AS biology unit 1- Chapter 3

Cells and movement

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  • Created by: Bela
  • Created on: 20-04-11 16:43

Nucleus

Nucleus functions:

  • acts as a control centre to the cell due to production of mRNA and so protien synthesis
  • It also contains the genetic information of the cell
  • Assembles ribosomes and RNA

Nuclear envelope: double membrane, extends to form endoplasmic reticulum, it controls entry and exit of materials into the cell. Contains reactions. With every membrane they 'Compartmentalise'

Nuclear pores: allow passage of large molecules e.g RNA

Nucleoplasm: bulk material within nucleus

Chromatin: genetic info within nucleus, is the diffuse form chromosomes take when the cell is not dividing

Nucleolus: spherical body within nucleus thatis involved in production of ribosomes

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Mitochondria

Double membrane= Outer membrane- controls entry and exit of materials within cells

Inner membrane fold to form Cristae- shelf like extensions which increase the surface area for attatchment of enzymes involved in respiration

Matrix- Make up rest of mitochondria- contain lipids, protiens and traces of DNA which enable it to produce its own protiens also it contains some more enzymes involved in respiration

Function of mitochondria:

  • They are sites for certain stages of respiration
  • Produce ATP out of carbohydrates (energy carrying molecule)
  • where there is an area with high metabollic activity (e.g muscles) you may find: more mitochondria, a bigger size of them, more cristae
  • Active transport requires ATP- more mitochondria at epithelial cells
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