microscopes/resolution :  principles and applications of science

Nucleus has a double membrane with many pores

• contains DNA associated with histone

• proteins called chromatins

• nucleolus produces ribosomes which are assembled from RNA and protein

• genes contain proteins

mitochondria is a site of aerobic respiration and production of ATP

• they have a double membrane

• they have their own DNA

Lysosomes has a single membrane and enzymes

• responsible for breakdown of waste materials

• contains hydrolytic enzymes

• they breakdown old organelles and pathogens

• they are very dark

Ribosomes are very small organelles with no membrane

• made of protein and rRNA

• synthesises proteins using instructions from DNA and mRNA

• ribosomes are made up of two sub units one large and one small

Rough endoplasmic reticulum is the site of protein synthesis

• series of interlinked membrane bound sacs and tubes

• ribosomes are attached to the surface of the membrane

• site of protein synthesis and transport

Smooth endoplasmic reticulum - membranes involved in lipid and carbohydrate synthesis and storage

• series of interlinked membrane bound sacs and tubes

Golgi apparatus - series of membrane bound discs

• Golgi apparatus modifies proteins and packs them into vesicles

• releases proteins from rough endoplasmic reticulum into vesicles

• releases modified proteins in vesicles from secretion or transport inside the cell

Cytoskeleton - gives the cell its structure

• microfilaments for movement and they are made-up of protein

• microtubules for structure (structural fibres) - also made up of protein

• intermediate fibers : gives mechanical strength to cells

Flagella and cilia - both have the same basic structures

• they are the extension of the cell membrane that contain a central pair of flagella and cilia

• flagella - is a whip like structure used for cell motility

• cilia - is a hair like structure surrounding the cells and is used for both cell motility and movement of fluids or small objects in close proximity to the cells that posses them.

Microvilli - are finger like extensions of the cell surface membrane

• their function is to increase the surface area for absorption of substances

• found on epithelial cells living in the small intestine