BSC 242 Exam 1 Study Guide
1. Know that microbial individuals are too small to be seen with the naked eye.
2. Know the Linnaeus system for the classification of organisms and how to correctly “format” scientific genus and species names.
∙ The genus is the first name and is always capitalized.
∙ The species name is second and is not capitalized.
∙ Both are underlined or italicized.
∙ After mentioning the full name once, the name may be abbreviated to the initial of the genus and the species name.
3. Know difference between viruses and cellular organisms.
DNA or RNA core
Cell membrane, cytoplasm, nucleus, organelles
Reproduces only in a host cell
Perform metabolism and use energy
If you want to learn more check out What are the themes of biology?
4. For cellular organisms, know the “3 domain” system of
∙ Bacteria – cell walls contain peptidoglycan (protein + carbohydrate complex) Don't forget about the age old question of What refers to the total amount of energy expended?
∙ Archaea – cell walls lack peptidoglycan
∙ Eukarya – includes protists, fungi, plants, and animals
5. Know “cell theory”
All living things are comprised of cells.
6. What is spontaneous generation?
The idea that some forms of life could arise spontaneously from nonliving matter.
7. Why did Pasteur perform the experiment with the S-shaped flask?
The design allowed air to pass into the flask but the curved neck trapped any airborne microorganisms that might contaminate the broth.
His experiment demonstrated that microorganisms are present in the air and can contaminate sterile solutions but that air itself does not create microbes – disproved spontaneous generation.
8. What is aseptic (sterile) technique?
Techniques that prevent contamination by unwanted microorganisms
9. What is contamination?
Introduction of infectious material like bacteria, yeast, mold, fungi, virus, prions, protozoa or their toxins and by-products.
10. What is fermentation?
Microorganisms (yeasts) converting sugar to alcohol in the absence of air.
11. What is pasteurization?
Heating substances just enough to kill most of the bacteria that might cause spoilage. If you want to learn more check out Which is more important: liberty or security?
12. What is a vaccine?
A living viral agent used for preventive inoculation.
13. What is an antibiotic?
Chemicals produced naturally by bacteria and fungi to against other microorganisms.
14. Be able to define the terms Bacteriology, Mycology, Parasitology. Immunology, and Virology.
∙ Bacteriology = study of bacteria
∙ Mycology = study of fungi
∙ Parasitology = study of protozoa and parasitic worms
∙ Immunology = study of immunity
∙ Virology = study of viruses
15. What is bioremediation and how does it involve microbes?
Using bacteria that produce enzymes to break down toxins into less harmful substances. For example, removing toxins from underground wells, chemicals spills, oil spills, etc. Sometimes microorganisms indigenous to the environment are used, other times modified microbes are used.
1. What are the 3 subatomic particles of an atom?
Proton, electrons, and neutrons.
2. What makes up the atomic number?
The number of protons in the nucleus
3. What makes up the atomic mass?
The number of protons and neutrons in the nucleus. Don't forget about the age old question of How do you interpret marginal rate of substitution?
4. What is the difference between a covalent bond and an ionic bond?
An ionic bond is an attraction between ions of opposite charge that holds them together to form a stable bond. One atom loses an electron and one atom gains an electron.
A covalent bond is formed by two bonds sharing one or more pairs of electrons. They are stronger and more common than ionic bonds.
5. What is a hydrogen bond?
A hydrogen, that is covalently bonded to an oxygen or nitrogen, is attracted to another oxygen or nitrogen atom. They serve as bridges between different molecules or portions of the same molecule (i.e. within proteins and nucleic acids). They are broken and formed relatively easily.
6. Which two elements are found in all organic compounds? Carbon and hydrogen.
7. Which 4 elements make up greater than 95% of an organism’s weight?
Oxygen, carbon, hydrogen, and nitrogen. Don't forget about the age old question of Is it better to have an episiotomy or tear?
We also discuss several other topics like What does a linear equation represent?
8. What are the basic properties of water?
∙ Cohesion – water molecules stick together. Used for movement of water in plants
∙ Adhesion – water sticks to another substance
∙ Solvent – can dissolve many substances
∙ High heat capacity - absorbs a large amount of energy/heat without much change in temperature
9. What are acids and bases?
∙ An acid
o is a substance that dissociates into one or more hydrogen ions and one or more negative ions.
o A proton (H+) donor
∙ A base
o Dissociates into one or more positive ions (cations) plus one or more negatively charged hydroxide ions (OH-) that can accept or combine with protons
10. What is a pH value?
The amount of H+ in a solution.
11. What is a “salt”?
A substance that dissociates in water into cations and anions, neither of which is H+ or OH-. Salts are held together by ionic bonds.
12. Table 2.4 on page 35 (know the overall structure, the name of the group, and its biological importance).
13. Know the four biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids). What are their monomers? Know the biological examples of each group that were presented in the lecture.
∙ Carbohydrates –
o Monomer: monosaccharides
o Polymers: starch, sugars
∙ Lipids –
o Monomer: fatty acid + glycerol
o Polymers: triglycerides
∙ Proteins –
o Monomer: amino acids
o Polymers: proteins
∙ Nucleic acids –
o Monomer: nucleotides
o Polymers: DNA and RNA
14. What does hydrophobic and hydrophilic mean? Hydrophobic means “water fearing” and hydrophilic means “water loving”.
15. What is dehydration synthesis?
When two monomers join, eliminating a hydrogen from one monomer and a hydroxyl from the other, releasing a molecule of water.
16. At the molecular level, what is the difference between saturated and unsaturated lipids?
Unsaturated lipids have at least one double bond.
17. Why are proteins important to cellular metabolism? They increase the rate of the reaction.
18. In proteins, what is primary, secondary, tertiary, and quaternary structure?
19. What is protein denaturation?
When a protein unravels, and loses some of its characteristics due to encountering a hostile environment in terms of temperature, pH, or salt concentration.
20. Why is DNA important to living organisms?
It is the substance of which genes are made.
21. What are the differences between DNA and RNA?
Double stranded in cells and most DNA viruses Single stranded in some viruses (paraviruses)
Single stranded in cells and most RNA viruses Double stranded in some viruses (reoviruses)
Sugar is deoxyribose
Nitrogen bases are
cytosine, & guanine
Sugar is ribose
Nitrogen bases are
cytosine, & uracil
Determines all hereditary traits
22. What is ATP?
Adenine triphosphate is the principle energy carrying molecule of all cells. It stores the chemical energy released by some chemical reactions and
provides the energy for reactions.
1. Know the differences between prokaryotes and eukaryotes.
DNA is not enclosed in a membrane DNA is a singular circularly
Not associated with histones
DNA is found in the cell’s nucleus, which is separated from the
cytoplasm by a nuclear membrane DNA is found in multiple
DNA is associated with histones (chromosomal proteins) and
No membrane bound organelles
Membrane enclosed organelles (i.e. ER, mitochondria, golgi complex, lysosomes)
Divide by binary fission
Cell division involves mitosis
Cell walls contain peptidoglycan (complex polysaccharide)
Cell walls are chemically simple
2. What are the three basic shapes of bacterial cells?
∙ Spherical coccus
∙ Rod shaped bacillus
3. Be able to define the terms monomorphic and pleomorphic.
Monomorphic bacteria maintain a single shape. Pleomorphic can have many shapes.
4. What is a glycocalyx?
∙ The general term used for substances that surround cells. ∙ It is a viscous (sticky), gelatinous polymer that is external to the cell wall and composed of polysaccharide, polypeptide, or both.
∙ If it is organized and firmly attached to the cell wall, it is a capsule. ∙ If it is unorganized and loosely attached to the cell wall, it is a slime layer.
5. What are flagella? Know the definition of monotrichous, lophotrichous, amphitrichous, and peritrichous.
Flagella are long filamentous appendages that propel bacteria.
6. What is chemotaxis?
The movement of bacteria toward or away from chemical stimuli.
7. What is phototaxis?
The movement of bacteria toward or away from light stimuli.
8. What are endoflagella, fimbriae, and pili? Each of these are different. What are they used for?
∙ Endoflagella (axial filaments)
o Bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell
o Can occur at the poles of the bacterial cell or can be evenly distributed over the entire surface of the cell.
o Vary from a few to hundreds per cell
o Tend to adhere to each other or surfaces
o Longer than fimbriae
o Only one or two per cell
o involved in motility (twitching motility or gliding motility) and DNA transfer
9. For prokaryotes:
a. What comprises the cell wall in bacteria?
A peptidoglycan cell wall composed of disaccharides and amino acids
b. What is the purpose of the cell wall?
It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
c. What is the difference between gram-positive and gram negative bacteria?
∙ Gram positive = thick peptidoglycan layer with teichoic acids = stain purple
∙ Gram negative = thin peptidoglycan layer (without techoic acids) surrounded by a thick plasma membrane. = stain red
d. What comprises the cell (plasma) membrane? What is its purpose?
It consists of the lipid bilayer with embedded proteins. It is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells, and to protect the cell from its surroundings.
e. Define diffusion, facilitative diffusion, active transport, and osmosis.
∙ Diffusion is the net passive movement of particles (atoms, ions or molecules) from a region in which they are in higher
concentration to regions of lower concentration until the
concentration of substances is uniform throughout.
∙ Facilitated diffusion is the process of spontaneous passive transport of molecules or ions across a cell's membrane via
specific transmembrane integral proteins.
∙ Active transport is a kind of transport where ions or molecules move against a concentration gradient using energy and a
∙ Osmosis is the movement of water molecules through a
selectively permeable membrane from higher water
concentration to a lower water concentration - or - down a
f. Which one requires energy (ATP)?
g. Know the difference between isotonic, hypotonic, and hypertonic solutions.
∙ Isotonic solution refers to two solutions having the same osmotic pressure across a semipermeable membrane.
∙ A hypotonic solution is one in which the concentration of solutes is greater inside the cell than outside of it
∙ A hypertonic solution is one where the concentration of solutes is greater outside the cell than inside it
h. What is cytoplasm?
The material within a living cell, excluding the cell nucleus.
i. What is a nucleoid?
An irregularly shaped region that houses genetic material found only in prokaryotes.
j. How is it different from a nucleus?
The nucleoid is not bound by a membrane.
k. Know that prokaryotic ribosomes are smaller than eukaryotic ribosomes
l. What is an endospore?
A dormant, tough, non-reproductive structure produced by a small number of bacteria to ensure the survival of a bacterium through periods of environmental stress.
10. For eukaryotes:
a. What comprises the eukaryotic cell wall?
∙ In algae and plant cells, the cell wall is usually composed of cellulose.
∙ In molds, it is composed of chitin and/or cellulose.
∙ Animal cells and protozoans lack cell walls
b. How is it different than the prokaryotic cell wall?
The cell walls of prokaryotes are generally formed of peptidoglycan (carb +protein complex). For eukaryotes, the walls are made of cellulose (plants) or chitin (fungi).
c. Be able to define cytoplasm, cytosol, cytoskeleton and cytoplasmic streaming.
- Cytoplasm is the material within a living cell, excluding the nucleus
- Cytosol is the aqueous component of the cytoplasm of a cell
- Cytoskeleton is made up of microtubules, actin filaments, and intermediate filaments. These structures give the cell its shape and help organize the cell's parts. In addition, they provide a basis for movement and cell division
- Cytoplasmic streaming is the movement of the cytoplasm within a plant or animal to transport nutrients, proteins, and organelles within cells.
d. Be able to define the function of all of the membrane bound organelles
Control Center of the cell.
Contains the cell's DNA (genetic information) in the form of genes
Contains one or more nuclei for the biosynthesis of ribosomal RNA and production (assembly) of ribosomes
Consists of many interconnected membranous sacs called cisternae, onto whose external surface ribosomes are attached
Ribosomes produce polypeptides that are inserted into the RER membrane, moved into the lumen (central region) of the cisternae, or moved to the Golgi complex and probably onwards from there
Consists of many interconnected membranous sacs called cisternae (without ribosomes)
Helps with protein folding and transport of synthesized proteins
Glycosylation - which involves the attachment of oligosaccharides.
Disulfide bond formation and rearrangement to stabilize the tertiary and quaternary structure of many proteins
Modification of some drugs
Production of energy by synthesis of ATP
Processing and storage of calcium ions (Ca2+). Apoptosis, i.e. the process of programmed cell death Regulation of cellular metabolism
Synthesis of certain steroids
Sites of photosynthesis within plant cells
Modifies, sorts and packages macromolecules for delivery to other organelles or secretion from the cell via exocytosis
Tiny sacs containing enzymes.
Main sites of intracellular digestion
Destroy the cell after it has died.
Breakdown of fatty acids by beta-oxidation
Breakdown excess purines to urea
Breakdown of toxic compounds in the cells of the liver and kidney.
Play a role in the biosynthesis of certain important molecules incl. cholesterol and (in liver cells) bile acids derived from cholesterol
Transport and delivery of their contents (e.g. molecules such as hormones or neurotransmitters) either into or out of the cell via the cell membrane.
Exocytosis - movement of the contents of secretory vesicles out of the cell.
Endocytosis - movement of the contents of secretory vesicles into the cell
Helps maintain turgor pressure (turgidity) inside the cell - which pushes the plasma membrane against the cell wall. Plants need turgidity to maintain rigidity.
e. Be able to explain endosymbiotic theory.
It states that some organelles were once independent prokaryotic organisms (chloroplast and mitochondria) and that these organisms (mitochondria) were consumed by larger prokaryotic organisms.
1. What is metabolism?
The chemical processes that occur within a living organism in order to maintain life.
2. What is the difference between catabolism and anabolism? ∙ Catabolism involves all of the metabolic processes that tear down biomolecules
∙ Anabolism is all of the metabolic processes that build biomolecules.
3. What molecule is used as an energy source for all biological organisms?
4. What are enzymes?
∙ Enzymes are macromolecular biological catalysts.
∙ Enzymes accelerate chemical reactions.
∙ The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products.
5. Know how collision theory relates to activation energy and reaction rate.
According to collision theory, the rate at which molecules collide will have an impact on the overall reaction rate. If the molecules do not collide with
sufficient energy or in the right orientation, the reaction will not occur. If they do not have sufficient energy, they cannot overcome the activation energy.
6. How does temperature and pressure affect reaction rate? ∙ Pressure:
o Increasing the pressure on a reaction involving reacting gases increases the rate of reaction because you squeeze it into a smaller volume.
o Changing the pressure on a reaction that involves only solids or liquids has no effect on the rate.
o Increasing the temperature increases reaction rates because it increases the number of high energy collisions
7. Be able to define apoenzyme, cofactor, coenzyme, and holoenzyme. ∙ Apoenzyme - an inactive enzyme
∙ Cofactor- nonprotein molecules, mostly metal ions or coenzymes, are inorganic and organic chemicals that assist enzymes during the catalysis of reactions
∙ Coenzyme- a nonprotein compound that is necessary for the functioning of an enzyme
∙ Holoenzyme- a biochemically active compound formed by the combination of an enzyme with a coenzyme
8. What is an active site and why is it important?
∙ This is where specific molecules bind to the enzyme and the reaction occurs.
∙ Anything that changes the shape of the active site stops the enzyme from working
∙ Like a key that opens a door lock.
9. What are three factors that influence enzyme activity (hint: see the three graphs)?
1) Temperature - as temperature increases, initially the rate of reaction will increase, because of increased Kinetic Energy
2) pH - any change in pH above or below the optimum will quickly cause a decrease in the rate of reaction, since more of the enzyme molecules will have active sites whose shapes are not complementary to the shape of their substrate
3) Concentration of enzyme or substrate- Changing the concentration of a substance only affects the rate of reaction if it is the limiting factor and only up to a certain point
a. Increasing Substrate Concentration increases the rate of reaction because more substrate molecules will be colliding with enzyme molecules, so more product will be formed
b. Increasing Enzyme Concentration will increase the rate of reaction, as more enzymes will be colliding with substrate
10. What is the difference between a competitive inhibitor and a noncompetitive inhibitor?
A competitive inhibitor will block the enzyme's active site (ie: it will occupy the same space as the natural substrate, blocking it from being catalyzed) A non-competitive inhibitor will bind to the enzyme somewhere other than the active site of the enzyme; an allosteric site.
11. What is feedback inhibition?
When the end product of a reaction interferes with the enzyme that helped produce it. The inhibitor does this by binding to a second active binding site that's different from the one attached to the initial reactant. The enzyme then changes its shape and can't catalyze the reaction anymore.
12. What is the difference between oxidation and reduction? ∙ Oxidation occurs when an atom loses electrons.
o OIL oxidation is loss
∙ Reduction occurs when an atom gain electrons
o RIG Reduction is gain
13. What are the 3 methods of ATP generation?
1) Substrate Level Phosphorylation
a. a process of forming ATP by the addition of a phosphate group to ADP
b. can take place in the cytoplasm during glycolysis or inside the mitochondrial matrix during the Krebs cycle
2) Oxidative Phosphorylation
a. the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron
b. takes place in the mitochondria for eukaryotic cells
a. the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight
b. occurs in the chloroplast, in the thylakoid membrane
14. What is carbohydrate catabolism?
The breakdown of carbohydrates to yield an energy rich compound called ATP through the oxidation of glucose molecules. In oxidation, the electrons are stripped from a glucose molecule to reduce NAD+ and FAD.
15. What is glycolysis? a 10-step metabolic pathway two convert glucose (6 carbon sugar) into two molecules of pyruvate (3 carbon sugar), ATP, and NADH each.
What does it cost? 2 ATP
What are the products? Two pyruvate molecules, four ATP molecules, and two NADH molecules
What is the net gain? A net gain of two ATP molecules
What part of the cell does it occur? In the cytoplasm
16. What is fermentation? A metabolic process that consumes sugar in the absence of oxygen; producing organic acids, gases, or alcohol. Is it aerobic or anaerobic? Anaerobic
What are the two types of fermentation that are named after their end products?
1) Alcoholic fermentation- the process by which certain cells convert pyruvate (a product of glycolysis) into ethyl alcohol and carbon dioxide. Yeast in bread carries out this process, and the CO2 causes the bread to rise
2) Lactic acid fermentation- the process that the dairy industry uses to produce yogurt and cheese. Lactic acid builds up in the muscles when the body doesn't get enough oxygen, causing the burning sensation you get when you exercise
17. Know pyruvate oxidation joins glycolysis with the Krebs (Citric acid cycle).
18. What is the Krebs (Citric acid or TCA) cycle? The sequence of reactions by which most living cells generate energy during the process of aerobic respiration
Where does it occur in eukaryotes? Mitochondria
How many reactions are in the cycle? 9 reactions
Know that the carbohydrates are turned into CO2.
Is it aerobic or anaerobic? Aerobic
19. Know that the NADH and FADH2 products from the Krebs cycle are used to drive (power) the electron transport chain.
20.Know that the electron transport chain is related to chemiosmosis and it powers oxidative phosphorylation which yields ~36 ATP (eukaryotes) or ~38 ATP (prokaryotes).