The Cell Flashcards
Cell Theory
- All living things are composed of cells
- Cells are the basic unit of all organisms
- All cells arise from preexisting cells
Nucleus
Contains chromosomes (DNA) wrapped with special proteins (his tones) into a chromatin network
Nucleolus
Inside nucleus in region that does not divide, synthesise components of ribosomes
Ribosomes
Site of protein synthesis
End plastic reticulum
System of membrane channels that transverse the cytoplasm
Rough ER
Site of protein synthesis & transport throughout cytoplasm
Smooth ER
Synthesise steroid hormones & other lipids, connects rough ER to Golgi apparatus, detoxifies the cell, carbohydrate metabolism
Golgi apparatus
Modify, store, & package substance produced in rough ER
Lysosomes
Site of intracellular digestion
Mitochondrion
Site of cellular respiration, contain their own DNA & can self replicate
Vacuoles
Store substances for cell
Vesicles
Small vacuoles
Plastids
3 types:
1) chloroplast - carry out photosynthesis, own DNA & can self-r.
2) leucoplasts - colourless, store starch, roots of turnips
3) chromoplasts - store carotenoid pigments
Cytoskeleton
Complex network of protein filaments, throughout cytoplasm - gives cell its shape & enables movement
2 types:
1) microtubules - hollow tubes that make up cilia, flagella, spindle fib.
2) microfilaments - help support cell, enable movement: skeletal muscles to contract, etc.
Centrioles & centrosomes
Outside nuclear membrane, organise spindle fibers required for cell division
Cilia & Flagella
Both made of microtubules
Cilia = short & Flagella = long
Move liquid past surface of cell
Cytoplasm
Region between nucleus & plasma membrane
Cytosol
Semiliquid portion of cytoplasm
Cell or Plasma Membrane
A selectively permeable membrane that controls what enters & leaves the cell
Selectively permeable
Finish
Solvent
Substance that does dissolving
Solute
Substance that dissolves
Hypertonic
Having greater concentration of solute than another solution
Hypotonic
Having lower concentration of solute than another solution
Isotonic
2 solutions containing equal concentration of solute
Passive transport
Movement of molecules down a concentration gradient
Never requires energy
Simple diffusion
Movement of particles from higher concentration to lower concentration
Facilitated diffusion
Relies on special protein membrane channels to assist in transporting specific substances across a membrane
Osmosis
Diffusion of water across a membrane
Water flows down a gradient toward a region with high solute concentration
Active transport
Movement of molecules against a gradient
Requires energy
Exocytosis
Active release of molecules from a cell
Endocytosis
Process by which cells take in various molecules & particles by forming new vesicles made form plasma membrane, 3 types:
Pinocytosis
Type of endocytosis
uptake of large, dissolved molecules
Cell drinking
Phagocytosis
Type of endocytosis
engulfing of large particles/small organisms by pseudopods
Receptor-mediated endocytosis
Types of endocytosis
enables cell to take up large quantities of specific substances
