Organelle Structure and Function Flashcards
Theory of Endosymbiosis
MItochondria and chloroplatss were once independent prokaryotes who eventually joined larger cells
Prokaryotic Cells
Small ribosomes No cytoskeleton Nor organelles (but has a nucleoid region) Plasmid sometimes present Anaerobic and aerobic metabolism Flagella made of the protein flagelin
Eukaryotic Cell
Nucleus and organelles present
Chromosomes long and bound with histones
Multicellular
Can be autotrophic or heterotropic
Flagella and Cilia in Eukaryotes
Made of tubulin
Arrange 9 +2
Autotrophs
Photoautotrophs
- Use photosynthesis to make food from sunlight
Chemoautotrophs
- Use chemosynthesis to make food from inorganic substance
Obligate Anaerobes
Need absence of oxygen to survive
Obligate Aerobe
Need oxygen to survive
Facultative Anaerobe
In absence of oxygen, can switch from aerobe to anaerobe
Ribosomes
On ER- proteins made here leave cell
In cytoplasm- proteins made here used within cell
SER
Synthesis of steroid hormones and lipids
Stores Ca in muscle cells
Also stores detox drugs and poisons
Peroxisome
In both plant and animal cells
Convert hydrogen peroxide into water using catalase
In liver, detox alcohol
Glyoxysomes
Germinating seeds of some plants have a specialized variation of peroxisome
Transport vacuole
Move materials between organelles or between organelles and PM
Central vacuole
Most of plant cell interior
Cause turgidity when fully filled to maintain rigidity
Also store nutrients, and carry out functions performed by lysosomes in aniamls cells
Have a specialized membrane (tonoplast)
Merge Vacuole
Merge with lysosomes which break down food
Storage vacuole
Plants store starch, pigments, and toxic substances (i..e nicotine)
Contractile vacuoles
In single celled organisms that collect and pump excess water out of the cell
Utilizes active transport
Found in protista (amoeba, paramecia) and organisms in a hypotonic environment
Cell Wall in Plants
Cellulose
Cell Wall in Fungi
Chitin
Cell Wall in Bacteria
Peptidoglycans
Cell Wall in Archea
Polysaccharides
Extracellular Matrix
Animal cells secrete collagen to form ECM
Found in area between adjacent cells
Fibrous structural proteins, adhesion proteins, polysaccharides
Made of collagen mainly
Also see integrin+fibronectin, laminin
Function of ECM
Provides mechanical support
Helps binds adjacent cells
Integrin+Fibronectin
Network of collagen and proteoglycans (glycosylated proteins) connected to integrins ( TM protein) in the cell membrane via fibronectin (glycoprotein)
Laminin
Also seen in ECM
Acts similar to fibronectin (adhesion protein, anchors cell to collagen or proteoglycans)
Focal Adhesions
Connection of ECM to actin filaments in cell
Hemidesmosomes
Connect 1 cell to basal membrane
Connection of ECM to intermediate filaments (i..e keratin)
Plastids
Found in plant cells
Chloroplasts
Leucoplasts
Chromoplasts
Leucoplasts
Can specialize to store starch/lipid/protein as amyloplasts/elaioplasts,proteinoplasts
Can also serve general biosynthetic functions
Chromoplasts
Store carotenoids
Microtubules
Made of tubulin
Found in flagella, cilia, spindle fibers during division
Microfilaments
Made of actin
Used for cellmovement and muscle contraction
Intermediate Filaments
Maintains and supports cells
i.e. Keratin found in hair
Types of Active Transport
Exocytosis Endocytosis (phagocytosis, pinocytosis, receptor mediated endocytosis)
Phagocytosis
Engulfing of particles (i..e white blood cells)
Pinocytosis
Uptake of dissolved particles
Cell drinking
Receptor mediated encodytosis
Form of pinocytosis
Specific molecules in the fluid around the cell binds to receptors
Aquoaporin
Type of porin found in plant roots and kidneys, allowing water to flow more rapidly than diffusion
Plasmolysis
MOvement of water out of a cell resulting in the collapse of the cell
Dialysis
Diffusion of solutes across a selective membrane
Bulk Flow
Movement of a fluid in one direction in an organism
Always from one source
i.e. Blood flow around the body
Cell Junctions
Anchor cells to each other or provide passageways for exchange of materials
Desmosomes
Anchoring junction
Connects 2 cells together
Provides stability and holds things together
Tight Junction
Seal, prevents things from passing from cell to cell
Found in digestive tract to get things into bloodstream
Gap Junctions
Allows ions and small molecules to pass from cell to cell
How the heart cells coordinate together to contract in unison
Plasmodesmata
Gap junctions of plant cells
Quorum Sensing
Bacteria secrete molecules ot communicate
Paracrine Siganlling
Local messages/signals are released (i.e. GF)
Includes synaptic signalling (NT release)
Long Distance Siganling
Endocrine system
Hydrophilic Messengers
First messenger or ligand
Binds to receptor
Message carried on inside by second messenger
Cytoplasmic receptor
Receptors inside cell that bind to smaller, nonpolar hydrophobic ligands that can diffuse through PM
i.e. Steroids, thyroid hormone, NO
Tonicity
Ability of an extracellular solution to make water move into or out of a cell by osmosis
Solution’s tonicity is related to its osmolarity
Osmolarity
Total concentration of all solutes in the solution
Plasmyolysis
Cell membrane shrinks and detaches from cell wall
Occurs when plant cells are in hypertonic solution (high concentration of solute outside cell)
Plant Cells in Hypotonic Solution
Water moves into cell
Cell wall counteracts osmotic pressure to prevent swelling and lysis
Golgi
Packages and modifies proteins
Transports lipids around cell
Produces lysosomes
Structure of Eukaryotic Ribosome
60S + 40S= 80 S
Structure of Prokaryotic Ribosome
50S + 30S= 70 S
Polar Microtubules
Nuclear division
Connect to push MTOC to opposite ends of cell
Astral Microtubules
Extend to cell membrane
Involved in spindle apparatus orientation
Facultative Aerobes
Can switch to aerobic respiration but prefer anaerobic environments
Microphiles
Organisms that need oxygen but are poisoned by high concentrations
Facultative Psychophiles
Organisms that will survive at temperatures below 20°C but will only grow at temperatures above 20°C.
Aerotolerant
Do not require oxygen to survive, but are not poisoned by it (unlike obligate anaerobes)