Cells Flashcards
Definition of cells
Functional structural and functional unit of body
Prokaryotic cells
Before nucleus
No organelles
Single celled organism
Cell walls and capsule
Eg bacteria
Eukaryotic cells
Nucleus with dna
Single celled and multicellular organisms
Eg plants funghi animals
What is cell plasma membrane
-thin and defines boundary cell
-gives form to cell separating contents of cell to extra cellular fluid
-controls which molecules exit and leave
-double layer of phospholipids
What are the factors that affect whether substances diffuse across the membrane?
-size of molecules
-ionic charger
-lipid solubility
-prescience of carrier molecules
-pressure differences
What is cillia?
-cytoplasmic projections that extend from the surface of the cell
-cillia bearing cells usually interspersed with mucous producing cells
-move particles across surface of cells
What is cytosol?
-viscous jelly like fluid
-80-90 % fluid
-contains organelles in suspension, ions and proteins
Mitochondria
-powerhouse of the cell
-enzymes break down foods to release energy some escapes as heat
-many in metabolically active cells such as liver
-present in all cells except mature red blood cells
Ribosomes
-synthesises proteins inside cells
-composed of rna and protein
-endoplasmic recticulum which is a complex network of interconnecting membranes
What are the two types of endoplasmic recticulum
-rough with ribosomes or smooth without
-smooth ER liver cells involved in detoxification and deactivation of a variety of chemicals
Gogi complex
-synthesises carbohydrates
-prominent in pancrease and salivary glands
-packages proteins into vesicles
-vesicle moves to and fuses with cell membrane
Exocytosis: fused vesicle ruptures releasing a secretion
Lysosomes
Scattered through cytoplasm
Lysis- bursting
-digest foreign molecules and worm or damaged cells
Phagocytise
Nucleus
Control centre of the cell
Largest structure
Contains dna
