Instructions: Fill in the columns by identifying the organelle and then find its function.
Image of organelle / Name of organelle / Function of organelle/ Plasma membrane, also known as cell membrane (less specific) and Plasmalemma (more specific) / Regulates passage of materials in and out of the cell. Glycoproteins and glycolipids are used for cell recognition (e.g. in the immune response)
Found in all organisms.
/ Chloroplast (often confused with mitochondria, which also have internal membrane systems. In chloroplasts the internal membranes are organized into discs, called grana, which contain photosynthetic pigments such as chlorophyll. / Site of photosynthesis –where light is used for energy to drive the conversion of low-energy Carbon dioxide and Water into energy rich Carbohydrates, at the same time releasing Oxygen as a by-product.
Found only in Eukaryotic plants and plant protists (algae)
/ Smooth (on the right) and rough (on the left) Endoplasmic reticulum. The presence of ribosomes (those little black dots) distinguishes one from the other. / Smooth ER—site of lipid (fats and oils) synthesis
Rough ER—site of protein synthesis.
The ER also transports synthesized molecules around in the cell.
/ Golgi Apparatus, also known as Golgi Body
Distinguished by their ‘stack of pancakes’ arrangement of membranes and budding of vesicles along their margins / Sorts and packages proteins for export (transport out of cell) of proteins. Found therefore mostly in cells that are secreting proteins. E.g. Salivary glands are packed with Golgi, as they secrete the protein enzyme called salivary amylase.
/ Mitochondria
This electron microscope photo clearly shows interior folded membranes called cristae. It is on these that enzymes involved in cellular respiration are located. / Site of cellular respiration. In this process high energy carbohydrates and O2 are converted to low energy CO2 and H2O. The energy released from this process is used to create ATP from ADP and Pi (more about this process later.)
/ Nucleus
Consists of a porous membrane surrounding chromatin (dark brown) and protein (lighter areas). Chromatin is unwound chromosomes. Nucleolus is missing because this section (think slice, like a slice of bread) did not contain one. (Imagine baking an orange into a loaf of bread. Would every slice contain a piece of orange?) / Nucleus controls the protein synthesis of the cell. It does this by sending out of the nucleus a coded message (mRNA) that is ‘read’ at the ribosome, which translates the code, into specific proteins.
The nucleus doesn’t ‘think’, so don’t get the idea that it ‘knows’ what to do, either. It is under chemical control—when a particular process or structural protein is required, it is triggered into releasing the correct mRNA. This is a complex process, beyond what you need to know for Bi. 12.
Side Note: Using terms like ‘think’ and ‘know’ is a classic mistake made by beginning biologists, imparting a human quality where none exists—called anthropromorphism (useful if you want to impress your friends or family) E.g. “The bee wanted to collect nectar” rather than “The bee instinctively collected nectar”.