L5 - Intro To Cell Flashcards
Cell theory
1) All living organisms are composed of 1+ cells forming collaborative, functional networks
2) The cell is the basic unit of structure and organisation as well as the smallest unit that makes use of survival needs of the body to undertake all functions necessary for life
3) All cells arise only from pre-existing cells
4) The total function of all cells in the body reflect the total function of the body
Eukaryotic vs. prokaryotic cells
Membrane-bound organelles/nucleus
Eukaryotic and prokaryotic cells similarities
have plasma membrane, cytosol, DNA, RNA, protein and ribosomes
Endomembrane system
Work with plasma membrane to package, label and ship molecules
- INCLUDES; nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes
- EXCLUDES: mitochondria (lots of membranes), ribosomes (don’t have a membrane)
Types of plasma membrane proteins
Integral (including transmembrane), peripheral
Functions of plasma membrane proteins
Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and ECM
Cell-cell recognition
- Some glycoproteins serve as identification tags/molecular signatures of the extracellular side of the cell that are specifically recognised by other cells
- More short-lived than intercellular joining proteins
Components of nucleus
Nuclear envelope, nuclear lamina, nuclear pores, nucleolus
Nucleus function
- House/protect DNA in eukaryotic cells
- Make RNA and assemble ribosomes
- Pores regulate movement of substances (e.g protein and mRNA) in and out of nucleus
- Molecule segregation to allow temporal and spatial control of cell function
Condensing of DNA
Double helix, histones, nucleosomes, chromatin, chromatin fibres, looped domains, chromosomes
Ribosomes
- made of rRNA
- small and large subunits
- protein production
- free in cytoplasm (cytosolic/non-endomembrane proteins) or attached to RER (non-cytosolic/endomembrane proteins)
Endoplasmic reticulum
Extensive networks of tubes and tubules (cisternae) stretching out from nuclear membrane
Cisternae function
Serves the biosynthesis of new lipids and of membrane anchored or secretory proteins
Rough ER function
Production of:
- Secreted proteins (which leave cell via exocytosis)
- Membrane proteins
- Organelle proteins
Rough ER
- Continuous with nuclear enevlope
- Dotted with attached ribosomes (synthesis proteins)
- Proteins enter lumen within rough ER for folding
- Rough ER membrane surrounds protein to form transport vesicle destined for Golgi