Cell Biology - Chapter 2

chichi's version from 2015-07-13 14:12

Chemical Bonds

Question Answer
An element may have more than a one isotope. Isotopes have different atomic weights, but exhibit the same chemical behavior. Carbon-14 is an unstable isotope of carbon that decays very slowly. Compared to the common, stable carbon-12 isotope, carbon-14 has two additional_____________neutrons
Which of the following elements is least abundant in living organisms?sulfur
An ionic bond between two atoms is formed as a result of the___________transfer of electrons from one atom to the other
Which of the following expressions accurately describes the calculation of pH?pH = -log10[H+]
Biological membranes are composed of specialized lipids that form bi layers. Which of the following is formed by unmodified fatty acids? micelles
Choose the answer that best fits the statement. Cholesterol is an essential component of biological membranes. Although it is much smaller than the typical phospholipids and glycoplipids in the membrane, it is a(n)____________________ molecule, having both hydrophilic and hydrophobic regionsamphipathic
DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but NOT true of RNA?It contains thymine
Which of the following statements about amino acids is TRUE?All amino acids contain an NH2 and COOH group
Which of the following statements is false?ATP can be incorporated into DNA
Electrons are constantly moving around the nucleus of the atom, but they can move only in discrete regionstrue
There is no limit to the number of electrons that can occupy the fourth electron shellFalse, 18 electrons can fill this shell only
Atoms with unfilled outer electron shells are especially stable and are therefore less reactiveFalse, atoms with completely filled electron shells are nonreactive- those with unfilled shells are very reactive
Covalent bonds are formed when electrons are either shared or transferred between atomsFalse, a covalent bond is the sharing of electrons not the transfer- the transfer of electrons is called an ionic bond
linkage between the sugar and the baseglycosidic bond
sugar unit linked to a basenucleoside
sugar linked to a base and a phosphatenucleotide
the linkage between the 5′ sugar hydroxyl and a phosphate groupphosphoester bond
the linkage between two nucleotidesphosphodiester bond
the nitrogen-containing aromatic ringbase
five-carbon sugar found in RNAribose
five-carbon sugar found in DNAdeoxyribose
linkages between phosophate groupsphosphoanyhydride bond

Macromolecules in Cells

Question Answer
Both DNA and RNA are synthesized by covalently linking a nucleotide triphosphate to the previous nucleotide, constantly adding to a growing chain. In the case of DNA, the new strand becomes apart of a stable helix. The two strands are complementary in sequence and anti parallel in directionality. What is the principal force that holds these two strands together?hydrogen bonds
Macromolecules in the cell can often interact transiently as a result of non covalent interactions. These weak interactions also produce stable, highly specific interactions between molecules. Which of the factors below is the most significant in determining whether the interaction will transient or stable?surface complementary between molecules
In folded protein, most of the non polar amino acids are buried inside the protein fold, whereas the polar and charged side chains are exposed to the components in the cytosol. This fold is more stable because of the expulsion of non-polar atoms from contact with water, favoring the interaction of non-polar atoms with each other. What is this fourth type of non covalent interaction called.?hydrophobic interaction
"Nonpolar interactions” is simply another way of saying "van der Waals attractions.” false
Condensation reactions occur in the synthesis of all the macromolecules found in cellstrue
All proteins and RNAs pass through many unstable conformations as they are folded, finally settling on one single, preferred conformationtrue
When nonpolar molecules are placed in an aqueous solution, the water molecules surrounding the nonpolar surface become completely disorderedtrue

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