Chapter 4: Nucleic Acids and the RNA World

Question 1

ribozyme

Answer 1

any RNA molecule that can act as a catalyst, that is, speed up a chemical react.

Question 2

template strand

Answer 2

original nucleic acid strand used to make a new, complementary copy based on hydrogen bonding between nitrogenous bases.

Question 3

antiparallel

Answer 3

describing the opposite orientation of nucleic acid strands that are hydrogen bonded to one another

Question 4

RNA

Answer 4

ribonucleic acid; nucleic acid of ribonucleotides that usually is single stranded. functions include structural components of ribosomes (rRNA), transporters of amino acids (tRNA), and messages of the DNA code required for protein synthesis (mRNA), among others

Question 5

ball-and-stick model

Answer 5

representation of a molecule where atoms are shown as ball and covalent bonds are shown as rods or sticks connecting the balls.

Question 6

DNA

Answer 6

deoxyribonucleic acid; nucleic acid composed of deoxyribonucleotides that carries the genetic info of a cell. occurs as two intertwined strands but can be separated

Question 7

nucleic acid

Answer 7

macromolecule composed of nucleotide monomers. gen. used by cells to store or transmit hereditary info. includes RNA and DNA

Question 8

phosphodiester linkage

Answer 8

chemical linkage between adjacent nucleotide residues in DNA and RNA

Question 9

pyrimidines

Answer 9

class of small, nitrogen-containing, SINGLE-ringed bases found in nucleotides

Question 10

Watson-Crick pairing

Answer 10

complementary base pairing

Question 11

nucleotide

Answer 11

molecule consisting of a five-carbon sugar (ribose or deoxyribose), a phosphate group and one of several nitrogen-containing bases.

Question 12

ribonucleotide

Answer 12

same as nucleotide

Question 13

purines

Answer 13

class of small nitrogen-containing DOUBLE-ringed bases found in nucleotides

Question 14

haripin

Answer 14

secondary structure in RNA consisting of a stable loop formed by hydrogen bonding between purine and pyrimidine bases on the same strand

Question 15

ATP

Answer 15

adenosine triphosphate;

Question 16

RNA world hypothesis

Answer 16

proposal that chemical evolution produced RNAs that could catalyze key reactions involved in their own replication and basic metabolism, which led to evolution of proteins and the first life-form

Question 17

X-ray crystallography

Answer 17

technique for determining the 3D structure of a large molecules, including proteins, nucleic acids, by analysis of the diffraction patterns produced by X-rays beamed at crystals of the molecule.

Question 18

complementary strand

Answer 18

newly synthesized strand of RNA or DNA that has a base sequence complementary to that of the template strand.