Unit 1 Review Flashcards
Water Properties
thermal - hydrogen bonding means that water can absorb a lot of heat, good for cooling (sweat)
cohesive - dipolarity means water sticks to itself, strong surface tension allowing animals to move across its surface
adhesive - dipolarity means water will stick to other polar surfaces, capillary action in plants
solvent - dipolarity means that polar substances dissolve in water, good transport medium (blood)
density - water is less dense as a solid, allows ice to float
transparent - allows aquatic plants to undergo photosynthesis
Endosymbiotic theory
Theory that one prokaryotic cell absorbed another prokaryotic cell via phagocytosis
The engulfed prokaryotic cell remained undigested as it contributed new functionality to the engulfing cell
Over generations, the engulfed cell lost some of its independent utility and became a supplemental organelle
Endosymbiotic theory evidence
MAD DR
Membranes - have double membranes
Antibiotics - susceptible to antibiotics indicating bacterial origins
DNA - has own DNA which is naked and circular
Division - reproduction happens in a fission like process
Ribosomes - has 70s ribosomes (just like other prokaryotes)
Prophase
- DNA supercoils and condenses
- sister chromatids are joined at a centromere
- centrosomes move to opposite poles of the cell and form microtubule spindle fibers
- nuclear membrane breaks down
Metaphase
- spindle fibers from each centrosome attach to the centromeres of each chromosome
- spindle fibers shorten and contract
- causes chromosomes to be aligned along the equator of the cell
Anaphase
- continued contraction of the spindle fibers causes genetically identical sister chromatids to separate
- once chromatids separate, they are considered chromosomes again
- chromosomes move to opposite sides of the cell
Telophase
- chromosomes arrive at the poles and spindle fibers dissolve
- chromosomes decondense
- nuclear membranes reform
- cytokinesis occurs concurrently, splitting the cell in two
Passive transport
Simple diffusion – movement of small or lipophilic molecules (e.g. O2, CO2, etc.)
Osmosis – movement of water molecules (dependent on solute concentrations)
Facilitated diffusion – movement of large or charged molecules via membrane proteins (e.g. ions, sucrose, etc.)
Active transport
Active transport involves the movement of materials against a concentration gradient
Requires the expenditure of energy
Sodium-potassium pump
Exocytosis in neurons that release neurotransmitters
Properties of phospholipids
Consist of a polar head (hydrophilic) composed of a glycerol and a phosphate molecule
Consist of two nonpolar tails (hydrophobic) composed of fatty acid (hydrocarbon) chains
Because phospholipids contain both hydrophilic (water-loving) and lipophilic (fat-loving) regions, they are classed as amphipathic
Cell Theory
All living things are composed of cells (or cell products)
The cell is the smallest unit of life
Cells only arise from pre-existing cells
Exceptions to cell theory
Striated muscle: composed of fused cells that are multinucleated
Giant algae: unicellular organisms that are very large in size (~7 cm)
Aseptate hyphae: lack partitioning and have a continuous cytoplasm
Magnification formula
image size = actual size x magnification
Cell Differentiation
Differentiation is the process during development whereby newly formed cells become more specialized and distinct from one another as they mature
All cells of an organism share an identical genome so each cell contains the entire set of genetic instructions for that organism
The activation of different instructions (genes) within a given cell by chemical signals will cause it to differentiate
Falsification for Davson-Danielli model
proteins were discovered to be insoluble in water
fluorescent antibody tagging of membrane proteins showed they were mobile and not fixed in place
freeze fracturing was used to split open the membrane and revealed irregular rough surfaces within the membrane
