Unit 2 - Cells and Organelles 2 Flashcards
2.4 Eukaryotic cell structure 2.5 The ultrastructure of plant cells 2.6 Prokaryotic & eukaryotic cells
Proteins are made…(where?)
Mainly at the ribosomes attached to the RER. These proteins are stored in the RER until they can be processed and packaged at the golgi apparatus. Some ribosomes are free in the cytoplasm and the proteins they produce also stay in the cytoplasm.
In the RER proteins are..
folded and processed, being modified in ways such as having sugar chains added.
Proteins are transported from the RER to the…
Golgi apparatus in vesicles.
At the Golgi apparatus the proteins…
undergo further processing where sugar chains are trimmed or more are added.
Proteins are transported in/out/around cells in…
vesicles.
Secretory cells, which release hormones or enzymes, have more…
rough endoplasmic reticulum than cells that do not release proteins.
Proteins may be stored…(in which organelle?)
in the rough endoplasmic reticulum until they are needed by the Golgi apparatus
The cytoskeleton is made of which three components:
- Microfilaments - contractile fibres formed from the protein actin.
- Microtubules - globular tubulin proteins polymerised to form tubes that act as a scaffold structure determining the shape of a cell. Also act as tracks for the movements of organelles.
- Intermediate fibre - fibres that give mechanical strength to cells and help maintain their integrity.
functions of Microtubules and microfilaments
Support the cell’s organelles keeping them in position,
strengthen the cell and help maintain it’s shape,
they’re responsible for the transport of organelles and materials within the cell.
define Vacuole give characteristics
Membrane lined sac in plant cells containing cell sap. Large permanent vacuoles as used to maintain turgor. The membrane of the vacuole is called the tonoplast. It is selectively permeable. if vacuoles appear in animal cells they are small and transient.
Prokaryotic vs. eukaryotic - cell size
Prokaryotic - extremely small, less than 2 µm diameter
Eukaryotic - Larger Cells, 2-200 µm diameter
Prokaryotic vs. eukaryotic - Nucleus & DNA
Prokaryotic - No nucleus, DNA free in cytoplasm, DNA is circular, organised by proteins folding and condensing DNA.
Eukaryotic - Nucleus Present, DNA inside nucleus in form of chromosomes, DNA is Linear. Organised by DNA molecules associating with histones to form chromatin, which is condensed to form chromosomes.
Prokaryotic vs. eukaryotic - Extra chromosomal DNA
Prokaryotic - found in plasmids
Eukaryotic - found in chloroplasts and mitochondria
Prokaryotic vs. eukaryotic - Organelles
Prokaryotic - non-membrane bound
Eukaryotic - both non-membrane bound and membrane bound
Prokaryotic vs. eukaryotic - Cell wall
Prokaryotic - peptidoglycan
Eukaryotic - chitin in fungi, cellulose in plants
