Theme 1: Cells and Organisms PDF

Theme 1: ======== - It can consist of a single cell or multiple cells - It\'s part of the living world hierarchy - Single celled = bacteria - Multiple celled= plants or animals Levels of Living world 1. Bacteria a. Single celled with no nucleus b. Gave rise to mitoc...

Theme 1: ======== - It can consist of a single cell or multiple cells - It\'s part of the living world hierarchy - Single celled = bacteria - Multiple celled= plants or animals Levels of Living world 1. Bacteria a. Single celled with no nucleus b. Gave rise to mitochondria 2. Archaea c. Similar to bacteria 3. Eukarya d. Has a nucleus e. Can be single or multicellular - Has nucleus, has a membrane organelle and has large 80s ribosomes - It has many features like : - cytoskeleton : supports the cell shape and has protein fibres to control membranes and the shape - It enables eukaryotes to engulf food particles → phagocytosis - Has microtubules → hollow tube formed from tubulin dimers - Has microfilaments → double helix of actin monomers for movement and transport - Has intermediate filaments that are made from proteins for support - It also has two elements allowing the cell to move - Cilla → shorter and made from many cells to help move fluid or the cell - Flagella→ which are long and works in paris to propel the cell forward - Endomembrane system - This is a collective term for nuclear envelope, lysosomes, golgi apparatus, vacuoles, and the endoplasmic retritum - They work to compartmertive the interior of the cell to increase available surface area for synthesis - Has multiple, linear DNA - Involves gametes fusion - Plastids found in plants Prokaryotes - Single loop of DNA - Good for rapid replication but gene regulation is dimple - 70s ribosomes (like mitochondria - Allows for the complex gene regulation - Allows for cell differentiation and production of tissue types - All the chromosomes replication happens in parallel - Site of oxidative phosphorylation - How cells use food to make ATP - Eukaryotic cells have chloroplast for photosynthesis to get energy - Increases the Surface area for energy production - Fusion of haploid gametes form two parents to form a new individual genetically different from either parents → Vertical transmission - Evidence (form of lateral transfer) - Circular DNA - Independent fission → remove mitochondria or plastids from the eukaryotic cell therefore it cant produce new ones - Size was smaller than eukaryotes - Double membrane - 70s ribosomes (not same as eukaryotes) Primary Hypotheses 1: - A heterotrophic eukaryotic cell engulfed a aerobic (oxygen using) proteobacterium to form a mutualistic relationship which became the mitochondria - A heterotrophic Eukaryotic cell engulfed a photosynthesis cyanobacteria which becomes the chloroplast 1. Archeaon developed a endomembrane system and then got a mitochondria 2. Archeoa engulfed the mitochondria and then developed the endomembrane a. This makes more sense because mitochondria would have provided energy to make other organelles. - A heterotrophic eukaryote cell engulfed an autotrophic eukaryotic? - Eukaryotes are larger than prokaryotic cells - Cube- square relationship shows that an object grows larger, its volume grows faster than the surface area → not linear → liming relationship - Rate as which materials enter and exit is SA - Rates at which gases and nutrients are used and wasted is the volume - Constraining relationship → diffusion or active transport allows for exchange across membrane and work better in very short ranges - Membrane floods in the mitochondria / golgi and plastids allows for greater entry and protein production 1. Simple : involves cell adhesion, cell to cell communication, no bulk flow a. Bulk flow is movement of fluids and gases through channels b. Examples : i. algae like volvox are colonial organisms where cells function as collective unit ii. Slimes molds forms aggregates of cell that act as a simple cellular organisation 2. Complex: cells adhere, communicate, differentiate and composed of many cells with specialized functions c. Arose independently at least 6 times 1. Symbiotic theory a. Different unicellular organisms that live together forming a symbiotic relation and specialise together to be a single organisms 2. Syncytial theory b. One cell divides into multiple cells with cytokinesis and differentiates 3. Colonial Theory c. Begins with a flagellated unicellular of same species who form colonies and differentiate - Cyanobacteria , the great oxygenation event - Gave rise to oxygen levels due to photosynthesis - Helped complex animals - Simple Multicellularity appeared at the end of the event - The 2nd rise showed the complex Multicellularity Cell adhesion - when cells stick together to form tissues 1. Tight junctions help penetrate cell membranes, fix cells and prevent movement of cells 2. Anchoring junctions helps link cells together and to the microfilaments Differentiation- when cells becomes specialised for certain functions - Begins with flagellated unicellular organisms - Cells needs to be able to adhere to one another - Be able to divide up to spelt tasks - Cells need to learn to communicate Why is Multicellularity important? - Unicellular organism carries out all functions in a single cell but multicellularity allows the tats and functions e be split up - Division of labour and economy of scale - Has increases size - Helps avoid predators - Can exploit newer laces, reach upwards - Increases in feed opportunities - Has produced internal environment - Cells can specialise - Has new metabolic functions - Has enhanced motility - Can share information with other cells - Increases traction in wind or current Disadvantages: - Has predator/ prey or host/parasite interactions - Increases opportunity for diversity in function and niches - Diffusion is short range so useful it cells are close together - Gap junctions help in communications - Bulk flow helps with gas or liquid movement - Nerves - Terrestrial animals can only get so big - Smaller animals lose heat faster - Smaller animals have a higher BMR while larger has less mass-specific metabolic rate 1. Gas exchange a. High folds to pack greater surface area into smaller volume 2. Nutrients absorption b. Has villi of small intestine to increase SA for absorption c. Needs bulk flow 3. Filtration d. Allows for high SA in capillaries What is Homeostasis? - Helps defend cells against hostile environment - Extracellular fluid is all the fluids outside the cell → must be kept stable - Intracellular fluid is all the fluids inside the cell Reproduction and Growth - Must be able to produce new bodies - Unicellular → fission or mitosis - Multicellular → fusion of gametes Characteristics of animals : - There is triploblastic (4 types of tissues) that arise from three embryonic germ layers - Muscles - Neural - Epithelia - Connective