Foundations in Biology - Cell structure

Light/optical microscopes

Provide poor resolution due to the long wavelength of light, suitable for examining living samples and obtaining colored images, cheap, and portable.

Transmission electron microscopes

Offer high magnification and resolution due to the short wavelength of electron beams, require thin specimens in a vacuum, and produce black and white images by passing electrons through the specimen.

Scanning electron microscopes

Provide high magnification and resolution with short electron beam wavelengths, create 3D images by bouncing electrons off the specimen, and do not require thin specimens.

Laser scanning confocal microscope

Offers higher resolution and 3D imaging using laser light, where resolution is the minimum distance to view objects as separate and magnification is the size difference between the image and the object.

Slide preparation techniques

Include dry mount, wet mount, squash slide, and smear slide methods for preparing specimens for microscopy.

Calibrating

Involves aligning stage micrometer and eyepiece graticule to determine magnification by counting divisions, essential for accurate measurements in microscopy.

Differential staining

Utilizes various stains like methylene blue, acetic orcein, eosin, Sudan red, and iodine to bind and differentiate structures in specimens.

Eukaryotes

Have a nucleus with a nuclear envelope, nucleolus, protein-bound chromosomes, flagella, cilia, centrioles, cytoskeleton, RER, SER, Golgi apparatus, lysosomes, and mitochondria, each with specific functions in the cell.

Protein production and secretion

• Involves mRNA leaving the nucleus

• attaching to ribosomes on the RER protein synthesis occurs

• processing in the Golgi apparatus, packaging in vesicles

• secretion through the plasma membrane.

Differences between prokaryotic and eukaryotic cells

Prokaryotes lack membrane-bound organelles, have DNA in the cytoplasm, a cell wall made of murein, and smaller 70s ribosomes compared to eukaryotes with 80s ribosomes.