Week 1 Lecture 1. BIOL10002 Revision Notes. Darwin s Observations 1. Individuals in a population vary fitness

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1 Week 1 Lecture 1 Foundations of Biology 1. Evidence for Evolution 1. Fossil record: observable increase in complexity with passage of time - Ontogeny Recapitulates Phylogeny: development is a fast action replay of ancestry - Homology: derived from a common ancestral feature, e.g. 2. Biogeography: unique Australian flora & fauna due to protracted evolution on isolated continent 3. Unity of biochemical processes Darwin s Observations 1. Individuals in a population vary fitness 2. Pass on traits (fitness) to offspring heredity 3. Never enough resources competition for survival & reproduction = natural selection Evolution is a two-step process: 1. Variability 2. Ordering that variability by natural selection Gene variation leads to ordering the variability by natural selection Environment changes cause populations to develop 2. Unity of Biochemical Processes All organisms share the main biochemical reactions Retained by evolution: 1. All organisms have DNA contains instructions on how that organism will develop. 2. Organisms also have proteins the hardware to carry out the instructions. Further evidence for evolution. 3. Cell Theory - All known living things are made up of one or more cells (excl. viruses) - All living cells arise from pre-existing cells by division - The cell is the fundamental unit of structure and function in all living organisms - Cells contain hereditary information (DNA) which is passed from cell to cell during cell division. DNA contains the history of evolution patterns Gene sequencing - determining the precise order of nucleotides within a DNA molecule gene sequences can be compared to determine relationships between organisms Main groups of cells: Eukaryotes and Prokaryotes Eukaryotes, Bacteria and Archaea

2 Lecture 2 Prokaryotic Cells Life depends on prokaryotes: 1. Archaea allow herbivores to break down the sugars in plants 2. Bacteria in intestines help to make essential vitamins 3. Harmless Bacteria on skin protect us from attack by other invaders 4. Prokaryotes generate much of the biosphere 5. Many food products rely on prokaryotes (fermentation) Note: Bacteria can cause disease, however Archaea do not Prokaryotic cells: - Usually microscopic (1-10µm) - DNA is single, circular chromosome (nucleoid) - No proteins attached to DNA in Bacteria - Proteins ( histones ) attached to DNA (Archaea) - Peptidoglycan wall - divide by binary fission Constricting ring pinches parent cell into two Bacteria cells: one surrounding membrane is Gram +, two surrounding membranes is Gram Note: Bacteria has no histone; Archaea and Eukaryotes have histone bound to the DNA. Ribosomes - All cells have ribosomes - Small machines composed of numerous proteins and several RNAs - Site of translation - Take mrna sequence and translate it to a protein sequence - Prokaryotic ribosomes are small (70s, 17-23nm) - Eukaryotic ribosomes are larger (80s, 25-30nm) Prokaryotic Flagellum - Long thin filament - Corkscrew action - One of only two rotating shaft designs in biology - Composed of flagellin protein Features of Eukaryotes not found in Prokaryotes - Division of labour in the cytoplasm - Nucleus & histones - Endoplasmic Reticulum - Golgi complex - Cytoskeleton - Microtubules - Microfilaments - Intermediate filaments -Motor proteins & movement

3 Lecture 3 Eukaryotic Cells Eukaryotic Nucleus - Surrounded by a double membrane or nuclear envelope - Presence of nuclear pores (75nm in diameter) - DNA in long, linear strands covered with histones = chromatin - Different organisms have different numbers of chromosomes - Nucleolus = subregion of nucleus where ribosomal genes are transcribed - RNA transcribed from DNA leaves nucleus via pores and goes out into the cell to be translated Pores - Lined with proteins and attached to lamina (nuclear skeleton) - Evenly spaced over nuclear envelope - Traffic of proteins and RNAs in/out of nucleus - Located at site where inner membrane curls around to become outer membrane Note: Endoplasmic reticulum is continuous with nuclear envelope extends throughout the cell. Endoplasmic Reticulum - Consists of membrane cisternae that ramify through the cytoplasm. The result is internal compartments and channels - The ER is a dynamic structure, ever changing in structure and functions - with ribosomes = rough ER neat, folded structure - no ribosomes = smooth ER tubular structure Ribosomes dock on ER to The protein can then be transported to Golgi complex. Intracellular membranes 1. Provide a surface for biochemical reactions. 2. To establish compartments to prevent mixing. 3. To provide for transport of materials within the cell, from the cell to its exterior, or from the cell to an adjacent cell Golgi Complex - Consists of flattened stacks of cisternae called Golgi bodies - Golgi bodies are functional extensions of the ER - involved in collection, packaging, and distribution of molecules synthesised elsewhere in the cell - Almost all the polysaccharide in cells is manufactured within the Golgi bodies - The polysaccharide may be attached to either protein or lipid molecules in the Golgi bodies Note: Polysaccharides on proteins may be used to distinguish between cells that are self and non-self The Cytoskeleton - Allows eukaryotes to be much larger than prokaryotes - Act as a form of scaffolding or as structural elements within the cytoplasm of cells - Involved in certain cell movements

4 Actin Intermediate Microtubule Monomers can be assembled and polymers can be disassembled controlled by gelsolin Composed of vimentin Myosin Predominately static Kinesin Dynein Muscle contractions, Cytoplasmic streaming, Microvilli Intra- and inter-cellular stabilisation Glycosylation adding a sugar molecule to an organic molecule, especially protein Glycoprotein a protein with a sugar attached to it 13 protofilaments form a hollow cylinder Spindle fibres are microtubules Kinesin moves vesicles along microtubules (Kenny) Dynein slides one microtubule against another, drives cilia and flagella beating Feature Prokaryotes Eukaryotes Bacteria Archaea Eukarya Single/multi-celled Single-celled Single/multi-celled Chromosome Circular Linear structure Chromosome number One Multiple Histones None Bound to DNA Cell Division Binary Fission Meiosis and Mitosis Autotrophism Nitrogen fixation Ribosomes Smaller 70s Larger 80s

5 Week 2 Lecture 4 Lipids and Membranes Lipids - fatty acid chain - protective coatings (wax) - chemical messengers (steroids) - energy storage (fats and oils) - structural component of phospholipid bilayer Note: fats solid at room temperature, oils liquids at room temperature Phospholipid Bilayer All membranes composed of; - phospholipid bilayer - other components: proteins, glycoproteins, sterols - different membranes have different ancillary components Movement across membranes Membranes are selective barriers - molecules can enter by: - Diffusion (incl. osmosis) - Facilitated diffusion - Active Transport - Pinocytosis & Phagocytosis Phospholipids have a hydrophilic (polar) head and a hydrophobic (non-polar) tail; - only small, uncharged, non-polar (+ some polar) molecules and all gases can pass through the phospholipid bilayer, e.g. lipids, CO 2, water Osmosis; - A special case of diffusion. - It is the movement of water through a differentially permeable membrane from a region of high water concentration to a region of low water concentration - Osmotic Potential: greater solute concentration = more negative potential. Water moves from higher to lower (more negative) potential = Pressure required to prevent the movement of water into a solution if the solution is separated from that water by a selectively permeable membrane Role of Membrane Proteins and Glycoproteins - Some are enzymatically active - Structure - Determinants of individuality - Surface receptors for stimuli - Transport mechanisms - Role as a selective barrier Note: Pino = drink, Phago = eat