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 

Cell size and scale

  • Adenine- A portion of a molecule; the nitrogenous base 

  • There is less DNA in a sperm cell then there is in a skin cell

  • When a cell is going through mitosis it shown as an X chromosome which is in the condensed state

  • A chromosome is made up of a genetic material wrapped around structural support protein (histones)

  • Histones organize the DNA and keep it from getting tangled

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