Biological Science Lab Review (5-9)

• Brownian Movement: when molecules move randomly, they are constantly colliding with other molecules
• Diffusion: the movement of molecules from an area of high concentration to an area of low concentration
• semi permeable membrane: a membrane that decides what molecules can go in and out of the cell
• Osmosis: a proccess by which two soultions of different conectrations on opposite sides of a semipermeable membrane. Solvent (dissolving agent) can pass but the solute (dissolved particle) cannot.
• hypotonic: a solution with a lower solute concentration than the cell
• Lyse: bursting of cell
• hypertonic: having a higher concentraion of solutes than the cell
• isotonic: the same concentration of solutes in the inside and outside of the cell
• rate of osmosis: the speed at which water moves along a concentration gradient . which is determined by the temerperature and the size.
• cellular respiration: the process by which glucose or food is broken down to release energy .
• The process of cellular resperation is the the grouping of enzyme reactions forming 3 pathways: glycolysis, krebs cycle and electron transport chain (oxidation)
• Plants produce glucose by photosynthesis and respiration.
• first step in glucose metabolism is glucose is converted to glycogen
• Fermentation: another method to generate ATP when oxygen isn't avaiable . It produces 2 ATP rather than 36 .
• When oxygen isn't avaiable, pyruvate (which is a product of glycolysis) is reduced by NADH, regenerating NAD+ and can re-enter the glycolysis pathway.
• Organisms can be divided into two catagories based on how they obtain their nutrition: autotrophs and heterotrophs
• Autotrophs: are organisms capable of synthesizing carbohydrates from CO2 (carbon dioxide), using sunlight as the energy source.
• Heterotrophs: organisms that obtain energy from other organisms
• In all organisms, autotrophs and heterotrophs, carbohydrates are broken down to release energy that is used to power all the cell’s activities
• chloroplast in plant leaves: harnesses the energy of sunlight and convert it to chemical energy
• Photosynthesis consists of two linked processes called the light reactions and the calvin cycle.
• Light reaction occur when the light splits water into oxygen and hydrogen
• the light reactions also form energy in the form of ATP by the process of photophosphorylation
• The calvin cycle is where sugar is made
• Photosynthesis: 6CO2 + 6H2O --> C6H12O6 + 6O2
• plants store glucose as starch while animals store it as glycogen
• plants must contain pigment molecules capable of absorbing light waves in order to use the energy they contain for photosynthesis.
• All photosynthetic organisms contain one primary photosynthetic pigment, chlorophyll a
• accessory pigments, such as chlorophyll b, carotene, xanthophylls, phycoerythrin, phycocyanin, assists by transferring the light energy that they absorb to chlorophyll a.
• Autotrophs that can photosynthesize contain organelles called chloroplasts, where photosynthesis takes place.
• thykaloid discs aare distributed throught the stroma (The semi-fluid internal substance)
• mitosis: the process of cell division that results in two identical daughter cells
• meosis: produces nonidentical haploid cells
• Both mitosis and meiosis involve a duplication and division of the nuclear material
• cell cycle: the series of events that occur in a cell to produce a new cell
• The majority of the cell’s life is spent in interphase
• G1: the cell grows and prepares for DNA replication.
• S phase: DNA replication, DNA is copied and chromosomes are duplicated
• G2: the cells prepare to be divided by mitosis
• During S phase, a cell duplicates (doubles) DNA so that, by the end of S phase, it has 4 copies of each chromosome.