Cell theory lecture 1

Question 1

What is the cell theory and who proposed it

Answer 1

Mathias Schleiden and Theodor Schawnn

• All living things are composed of one or more cells,and the life processes of metabolism and heredity occur within these cells
• Smallest living unit of structure and function of all organisms is the cell
• All cells arise only by division from preexisting cells

Question 2

Types of microscopes

Answer 2

Ligth microscopes
- visible ligth is passed through the specimen and through the lenses glass that magnifies the specicmen
- can be used on live specimens
- Finest resolution = 200nm
elctron micrscopes
- focuses a beam od electrons through the specimen onto its surface
- allows to reveal many organelles and has a fine resolution of 0.2 nm apart
- cannot be used with live specimens

Question 3

What are coumpound microscopes and the use of stains

Answer 3

• microscopes that magnify in stages using several lenses

stains can help improving the quality of the image + increases the contrat between different structures

Question 4

the types of electron microscopes

Answer 4

• transmission electron microscope
   Used to study the internal structure of a cell
   Need thin slices of the specimen
   Surface usually stained with heavy metals
  -scanning elctron mycroscope
   For viewing the detailed surface of a specimen
   Surface usually coated with gold

Question 5

Surface area to volume ratio

Answer 5

As cell size increases, it takes longer for material to diffuse from the cell membrane to the interior of the cell.
Surface area-to-volume ratio: as a cell increases in
size, the volume increases 10x faster than the
surface area

Question 6

Characteristic common to all cells

Answer 6

1. A surrounding membrane – plasma membrane
2. Cytoplasm – cell contents in thick fluid
3. Organelles – structures for cell function
4. Control center with DNA

Question 7

What do we know about archeas cell structure

Answer 7

our knowledge of archea cell structure is relatively poor

Question 8

what are strutural similarities shared by all bacterias and what structures vary between them

Answer 8

Similarities
- plasma membrane
-cell wall made of peptidoglycan
- robosomes, which synthesise proteins
- stiff cell wall
Vary
- Photosynthetic membranes
- Bacterial microcompartments
- Cytoskeleton
-Flagella
- Magnetosome