Cellular components & microscopy
- Created by: HeHeHe24
- Created on: 05-12-19 20:56
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- Cellular components
- Magnification
- how many times larger the image is compared to the actual size
- = Image size / actual size
- resolution
- degree of clarity to which you can distinguish between 2 different objects
- Limitations
- diffraction of light through the sample
- microscopy
- light microscope
- advantages
- observe living things
- cheap
- easy to set up & portable
- no harsh chemicals
- disadvantage
- low resolution
- low magnification(x2000
- sample preparation
- dry mount - cut thinly and place with a cover slip
- wet mount - suspend in liquid, place cover slip over at an angle
- squash slide - prepare a wet mount and press down with lens slip
- smear slide - edge of slide used to smear at an angle
- differential stain
- used to distinguish between different organelles otherwise hard to identify
- stain cell cytoplasm
- congo red
- nigrosin
- negatively repel cytosol
- stain cell component
- crystal violet
- methylene blue
- attracts negatively charged cytosol
- advantages
- Electron microscope
- disadvantage
- non living materials used
- expensive
- non portable & hard to use
- harsh chemicals needed- cause artefacts
- Scanning EM
- advantages
- high magnification (x500000)
- high resolution
- see detailed 3D images
- advantages
- Transmission EM
- advantages
- high resolution
- high magnification (x20000000)
- see detail
- advantages
- disadvantage
- light microscope
- prokaryotic cells
- single celled
- no membrane bound organelles
- nucleus
- Naked DNA
- not present
- circular DNA not wound around histone proteins into chromosome
- Plasmids
- ribosomes
- smaller 70s
- cell wall
- peptidoglycan
- replication
- binary fission
- DNA replicated
- split by cytokinesis
- binary fission
- single celled
- Eukaryotic cells
- multicellular
- Plasma membrane
- selectively permeable
- allows small non polar molecules to pass
- nucleus
- contains genetic information
- DNA in linear chromosomes
- histone proteins
- nuclear envelope
- double membrane to protect
- nucleolus
- produces ribosomes
- nuclear pore
- allows mRNA to leave
- contains genetic information
- Mitochondria
- cellular respiration to produce ATP
- Vesicles
- membrane bound sacs
- transport materials in and out
- stores material
- lysosomes
- release hydrolytic enzymes
- Cytoskeleton
- microfilament
- contractile actin fibres for cell movement
- microtubules
- globular tublin proteins
- polymerise to tubes
- determine shape
- intermediate fibres
- mechanical strength
- maintains cell integrity
- centrioles
- 2 microfilaments at 90o
- spindle fibre formation
- microfilament
- flagella
- movement
- cilia
- fluid movement
- ribosomes
- synthesise proteins
- SER
- no ribosomes
- lipid and carbohydrate synthesis and storage
- RER
- ribosomes
- synthesis and transport protiens
- golgi apparatus
- processes and packages proteins into vesicles
- transport or storage
- processes and packages proteins into vesicles
- plant components
- Cell wall
- Cellulose
- Yeast
- Chitin
- freely permeable
- rigid to give shape
- defence mechanism against pathogens
- Chloroplasts
- photosynthesis
- permanent vacuole
- tonoplast membrane has cell sap
- Untitled
- Cell wall
- Magnification
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