Cell Structure Notes

Animal and Plant Cell Functions

• Cell Wall- A rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. 

• In the algae and higher plants, it consists mainly of cellulose.

• Centrosome- An organelle near the nucleus of a cell that contains the centrioles (in animal cells) and from which the spindle fibers develop in cell division.

• Nuclear Membrane- The nucleolemma or karyotheca,is the phospholipid bilayer membrane which surrounds the genetic material and nucleolus in eukaryotic cells.

• Nucleus- The central and most important part of an object, movement, or group, forming the basis for its activity and growth.

• Amyloplast- Non-pigmented organelles found in some plant cells.

• Cytoskeleton- A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.

• Tonoplast- A membrane that bounds the chief vacuole of a plant cell.

• Plasmodesmata-  A narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them.

• Cell Membrane- The semipermeable membrane surrounding the cytoplasm of a cell.

• Cytoplasm- The material or protoplasm within a living cell, excluding the nucleus.

• Chloroplast- A plastid that contains chlorophyll and in which photosynthesis takes place.

• Vacuoles-  A space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.

• Plasma Membrane- A microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm.

• Peroxisome- Small membrane sacs which aid the cell in breaking down and disposing of waste

• Grouped together under a general heading “microbodies”

• Centrosomes- A structure that generally contains a pair of centrioles, used by the cell for microtubule organisation. 

• Mitochondria-   

• Golgi Apparatus- A cell structure used to modify, store, and transport products of the ER

• Composed of a grouped series of membrane sacs

• Lysosomes- An organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane.

• Rough ER (Endoplasmic Reticulum)- A network of membranes extended from the outer nuclear membrane used for protein synthesis and transport

• Divided into two section each with different specialised functions

• Rough ER is a section that is dotted with ribosomes

• Smooth ER- A network of membranes extended from the outer nuclear membrane used for protein synthesis and transport.

•  It is divided into two sections each with different specialised functions 

• The smooth ER is a section devoid of ribosomes

• Ribosomes- A minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. 

• They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.

• Nucleus- The central structure which contains the cell’s genetic material