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Flashcards in Chapter 4 Deck (16):
1

Antiparallel

Describing the opposite orientation of nucleic acid strands that are hydrogen bonded to one another, with one strand running in the 5′ - 3′ direction and the other in the 3′ - 5′ direction.

2

ATP

See adenosine triphosphate.

3

Ball-and-stick model

A representation of a molecule where atoms are shown as balls—colored and scaled to indicate the atom's identity—and covalent bonds are shown as rods or sticks connecting the balls in the correct geometry.

4

Complementary strand/Watson-Crick pairing

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

5

Deoxyribonucleic acid (DNA)

A nucleic acid composed of deoxyribonucleotides that carries the genetic information of a cell. Generally occurs as two intertwined strands, but these can be separated. See also double helix.

6

Hairpin

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

7

Nucleic acid

A macromolecule composed of nucleotide monomers. Generally used by cells to store or transmit hereditary information. Includes ribonucleic acid and deoxyribonucleic acid.

8

Nucleotide

A molecule consisting of a five-carbon sugar (ribose or deoxyribose), a phosphate group, and one of several nitrogen-containing bases. DNA and RNA are polymers of nucleotides containing deoxyribose (deoxyribonucleotides) and ribose (ribonucleotides), respectively. Equivalent to a nucleoside plus one phosphate group.

9

Phosphodiester linkage

Chemical linkage between adjacent nucleotide residues in DNA and RNA. Forms when the phosphate group of one nucleotide condenses with the hydroxyl group on the sugar of another nucleotide. Also known as phosphodiester bond.

10

Purines

A class of small, nitrogen-containing, double-ringed bases (guanine, adenine) found in nucleotides. Compare with pyrimidines.

11

Pyrimidines

A class of small, nitrogen-containing, single-ringed bases (cytosine, uracil, thymine) found in nucleotides. Compare with purines.

12

Ribonucleic acid (RNA)

A nucleic acid composed 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.

13

Ribozyme

Any RNA molecule that can act as a catalyst, that is, speed up a chemical reaction.

14

RNA world hypothesis

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

15

Template strand

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

16

X-ray crystallography

A technique for determining the three-dimensional structure of large molecules, including proteins and nucleic acids, by analysis of the diffraction patterns produced by X-rays beamed at crystals of the molecule.