All living organisms are comprised of cells
Cells are the smallest unit of life
Cells come from pre-existing cells
Do unicellular organisms carry out all the functions of life?
Yes, including but not limited to: Metabolism, homoeostasis, growth, reproduction and nutrition
Relative Sizes of Molecules
molecules = 1nm
membrane = 10nm
viruses = 100nm
bacteria = 1μ
organelles = (up to) 10μ
cells (most) = 100μ
Surface Area/Volume Ratio
Rate of heat production/waste production/resource consumption is a function of volume, whereas the rate of material exchange and energy (heat) is a function of surface area.
Emergent Properties (Multicellular Organisms)
Emergent properties arise from the interaction of component parts: the whole is greater then the sum of its parts
"When individual components in an environment come together to create distinct, collective and interactive properties and functions, the results are called emergent properties. These emergent properties do not and cannot manifest themselves unless an organism is looked at in its entirety. "
What's the point of cell differentiation?
So that differentiated cells may carry out different functions through-out the Multicellular organism.
Do stem cells retain the capacity to divide?
yes, they also have the ability to differentiate along different pathways.
Example of therapeutic use of stem cells
"it may become possible to generate healthy heart muscle cells in the laboratory and then transplant those cells into patients with chronic heart disease. Preliminary research in mice and other animals indicates that bone marrow stromal cells, transplanted into a damaged heart, can have beneficial effects. Whether these cells can generate heart muscle cells or stimulate the growth of new blood vessels that repopulate the heart tissue, or help via some other mechanism is actively under investigation."
Prokaryotic cells (Diagram)
The cell wall, plasma membrane, cytoplasm, pili, flagella, ribosomes, nucleoid (region containing naked DNA)
"A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell."
The plasma membrane is a very important structure which functions to allow certain substances to enter or leave the cell.
The cytoplasm plays a mechanical role, i.e. (example) to maintain the shape, the consistency of the cell and to provide suspension to the organelles.
attachment to solid surfaces, apparatus for use in transfer of DNA from one cell to another, twitching motility, and cell-cell adhesion.
flagella are hairlike structures projecting from the cell that function to move the cell by their movements.
The primary function of ribosomes is synthesis of proteins according to sequence of amino acids as specified in messenger RNA.
Store the genetic information of the cell.
The cells divide by binary fission
Eukaryotic Cells (Diagram)
Draw and label a diagram of the ultrastructure of a liver cell include:
Free ribosomes, rough endoplasmic reticulum, lysosome, Golgi apparatus, mitochondrian and nucleus
Rough endoplasmic reticulua synthesize proteins.
Lysosomes function entails destroying any foreign body and unwanted cell organelles that may be present in cytoplasm.
The Golgi Apparatus is an important organelle found in eukaryotic cells that helps with the creation, sorting and modification of molecules
Mitochondria are called 'powerhouse of cell'. Mitochondria contain a number of enzymes and proteins that help in processing carbohydrates and fats. (Through the creation of ATP)
Prokaryotic vs Eukaryotic Cells
Naked DNA vs DNA associated with proteins
DNA in cytoplasm vs DNA enclosed in a nuclear envelope
No mitochondria vs mitochondria
70s ribosomes vs 80s ribosomes
Eukaryotic cells have internal membranes that compartmentalise their functions
Plant vs Animal Cells
Animal cells do not have rigid cell walls like plant cells
Plant cells include chloroplasts for use in photosynthesis
Plant cells have a larger central vacuole (enclosed by a membrane)
Two Roles of Extracellular Components
The plant cell wall maintains cell shape, prevents excessive water uptake, and holds the whole plant together up against the force of gravity.
Animal cells secrete glycoproteins that form the extracellular matrix. This functions in support, adhesion and movement.
Should show the Phospholipid bilayer, cholesterol, glycoproteins, and integral peripheral proteins
Functions of membrane proteins
Hormone binding sites, immobilised enzymes, cell adhesion, cell-to-cell communication, channels for passive transport, and pumps for active transport.
Diffusion is the passive movement of particles from a region of high concentration to a region of low concentration
Is the passive movement of water molecules, across a permeable membrane, from a region of lower solute concentration to a region of higher solute concentration