B4 The Processes of Life

B4 The Processes of Life

1. Cells

   • Animal Cells
     • Cytoplasm
       • Where most chemical reactions take place, including anaerobic respiration, the production of enzymes and other proteins
     • Mitochondria
       • Contain the enzymes needed for aerobic respiration
     • Nucleus
       • Contains the DNA that carries the genetic code for making enzymes and other proteins used in all chemical reactions in the cell
     • Cell Membrane
       • Allows chemicals like gases and water to pass in and out freely, but prevents other chemicals from leaving or entering the cell
   • Plant Cells
     • Cell wall
       • Made of cellulose to strengthen the cell
     • Permanent Vacuole
       • Helps support the cell
     • Chloroplasts
       • Contain the green pigment, chlorophyll (which absorbs light energy), and some enzymes needed for photosynthesis
   • Microbial Cells
     • Bacteria
       • Cytoplasm
         • Where proteins, including enzymes used in aerobic and anaerobic respiration, are made.
       • Circular DNA
         • The DNA floats freely int the cytoplasm.
       • Cell Membrane
         • Allows gasses and water to enter and leave the cell freely while acting as a barrier to other larger chemicals
       • Cell Wall
         • Gives strength to the bacterial cell
     • Yeast cells
       • cell wall
         • Gives the yeast cell strength
       • Nucleus
         • Contains DNA that carries the genetic code for making the enzymes needed in respiration
       • Cytoplasm
         • Where proteins including enzymes used in anaerobic respiration are amde
       • Mitochondria
         • Where aerobic respiration occurs

2. Enzymes

   • These are proteins which speed up the rate of chemical reactions.Cells produce enzymes according to the instructions carried in genes
     • Enzymes need a specific temperature to work at their optimum. At low temperatures, small increases in temperature cause an increase in the frequency
       • After the optimum enzyme activity is reached, the enzymes start to get damaged, so the reaction slows
         • Eventually the enzymes structure is permanently destroyed and it stops working, the enzymes has become denatured
   • Lock and Key model

3. Respiration

   • Aerobic Respiration
     • Aerobic respiration needs oxygen and occurs in animal cells, plant cells and many microbial cells.
     • C6H12O6+6O2=6CO2+6H2O+Energy/ATP
   • Anaerobic Respiration
     • Anaerobic respiration occurs in conditions of very low oxygen or where no oxygen is present.
       • Animal
         • Glucose=Lactic Acid+Energy/ATP
     • Plant + Yeast
       • Glucose=Carbon Dioxide+Ethanol+Energy/ATP

4. Molecule Synthesis

   • Glucose, produced in photosynthesis in plants, can build up into a polymer as cellulose (for building cell walls) or as starch ( stored in roots).
   • Glucose nitrates can be joined to make larger molecules of amino acids. In turn, amino acids can be joined together to make proteins.

5. Photosynthesis

   • 1). Light energy is absorbed by chlorophyll in green plants
     • 2). Within the chlorophyll molecule, the light energy is used to rearrange the atoms of carbon.
       • 3). oxygen is produced as a waste product.
   • Carbon dioxide+water+light energy/chlorophyll= glucose+ oxygen
     • 6CO2+6H2O+light energy/chlorophyll=C6H12O6+6O2
   • Limiting Factors
     • Temperature, as it rises so does photosynthesis but at 45 degrees the enzymes denature
     • Carbon dioxide concentration; the rise in carbon dioxide makes photosynthesis rise until it get to such a concentration where it stops.
       • Light intensity is the same as Carbon dioxide, more is better but it reaches a point where the plant can only photosynthesis a certain amount.

6. Diffusion

   • Diffusion is overall movement of substances from the regions of high concentration, to regions of low concentration.
     • Oxygen and carbon dioxide are exchanged in the leaf by diffusion of the gases in and out.
       • Substance that move in and out of cells by diffusion include oxygen, carbon dioxide and dissolved food.

7. Active Transport

   • Some chemicals can be moved by active transport. This is the movement of a substance against a concentration gradient, it requires respiration.

8. Osmosis

   • osmosis is a type of diffusion. It's the overall movement of water from a dilute solution to a more concentrated solution.
     • Happens through a Partially permeable membrane.