Zoology (laboratory) coverage
- 3. MICROSCOPE • A compound microscope consists of certain precise mechanical parts (chiefly of metal) to support and facilitate the use of optical parts (of glass) that provide the magnified image. • Although compound microscopes are very common, the microscopes used in the laboratory are Trinocular microscopes
- 4. MICROSCOPE • Trinocular microscope has two eyepieces but with a third eyepiece tube for connecting a microscope camera. It is a binocular with a moving prism assembly in which light is either directed to the binocular assembly of the microscope or to the camera.
- 5. Parts of a Compound microscope Parts of a Trinocular microscope
- 6. Specimens: Cut-out of letter e Skin hair Mosquito Larva These are the desired images of the specimens under a microscope (taken from the internet and not the actual photos from the experiment).
- 7. • The letter “e” as viewed in the microscope is positioned upside down while the skin hair and mosquito larva, is observed to have been magnified, its parts were seen accordingly, based on the objectives used. • Low Power Objective (LPO) has a magnifying power of 10x which means that the specimen is 10x magnified when it is viewed under the microscope. Meanwhile, HPO (High Power Objective) has a magnification of 40x which means that, the specimen viewed under the microscope is magnified 40x. Thus, specimens are more visible and clear when it is viewed under HPO rather than LPO. However, only a part/ fraction will be seen under HPO depending on what you have focused.
- 9. MAGNIFICATION • It is defined as the number of items an object is enlarged or reduced by a lens system. • It is important to identify the magnification especially on the microscope used to know how many times a specimen is magnified and how it actually differs as seen in the naked eye. Microscope Magnification: • Linear Magnification (LM) is the product of the ocular magnification and the magnification of the objective or: • LM = OcM X ObM
- 10. Linear Magnification (LM) • Using the Trinocular microscopes, since the ocular is stamped 10x, • LM at LPO (Low Power Objective, 10x) : LM= 10x (10x) = 100x • LM at HPO (High Power Objective, 40x): LM= 10x (40x) = 400x (Note: Scanner, stamped 4x as an objective which is not usually used to focus but only to scan and have greater field of view of the specimens before viewing on LPO and HPO, has LM = 10x (4x)=40x .)
- 11. Magnification of the Drawing • Formula: M = SD / SO • Where: • M= magnification of the drawing • SD = size of the drawing • SO = actual size of the object (Note: Always remember that the size of the drawing is given and the actual size of the objects, seashell/ starfish is measured using a ruler, in mm or cm)
- 13. Cells • It is the structural and functional unit of life • The study of cell, its structure, and its activities is known as Cytology (now evolved into its progressive alter ego, Cell Biology) • Although cells show great diversity in form and function, all cells are built to a fundamental design and share certain common features. • There are two types of cells: Prokaryotic (no true nucleus) and Eukaryotic (membrane-bound nucleus) organisms. • In this exercise, we focused on examining Eukaryotic organisms as such are Animal cells (oval/spherical/irregular-shaped) and Plant cells (rectangular shaped).
- 14. Specimens: Animal cells: • Cheek cells • Human blood cell • Chicken egg Plant cells • Onion cells • Stomata with guard cells • Preserved specimen (monocot/dicot stem, Hydrilla verticillata)
- 15. Animal Cells (with some of its parts) These are the desired images of the specimens with its parts that can possibly be seen under a microscope (taken from the internet and not the actual photos from the experiment). Cheek cell (400x) Human blood smear (400x) Erythrocytes (red blood cells) are only evident
- 16. Animal Cells (with some of its parts) Chicken egg when cracked open (labeled)
- 17. Animal cell parts • The description below of the parts of an animal cell that can obviously be seen using the microscopes: • Cell membrane/ Plasma membrane – the thin limiting membrane enclosing the cell • Cytoplasm – materials/ the matrix between the cell membrane and nuclear membrane • Nucleus- usually oval or spherical body found or near center of the cell that is darker or more heavily stained (Note: These parts are visible when stained with iodine solution)
- 18. Animal cell parts • The description below of the parts of chicken egg: • Yolk – the inner yellow portion of the egg • Albumin – the egg white, surrounds the yolk • Vitelline membrane – the thin delicate membrane that surrounds the entire ovum • Chalaza- the twisted albumen on the opposite poles of the yolk • Blastodisc (germinal disc) – a minute island of whitish cytoplasm floating on the yolk which will give rise to a new individual
- 19. Plant Cells cytoplasm Peel of Onion cell Usually in scraping off an onion, the parts that are evident when viewed under a microscope are the ff: Cell wall, cell membrane, cytoplasm and nucelus. Stomata with guard cells These are the desired images of the specimens with its parts that can possibly be seen under a microscope (taken from the internet and not the actual photos from the experiment). Cell membrane
- 20. Preserved specimens (Plant) MONOCOT Hydrilla verticillata These are the desired images of the specimens with its parts that can possibly be seen under a microscope (taken from the internet and not the actual photos from the experiment).
- 21. Plant cell parts • The description below of the parts of plant cell that can obviously be seen using the microscopes: • Cell walls – the “lines” forming the network between the individual cells are nonliving cell walls composed chiefly of cellulose • Cell membrane – the layer immediately beneath the cell wall. This encloses the cell cytoplasm. • Nucleus – appears as a rather dense body in the transparent cytoplasm; in some cells, the nucleus seems to belying centrally and will look circular. (Note: These parts are visible when stained with iodine solution)
- 22. Plant cell parts • Stomata (stoma) with guard cells -Pores in a plant’s cuticle through which water vapor and gases (CO2 & O2) are exchanged between the plant and the atmosphere • Chloroplast (can only be found in plants) -Organelle where photosynthesis takes place.
- 23. Animal Cells vs. Plant cells
- 24. Animal Cells vs. Plant Cells
- 25. ANIMAL CELLS • Unique parts of the animal cell • Centriole – a feature of animal cells important for coordinating cell division
- 26. PLANT CELLS • Unique parts of the plant cell • Cell wall – a feature of plants cells that functions like stiff lattice-like wall which helps plant cells maintain their structure and shape • Chloroplast – a feature of plant cells that allows plants to do photosynthesis and make their own glucose from sunlight, water and carbon dioxide
- 28. Carbohydrates • Large biological molecules • Simple sugars, such as glucose, are the monomers of complex carbohydrates.
- 29. • In Food science – polysaccharides are starch and fiber. • Polysaccharides are complex carbohydrates. Starch and fiber are complex carbohydrates. • Mono and di saccharides are simple carbohydrate. Sugar is a simple carbohydrate. • Simple carbohydrates are digested faster and give you quick energy.
- 30. FOOD SAMPLE COLOR SIMPLE OR COMPLEX 1. Flour Dark blue-black comples 2. Sugar Brown tan simple 3. Apple Brown tan simple 4. Potato Dark blue-black complex 5. Bread Dark blue-black complex 6. Honey brown-tan simple 7. Vanilla wafer dark, blue-black complex 8. Marsmallow (inside) brown-tan simple 9. Banana dark, blue-black (green) Brown-tan (ripe) complex simple *These are the desired results of the experiment however, it may vary upon groups since after putting iodine solution, the color will not be evident and may take a long while; this might be confusing (e.g. banana). • Brown –tan (after putting iodine)= simple carbohydrate; foods with sugars usually • Dark, blue-black (after putting iodine) = complex carbohydrate; foods with/rich in starch and fiber