*Chapter 8- Section 1 Notes*

Section 1- How Organisms Obtain Energy

  • Transformation of Energy
-Energy is the ablility to do work.
-Thermodynamics is the study of the flow and transformation of energy in the universe.
-Chemical Potential Energy (think of it as a loaded spring)

  • Law of Thermodynamics
-First law - energy can be converted from one form to another, but it cannot be created nor destroyed.
-Second Law - energy cannot be converted without the loss of usable energy (heat, friction, sound, light, etc.)

  • Autotrophs and Heterotrophs
-Autotrophs are organisms that make their own food. Examples: plants, some protists (algae), and some bacteria.
-Heterotrophs are organisms that need to ingest food to obtain energy. Examples: animals, fungi, some protists (amoeba, paramecia), and some bacteria.

  • [[overlin6th:Margaret#|Metabolism]]
-All of the chemical reactions in a cell.
-Photosynthesis - light energy from the Sun is converted to chemical energy (glucose) for use by the cell
-Cellular respiration - are broken down to release energy for use by the cell.
-Glucose - C6H12O6 CH20

  • ATP: The Unit of Cellular Energy
-ATP - the "energy currency" of the cell.
-ATP stands for Adenosine Triphosphate
-ATP stores and releases a small amount ($1) of energy for movement, transport and other active processes in the cell.
-Both heterotrophs and autotrophs use ATP as an energy storage molecule in their cells.
-ATP is used to power processes in the cell such as the Calvin Cycle of photosynthesis in which CO2 is converted into glucose.
-Atp is also used for movement within the cell.
-It is produced during cell respiration when carbohydrates such as glucose are broken down.
-Energy is realeased when the third phosphate on ATP is removes and transferred to anotoher molecule.
-This leaves behind [[overlin6th:Margaret#|ADP]] (adenosine diphosphate)

*Chapter 8- Section 2 Notes*

Section 2 -Photosynethesis

-Photosynthesis - the process by which the energy of the sun is used to convert H2O and CO2 into high enrgy sugars (glucose).
-Importance - We need glucose and other carbnohydrates for energy but we cannot produce them oursleves. We also need oxygen and this is produced during photosysnthesis by plants and algae.

  • Light Energy:
-Light is a form of energy that travels in the form of particles or waves. The waves are measured in wavelengths, which vary in length. Humans can see violet through red wavelengths. (Remember "ROY G BIV")
-Color - Reflected light. We see color.
-Pigment - a molecule that absorbs light.
-Whatever colors the pigment does NOT absorb are what we see.

  • Pigments:
-Cholorphyll A is a pigment that ABSOBS violet, ted, and vlue wavelegnths of light.
-Green is REFLECTED by cholorphyll A. That's why most leabes appear green to us.
-Other pigments called Accessory Pigments (cholorphyll B, xanophyll, and carotene) help cholorphylll A absorb a greater spectrum of light.

  • Chloroplasts:
-Photosynthesis takes place in the chloroplast.
-A chloroplast is a double-membraned, disk-shaped organelle.
-located inside this disk are stacks of stacks.
-Each sack is called a thylakoid.
-Inside each thylakoid is chlorophyll and other pigments.
-Stacks of sacks are called grana.
-Surrounding the grana is a fluid called stroma