Week 1 Flashcards
Cell theory concepts
Cells are the basic structural units of living organisms
Cells are alive
The principle of complementarity of structure (relationship of structure and function)
The circle of life (cell cycle)
Cell theory - concept 1
• Cells classified 1 of 2 groups – prokaryote and eukaryote
• Prokaryotic cells
o Prokaryotic – have plasma membrane
o DNA (genetic material) not contained in a nucleus
o Cytoplasm lacking internal organisation (organelles)
o Examples: bacteria and archeans
• Eukaryotic cells
o Organisation of intracellular environment into membrane compartments, serve specific functions (organelles)
o Have nucleus and cytoplasm
o Examples: human/animal cells, plant cells and fungal cells
Cell theory - concept 2
- Cells are alive
- Cellular activity dictates activity of an organism
- Cells must be able to adapt, grow and reproduce
- Meaning, cellular activity relates to healthy functions (physiology) and abnormal functioning (pathophysiology) in humans
Cell theory - concept 3
- Structure dictates function – links to cellular diversity
- Structure/function linked anatomy and physiology linked
- Concept = idea anatomical and physiological disruption at a single cellular level can lead to disruption in structure and function at a cellular community level
Cell theory - concept 4
- Have own life cycle and reproduce through mitotic cell division (mitosis) continually changing
- Two major parts – interphase and the mitotic phase
- Mitosis: Prophase, metaphase, anaphase, telophase, cytokinesis
General overview of cell cycle
• G1 phase:
o Metabolic changes prepare for cell division
o At restriction point, cell is committed to division and moves into the S phase
• S phase
o DNA synthesis replicates genetic material
o Each chromosome now consists of two sister chromatids
• G2 phase
o Metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis
• M phase
o Nuclear division (mitosis)
o Cell division (cytokinesis)
3 important components of a cell (description)
- Cell Membrane - allowing cells to be self contained and forming a barrier
- Nucleus - control centre of cell; controlling activity and the life cycle; DNA inside there is replicated in mitosis; DNA important for growth, synthesis and repair (dictating what will happen in the cytoplasm)
- Cytoplasm (that contains organelles) - intracellular solution containing organelles and structures for functioning; different cell types have different organelles
Cell membrane
- Phospholipid bilayer
- Primary function is not only as a barrier, but also for communication
- Can create small channels for communication and transport in and out of the cell
- Can anchor proteins to the membrane cytoskeletal example help maintain or even change shape
- Allows to speak to other cells and to interact with external environment
- Allows to organise its structure
Cytoplasm
- Mitochondria energy (ATP)
- Golgi Apparatus creating export out the cell
- Endoplasmic Reticulum important for synthesis of proteins and lipids
- Lysosomes waste component, used for biodegradation processes
Nucleus
- DNA contained
- Nucleolus in middle
- Membrane bound organelle, allowing to communicate with rest of cytoplasm
- Important for ability to access information within DNA and to allow other macromolecules (i.e proteins) to be accessed and biosynthesis to occur
Eukaryote vs Prokaryote
- Cell wall present in prokaryote and bounded by wall or membrane
- Eukaryote has membrane bound nucleus, prokaryote do not
- Membrane bound organelle, allowing to communicate with rest of cytoplasm
- Eukaryote have membrane bound organelles, prokaryote do not
- Prokaryote do not have endoplasmic reticulum
- Ribosomes are larger in eukaryotes compared with prokaryotes
- Prokaryote mostly asexual reproduction, while eukaryote does both
Cell wall (in bacteria)
- Determines the shape of cell and provides important mechanical support
- Gram positive or gram negative (based on composition)
- Difference of two groups depends on position of peptidoglycan layer
Gram-positve cell wall
• Thick outer layer of peptidoglycan (surrounds plasma membrane)
• Attached to PG are other complex poly-saccharides called teichoic acids
o Play role in passage of molecules in and out of cell
Gram-negative cell wall
- Thin layer of peptidoglycan
- This is sandwiched between plasma membrane and an outer membrane (DIFFERENCE) containing lipo-polysaccharides, lipoproteins and phospholipids
- This makes it harder to treat with antibiotics
Gram stain
- most important microbiological staining method
* gram negative bacteria = red, positive = purple
