Organelles Flashcards
Microvilli
Structure: Finger-like projections of the surface membrane
Function: increase surface area of the surface membrane
Cell Surface Membrane
Structure: Made up of lipids and proteins. Found surrounding a cell
Function: to control what substances go in and out of the cell
Nucleus
Structure: Enveloped by double membrane. Gaps in envelope called nuclear pores. Largest organelle in the cell
Function: Contains DNA which holds the genetic info needed to control the cell
Nucleolus
Function: Forms ribosomes
Mitochondrian
Structure: Double membrane layer. The inner layer has folds called cristae. Sausage-shaped
Function: Produces ATP from respiration which is the source of energy for a cell
Lysosome
Structure: Contains digestive enzymes which are surrounded by one membrane
Function: to digest unwanted material in the cell
Ribosome
Structure: No membrane. Very small
Function: Assembles amino acids into proteins
Rough Endoplasmic Reticulum
Structure: Membranes which form a series of tubes in the cytoplasm with ribosomes on the cytoplasmic side
Function: To collect and transport proteins around the cell
Smooth Endoplasmic Reticulum
Structure: the same as rough
Function: To synthesise lipids
Golgi Body
Structure: a stack of flattened sacs, each surrounded by a membrane.
Vesicles are pinched off the end of the sacs
Function: Packages and processes molecules that are made in the cell eg proteins. Forms lysosomes
What is Cell Fractionation?
The separating of organelles by centrifugation.
Talk me through cell fractionation…
- tissue broken up by homogeniser
- tissue suspended in buffer solution (keeping pH constant) which is kept cold so osmosis does not occur and lysosomes don’t digest the damaged material
- homogenised mixture is filtered
- filtrate put in a centrifuge and spun at low speed
- large organelles fall to the bottom, making a pellet, while smaller ones stay liquidised at the top, the supernatant
