Ultrastructure of Nucleus
Surrounded by a double membrane called the nuclear envelope with pores. Contains chromatin (DNA+Proteins) and nucleolus
Function of Nucleus
Controls cell activities (growth,metabolism, reproduction).
Stores genetic material.
Nucleolus is site of ribosome synthesis
Ultrastructure of Nucleolus
Dense, spherical structure inside the nucleus
Function of nucleolus
Produces rRNA.
Assembles ribosome subunits
Ultrastructure of Ribosomes
Small particles, non-membrane bound. Made of rRNA+proteins.
Function of ribosomes
Site of protein synthesis
Ultrastructure of Rough endoplasmic reticulum
Membranous network with ribosomes on the surface
Function of rough endoplasmic reticulum
Synthesises proteins
Ultrastructure of smooth endoplasmic reticulum
Membranous network without ribosomes
Function of smooth endoplasmic reticulum
Synthesises lipids and steroids.
Ultrastructure of Mitochondria
Oval shaped, bound by double membrane (envelope). Inner lining is folded (cristae). Internal fluid called matrix which contains enzymes and DNA
Function of mitochondria
ATP production via cellular respiration
Ultrastructure of centrioles
Cylinder shaped, contains a ring of microtubules arranged at right angles at each other
Function of centrioles
Organises spindle fibres during cell devision.
Ultrastructure of Lysosomes
Spherical, membrane bound organelle that contains digestive enzymes
Function of lysosome
Digests waste and cellular debris. Breaks down old organelles, pathogens and macromolecules
Ultrastructure of Golgi apparatus
Stacked, flattened membranous sacs with vesicles surrounding the edges
Function of Golgi apparatus
Processes and packages proteins and lipids. Forms lysosomes.
Stem cell
A type pf undifferentiated cell which has the ability to divide many times and differentiate into many different cell types
