Lecture 1 Flashcards
What are the main types of microscopes?
• Optical
• electron
• fluorescent
Why are most cells small?
1 they have a finite life
2. They can be replaced without disruption of function
3. They need to kap distances short to facilitate transport of molecules
What are the 2 different types of electron microscopy?
TEM - transmission electron microscopy
SEM - scanning electron microscopy
Why is there an advantage to having a small cell size when the cells themselves have a finite life span?
Becasue when cells break down the smaller size is better - they can be easily repaired or discarded
Whay are most cells specialized to perform a particular function?
Because it is easier to replace them without disrupting the function of the organism.
What would happen if organisms were made up of just a few very large cells?
If one of those large cells died or got injured, it would make the organism vulnerable becasue it would be harder for it to recover.
Large cells also have less sruface area for oxygen and nutrients to diffuse into the cytoplasm.
Why do cells need to keep the distances short between each other?
They rely on simple diffusion to take in nutrients, oxygen, water and to remove waste.
What is simple diffusion in cells?
a form of diffusion that does not require the assistance of membrane proteins. Nutirents move through a membrane from areas of higher concentration to areas of lower concentration.
Why is surface area to volume so important in cells?
The volume of a cell determines the amount of chemical activity that can take place within it.
The surface area determines the amount of substances that can be exchanged between the cell and the outside environment
Considering SA/Volume ratio, why is cell size limited?
The speed of diffusion depends on the suface area to volume ratio.
If the surface area is too small and the volume is too big then it will not be able to get enough nutirents through simple diffusion fast enough and the cell will die.
What happens if a cell requires a lot of surface area?
The cell will develop convoluted / branchy surfaces (villi)
