solvent: in biology it is typically water.
A solute: in biology they are often ions, proteins, and hormones.
Define hypertonic
When concentration of solute is greater outside than inside. Ex: A hypertonic solution has a HIGHER concentration of a solute than what is found inside the cell.
The 5% NaCl solution will draw water out of the cell and into the area around the cell thus crenating the cell.
Define isotonic
When concentration of solute is the same inside and out.
Define hypotonic
When concentration of solute is lower outside THAN INSIDE. Ex: The hypotonic solution has a LOWER concentration of a solute than what is found inside the cell.
The 0% NaCl solution has more NaCl inside the cell (0.9%) and so water moves into the cell to dilute the NaCl in the cell to that of the concentration outside of the cell.
What is the rule about solute movement across a cell membrane?
Solutes move from high concentration to low concentration.
What are the two types of Carrier-Mediated transport? What is transported?
Facilitated Diffusion and Active Transport
Solutes (ions, proteins, ect..) are transported. Things that cannot otherwise diffuse freely across the cell membrane.
Transporters are membrane proteins and are very specific about what solutes they can transport.
Describe Facilitated Diffusion
A situation in which a solute travels across the cell membrane DOWN ITS CONCENTRATION GRADIENT.
The solute travels across the plasma membrane using a membrane protein but does NOT REQUIRE ATP, this occurs as long as the concentration is unequal on each side of the plasma membrane.
Describe Active Transport
A situation when a solute travels AGAINST ITS CONCENTRATION GRADIENT.
This process USES ATP and creates or maintains a concentration gradient where solute concentrations are higher on one side of the membrane.
The Na/K ATPase is an example of what?
Active Transport: Very important for maintaining cell ion concentrations and cell volume.
Na/K ATPase is a very important Enzyme.
Define a Uniporter
Moves One solute in One direction.
Define a Symporter
Moves Two solutes in One direction
Define an Antiporter
Moves Two solutes in Two directions
Na/K ATPase is an Antiporter
What is Vesicular Transport ideal for?
Transporting very large molecules, large numbers of molecules, and liquids.
This is how glands release hormones into the bloodstream.
Vesicles are…
Bubble like structures made up of pieces of the plasma membrane.
Endocytosis is…
The process by which particles or liquid are brought INTO the cell.
Involves the formation of a pit, invagination of the PM and pinching off and separation of the vesicle from the PM.
Exocytosis is…
The process that sends particles or liquids OUT of the cell.
The reverse of endocytosis.
What are the types of Endocytosis?
Phagocytosis, Pinocytosis and Receptor-Mediated Endocytosis
Describe Phagocytosis
What Types of Cells Employ Phagocytosis?
The “cell eating” process by which a cell engulfs particles or debris. Only a few cells in the body use this process.
Immune System Cells, White Blood Cells
Describe Pinocytosis
Process by which a cell takes in droplets of liquid containing solutes. This process is non-specific because the cell brings in whatever particles are found in the fluid, this can be a disadvantage.
Virtually every cell in the body employs this process.
Describe Receptor-Mediated Endocytosis
Uses a plasma membrane protein to selectivly collect specific solutes in specific quantities and bring them inside the plasma membrane. This involves the use of receptors on the outer surface of the plasma membrane. Many growth factors and hormones enter the cell this way.
The process in more detail: Begins with extracellular solutes binding to receptors on the surface causing the receptors to cluster together.
Clustering causes the plasma membrane to invaginate around receptors forming a pit.
Invagination continues until the newly formed vesicle pinches off from the plasma membrane and is released into the cytoplasm of the cell.