Foundations (Module 2) Flashcards
What is the difference between organelles and ultrastructures
Ultrastructures are organelles that can only be seen by an electron microscope
What is the division of labour
The idea each organelle has a specific role in the function of the cell and that all organelles work together for the survival of the cell
What organelles are exclusive to only plant or animal cells
Plants-cellulose cell wall
plasmodesma
chloroplasts
tonoplast/permanent vacuole
Animal-centrioles
-lysosomes
What are the three purposes of staining
- Makes cells more visible
- Increase contrast as different organelles take up different volumes of stain
- Identify organelles and details inside more easily
What is the magnification formula and definition
I = A x M
The number of times larger an image appears than the actual object
What is resolution and what is the benefit of having high reslution
The ability to distinguish between two separate points that are very close together.
More detail can be seen at higher resolution
What are the resolutions and magnifications of TEMs and SEMs
magnification TEM = x2,000,000 resolution = 0.2nm
SEM = x200,000 = 2nm
What are other differences between TEMs and SEMs
SEM-3d
surface only
dry sample coated in gold
beam moves back and forth across specimen. Electrons
knocked off are detected
TEM-2d
can view organelles and organelles
has to be sliced very thinly less than 100nm
electrons pass through specimen and number of electrons
absorbed or passed through are detected forming the image
Differences between light and electron microscopes
Light - lower resolution 200nm
lower magnification x2000
cheaper
can use live specimens
images in colour
smaller
no vacuum required
What are the 5 structures and functions of the nucleus
Nucleoplasm containing chromatin - Contains DNA that codes for proteins. During cell division chromatin condenses into chromosomes
Nuclear envelope - double membrane encloses DNA to keep it separate from reactions in the cytoplasm
Nuclear pores - let out mRNA and other molecules
Nucleolus - produces ribosomes
Outer membrane attached to RER - Allows easy transport of mRNA and ribosomes
Structures and functions of the two ERs
Cisternae - membrane bound sacs that allow transport within the cell
Rough ER - covered in ribosomes to perform protein synthesis and transport them to the golgi apparatus
Smooth ER - synthesis lipids and steroids and transports to golgi apparatus
structure and function of ribosomes
2 subunits of rRNA (one large and one small) that mRNA passes through - Protein synthesis
- bind to mRNA and translates
structure and function of the cytoskeleton
Structure - composed of microtubules, microfillaments and intermediate fillaments
Function - support cell organelles position
enable movement of organelles like vesicles
strengthen cell and maintain shape
allow cell movement like phagocytosis
enable cilia and flagellum movement
structure and function of the vacuole
cell sap contained by tonoplast - maintains turgor for support
stores dissolved sugars minerals pigments enzymes amino acids and other waste materials
structure and function of the cell wall
made of cellulose which is rigid and permeable - support and protection
- allows for turgor by preventing osmotic bursting
- can be modified by lignin
can contain pores penetrated by plasmodesma - links neighbouring cells
middle lamella - contains pectin and joins cells together
what prokaryotic cells have
Always - 70s ribosomes, cytoplasm, nucleoid, circular DNA, peptidoglycan cell wall
Sometimes - pill, plasmid, capsule, mesemome, plasma membrane infolding, flagellum
