Tour of the Cell Flashcards
Plasma Membrane
Membrane enclosing cell
Endoplasmic Reticulum
Network of membranous sacs and tubes (cisternae); active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth regions
Function of the endomembrane system?
Regulating protein traffic and performing metabolic functions in the cell
What makes up the endomembrane system?
- Nuclear envelope
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Various kinds of vesicles and vacuoles
- Plasma membrane
How are membranes in the endomembrane system related?
Either through-
- Physical continuity
- By transfer of membrane segments as vesicles
Vesicle
Sac made of membrane
Internal Compartment of ER?
ER Lumen
Smooth ER? Why called smooth?
Lacks ribosomes
Rough ER? Why called rough?
Studded with ribosomes on outer surface of the membrane
What does the smooth ER do?
- Synthesize lipids
- Metabolize carbohydrates
- Detoxify drugs and poisons
- Store calcium ions
What does the RER do?
Make secretory proteins, acting as a membrane factory (making membrane proteins and phospholipids)
Where do transport vesicles go after the ER?
Golgi apparatus
What does the Golgi apparatus do?
Modifies, stores, and sends products of ER to other places; warehouse
Cis Face
In Golgi stack; receives
Trans Face
In Golgi stack; ships/sends
How does the Golgi sort?
Add phosphate groups aka ID/Zip Code
How does the Golgi ship?
External molecules (aka tour guides) that know the docking sites of surfaces of other organelles or plasma membrane
Lysosome
Membranous sack of hydrolytic enzymes that hydrolyze (aka digest) macromolecules; aka stomach
Where do lysosome enzymes work best?
Acidic environment on lysosome
What if the lysosome leaked?
Not much will happen; pH of cytosol is near neutral
What if a lot of lysosomes leaked a lot of enzymes?
Cell destroys itself by self-digesting
Phagocytosis
When cells engulf/eat smaller organisms or food particles; carried out by lysosomes
Human Cell Phagocytosis?
Macrophages–eat/destroy bacteria and invaders
Autophagy
Process used by lysosome to recycle cell’s own organic material
Why are lysosome super important?
Helps cell renew/rejuvenate itself
Vacuoles
Large vesicles that come from the RER and Golgi; have a variety of functions
How does the Endomembrane System flow?
ER to Golgi to elsewhere
Any structural differences between ribosomes in the RER compared to the ones found in the cytoplasm?
Nope
Cytoskeleton
Network of fibers that organizes structures and activities in the cell
What does the cytoskeleton do?
Gives mechanical support to cell and maintains its shape; super important for animal cells (no cell walls); anchors organelles
What’s required for cell motility?
Interaction between cytoskeleton and motor proteins
Microtubules
Thickest type of fiber that makes up the cytoskeleton
Microfilaments
Aka actin filaments; thinnest fiber
Intermediate Filament
Middle range fiber
Function of Microtubules?
- Shape and support cell
- Serve as tracks in which organelles with motor proteins can move
- Compression resisting
Centrosome
Located near nucleus; where microtubules grow out of
Cilia and Flagella
Have microtubules extending that help move the cell
Function of Microfilaments?
- Support cell shape
- Tension bearing
- Form structural networks
Function of Intermediate Filaments?
- Reinforce cell shape
- Bear tension
- Fix positions of organelles
Function of ECM?
Coordinate behavior of cell(s)
