Diffusion- The process by which molecules spread themselves out evenly in a given area. This happens by natural molecular movement.How do particles move across membranes?- by osmosis, active transport, simple diffusion and facilitated diffusionSimple/Passive Diffusion- No energy
- Happens across cell membrane
- From high to low concentration ("down the concentration gradient")Controlled/Facilitated Diffusion- diffusion across a membrane through specific protein channels in the membrane, with no energy costOsmosis- Simple diffusion of waterActive Transport- Requires energy
- Happens only at specific channels
- From low to high concentration ("against the concentration gradient")Concentration Gradient- difference in concentration of a substance between one area and anotherGradient- Different or unevenSemi-Permeability- a type of biological membrane that will allow certain molecules or ions to pass through it by diffusion
(- maintain a balance of water in the cell
- ability to differentiate materials that are needed and those that are not needed in the cell, keeping the cell healthy
- ability to control the amount and kind of substances through the cell membranes )What must we understand? (homeostasis- cells)- Cells constantly change concentrations to their benefit and to maintain stable internal conditions.Endocytosis- the movement of bulk liquids or solids into a cell, by the indentation of the plasma membrane to form vesicles containing the substance; active process requiring ATPEndo--means 'inside'Exocytosis- the movement of bulk liquids or solids out of a cell by fusion of vesicles containing the substance with the plasma membrane; active process requiring ATPExo--means 'outside'How many types of Endocytosis are there?- 3 types of endocytosis-- phagocytosis, pinocytosis and receptor mediated endocytosisPhagocytosis- In endocytosis, if the substances being taken in are particles, such as bacteria, then process is called phagocytosisPinocytosis- In endocytosis, if the substances are in solution, such as the end products of digestion, then the process is called pinocytosisReceptor-Mediated Endocytosis- is an endocytotic mechanism in which specific molecules are ingested into the cell.Water Potential- the tendency of water molecules to move from an area of higher concentration to an area of lower concentrationPlasmolysis- Shrinkage of protoplasm away from the cell wall of a plant or bacterium due to water loss from osmosis, therefore resulting in gaps between the cell wall and cell membrane.Protoplasm- the fluid living content of the cell-- composed mainly of nucleic acids, proteins, lipids, carbohydratesTypes of Solutions- hypotonic
- isotonic
- hypertonicHypotonic- concentration of dissolved substances is greater INSIDE the cell
- through osmosis, H2O diffuses INTO the cell
- hippos get fat, so will the cell
[a less concentrated solution (one with a more negative water potential) than the cell solution]Isotonic- concentration of dissolved substances is EQUAL INSIDE and OUTSIDE the cell
- H2O diffuses INTO the cell and OUT of the cell at the same rateHypertonic- concentration of dissolved substances is greater OUTSIDE the cell
- through osmosis, H2O diffuses OUT of the cell
- this cell will shrink
[a more concentrated solution (one with a less negative water potential) than the cell solution]Gene- a length of DNA at a specific location on a chromosome that controls a specific heritable characterisicStandard Deviation (SD)- measures the spread of the data in a set by describing how far the numbers are from the mean
(- a valuable method of analysis
- it takes into account all values & it's not affected by extreme values
- gives you a hint on how accurate the data is- if the method is good- if you can draw a valid conclusion)Equation for Standard Deviationn= # of data pointsHow do you find the mean?- in a data set, add all the values together then divide by the total number of values in the setHigh SD- the data is widely spread (less reliable)Low SD- the data is clustered closely around the mean (more reliable)Cell Membrane- controls what comes in and out of the cellCell Wall- composed of cellulose and other carbohydrates, giving plant cells further support and a more rigid structure than animal cellsNucleus- the brain and control center of the cell:
contains DNA
controls all cellular functions in the cellNucleolus- small body found in the nucleus of eukaryotic cells where ribosomal RNA is synthesisedCytoskeleton- in the structural support;
