Ivo Flashcards
What were the 3 lenses used in Hooke’s microscope?
Bi-convex objective lens, eyepiece lens, and a tube or field lens
what optical issues did Hooke’s microscope suffer from?
Significant chromatic and spherical aberration
How did Hooke’s microscope correct aberrations?
By placing a small diaphragm into the optical pathway to reduce peripheral light rays and sharpen the image
What was used for illumination in Hooke’s microscope?
An oil lamp with light passed through a water-filled glass flask to diffuse and provide even, intense illumination
How was Leeuwenhoek’s microscope constructed?
It consisted of two flat and thin brass plates riveted together with a bi-convex ground lens sandwiched between
What were the magnification and resolution capabilities of Leeuwenhoek’s microscope?
magnifcation of 70-270x and resolution approaching 1 micron
What discoveries did Leeuwenhoek make using his microscope?
He observed “extremely small animals” in “pepper” water (1676) and studied “cloudy water” from the Berkelsemeer near Delft
What is the resolution limit of optical microscopy?
200nm (1000x magnification, 0.2 microns)
How can objects be tracked with nanometer accuracy despite the resolution limit?
By visualising them using advanced microscopy techniques
What technological advancements have extended resolution in light microscopy?
Development of fluorescent microscopy and confocal microscopy
What technological innovation enabled atomic resolution imaging in electron microscopy (EM)?
The use of complementary metal-oxide-semiconductor (CMOS) chips
Why are CMOS chips superior to film and CCD detectors in EM?
They offer greater resolution and sensitivity with a much faster readout rate
What computational advancements have improved EM?
Advanced computational methods for image analysis and processing
What contributions did Albert Claude make to the discovery of organelles?
He developed fractionation and differential centrifugation techniques
What was George E. Palade’s contribution to cell biology?
He combined EM with differential centrifugation to study ribosomes and secretory vesicle pathways
How did Christian de Duve contribute to organelle disocvery?
He described enzymes in compartments, discovering lysosomes and peroxisomes
What techniques are used to separate viruses and organelles?
Fractionation and centrifugation techniques
How are cell contents released during fractionation?
By removing the outer membrane and applying mechanical force through stirring, osmotic pressure, sonication, or tissue homogenisers
What solutions are typically used to keep organelles intact during separation?
Isotonic solutions, such as sucrose
How are organelles separated in centrifugation?
Based on their size and density
What is primary endosymbiosis?
The internalization of a prokaryote by a host cell to form ancestral eukaryotic cells, such as mitochondria and chloroplasts.
How is the double membrane of mitochondria and chloroplasts formed?
The inner membrane comes from the bacterial ancestor, while the outer membrane originates from the host cell.
What is secondary endosymbiosis?
The internalization of a single-celled eukaryote by another eukaryote.
How many membranes typically surround chloroplast organelles in secondary endosymbiosis?
Four membranes.