GCSE Biology Microscopy Calculations PDF

# It Microscopy calculations, Edexcel 9-1 GCSE Biology, ## Topic 1 key concepts in Biology. 1. Last week, in biology, we observed our cheek cells and stem through a microscope. We familiarised ourselves with the microscope and looked at the difference between animal and plant cells. 2. The magnifi...

# It Microscopy calculations, Edexcel 9-1 GCSE Biology, ## Topic 1 key concepts in Biology. 1. Last week, in biology, we observed our cheek cells and stem through a microscope. We familiarised ourselves with the microscope and looked at the difference between animal and plant cells. 2. The magnification on a microscope calculated by multiplying the power of the objective lens with the power of the eyepiece lens. 3. 4 x 10 = 40 magnification 4. 100 x 10 = 1000 magnification ## MAGNIFICATION EQUATION TRIANGLE: | | L: AM | | |---|---|---| | | image size | | | A | | | | | | M | | | actual size | | | | | magnification | * A & M have to be the same unit! ## TOT. MAGNIFICATION: LIGHT MICROSCOPE Power of eyepiece lens x power of objective lens **Ex.** Always 10x Objective lens = 60x Tot magnification? 10 x 60 = 600x **Ex.** l = 40mm Δ = 80 μm ?Tot magnification? 40 x 1000 = 40,000 μm 40,000 / 80 = tot. magnification. 500 *** ## EXCERCISE QUESTION l = 10mm Objective lens power = 50 A? tot. magnification = 50 x 10 = 500 10mm : 0.02 mm 500 0.02 mm = 20 μm # Microscopes: 1. Compound microscope (type of light microscope): used in school uses a beam of light rays. 2. Electron microscope uses a beam of electrons instead of light rays. 3. Max. magnification of light microscope = around 1500x 4. Max. magnification of electron microscope: around 1,000,000x 5. Electron microscope: higher resolution and higher magnification (but can only see dead things). 6. Light microscope - can view live specimens and cheap than the electron. ## Pros: ### **Light:** * Used in schools * Easy to use * Cheaper * Portable * Can view live specimens ### **Electron:** * High magnification (~ 1,000,000x) * High resolution ## Cons: ### **Light:** * Low magnification * Low resolution ### **Electron:** * Expensive * Can't be moved * Can only see dead specimens The greater detail you can see, the greater the resolution. When we look through a microscope, you're looking at what light doesn't go through. # How are things arranged?: ## ORGANISM: * **UNICELLULAR ORGANISMS:** organism made only of a single cell. * **MULTICELLULAR ORGANISMS:** organism consisting of many cells. ## Amoeba ## Paramecium ## Bacteria ## Plants ## Animals ## Prokaryote: * Have no nucleus. Very old life forms (only unicellular) ## Eukaryotes: * Have a nucleus. (Can be either uni/multicellular) ## HIERARCHY OF ORGANISATION: **Organelles** - components of cells **Cells** - basic building blocks of living organisms **Tissue:** a group of cells, working together to carry out the same function. **Organ:** a group of tissues working together to carry out the same function. **Organ system:** a group of organs working together to carry out the same function. **Organism:** all of the different levels working together/ living things. Ex. Us # DOMAIN ## Bacteria: * Unicellular * Prokaryotic * No membrane-bound organelles * Have ribosomes * Cell wall made of peptidoglycan * Cell membrane made of fatty acids * Can cause disease * Non-harsh environment * Circular chromosome ## Archaea: * Unicellular * Prokaryotic * No membrane-bound organelles * Have ribosomes * Cell wall made of pseudopeptidoglycan * Cell membrane made of isoprene chains. * Doesn't cause disease * Can live in very harsh environments * Circular chromosome ## Eukarya: * Multicellular and unicellular * Eukaryotic * Membrane-bound organelles * Have ribosomes * Cell wall made of cellulose in plants, and no cell wall in animal cells * Cell membrane made of phospholipids * Can cause disease * Non-harsh environment * Linear chromosomes * It is the man who named everything by a Swedish scientist * Carl Von Linneaus ## SYSTEMA NATURAE 1735 ## SYSTEMA NATURAE 1753 # Binomial Names: Two names: * Genus species * Written in italic or underlined * 1 word = capital * 2 word = lowercase * Ex. Homo sapiens # Taxonomic Rankings More specific as you go down. * Domain * Kingdom * Phylum * Class * Order * Family * Genus * Species ## If two animals from different species have an offspring, the child is infertile. ## Variation within species: * Ex. Dog breeds # RELATIONS: ## How can we determine how organisms are RELATED? * **Genetics** * **Form** * **Behaviour** * **Geography** ## Genome: * Every organism has a genome: the complete set of genes or genetic material present in a cell or organism. * We compare genomes to see how related differentorganisms are. * We can also use the genomes to determine how long different organisms began to diverge from one another and form separate species. # CLASSIFICATION ## Mammals * Hair or fur * Give birth to live young * Mammal mothers nurse their young with milk * Have lungs and need air to breathe * Warm blooded ## Reptiles * Have scales * Dry skin * Usually lay eggs but sometimes live young * Ear holes instead of ears * 4 legs or no legs * Cold-blooded ## Birds * Feathers * Wings * 2 legs * Ear holes instead of ears * Warm blooded * Lay eggs ## Amphibians * Land & water * Webbed feet * Breathe with lungs & gills * Moist, smooth skin (no hair) * 4 legs/none sometimes * Lay many eggs * Cold blooded ## Fish * Breathe underwater (gills, not lungs) * Live in water * Scales & fins (no hair) * Lay many eggs * Cold blooded # Archaea * Cell wall - Made of pseudopeptidoglycan * Chromosome - Circular * Nucleus - Not present * Cytoplasm - Not present * No mitochondria or other membrane-bound organelles * Unicellular with a limited range of cell shapes, mostly spheres, rods and spirals. # Bacteria * Cell wall - Made of peptidoglycan * Chromosome - Circular * Nucleus - Not present * Cytoplasm - Not present * No mitochondria or other membrane-bound organelles * Unicellular with a limited range of cell shapes, mostly spheres, rods and spirals. # Eukaryotes * Cell wall - Made of cellulose or chitin if present * Chromosome - Linear * Nucleus - Present * Mitochondria and other membrane-bound organelles are present * Unicellular or multicellular with a huge range of cell shapes. -Archaea from a hot spring in Yellowstone National Park. -Bacteria from plaque on teeth. -Eukaryote cells (diatoms) in plankton from a lake.