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Chemistry
Proteins
Nucleic Acids
Carbohydrates
Lipids
100
Asymmetrically or unequally.
In a polar bond, electrons are shared how?
100
a)acidic b)polar c)nonpolar d)basic
Tell wether each amino acid is nonpolar, polar, acidic, or basic. a)glutamate b)serine c)glycine d)lysine
100
The 2' hydroxyl group on RNA makes the molecule much more reactive.
If RNA came before DNA, why is genetic information stored in DNA rather than RNA?
100
Energy storage, cell identification, and structure
What are the three main functions of carbohydrates?
100
b
What If a solution surrounding a cell is hypertonic relative to the inside of the cell, how will water move? a. It will move into the cell via osmosis. b. It will move out of the cell via osmosis. c. It will not move, because equilibrium exists. d. It will evaporate from the cell surface more rapidly.
200
Because the partial positive charge on on hydrogen attracts the partial negative charge on oxygen. This weak electrical attraction forms a hydrogen bond between the molecules. Hydrogen bonding between water molecules allows almost any polar molecule to be dissolved in water.
Why is water such an effective solvent?
200
Condensation, hydrolysis, water.
Polypeptides are extended by ____ reactions, and broken apart by _____ reactions. What is the additional product formed in the later reaction?
200
Phosphodiester bonds for both molecules.
What type of bond joins adjacent nucleic acids of DNA? What about RNA?
200
a; lactose is a disaccharide formed from a β-1,4-glycosidic linkage, so if two glucose mol- ecules were linked with this bond, they would resemble units of cellulose and not be digested by human infants or adults.
What would most likely occur if the galactose in lactose were replaced with glucose? a. It would not be digested by human infants or adults. b. It would be digested by most adult humans. c. It would be digested by human infants, but not adults. d. It would be digested by human adults, but not infants.
200
Channel proteins form pores in the membrane and carrier proteins undergo conformational changes to shuttle molecules or ions across the membrane.
In terms of structure, how do channel proteins differ from carrier proteins?
300
Adhesion, cohesion, and surface tension.
What 3 properties are correlated with water's structure?
300
Amino acid sequence. Alpha helices and beta pleated sheets, hydrogen bonds. Hydrogen bonding, hydrophobic interactions, van der walls interactions, covalent bonds, and ionic bonds. Complex of 2 or more polypeptides.
Protein primary structure is the ______. Secondary structure consists of _____ and _____ which are stabilized by ____ bonds. Tertiary structure of proteins are stabilized by ____, ____, _____, _____, and _____. Quatertnery structure refers to _____.
300
phosphate, hydroxyl
The 5' end of a nucleic acid contains an unlinked ____, while the 3' end has an unlinked _____.
300
d; lactose is a disaccharide of glucose and galactose, which can be cleaved by enzymes expressed in the human gut to release galactose
Galactosemia is a potentially fatal disease that occurs in humans who lack the enzyme that converts galactose to glucose. To treat this disease, physicians exclude the monosaccharide galactose from the diet. Which of the following would you also predict to be excluded from the diet? a. maltose b. starch c. mannose d. lactose
300
c.
If a cell were placed in a solution with a high potassium concentration and no sodium, what would happen to the sodium– potassium pump’s activity? a. It would stop moving ions across the membrane. b. It would continue using ATP to pump sodium out of the cell and potassium into the cell. c. It would move sodium and potassium ions across the membrane,but no ATP would be used. d. It would reverse direction of sodium and potassium ions to move them against their gradients.
400
c. chemical energy present in the reactants
Which of the following is most likely to have been the energy source responsible for the formation of acetic acid in deep-sea hydrothermal vents? a. heat released from the vents b. solar radiation that passed through the ocean water c. chemical energy present in the reactants d. the increase in entropy in the products
400
d. an amino group and a carboxyl group
What two functional groups are present on every amino acid? a. a carbonyl (C=O) group and a carboxyl group b. an N–H group and a carbonyl group c. an amino group and a hydroxyl group d. an amino group and a carboxyl group
400
CG
Which is more strongly held together? DNA rich in AT base pairs, or DNA rich in CG base pairs?
400
Carbohydrates are ideal for displaying the identity of the cell because they are so diverse structurally. This diversity enables them to serve as very specific identity tags for cells.
Explain how the structure of carbohydrates supports their function in displaying the identity of a cell
400
Adding a methyl group makes a drug more hydrophobic and thus more likely to pass through a lipid bilayer. Adding a charged group makes it hydrophilic and reduces its ability to pass through the lipid bilayer. These modifications would help target the drug to either the inside or outside of cells, respectively.
When biomedical researchers design drugs, they sometimes add methyl (CH3) groups or charged groups to the molecules. If these groups are not directly involved in the activity of the drug, predict the purpose of these modifications and explain why these strategies are necessary.
500
a. The products have lower potential energy than the reactants.
If a reaction is exothermic, then which of the following statements is true? a. The products have lower potential energy than the reactants. b. Energy must be added for the reaction to proceed. c. The products have lower entropy (are more ordered) than the reactants. d. It occurs extremely quickly
500
b. basic amino acids
Proteins that interact with DNA often interact with the phosphates that are part of this molecule. Which of the following types of amino acids would you predict to be present in the DNA binding sites of these proteins? a. acidic amino acids b. basic amino acids c. uncharged polar amino acids d. nonpolar amino acids
500
b; the high temperature would make it more likely that the secondary and tertiary structures would be denatured in the ribozymes. To overcome this effect, you would expect the hairpins to possess more G-C pairs, since they consist of three hydrogen bonds compared to the two found in A-T pairs.
How would you expect the structure of ribozymes in organisms that grow in very hot environments, such as hot springs or deepsea vents, to differ from those in organisms that grow in cooler environments? a. These ribozymes would have more hairpin secondary structures. b. The hairpins would have more G’s and C’s in the primary structure. c. The hairpins would have more A’s and U’s in the primary structure. d. These ribozymes would exhibit no tertiary structure.
500
Monosaccharides can differ from one another in three ways: (1) the location of their carbonyl group; (2) the number of carbon atoms they contain; and (3) the orientations of their hydroxyl groups.
What are three ways monosaccharides differ from one another?
500
c.
In an experiment, you create two groups of liposomes—one made from red blood cell membranes and the other from frog egg cell membranes. When placed in water, those made with red blood cell membranes burst more rapidly than those made from frog membranes. What is the best explanation for these results? a. The red blood cell liposomes are more hypertonic relative to water than the frog egg liposomes. b. The red blood cell liposomes are more hypotonic relative to water than the frog egg liposomes. c. The red blood cell liposomes contain aquaporins, which are not abundant in the frog egg liposomes. d. The frog egg liposomes contain ion channels, which are not present in the red blood cell liposomes.