Cells Flashcards
Cell
smallest independent structural & functional unit of Life
Hooke
Cell theory
Cell theory states: 1.All living organisms are composed of cells
2. All cells come from pre-existing cells.
Why are cells small?
If cell volume is large, surface area:volume ratio too small for adequate exchange of nutrients, wastes
Eukaryotic cells HAVE
- true membrane bound nucleus
- DNA bound with histone proteins
- Cell organelles: mitochondria, endoplasmic retic, golgi bodies
Prokaryotic cells DO NOT HAVE:
- true membrane bound nucleus
- DNA bound with histone proteins
- Cell organelles: mitochondria, endoplasmic retic, golgi bodies
Endosymbiont Theory
Eukaryotics evolved from different prokaryotics coming together to take advantage of their different abilities. For example, organelles like mitochondria & chloroplast could originally have been independent prokaryotics.
Plasma Membrane
Fluid, phospholipd bilayer; hydrophilic ends to outside; hydrophobic ends to inside; surrounds cell, regulates movement of material, site for receptors & reactions; selective permeability
Nucleus
Control center; stores, transcribes genetic info; contains DNA bound with chromatin; condenses into chromosomes during cell division; enclosed by nuclear envelope; sites of nucleolus within that synthesize ribosomes
Ribosomes
Sites of protein synthesis in cytoplasm; contain protein & r-RNA
Endoplasmic Retic
system of channels in cytoplasm used for moving materials.
Rough ER
covered with ribosomes and packaged proteins
Smooth ER
lacks ribosomes and synthesizes lipids
Golgi Complex or bodies
Stack of sacs that modifies and packages proteins and lipids for secretions
Lysosomes
Sacs containing enzymes that breaks unwanted material
Mitochondria
sites of aerobic metabolism; contain DNA, can self-replicate
cytoskeleton
tubules & filaments radiating from centrosome; provide support; allow cell to move
3 types of MEmbrane transport: Diffusion & Active Transport, Bulk transport
Movement of particles from an area of high to low concentration.
Osmosis
when water moves thru a semi-permeable membrane by diffusion
Facilitated diffusion
when charged or large particles move thru chemically or voltage gated ion channels; does not require energy ie water, O2
Active transport
Movement of molecules ag. concentration gradient using energy by binding to transporter; shows saturation effect; ie glucose, sodium-potassium pump
Bulk transport
MOvement of material by enclosing within a vesicle; requires energy ie white blood cells, protozoans
Cilia and flagella
Motile extensions of cell surface that propel cell or move materials over cell. Each: 9 prs of microtubules enclosing a central pair (9+2 pattern) ie sperm cell
Pseudopodia
lobes produced by cytoplasmic streaming that help some cells move ie WBC
Microvilli
infoldings of cell surface; increase surface of cells for absorption or secretion ie intestine lining
Epithelial tissues
Covers & lines organs; participates in secretory, excretory activities.
Connective tissues
supports and binds. ie cartilage, bone, blood
Nervous tissues
conducts electrical impulses; allowing communication
Muscle tissues
allows movement; Skeletal, smooth and cardiac muscle tissues
