Nucleic Acids Flashcards
What is adenosine triphosphate (ATP)
An activated nucleotide composed of adenine, a ribose sugar and three phosphate groups. Acts as the universal energy currency for cells.
What’s an anticodon
A sequence of three bases at the end of a tRNA molecule that determines the specific amino acid carried by the tRNA. Forms hydrogen bonds with the codon in mRNA during translation.
What’s the coding strand
The strand of DNA with the same base sequence as the mRNA (except T is replaced with U in mRNA)
What’s a codon
A sequence of three bases in mRNA that codes for one amino acid.
What are complimentary base pairs
Specific base pairing rules in DNA and RNA. A pairs with T (DNA) or U (RNA) forming two hydrogen bonds and C pairs with G forming three hydrogen bonds.
What is deoxyribonucleic acid
The molecule responsible for the storage of genetic information in a cell.
What’s DNA gyrase
Unwinds a specific section of the DNA molecule
What is DNA helicase
Unzips a specific section of the DNA molecule by breaking the hydrogen bonds between the two DNA strands.
What’s a DNA mutation
A change to the sequence of bases in DNA.
What’s a gene
A length of DNA that carries the code for the synthesis of one (or more) specific polypeptide chains or for other RNA molecules that regulate other genes.
What is genetic code
A sequence of three bases in DNA codes for a particular amino acid in a polypeptide chain
What is messenger RNA (mRNA)
A single-stranded polynucleotide formed as a result of the transcription of a gene from the template strand of the DNA. Carries the information coding for a polypeptide from the nucleus to the ribosomes in the cytoplasm.
What is a mutation
A change in the base sequence of DNA, or in the structure or number of chromosomes
What is a nucleotide
The monomer of nucleic acids consisting of a phosphate group, a pentose sugar and a nitrogen-containing organic base
What is a phosphodiester bond
Covalent bond joining the 3’ carbon atom of one nucleotide to the 5’ carbon of another.
What’s a polynucleotide
Large polymer molecule made of many nucleotide monomers joined by phosphodiester bonds.
What’s a promoter
DNA sequence at the start of a gene, to which RNA polymerase binds to start transcription.
What’s a purine
Nitrogenous base consisting of a double ring structure e.g. adenine and guanine.
What’s a pyrimidine
Nitrogenous base with a single ring structure e.g. thymine, cytosine and uracil.
What’s reverse transcriptase
An enzyme originally derived from retroviruses. This enzyme catalyses the synthesis of a DNA strand using an RNA molecule as a template.
What’s ribonucleic acid (RNA)
Single-stranded polynucleotide that exists in three forms. Each form plays a part in the synthesis of proteins within cells
What is ribosomal RNA (rRNA)
Types of RNA molecules found in both small and large subunits of ribosomes.
What are ribosomes
Structures composed of two subunits, made from RNA and proteins, which are the site of protein synthesis
What is RNA polymerase
Binds to a specific binding site on the DNA at the start of the gene.
