A&P1 - LP#3 Flashcards
Cellular Level of Organization: Parts of the cell; Transport Across the Plasma Membrane; Cytoplasm
What are the THREE main parts of the cell?
- Plasma Membrane
- Cytoplasm
- Nucleus
This forms the cells flexible outer surface separating the cells internal and external environment.
Plasma Membrane
Regulates the flow of material into and out of the cell
Plasma Membrane
Plays a key role in communication among cells and between their external environment.
Plasma Membrane
Consists of all the cellular contents between the plasma membrane and the nucleus:
Cytoplasm
A large organelle which houses most of the cell’s DNA’s
Nucleus
Chromosomes are found within the ____________ and contain 1000’s of genes responsible for cellular structure and function.
Nucleus
The molecular arrangement of the plasma membrane resembles an ever-moving sea of fluid lipids that contain a mosaic of many different proteins.
The Plasma membrane is best described by using this structural model. It is called __________________
Fluid Mosaic Model
Plasma Membrane has 2 main structures:
- Lipid Bilayer
2. Membrane Proteins
This is the basic structural framework of the plasma membrane.
Lipid Bilayer
The lipid bilayers consists of THREE types of molecules
- Phospholipids
- Cholesterol (steroid)
- Glycolipids
The lipid bilayer is AMPHIPATHIC - What does this mean?
It has both polar and non-polar parts.
There are TWO categories of membrane proteins according to whether or not they are firmly embedded into the membrane. What are these 2 categories?
- Integreal Proteins
2. Peripheral Proteins
This category of membrane protein is firmly embedded within the hydrophobic regions of the plasma membrane It extends through the lipid bilayer and can be transmembrane
Integral Proteins
This category of membrane protein is NOT firmly embedded in the plasma membrane. It associates more loosely with the polar heads or with other proteins inner or outer surface.
Peripheral Proteins
These proteins can also be found in the plasma membrane. These proteins have carbohydrate groups attached to their ends that protrude into the extracellular fluid.
Glycoproteins
The carbohydrate portions of glycoproteins and glycolipids form this extensive sugary coat. It acts as a molecular signature that enables cells to recognize each other.
Glycocalyx
What are the three functions of Glycocalyx?
- Enable cells to recognize each other
- Enables cells to adhere to one another in some tissues
- Protects cells from being digested by enzymes in extracellular matrix.
What are the SIX functions of membrane proteins?
- Ion Channels
- Carriers
- Receptors
- Enzymes
- Linkers
- Cell-Identity Markers
When a structure permits the passage of substances through it
Permeable
When a structure does NOT permit the passage of substances through it.
Impermeable
When the plasma membranes permit some substances to pass more readily through it than others
Selective Permeability
________________ is a difference in the concentration of a chemical from one place to another, such as from the inside to the outside of the plasma membrane.
Concentration Gradient
________________ is a difference in the electrical charges between the inner and outer surfaces of the membrane.
Electrical Gradient
There are TWO methods of transport across the membrane
Passive and Active Transport
THREE types of Passive Transport
- Simple Diffusion
- Facilitated Diffusion
- Osmosis
TWO types of Active Transport Processes
- Primary Active Transport
2. Secondary Active Transport
_______________ is a passive process in which the random mixing of particles in a solution occurs because of kenetic energy.
Diffusion
Factors that affect the rate of diffusion:
- Steepness in the concentration gradient
- Temperature
- Mass of diffusing substance
- Surface Area
- Diffusion distance
Substances move freely through the lipid bilayer of the plasma membrane of the cells without the help of the membrane transport proteins.
Simple Diffusion
In this process an integral membrane protein assists a specific substance across the membrane because the substance is too polar or highly charged to move through the lipid bilayer by simple diffusion. The integral protein can either be a membrane channel or carrier.
Facilitated Diffusion
A type of passive diffusion where there is net movement of a solvent through a selectively permeable membrane.
Osmosis
TWO types of facilitated Diffusion are:
- Channel-mediated
2. Carrier-mediated
_________________ is the pressure that is exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity
Hydrostatic Pressure
____________________ is the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution
Osmotic Pressure
_______________ measures the solutions ability to change volume of cells by altering water content
Tonicity
______________ maintains normal shape and volume within a cell
Isotonic Solution
Lower solute concentration than the cytosol inside the cell. Water molecules will enter the cells father than they leave, causing the cell to swell and eventually rupture.
Hypotonic Solution
__________ is the rupture of cells due to placement in a hypotonic solution
Lysis
The rupture of Red Blood Cells
Hemolysis
Higher solute concentration than the cytosol inside the cell. Water molecules will move out of the cells faster than they enter, causing the cells to shrink
Hypertonic Solution
The shrinkage of cells
Crenation
This type of transport requires energy
Active Transport
Two sources of cellular energy can be used to drive active transport
- ATP
2. Stored Energy
Energy derived from hydrolysis of ATP changes the shape of a carrier protein, which pumps a substance across a plasma membrane against its concentration gradient.
Primary Active Transport
The energy stored (potential energy) that is created by pumping ions of the of the cell is used for this transport
Secondary Active Transport
This is the most common primary active transport mechanism, all cells have 1000’s of these pumps in their plasma membrane, it expels sodium ions from cells into the extracellular fluid which is against the gradient and bring potassium ions in.
Sodium/Potassium Pump
As a result of the Sodium/Potassium Pump, how many Sodium Ions leave the cell and how many Potassium Ions enter the cell?
3 Sodium ions leave
2 Potassium ions enter
_________ are small blisters or bladders that transport substances from one structure to another structure within a cell. They also import materials from and release materials into the extracellular fluid.
Vesicles
Materials move into the cell in a vesicle formed from the plasma membrane.
Endocytosis
Materials move into a cell in a vesicle formed from the plasma membrane
Exocytosis
___________________ is a form of endocytosis where cells engulf large particles.
Phagocytosis
_____________ consists of all the cellular components between the plasma membrane and the nucleus
Cytoplasm
The cytoplasm has TWO compartments:
- Cytosol
2. Organelles
The fluid portion of the cytoplasm containing water and dissolved solutes
Cytosol
Tiny structures that perform different function in the cell.
Organelles
A network of protein filaments in the cytosol
Provides structure and support and allows for movement of the organelles
Cytoskeleton
Located near the nucleus and consists of centrioles and pericentriolar complexes
Functions in cell division and growth
Centrosomes
Short hair like projections from the surface of the cell
Cilia
Similar to cilia but much larger. Can be used to move the entire cell
Flagella
Composed of two subunits containing ribosomal RNA and proteins; can be found free in the cytosol or attached to the rough Endoplasmic Reticulum.
Function: Protein Synthesis
Ribosomes
Membranous network of flattened sacs or tubules. Two types: Rough and Smooth
Endoplasmic Reticulum
Covered by ribosomes and is attached to the nuclear envelope
Rough ER
Vesicles formed from the Golgi complex; contains digestive enzymes.
Function: cellular digestion
Lysosome
Powerhouse of the cell. ATP is produced here. Also contains their own copy of DNA
Mitochondria
Consists of a nuclear envelope with pores, nucleoli, and chromosomes, which exist as a tangled mass of chromatin in interphase cells.
Nucleus
