Eukaryotic Cell

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THE nucleus

It is the most prominent feature.It contains the organisms hereditary material and controls the cells activities 

 Nuclear envelope:

  • ·      Double membrane that surrounds the nucleus
  • ·      Outer membrane is continuous with the endoplasmic reticulum of the cell
  • ·      Has ribosomes on its surface
  • ·      Controls the entry and exit of materials in the nucleus and  Contains the reactions taking place within the nucleus 

Nuclear pores

  • ·      Allows the passage of large molecules out the nucleus

 Nucleoplasm

  • ·      Granular, jelly like material that makes up the bulk of the nucleus

 Chromosomes

  • ·      Consists of protein bound linear DNA 

Nucleolus

  • ·      Small spherical region within the nucleoplasm
  • ·      Manufactures ribosomal RNA  and Assembles ribosomes
  • ·      May be more than one nucleolus in the nucleus

 FUNCTIONS:

  • ·      Act as a control center, through the production of mRNA and tRNA and protein synthesis.
  • ·      Retain the genetic material of the cells – form of DNA and Chromosomes
  • ·      Manufacture ribosomal RNA and Ribosomes
  • .(http://www2.estrellamountain.edu/faculty/farabee/BIOBK/nucleus_1.gif) 

The Mitochondrian

Rod shaped and made up of:

Double membrane

  • ·      Surrounds organelle
  • ·      Controls entry and exit of material
  • ·      The inner two membranes is folded to form extensions – CRISTAE

Cristae

  • ·      Extensions of inner membrane
  •       In some species – extend across the whole width of the mitochondria – provides a large surface area for the attachment of enzymes and other proteins involved in respiration

Matrix

  • ·     Makes up the remainder of the mitochondria
  • ·      Contains proteins, lipids, ribosomes
  • ·      Contains DNA which allows mitochondria to control production of their own proteins.
  • ·      Respiration enzymes are found in the matrix

FUNCTIONS

  • ·      Sites of aerobic stages of respiration – responsible for the production of ATP
  • ·      Number and size of mito and number of cristae is high in cells that have a high level of metabolic activity and require a lot of ATP

E.G

  • ·      Muscle and epithelial cells
  • ·      Epithelial cells require a lot of ATP in the absorbance of substances in the intestines by active transport.

(http://static1.squarespace.com/static/5006630dc4aa3dba7737ef40/t/520e79f6e4b061d57274d22a/1376680439650/cyanide.+Animal_mitochondrion_diagram_en.png)mitochondria

                                                                                                       

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