Chapter 10 Vocabulary

Molecular biology

Study of how DNA, RNA, and proteins worktogether to control the structure, function, and behavior of cell s

Bacteriophages

Viruses that infect and replicate inside bacteria

Phages

infect and replicate

Nucleotides

Basic building blocks of DNA and RNA

Polynucleotides

Long chain of nucleotides linked together by chemical bonds

Sugar-phosphate backbone

• Structural framework of DNA and RNA molecules

• Consists of alternating sugar and phosphate groups linked by strong covalent bonds

DNA

• deoxyribonucleic acid

• carries genetic information

• forms a double helix; two strands

Thymine (T)

• connects to adenine (a) through two hydrogen bonds

• one of the nitrogenous bases

• Prymadine base, has a single ring structure

Cytosine (C)

• pairs with guanine through the three hydrogen bases

• pyrimidine base, single ring structure

Adenine (A)

• pairs with thymine through 2 hydrogen bonds

• pairs with uracil in RNA

• purine base, double ring structure

Guanine (G)

• pairs with cytosine through three hydrogen bonds

• purine base; double ring structure

Uracil (U)

• replaces thymine in RNA and pairs with adenine

• not present in DNA

• has a single ring structure (pyrimidine base)

Double helix

• spiral shaped structure of DNA

• consists of two strands twisted around each other

• allows DNA to replicate genetic info

Semiconservative model

• process where DNA is copied

• each two strands of the original DNA molecule, one with parental (original) and one with newly synthesized strand

DNA polymerase

• enzyme that synthesizes new DNA strands during replication

• adds nucleotides to growing DNA

• “proof-reas” and corrects errors to ensure corret replication

DNA ligase

• enzymes that helps join DNA fragments together by forming phosphodiester bonds

• seals gaps between Okazaki fragments on lagging strand during replication

Transcription

• process where RNA molecule is synthesized from a DNA molecule

• enzyme called RNA polymerase reads the DNA sequence and creates a complementary RNA strand

• creates genetic information for translation

Translation

• process where info encoded in messenger RNA (mRNA) is used to build a protein

triplet code

• the way genetic info is stored in DNA and RNA

• three consecutive nucleotide bases (a codon) specify which amino acid during will be added to a growing protein during protein translation

codons

• sequences of three nucleotide bases in mRNA that specify which amino acid will be added to a growing protein during translation

genetic code

• set of rules that determine how the sequence of nucleotide bases (A, U, G, C in RNA or A, T, C, G in DNA)

• based on codons

• nearly universal

RNA polymerase

• enzyme that synthesizes RNA from DNA template during transcription

• unwinds the DNA, reads one strand and assembles the complementary RNA strand by adding ribonucleotides

promoter

• specific DNA sequence located near the start

Terminator

• sequence of DNA that signals the end of transcription

• causes RNA polymerase to stop and release the RNA transcript

messenger RNA (mRNA)

• carries the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm

introns

• non-coding section of a gene that are transcribed into RNA but is removed during RNA processing before translation

• found between coding sequences

exons

• coding regions of a gene that remain to the mature mRNA

• translated into proteins

RNA splicing

• is the process of removing introns and joining exons in pre-mRNA to form mature mRNA, which is used for protein synthesis

anticodon

• sequence of three bases on the tRNA molecule

• pairs with a matching codon on the mRNA during protein synthesis