Chapter 4 Flashcards
(39 cards)
What are two tenets of the cell theory?
- modern cell theory
o the cell is the simplest unit of life
o all cells come from preexisting cells
What is the function of membrane bound organelles?
- Enclosed by phospholipid bilayer
- Separates cytosol
o Ex: endoplasmic reticulum (rough and smooth), Golgi apparatus, lysosomes, peroxisomes, mitochondria
What is the function of a non membrane bound organelle?
- NOT enclosed in the membrane
- Composed of protein
o Ex: Ribosomes, cytoskeleton, centrosome, inclusions
What is the role of a proteasome?
It is a barrel shaped structure, primarily made of protein. It’s function is to tag and digest damaged or old proteins. (disposal unit)
What is the function of the cell (plasma) membrane and what is it composed of?
Plasma membrane forms outer, limiting barrier separating internal contents from external environment
Composed:
- phospholipids cholesterol, glycolipids
What is the function of cholesterol in the membrane?
Strengthens cell membrane
Stabilizes against temperature extremes
What are the transmembrane proteins?
Integral Proteins
- Transport Proteins
- Cell Surface Receptors
-Identity Markers
-Enzymes
-Anchoring Sites
- Cell Adhesion Proteins
What is the function of integral proteins?
- embedded in and extend across phospholipid bilayer
What is the function of peripheral proteins?
- NOT in the phospholipid bilayer
- Attached to external surface of the bilayer
- Provides support, communication, and enzyme function
What are the three types of cell membrane extensions?
Microvilli, Cilia, Flagella
What is the function of microvilli and where in the body can you find it?
small protection that increases surface are and used for absorption
What is the function of cilia and where in the body can you find it?
larger protection that has active motion and moves substances along its surface
What is the function of flagella and where in the body can you find it?
largest projections that are found only in male sperm cells
What are the two categories of plasma membrane transport? Which one does not require energy?
Passive Transport - does NOT require energy
Active Transport - requires energy
What is the function of Passive Transport?
- does not require energy
- moves substances down concentration gradient
What is the function of Active Transport?
- requires energy
- moves substances up concentration gradient
What is diffusion?
- net movement of particles from area of high concentration to low
- requires ATP
What is the function of osmosis?
- flow of water from one side of selective permeable membrane to other
What is facilitated diffusion and an example?
- transport process for small charged or polar solutes requires assistance from plasma membrane proteins.
What happens to a cell in a hypotonic solution?
- fluid inside cell has a higher concentration of solutes than fluid outside of the cell
- water then moves down gradient from outside to inside
- cells absorb water, swell, and may burst
What happens to a cell in a hypertonic solution?
- inside cell has lower concentration of solutes than outside cell
- water moves outside of cell
- cell loses water and shrivels (crenate)
What happens to a cell in a isotonic solution?
- concentrations in cells and ICF are the same
- no changes in shape or volume of cell. normal saline
What is active transport?
requires ATP (battery of the cell)
- through “pumps” or “carriers” in cells outer membrane, the pumps serve as gates with motos. they help push molecules from one side of the membrane to the other, even if it’s against natural flow.
What is an example of active transport?
- Ex: Sodium potassium pump keeps K+ concentration higher inside cell
- Ex: Pump Na+ out of cell
