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