1. Hierarchy of Ecological Organizational Levels: individual < population< community < ecosystem < biosphere
Each higher level includes all of the levels underneath it. Populations are made up of individuals and communities are made up of several populations, etc. Review this on pgs 10-12 in the OpenStax textbook. We will be returning to this topic in Week 7 when we discuss Ecology.
2. Control Group vs. Experimental Group: Control groups are an important part of an experiment. The control group is sometimes refe
ed to as the Experimental Control. This is the group that does not get the independent variable and is used as a baseline or comparison for your experimental group that does get the independent variable. See the Scientific Method Tutorial to review this under item 4, the scientific method.
3. Energy Flows while Matter (nutrient, molecules, atoms) is recycled: This is a recu
ing theme in biology. Energy is not made up of matter, so it can only be transfe
ed or changed from one form to another (light to heat or chemical energy to heat and work). Matter on the other hand has mass, is composed of atoms, and takes up space. Atoms can recombine to form different molecules, and are continually reused in living systems.
4. Independent vs. Dependent Variables: the independent variable is what you are manipulating or changing in the experiment, while the dependent variable is the outcome you are observing. See the Scientific Method Tutorial to review this under item 4, the scientific method. You can also watch this short movie on Scientific Variables.
5. Subatomic Particles and Properties of Atoms: Here are a few things to remember about subatomic particles and atoms. First, the number of electrons in an atom equals the number of protons (atoms are neutral so the number of negatively charged particles, electrons, is the same as the number of positively charged particles, protons). The atomic number is equal to the number of protons in an atom. Atomic mass is equal to the number of protons plus the number of neutrons (which have no charge). Protons and neutrons are found in the nucleus or core of the atom while electrons o
it around the atom’s nucleus. Review pgs XXXXXXXXXXin the OpenStax Textbook.
6. Number of Electrons in Electron Shells: The first electron shell can hold up to two electrons, while the second and third can each hold 8. The outermost shell of electrons is call the valence electron shell, and the electrons here are the ones that can for chemical bonds. This is
iefly discusses on pg 31 in the OpenStax textbook.
7. The Difference between Ionic, Covalent and Hydrogen bonds: Chemical bonds are discussed on pgs.31-33 in the OpenStax textbook. Understanding the differences among these types of chemical bonds is important for understanding the properties of biological macromolecules as well as the properties of cell mem
anes and mem
ane transport. Remember that hydrogen bonds are responsible for the 3D shape of nucleic acids and proteins. You can also look at my Chemical Bond Cheat Sheet found in the Week 1 Course Content area of our LEO classroom.
8. Emergent Properties: This is a property that emerges or comes to exist only when component subparts are joined together in a certain way and that does not exist in any of the subparts alone. Any one of the subcomponents of a cell (DNA, cell mem
ane, cytoplasm, etc.) is not alive, but when they are joined together, a cell is able to live.
9. The Properties of Water: There are several unique properties of water that make it essential for life and living organisms. They are discussed on pgs XXXXXXXXXXin the OpenStax textbook. Review these properties. Also, there is a nice summary provided here: The Properties of Water.
10. Hierarchy of Atoms to Organism: Remember that subatomic particles < atoms < molecules < organelles < cells < tissues < organs < organ systems < organisms/individuals. You could finish this is what is listed in item 1 above. Again, refer to pgs 10-12 in the OpenStax textbook to review this. The point is that larger, more complex things are composed of simpler, smaller things.
11. The Charge of Atoms (when they become ions): When atoms gain or lose a valence electron they become charged atoms, which are called ions. This was discussed
iefly on pg. 31 in the Openstax textbook. Here are few rules to help you determine what type of ion an atom will become. All atoms in column 17 of the periodic table contain 7 electrons in their valence shell; therefore, they will gain one electron to complete their shell giving them a charge of -1. They become anions. All atoms in column 16 of the periodic table contain 6 electrons in their valence shell; therefore, they will gain two electrons to complete their shell giving them a charge of -2. They become anions. All atoms in column 1 of the periodic table contain 1 electrons in their valence shell; therefore, they will lose one electron to empty their shell giving them a charge of +1. They become cations. All atoms in column 2 of the periodic table contain 2 electrons in their valence shell; therefore, they will lose those electrons to empty their shell giving them a charge of +2. They become cations. What happens in the middle of the periodic table gets to be confusing. For our purposes, you should know that Ca
on atoms have 4 electrons in their valence shell and ca
on atoms for only covalent bonds not ionic bonds.
12. Cells are the fundamental unit of life: There is no getting around this one. The cell is the first organization unit or hierarchical level where the property of life exists. Memorize this! The cell is the basic unit of life.
13. Definition of homeostasis: We will be returning to the topic of homeostasis in upcoming weeks. We define homeostasis as the tendency of organisms and cells to maintain stable internal conditions. The term comes from the Greek words homeo (same, alike) and stasis (standing). This will be further discussed in Chapter 16 of the Openstax textbook.
14. Common traits of Ca
on, Oxygen, Nitrogen and Hydrogen atoms: These atoms all have unpaired valence electrons which allow them to readily for bonds with each other as well as other atoms. These are important atoms in biology.
15. Polarity and Electronegativity: Electronegativity (The ability of an atom to draw shared electrons closer to itself. Strongly electronegative atoms bonded to weakly electronegative hydrogen atoms, in a molecule, result in hydrogen bonding. The most important strongly electronegative elements in biological systems are oxygen and nitrogen) is the property of an atom that allows for the formation of polar covalent bonds. Hydrogen bonding forms between two polar molecules. Revisit pg. 32 and 33 in the Openstax textbook.
16. The Characteristics of Life: This too is on you cannot get around. Memorize the 8 Characteristics of Life found on pgs. 6-9 in the OpenStax textbook.
17. Solutes vs. Solvents: Solvents are the majority of the solution (what a solute is dissolved into). Solutes are the component(s) that make up less of the solution. You make a salt water solution. Water is the solvent while sodium chloride (NaCl), table salt, is the solute. This was mentioned
iefly on pg. 36 because water is an excellent solvent. Chapter 3 of the OpenStax textbook will go into more detail.
18. Isotopes: Isotopes are different forms of the same atom that have identical numbers of protons, but different numbers of neutrons. The isotope with the non-typical number of neutrons is radioactive. See pg. 29 in the OpenStax textbook to review.
19. The pH Scale: Review pgs XXXXXXXXXXin the OpenStax textbook. Acids donate H+ ions when dissolved in water while bases donate OH- ion when dissolved in water. The pH scale ranges from 1-14. If the pH is <7 the substance is an acid. If the pH is >7 the substance is a base. A pH of 7 is neutral because it contains equal numbers of H+ and OH- ions. Remember that the pH scale is logarithmic meaning that there is a 10-fold different in the number of hydrogen atoms between each pH unit. If you compare a solution at pH 4 and a solution at pH 2, the pH 2 solution has 100 times as many hydrogen atoms (these solutions differ by 2 pH units, so there is a 102 = 100 fold difference in the number of hydrogen atoms). Likewise, when comparing two bases at pH 8 and 10, the solution at pH 8 has 100 times more hydrogen ions as compared to the pH 10 solution.
20. The Purpose of Experiments: The purpose of experimentation is to disprove a hypothesis. See pg 26 in the OpenStax textbook.
21. The Hierarchy of the Linnean Taxonomic Classification of Organisms: See pgs XXXXXXXXXXin the OpenStax textbook. Remember that the most
oad classification is the Domain and the most na
ow is the species. The order is as follows: Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species.
22. Natural Law vs. Scientific Theory: See pg. 18 of the OpenStax textbook to review these definitions. A Natural Law is a summary of observed behaviors in nature (think the Law of Gravity). A Scientific Theory is a proposed explanation or working model for why a behavior occurs.
23. Prokaryotic vs. Eukaryotic Cells: These terms are introduced on mg. 10 in the OpenStax textbook. They will be covered more in depth in Chapter 3. Remember that the biggest difference between the two is that Eukaryotic cells contain a nucleus and mem
ane bound organelles while prokaryotic cells do not.
24. Define pH: pH is the measurement of the acidity of a solution. Acids are solution where the concentration of hydrogen ions (H+) is greater than the concentration of hydroxide ions (OH-). This of pH as “parts hydrogen”.
25. Litmus paper: This is one way in which we can determine whether or not a solution is acidic or basic. Red litmus paper will turn blue (blue for base) when put in a base. Red litmus paper stays red in an acid. Blue litmus paper turns red when put in an acid.
26. Buffers: Buffers are solutions that contain substances in them that allow the pH of the solution to be maintained when small amount of acids or bases are added to them. Typically, buffers can either give off a hydrogen ion to “buffer” the solution if a base is added, and they can give off a ion that will bind up excess hydrogen ions to “buffer” the solution if an