Anatomy Week 1 Flashcards
List the 3 main components of the cytoskeleton:
- Microfilaments
- Intermediate Filaments
- Microtubules
_______ extend through the cytoplasm are are associated with cell-cell junctions called ______ and cell-matrix junctions called ______.
- Intermediate filaments
- Desmosomes
- Hemi-desmosomes
Microfilaments are also called _____ and they form the core of ______. Also __________ is required for cell motility.
- Actin filaments
- Microvilli
- Actin Polymerization
Intermediate filaments are _______ structures that form _______ which come together to ultimately form ________.
- Non-polar
- Staggered Tetramers
- A rope-like structure
What are the two main functions of Intermediate filaments?
- Stabilize cell structure: Maintain organelle position, give mechanical strength
- Resist Shearing Forces: Extend across cytoplasm, form desmosomes and hemi-desmosomes
Differentiate between the 2 types of Actin:
- G-Actin: Free actin molecules in the cytoplasm.
2. F-Actin: Actin bound to ATP that is polymerized to form a filament.
Actin filaments are _______ structures, in which the _____ end is _______.
- Polar
- (+) ATP-bound
- Polymerizing (Fast-Growing)
List the 4 main functions of Actin Filaments:
- Anchorage (gap junctions)
- Structural core of microvilli/stereocillia
- Extension of Cell Processes
- Cell motility (via actin polymerization)
Define Microvilli:
Small, finger-like projections at the apical surface of some epithelial cells
What is the function of Microvilli/Stereocillia and where are Stereocillia found?
- To increase the surface area of the cell to allow for more absorption or other activity.
- Only in the inner ear and male reproductive tract
Stereocillia are essentially _______.
Very Long Microvilli
What is the Myosin family?
The only class of Actin Motor Proteins, of which there are many.
What is the function of Myosin 2?
It binds to Actin to cause a conformational change that leads to contraction in muscle
Describe the 3 types of Protrusions formed of various actin structuring:
- Filopodia: Finger-like projections.
- Lamellipodia: Ruffled, sheet-like protrusions found at the LEADING edge of motile cells.
- Pseudopodia: 3-D projections, found on macrophages and essential for phagocytosis.
Describe the 3 steps of cell movement:
- Protrusion: Actin polymerization at (+) end protrudes lamellipodia.
- Attachment: Focal adhesions anchor the actin cytoskeleton to the extracellular matrix via integrin proteins.
- Contraction: Bulk of the rear-end of the cell and cytoplasm is drawn forward.
What are the 3 domains of cellular life?
- Bacteria
- Archaea
- Eukaryota
What are the 3 main components of a Eukaryotic cell?
- Plasma Membrane
- Nucleus
- Cytoplasm
What are the two main components of the plasma membrane?
- Lipids
2. Proteins
What 3 types of lipids are in the plasma membrane?
- Phospholipids
- Cholesterol
- Glycolipids
Describe how lipids are “amphipathic”:
They two components:
- Hydrophobic NONPOLAR TAIL
- Hydrophilic POLAR HEAD
What are the 2 major classes of plasma membrane proteins?
- Integral Membrane Proteins: Embedded/Pass Through the lipid bilayer.
- Peripheral Membrane Proteins: Associate with Integral Membrane Proteins (NOT embedded though).
How are phospholipids arranged in the bilayer?
With polar heads facing out and non-polar tails towards the center of the bilayer.
How is Cholesterol arranged in the membrane and what function does it serve?
- Intercalated between phospholipids (also amphipathic)
2. Gives structural RIGIDITY to the membrane
How are glycolipids arranged in the membrane and what function do they serve?
- In the OUTER LEAFLET of the membrane
2. Important in cell recognition and distinguishing “self” from “non-self”