B. The characteristics of populations change through time.
What does it mean to say that a characteristic of an organism is heritable?
B. the characteristic can be passed on to offspring.
Why was it important for Linnaeus to establish the rule that only one type of organism can have a particular genus and species name?
To ensure that two different organisms would never have the same name.
What does it mean to say that a species is adapted to a particular habitat?
Overtime, traits that helped with survival and fitness became more dominant in the population.
Explain how selection occurs during natural selection. what is selected and why?
Individuals with certain traits are selected, in the sense that they produce more offspring.
Explain the physical basis of the expression, "oil and water don't mix."
Oil is hydrophobic and will not dissolve in an aqueous solution.
or
Oil is nonpolar, nonpolar molecules do not dissolve in water.
How is the pH of Black coffee (pH: 5) affected when you add milk (pH: 6.5)?
The coffee becomes less acidic, or more basic.
Which of the following occurs when a covalent bonds forms?
A. electrons in valence shells are shared between nuclei.
If a reaction is exergonic, then which of the following statements is true?
A. the product will have lower energy that the reactants.
What is thermal energy?
D. the kinectic energy of molecular motion, measured as heat.
Why isn't CO2 bent and polar like H2O? Why is H2O much more likely to participate in chemical reaction than CO2?
CO2 is nonpolar. In water, H2O is able to react with other molecules because of the partial charges and the weak hydrogen bonds are able to be easily broken, unlike the double bond of CO2, which is much stronger.
Explain why secondary, tertiary, and quaternary structure depend on a ploypeptide's primary structure.
All the bonds in the second, tertiary, and quaternary structure depend on the chain of amino acids in the primary structure.
What two functional groups are present in every amino acid?
C. an amino group and a carboxyl group
Twenty different amino acids are found in the proteins of cells. What distinguishes these molecules?
B. composition of the side chains (R-groups)
What determines the primary structure of a polypeptide?
B. the sequence of amino acids
Isoleucine, valine, leucine, phenylalanine, and methionine are amino acids with highly hydrophobic side chains. Suppose a section of a protein contains a long series of these hydrophobic residues. How would you expect this portion of the protein to behave when the molecule is in an aqueous solution?
It would fold in on itself, away from the water, in an aqueous solution.
Compare and contrast competitive inhibition and allosteric regulation.
They both regulate enzyme activity. Competitive inhibition stops a substrate from binding to an active site. Allosteric regulation deactivates the enzyme by binding a different substrate to the allosteric site of the enzyme.
Does it take an input of energy for polymerization reactions to proceed, or do they occur spontaneously? Why or why not?
Energy is required. Polymerization is a nonspontaneous reaction because the product has lower energy than the reactants.
Explain why pH and temperature affect enzyme function.
Because they can change the shape and chemical reactivity of the active site. Either by disrupting bonds or interferring with acid-base reactions.
What are thye four nitrogenous bases found in RNA?
B. adenine, uracil, guanine, cytosine (AUGC)
DNA attains a secondary structure when hydrogen bonds form between the nitrogenous bases called purines and pyrimidines. What are the complementary base pairs that form in DNA?
B. A-T and G-C
The secondary structure of DNA is called a double helix. Why?
A. two strands wind around on another in a helical or spiral srrangement.
Explain why nucleic acids are directional. In a nucleic acid, what are the 5' carbons bonded to? What are the 3' carbons bonded to?
Because the two ends of the polymers are different. The 5' carbon is bonded to a phospate group. The 3' carbon is bonded to free hydroxyl group.
What is the difference between a mono-, di-, and polysaccharide?
C. the number of monomers in the molecule.
What are the primary functions of carbohydrates in cells?
D. energy storage, cell identity, structure, and building blocks for synthesis.
A weight loss plan for humans emphasizes minimal carb consumption. What is the logic behind this?
Carbohydrates are the main energy storage molecules. Lack of carbs would force the body to use stored fats for energy.
Amylase, an enzyme found in human saliva, catalyzes the hydrolysis of the alpha-1,4-glycosidic linkages in starch. If you hold a salty cracker in your mouth long enough it will begin to taste sweet. Why?
Amylase breaks down the starch into glucose (sugar).
Lysozyme, an enzyme found in human saliva, tears, and other secretions, catalyzes the hydrolysis of the beta-1,4-glycosidic linkages in peptidoclycan. What effect does contact with this enzyme have on bacteria?
Lysozyme will cause the bacteria to degrade and die because their cell walls contain peptidoclycan.
Compare and contrast the structure of fats, steroids, and phospholipids.
Fats have 3 fatty acids tails linked to a glycerol molecule.
Steroids have 4 linked rings and a side group.
Phospholipids have a polar head and nonpolar tails (amphipathic).
Based on their structure, explain why phospolipids and cholesterol are amphipathic.
Phospholipids have a hydrophillic head and hydrophibic tail. Cholesterol has hydrophobic steroid rings and hydrophillic hydroxyl group.
Explain what is passive transport, what is active transport, and what is "co" about cotransport.
Passive transport does not require energy. Active transport requires ATP. In cotransport, a second ion is transported against its electrochemical gradient with another ion that is transported along its electrochemical gradient.
What does the term hydrophillic mean when translated literally?
"Water loving"
If a solution surrounding a cell is hypotonic in relation to the cell's interior, how will the water move?
Inside the cell via osmosis.
If a solution surrounding a cell is hypertonic in relation to the cell's interior, how will the water move?
Outside the cell via osmosis.
When does a concentration gradient exist?
D. when solute concentrations differ on the two sides of a membrane.
True or False: In order for osmosis to occur, solutions with different concentrations of solutes must be seperated by a selectively permeable membrane
True
Why are the lipid bilayers in cells called "selectively permeable"?
B. they are permeable to some substances but not others
Ethanol, the active ingredient in alcoholic beverages, is a small, polar, uncharged molecule. would you predict this molecule crosses the plasma membrane quickly or slowly? Explain.
Yes, because it is small enough to move through the membrane quickly and can interact with the hydrophobic center of the bilayer.
The portion of the membrane proteins that spans the hydrophobic tails of phospholipds is itself hydrophobic. Why is that logical?
Because only hydrophobic regions interact with other hydrophobic regions.
True or False: When electrons are shared, it is called a covalent bond.
True
True or False: Ions of opposite charges interact to form ionic bonds.
True
True or False: Polar molecules interact to for hydrogen bonds.
True
True or False: Polar molecules do not have partial charges.
False: Polar molecules carry partial negative or partial charges.
What does it mean for a molecule to be hydrophillic?
They interact with water
Water loving
Polar
Charged
What does it mean for a molecule to be hydrophobic?
They do not interact with water
Water fearing
Nonpolar
Uncharged
What's the difference between potential and kinectic energy?
Potential energy = stored energy. Kinect energy = energy in use.
The more hydrogen ions, H+ a solution has, the more ___ it is said to be.
Acidic
The less hydrogen ions, H+ a solution has, the more ___ it is said to be.
Basic
What's the difference between endergonic and exergonic reactions?
Endergonic require energy and exergonic release energy.
What are the three components of a nucleotide?
Phosphate group (PO4), nitrogenous base, and a pentose sugar.
