The Cell and its Organelles Flashcards
Cell definition
the basic structural and functional unit of all living things
Functional characteristics of cells
- cell metabolism and energy use
- synthesis of molecules (lipids, phospolipids, DNA, RNA, proteins) for normal cell functioning
- communication with other cells through chemical/electrical signals
- reproduction and inheritance
Plasma membrane
More a structure than an organelle
- encloses and supports cellular contents
- controls what goes in and out of cell
- involved in intercellular communication
- “security gate”
Plasma membrane: structure
- lipid bilayer, phospholipids and cholesterol (45-50%); provides flexibility
- carbohydrates (4-8%)
- glycocalyx (outer surface of cell membrane)
- glycoproteins (carbohydrates and proteins)
- glycolipids (carbohydrates and lipids)
- carbohydrates
Cytoplasm - cellular fluid outside the nucleus but within the plasma membrane;
contains organelles, cytosol (ions, molecules, proteins)
Cytosol
Fluid portion of cytoplasm; water containing ions and proteins
- cytoplasmic inclusions - aggregates of chemicals (melanin, glycogen)
- cytoskeleton - support cell, gives shape, movement of organelles
Microtubules, microfilaments, intermediate filaments - provides structural support, mechanical strength
Nucleus
“control centre” - most prominent structure when viewed
DNA is code fro structural and functional characteristics
Structure - nuclear envelope; bilayer membrane surrounding nucleus (porous)
> holds nucleus together; covered in nuclear pores - facilitates movement of molecules
Nucleoplasm
cytoplasm in the nucleus
Nucleolus
produces ribosomes
Ribosomes
Site of protein synthesis
Found in nucleus, nucleolus, cytoplasm
Ribosomes: structure
2 subunits - one large, one small
Can float freely, may be attached to endoplasmic reticulum (membrane bound)
Endoplasmic reticulum
Rough ER - synthesises and modification of proteins
Smooth ER - site of lipid and steroid and carbohydrate synthesis; detoxification of harmful substances,; breakdown of glycogen to glucose
Endoplasmic reticulum: structure
flattened interconnecting sacs and tubules
Rough ER - with ribosomes
Smooth ER - without ribosomes
Golgi apparatus
Modifies, packages and distributes proteins and lipids made in rough ER
Golgi apparatus: structure
Flattened membranous sacs with cisternae; secretory vesicles
Lysosomes
Contains enzymes; digests unneeded molecules (nucleic acid, proteins, lipids, carbohydrates)
Lysosomes: structure
Membrane-bound vesicles formed at the Golgi apparatus
Mitochondria
Provides energy for “factory” to run; produces ATP
Mitochondria: structure
Smooth outer membrane, intermembrane space, inner membrane, matrix (space between folds)
Centrioles
Assists in mitosis - produces spindle fibres
Centrioles: structure
Barrel-shaped organelles orientated at right angles to each other
Made of microtubule proteins (wall)
Two centrioles can be found in centrosome (cell’s centre)
Cilia
Move substances across outer surface of cells
Cilia: structure
Whip-like, motile cellular extensions which project from outer surface of certain cells
Flagella
Move the cell independently
Flagella: structure
Similar to cilia but longer; only found on sperm cells
