Chapter 3 Quiz- Cell Biology Flashcards
What are the building blocks to all organisms?
Cells
What are the common features of cells?
Plasma Membrane
Cytoplasm
Nucleus
What is the outer boundary of the cell?
Plasma Membrane
What is located between the plasma membrane and nucleus?
Cytoplasm
What is the selectively permeable barrier called?
Plasma Membrane
What contains organelles?
Cytoplasm
What is the control center of the cell?
Nucleus
What contains DNA?
The Nucleus
What does the Plasma Membrane consist of?
Lipids- form a flexible lipid bi-layer
Proteins float through the fluid membrane
Surface Carbohydrates form Glycocalyx
What do cell junctions do?
They help to hold cells together
What model shows the plasma membrane composed of a double layer of lipids with proteins dispersed in it?
Fluid Mosaic Model
What are the five functions of the plasma membrane?
- Mechanical Barrier- separates intracellular fluid from extracellular fluid
- Selective Permeability- determines what goes in and out
- Electrochemical Gradient- generates and helps maintain the electrochemical gradient (charge difference) required for muscle and neuron functions
- Communication- allows cell-cell recognition and interaction
- Cell Signaling- membrane proteins interact with specific chemical messengers and relay messages to the cell interior
What forms the basic structure of the plasma membrane?
Phospholipids
What are the two types of phospholipids?
Polar and Nonpolar
What are Polar (hydrophillic heads)
Attracted to water
Facing water in the interior and exterior of the cell
What are Nonpolar (hydrophobic) heads?
Repel water
Facing each other (towards interior of the membrane)
What happens when there is more cholesterol in the membrane?
The membrane becomes less fluid=stiff
What are the two types of plasma membrane proteins?
Integral and Peripheral
What are Integral Proteins?
Extend deep into the membrane
Usually from one surface to another (transmembrane)
What are Peripheral Proteins?
Attached to inner or outer surfaces of the lipid bi-layer
Functioning depends on 3-D shape and chemical characteristics (as most proteins)
What are the five functions of the plasma membrane (MATER)
Marker Molecules Attachment Proteins Transport Proteins Enzymes Receptor Proteins
What are Marker (Recognition) Molecules?
Glycoproteins and Glycolipids
Allow cells to identify each other or other molecules
What are Attachment Proteins?
May attach to the cytoskeleton
May attach to the extracellular matrix (fibers and other substances around the cell)
May bind adjacent cells together
What are Transport Proteins?
Span the membrane
Some provide a channel across the membrane that is selective for a particular solute
Some break down ATP as an energy source to actively pump substances across the membrane
What are the 3 major types of Transport Proteins
Channel Proteins
Carrier Proteins
ATP Powered Pumps
How do channel proteins work?
Form passageways through plasma membrane
Allow specific molecules/ions to enter/exit the cell
What are the types of channel proteins?
Non- gated (Leak) ion channel
Always open
Responsible for permeability to ions when plasma membrane is at rest
Gated ion channels
Opened/closed by stimuli
Ligand- gated ion channels
Responds (open) when chemical signals (ligands) bind to the chemical
Voltage- gated ion channels
Respond (open) when there is a change in the membrane potential (electrical charges) across the plasma membrane.