DNA/RNA/Synthesis Vocab

nucleotide

subunit of a nucleic-acid; consists of a 5-carbon sugar, a phosphate, and a nitrogenous base

radioactive isotopes

Hershey and Chase identified DNA as the genetic material when they used to label the DNA and protein coat of viruses that were used to infect bacteria

Rosalind Franklin

First person to see DNA, she provided Watson and Crick with key data about DNA shape

nitrogenous base

an organic base that contains nitrogen, such as a purine or pyrimidine; a part of a nucleotide in DNA or RNA

pyrimidine

a nitrogenous base that has a single-ring structure; thymine, cytosine, or uracil

purine

a nitrogenous base that has a double-ring structure; either adenine or guanine

complementary base pair

the nucleotide bases in one strand of DNA or RNA that are paired with those of another strand; adenine pairs with thymine or uracil, and guanine pairs with cytosine

deoxyribose

the five-carbon sugar that is found in DNA nucleotides

base pairing rules

the rules stating that cytosine pairs with guanine in both DNA and RNA and that adenine pairs with thymine in DNA, and that adenine pairs with uracil in RNA

base sequence

the order of nitrogenous bases on a chain of DNA

DNA replication

the process of making a copy of DNA; occurs during S phase of Interphase; produces 2 DNA molecules from the original DNA molecule; takes place in the nucleus of eukaryotic cells

replication fork

a y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated

semi-conservative replication

in each new DNA double helix, one stand is from the original molecule, and one strand is new

DNA helicase

an enzyme that separates, or unwinds, DNA strands so that replication can take place

DNA polymerase

an enzyme that catalyzes the formation of the DNA molecule by adding complementary nucleotides

ribonucleic acid (RNA)

copied from DNA, this nucleic acid moves to the cytoplasm where it is used to make proteins

transcription

the process of making RNA by using one strand of a DNA molecule as a template; takes place in the nucleus of the eukaryotic cell, makes the DNA readable

translation

the process of reading the message in mRNA to join amino acids together in a specific sequence, producing a polypeptide chain; takes place at the ribosomes in the cytoplasm of cells, makes the DNA usable

protein synthesis

the formation of proteins by using information contained in DNA and carried by mRNA

ribose

a five-carbon sugar present in RNA

messenger RNA (mRNA)

a single-stranded RNA molecule that carries the instructions from a gene to make a protein; functions as a "blueprint" of the genetic code

ribosomal RNA (rRNA)

RNA that interacts with proteins to form the ribosomes

transfer RNA (tRNA)

RNA that pairs with complementary mRNA and carries amino acids to the ribosome to make a protein; has an attachment site for carrying amino acids

codon

a three-nucleotide sequence in mRNA that codes for a specific amino acid or signifies a start or stop signal

anticodon

the triplet sequence of nucleotides on tRNA that is complementary to and pairs with the codon of mRNA

double helix

structure of DNA; inferred from the X-Ray photographs of Franklin and Wilkins

hydrogen bonds

join the complementary nitrogenous bases of the two DNA stands

adenine, thymine, guanine, cytosine

the four nitrogenous bases in DNA nucleotides

uracil

found in RNA, but not DNA, it substitutes for the thymine of DNA

proteins

polymers made up of amino acid monomers

amino acids

the monomers (subunits) of proteins; 20 different types; the specific order of these monomers determines the function of a protein

ribosome

the organelle involved in protein synthesis

start codon

the triplet sequence of nucleotides on mRNA where protein synthesis begins; always AUG

stop codons

triplet sequences of nucleotides on mRNA that signals the ribosome to end translation

DNA primase

enzyme that synthesizes an RNA primer to signal DNA polymerase where to start

Okazaki fragment

short sequence of DNA nucleotides synthesized on the lagging strand

DNA ligase

enzyme that "glues" the replicated strands of DNA together

Lagging strand

strand of replicated DNA whose synthesis is opposite the replication fork and so is made in fragments

Leading strand

strand of DNA during replication whose direction of synthesis is in the direction of the replication fork and so is seemless

RNA primer

small section of RNA added by primase that initiates DNA synthesis