Identify the Independent and Dependent Variables from Questions
2012 Final Review
Identify the independent and dependent variables from questions
Know the difference between quantitative and qualitative
Chapter 1- Wade and Omar
- Describe the ten levels of the hierarchy of biological organization.
- Atom—chemical building blocks of all matter
- Molecule—made of atoms
- Organelle—components of cells
- Cell—basic unit of life
- Tissue—collection of cells with similar purpose
- Organ—specific arrangement of tissue
- Organ system—organs working together
- Organism—living being
- Population—organisms of same species
- Community—all living things in an area
- Ecosystem—all living and nonliving things in area
- Biosphere—all ecosystems as a whole (Earth)
- Distinguish between prokaryotic and eukaryotic cells. Name examples of each.
- Prokaryotic—simple; DNA loop; ribosome is only organelle; no membrane-bound organelles; found in bacteria and archaea
- Eukaryotic—complex; DNA in nucleus; many membrane-bound organelles; found in all non-microorganisms (like plants and animals)
- Contrast emergent properties with reductionism.
- Emergent properties—characteristics that appear in a level of organization due to the complex organization of lower levels
- Reductionism—taking apart something at a higher level of organization to see what gives it its properties at lower levels
- Contrast negative feedback with positive feedback.
- Negative feedback—when a reaction or process reaches a certain point, the body reacts oppositely to send it back to homeostasis; most feedback is negative
- Positive feedback—when a reaction or process strays from homeostasis, the body assists it and increases it (ex. pregnancy—contractions are increased, which strays further from equilibrium)
- Describe/contrast the three domains of life. Name example organisms in each.
- Bacteria—prokaryotic; most diverse and widespread; single-celled; ex. E. coli
- Archaea—prokaryotic; live in extreme environments; have much in common with eukaryotes; ex. microorganisms in hot springs
- Eukarya—all eukaryotic; consists of four kingdoms: Protista, Plantae, Fungi, Animalia; humans are of this domain
- Explain Darwin’s views on (a) “descent with modification” and (b) natural selection. Give examples.
- (a) All organisms on Earth have descended from a common ancestor; over billions of years, they have modified piece by piece. (b) Only the organisms that are strongest can live: “survival of the fittest”; organisms that are overshadowed by others will cease to exist
- Why is a hypothesis often framed in the form of “If…then”? What is the difference between a theory and a hypothesis?
- Deduction: the “if” part is a general statement, whereas the “then” is a specific possibility that can be tested; theories are comprehensive explanations of observations, whereas hypotheses are possible answers that can be tested
- What is meant by a “controlled experiment”?
- An experiment in which all variables are kept the same in each group (control and variable) being tested except for one variable
- Explain the eleven themes that pervade all of biology.
- Emergent properties—life has hierarchical organization, with properties emerging
- Cell—basic unit of life; prokaryotic and eukaryotic
- Heritable info—continuity of life depends on inheritance of biological info through DNA
- Structure & function—form and function correlate
- Environmental interaction—organisms are open systems that exchange materials and energy with surroundings
- Energy & Life—every organism does work, which requires energy
- Regulation—feedback maintains homeostasis and enhances activity when necessary
- Unity and diversity—all organisms are related, yet over time have changed increasingly
- Evolution—the Darwinian theory of natural selection says that adaptations over time have led to current life
- Scientific inquiry—observations lead to discovery and testing explanations through hypotheses and experiments
- Science, technology, and society—many technologies can apply to science; the relationships of science and technology to society are more crucial now than ever
Chapter 2- Vivian
Chapter 2 Chemical Context of Life
1. Describe the structure of an atom.
The atomic number of an atom is the number of protons found in the nucleus of that atom.
The atomic mass of an atom is the sum of the protons and neutrons in that atom when it is at rest. You get the atomic mass by adding the number of protons and neutrons together.
The equation for finding the number of neutrons in an atom is:
N = M – n
N = number ofNeutrons
M = atomicMass
n = atomicnumber
Atomic Charge is the charge of an atom. A normal atom has a neutral charge in where the number of electrons is equal to the atomic number, but an ion is an atom that with extra or missing electrons. When you are missing an electron you have a positive charge, when you have extra electrons you have a negative charge.
The outermost shell of an atom is called itsValence shell.The electrons of only this outermost shell are involved during chemical combinations; electrons are either given out from the outermost shell, or accepted into the outermost shell, or shared with the electrons in the outermost shell of another element.
Elements having same number of valence electrons in their atoms possess similar chemical properties. All alkali metals have one valence electron in their atom. Thus, their chemical properties are similar.
The number of the valence shell in an atom determines its position in the Periodic Table i.e. the period to which the element belongs.
Elements having 1, 2 or 3 electrons in the valence shell are metals. Exception is H and He. Elements having 4 to 7 electrons in their valence shell are non-metals.
Radioactive tracers also known as radio active isotopes are used to identify and treat diseases. These Isotopes can be used to detect the exact position of a blood clot or tumor in the human body once introduced into the system. These tracers can also be used to study the movement of ions across the membrane. They are even used in carbon dating to find the age of old living things.
Chemical Context of Life- Jared Davis
Question 2: Explain the different types of bonds between atoms. Give an example of each. Then rank them from strongest to weakest.
- Covalent (polar versus nonpolar)
-A covalent bond is the sharing of a pair of valence electrons by two atoms.
-A nonpolar covalent bond is a bond in which the electrons are equally shared (occurs when the atoms in the bond are equally electronegative - the attraction of an atom for the electrons of a covalent bond.) for example: a bond between two oxygen molecules.
-A Polar Covalent bond is one in which the electrons are not shared equally. A water molecule is an example of a molecule bonded through a Polar Covalent bond.
- Ionic
-A charged atom (or molecule) is called an ion.
-A positively charged ion is called a cation, while a negatively charged ion is called an anion.
-An Ionic Bond is a chemical bond resulting from the attraction between oppositely charged ions.
-Salts are compounds formed by ionic bonds and are called Ionic Compounds.
- Hydrogen
-A Hydrogen Bond a type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
-Water molecules bond together through Hydrogen bonding.
- Van der Waals interactions
-Van der Waals Interactions – weak attractions between molecules or ports of molecules that are brought about by localized charge fluctuations.
-Vad der waals Interactions also play a role in the bonding between water molecules.
Strength Ranking
- Covalent bonds
- Ionic bonds
- Hydrogen Bond
- Van der Waals Interactions
Chapter 3- William Tarte
Water and the Fitness of the Environment
1. Water is H2O the two hydrogens bond with the oxygen on top if the molecules kind of like ears. This molar structure gives the molecule polarity which attracts other atoms to it. One side has a positive charge and the other is negative and it attracts its opposites. This is what makes water so unique.
• it's polar structure: it is polar because the two hydrogens are on top and the oxygen is on bottom which makes it so the top of the water molecule has a positive charge and the bottom is negatively charged making it polar.
• Ability to Ron H-bonds: hydrogen bonds happen when hydrogen atoms are attracted to a negatively charged atom. Normally it bonds with oxygen and nitrogen.
•Cohesive properties: cohesion is hen water is attracted to water. In liquid form the hydrogen bond is weak so it keeps forming and breaking bonds, but these bonds are what hold the water together
•Adhesive bonds: adhesion is the clinging of one substance to another. When water evaporates from leaves it pulls up the other water molecules this kind of counteracts the pull of gravity.
2.
3. a. Be very specific in defining what the pH scale is in terms of hydrogen and hydroxide ions.
In a solution there is a certain concentration of hydrogen ions and hydroxide ions produced from the splitting of water. When this concentration of hydrogen ions and hydroxide ions are the same then the pH of the solution are 7 and neutral. As the concentration of hydrogen ions increases the pH goes up and becomes for acidic. As the hydroxide ions concentration increase the pH goes down and becomes more basic.
b. How do buffers minimize changes in pH? Give an example:
A buffer acts as a donor or acceptor of hydrogen ions. For example if an acidic solution is added to a buffer solution then the buffer will accept hydrogen ions and make the solution more basic. The same is for a basic solution only hydrogen ions are donated to make the solution acidic. An example of a buffer is ethanoic acid and sodium ethanoate.
4. Describe the causes and effects of acid precipitation,
Acid precipitation is caused by the burning of fossil fuels and the gasses they release mixing with water vapor such as sulfur dioxide. This turns into sulfuric and nitric acid which falls as acid rain causing the environment to be weaken, sickness to spread and corrosion of buildings
Chapter 4 – Jason & Charlie
Carbon and the Molecular Diversity of Life
- Carbon is a highly diverse atom. It can bond to all of the other major elements of life such as C, H, O, N, and S. Due to its unique bonding structure it can bring these biologically essential elements together in a variety of ways which allow organisms to be so wonderfully diverse.
Carbon has 6 total electrons. There are 2 in the first electron shell and 4 in the second electron shell. That means carbon has 4 valence electrons which leaves 4 empty spots since the second shell may contain 8 electrons. Since there are 4 valence electrons, Carbon has little tendency to gain or lose electrons because most atoms will not take or give 4 electrons at a time. Instead of bonding with one atom carbon can bond with four other atoms and acts as the intersection between them. This ability to bond 4 ways is called tetravalence, which is a special characteristic of carbon that makes it so diverse when constructing macromolecules.
Carbons are vital in forming hydrocarbons. Hydrocarbons are organic molecules that consist of only carbon and hydrogen. In these hydrocarbons, hydrogen atoms are attached to a carbon skeleton. Hydrocarbons cause the hydrophobic behavior of fats.
The following functional groups increase the solubility of organic compounds in water.
1. hydroxyl- In this group a hydrogen atom is bonded to an oxygen atom which is bonded to the carbon skeleton. This group is present in alcohols.
2. carbonyl- In this group a carbon atom is joined to an oxygen atom by a double bond. If the carbonyl group is at the end of a carbon skeleton the organic compound is called an aldehyde. If not, the organic compound with carbonyl in it is called a ketone.
3. carboxyl- In this group an oxygen atom is bonded to a carbon atom that is bonded to a hydroxyl group. This whole assembly of atoms is called a carboxyl group. Carboxyl groups are present in carboxylic acids (organic acids).
4. amino- In this group a nitrogen atom is bonded to two hydrogen atoms and to the carbon skeleton. Organic compounds in this group are called amines. This group is present in glycine.
5. sulfhydryl- In this group a sulfur atom is bonded to a hydrogen atom. This group has a similar shape to that of the hydroxyl group. Organic compounds containing sulfhydryls are called thiols.
6. phosphate- In this group a phosphate ion is covalently attached by an oxygen atom to the carbon skeleton. This can be found in ATP.
Chapter 5- Luis
The structure and Function of Macromolecules
- Contrast condensation (dehydration) with Hydrolysis reactions. Give an Example of each.
A similarity: both reactions occur in the human body and both reactions have to do with water.
Differences: In Dehydration reactions (Condensation), water is removed to join two molecules together. Ex: the condensation of ethanol to form ether: 2CH3CH2OH (CH3CH2)2O + H2O
Hydrolysis is the opposite. A water molecule is added to break apart two molecules.
Ex: Alkyl halide to alcohol : R-Cl + H2O ROH + H+ + Cl-
- Name the monomers that compose each of the following: carbohydrates, lipids, proteins and nucleic acids.
Carbohydrates – Monosaccharides
Lipids – glycerol and 3 fatty acid molecules
Proteins – Amino Acids
Nucleic Acids – Nucleotides
- Distinguish between and give examples of :
a)Monosaccharides, disaccharides and polysaccharides
Monosaccharide - A monosaccharide is the simplest sugar, a sugar building block. This is something like glucose, fructose, or galactose.
Disaccharide - If you put two monosaccharides together and let them bond, they form a disaccharide, like maltose or sucrose or lactose.
Polysaccharide - A polysaccharide is basically a chain of monosaccharides bonded together. This is something like cellulose.
b)Glucose and Sucrose
Glucose - Its chemical formula is C6H12O6. If this is re-written as C6(H2O)6 – it is seen that it is a hydrate of carbon. It is a simple monosaccharide.
Sucrose - Sucrose is a disaccharide formed from glucose and fructose. It is also a carbohydrate its formula is C12H22O11 or C12(H2O)11. The molecules are joined by loss of water to give the disaccharide sucrose.
c)Starch, glycogen, cellulose and chitin
Starch: it is a polymer of glucose monomers. Synthesizing starch enables the plant to stockpile surplus glucose. It is known as “stored energy” in plants.
Glycogen: a polymer of glucose, also known as “stored energy” in animals.
Cellulose: like starch, cellulose is a polymer of glucose but the glycosidic linkages in these two polymers differ. Cell walls of plants are an example of cellulose.
Chitin: carbohydrate used by insects to build exoskeletons. Similar to cellulose except that the glucose monomer of chitin has a nitrogen containing appendage.
d)Fatty acid and glycerol
Fatty acid : fatty acids are long chains of carbons (C16-C20) with a Carboxyl acid group at the end which can be made up to for a larger macromolecule called triglycerides.
Glycerol: it is only a 3 carbon molecule with 3 OH groups. Its function in biology is to be the backbone to triglycerides.
e)Saturated and Unsaturated fatty acids
Saturated fatty acids:saturated fatty acids are solid at room temperature. They are linked by single bonds. They’re commonly known as the “bad” fatty acids.
Unsaturated fatty acids:they are liquid at room temperature andhave some double bonds. The double bond is a prominent characteristic of unsaturated fatty acid chains, as there is a “bend” in the chain.
f)Fat and Phospholipid
Fat: made of triglycerides, where all three hydroxyl groups are attached to fatty acid chains.
Phospholipid: Like fats (triglycerides), but the third hydroxyl group of gycerol is linked to a phosphate group instead of another fatty acid. In phospholipids, a small polar or charged nitrogen-containing molecule is attached to this phosphate. The gycerol "backbone", phosphate group, and charged molecule constitute a polar hydrophilic region at one end of the phospholipid,
g)Polysaccharide and Polypeptide What are polysaccharides function?
Polysaccharide: a long string of sugar building blocks, forming a large, complex sugar molecule.
Polypeptide: a long chain of amino acids, forming a protein.
h)DNA and RNA
DNA: DNA (deoxyribonucleic acid) is double stranded (double helix).The two strands are complementary to each other (G with C and A with T). DNA codes for everything, sometimes directly, but often indirectly. It even codes for RNA.
RNA: RNA (ribonucleic acid) is single stranded. RNA is made up of base pairs (so is DNA). 3 base pairs comprise a codon, which codes for different amino acids, which make up proteins. So with the help of ribosomes, RNA makes proteins. Also there are three types of RNA, rRNA (ribosomal RNA) mRNA (messenger RNA) and tRNA (transfer RNA) which are complementary to each other when making a protein, this time however the A is not complementary with T, but instead it is complementary with U.
i)Purine and Pyrimidine
Purine: A nitrogenous base, Purines have a two ring structure and it is the bigger of the two. The Purines in DNA are Adenine and Guanine. In RNA, the purines are the same as DNA.
Pyrimidine: A nitrogenous base, Pyrimidine is a one ring structure, smaller than purine. In DNA, the Pyrimidines are thymine and cytosine, while in RNA they are Uracil and Cytosine. Uracil is the RNA substitute for Thymine.
j)Nucleoside, Nucleotide and Nucleic Acid
Nucleoside: Any of various compounds consisting of a sugar, usually ribose or deoxyribose, and a purine or pyrimidine base, especially a compound obtained by hydrolysis of a nucleic acid, such as adenosine or guanine.
Nucleotide:Any of various compounds consisting of a nucleoside combined with a phosphate group and forming the basic constituent of DNA and RNA.