Cells I Flashcards
What is the cell wall composed of?
- sugars and amino acids (peptidoglycan)
Use of cell wall
- provides strength, rigidity and protection
What can the destruction of the cell wall do to the cell?
can lead to lysis
What is gram staining?
- a dyeing system to examine cell walls
What does gram-positive staining mean?
the cells look purple and it means the cell wall has an extensive amount of carbohydrate peptidoglycan
What does negative-gram staining mean
cell looks pink and the cell wall has a thing layer containing peptidoglycan+ outer phospholipid bilayer
Prokaryotes are generally bigger eukaryotic (t/f)
false. eukaryotic cells are generally bigger
Why are most cells small
surface to volume ratio is important- to maintain high surface area low volume ratio. high surface area and low volume facilitate the transport of material across the cell membrane. Surface area must be able to sustain the volume.
How do cells overcome surface area to volume ratio?
- by being thin
- many thing projections (dendrites and an axon)
-surface area is high and cytoplasm is close to the membrane to optimize transport - folds and microvilli can also increase surface area while minimizing volume
How do eukaryotic cells compensate for lower surface area to volume ratio?
- compartmentalization
- large area of internal membranes (endomembrane system) facilitating movement of proteins and lipids
- specialized structures with specialized functions
What is endosymbiosis theory
- chloroplasts and mitochondria may once have been free-living bacteria
-mitochondria originated when a bacterial cell took up residence inside another cell
What is chromatin
DNA plus associated proteins
Function and characteristics of nuclear envelope
- the compartment that holds eukaryotic genetic material
- a series of compartments itself
- continuous with the ER
- lined on the inside with proteins to give the nuclear lamina support
- dotted with pores which are equipped with a pore complex
Euchromatin
- less packed, lighter
- part of chromatin
