Cells 1, 2 & Cell Histology Flashcards
Emily
Apoptosis
Normal programmed cell death
Necrosis
Cell death occurring due to disease/infection
Communication between cells x4
- Endocrine (hormones)
- Paracrine (more local signalling)
- Neuronal (neurotransmitters)
- Contact dependent (signalling, receptors)
Plant & animal cells - size
10-100 micrometres
Bacteria cells - size
1-10 micrometres
Fundamental properties of cells x4
- Act as independent units
- Come from pre-existing cells
- Finite lifetime
- Can change/adapt/respond
Euchromatin vs Heterochromatin
Euchromatin = active genetic material, site of transcription Heterochromatin = inactive genetic material, denser
Synthesis in free ribosomes
- Proteins then go either to other organelles, or function in cytoplasm
Synthesis in rER
- How occurs
- What happens in rER
- A signal sequence on mRNA signals ribosomes to tether to ER
- Proteins released straight into rER
- Proteins are folded
Secretion pathway
rER –> Golgi apparatus –> cell surface
Parts of Golgi
- CIS –> reception site
- MEDIAL
- TRANS –> vesicles are released
Folding of proteins
- In rER
- If not correctly folded, disposed of
Phagocytosis
Endocytosis of larger particles
Pinocytosis
Endocytosis of molecules (non-specific)
Receptor mediated endocytosis
Specific form of pinocytosis
Uptake pathway
Cell surface –> endosomes –> lysosomes
Uptake pathway (pH)
- Cell surface –> neutral
- Endosomes –> mildly acidic
Lysosome –> acidic
Lysosomes are acidic as…
Better at degradation
Autophagy
When portions of the cell are ‘walled off’ and digested in the lysosome
Plasma membrane function x3
- Motility
- Adhesion
- Ion transport
ER function
Membrane synthesis
Golgi apparatus function
Modification (e.g. adds phosphates) & sorting of secretory proteins into vesicles
Lysosome function
Degradation of internalised material
Microtubule function x2
- Vesicle tracks that move organelles
- Cell division
Microfilament function
Generates contractile force
Intermediate filament function
Strength, support
Vesicle transport
- how
- how mediated
Occurs along microtubule ‘tracks’
- Mediated by motor proteins
Centrosome
- function
- structure
- Centre for organising microtubules
- 2 centrioles, each = 9x microtubule triplets
Advantage of compartmentalisation
Can regulate internal conditions for necessary reactions
Clathrin
- what
- function
- advantage
- ‘scaffold’ coat
- helps form & seal vesicle
- clathrin coated pit formed, concentrates receptors for endocytosis
Endosymbiosis
Non-nucleated cells took up a bacterium –> replicated –> provided ATP –> cell survived by natural selection
Mitochondria & DNA - & example
Have their own DNA from MATERNAL lineage
- Defects can cause metabolic disease
Light microscopy samples - frozen
- +ves
- -ves
- Faster
- Not easily preserved, less clear
Light microscopy samples - embedded in paraffin wax
- +ves
- -ves
- Preserved, clearer
- Long process, can damage e.g. proteins
Haematoxylin
- stains
- colour
- example
- -ve charged (DNA, RNA)
- Purple
- e.g. rER
Eosin
- stains
- colour
- Proteins
- Pink
Toluidine blue
- stains
- colour
- example
- Nissl susbtance
- Blue
- e.g. rER
PAS
- stains
- example
- PAS +ve?
- Saccharide structures of glycoproteins
- e.g. mucin
- A cell containing significant glycoproteins
Sites of chromatin condensation x3
- Inactive genetic material
- Chromosomes of mitosis
- Programmed cell death
Chromatin condensation in apoptosis
Condensation = more disorganised
Plasma membrane & histology
- Not visible in light microscopy
- BUT membrane assoc. structures stain
Cilia
- contain…
- function
- Contain microtubules
- For movement & sensing
Microvilli
- contain…
- function
- Contain actin filaments
- For absorption
