Eukaryotic cell ultrastructure

• The Golgi apparatus is involved in the modification, sorting, packaging, and transport of proteins.
• Eukaryotic cell ultrastructure includes the rough and smooth endoplasmic reticulum, Golgi body, mitochondria, ribosomes, lysosomes, chloroplasts, cell surface membrane, nuclear envelope, centrioles, nucleus and nucleolus.
• As the objective lens power increases, the field of view gets smaller because the diameter of the objective lens gets smaller.
• If you see only your eyelashes, move slightly closer or further away from the eyepiece.
• If you wear glasses, do not remove them.
• Students should be able to interpret and recognise drawings, photomicrographs and electronmicrographs of these organelles.
• Students should be able to state the functions of the organelles listed in the previous paragraph.
• Students should be able to outline the functions of the membrane systems involved in the secretory pathway of proteins.
• Students should be able to compare the structure of typical animal and plant cells.
• Students should be able to use a light microscope competently to collect data and make observations.
• Students should be able to make and record accurate observations with good details and measurements to an appropriate degree of precision.
• The Cell Theory states that the cell is the basic unit of life, carrying out all the essential processes of life that makes the organism a living entity.
• Animal cells have a centriole usually present, are often compared to plant cells, and have lysosomes usually absent, chloroplasts usually absent, and vacuoles present, small and scattered or absent.
• Lysosomes are present in both plant and animal cells, have a specific structure, and perform specific functions.
• Synthesis of proteins and transport of proteins out of the cell occurs in the cytoplasm, protoplasm, and endoplasmic reticulum.
• Plant cells have a cell wall that contains cellulose, are often compared to animal cells, and have lysosomes usually absent, chloroplasts usually present, and vacuoles present, large and central.
• Chromosomes are composed of linear DNA wound around proteins.
• Plant cells and animal cells have similarities such as the presence of protoplasm, cell surface membrane, nucleus, and cytoplasm consisting of organelles; endoplasmic reticulum, Golgi apparatus, mitochondria, and ribosomes.
• All organisms are made up of cells, with organisms composed of a single cell being unicellular and those made up of many cells being multicellular.
• All cells arise from pre-existing cells by division.
• The cell contains information (hereditary materials/DNA) which is used as instructions for growth, development and functioning.
• The cell is the functional unit of life in which chemical reactions that maintain life take place within it.
• Biologists today recognise that cellular organisms fall into two main categories: the eukaryotes, which include all plants and animals, and the prokaryotes, which include bacteria and archaea.
• When placing the microscope on a table, keep it away from the edge.
• Wipe off any moisture that may get on or into the stage or moving parts of the microscope.
• Always use both hands when carrying your microscope: one hand on the microscope arm, the other under the base for support.
• Focus using the coarse adjustment knob (only for 4 X objective lens) by turning the knob to raise the stage to the highest position, positioning eye at the eyepiece, and slowly lowering the stage with the coarse adjustment knob.
• Specimen should appear in the field of view and a sharp image is obtained.
• When packing the microscope, make sure to adjust the 4 X objective lens is aligned to the round glass of the stage, adjust the stage is at the highest position, then coil the electrical wires.
• Lower the stage to the lowest point before packing the microscope.
• Never clean exposed eyepiece, objective lens or condenser lens with anything other than lens paper as the magnifying lenses are easily scratched.
• Carry the microscope in an upright position.
• When unpacking the microscope, make sure the 4 X objective lens is aligned to the round glass of the stage, the stage is at the highest position, then uncoil the electrical wires.
• Do not tilt the microscope forward as the eyepiece might fall off.
• Adjust the distance between the two eyes so that both eyes can see one complete field of view at the same time.
• Carry the microscope close to your body.
• Do not touch the lens surface with your finger as the small amount of oil on the surface of the skin will leave a film on the glass.
• The cell of an eukaryote possesses a true nucleus containing genetic materials known as DNA, enclosed within the nuclear envelope.
• Two centrioles make up a centrosome.
• The cytoplasm is organized into compartments called organelles.