OCR ALevel Biology - Module 2 - Definitions - Topic 2.3 : Nucleotides And Nucleic Acids Flashcards
What is adenosine triphosphate (ATP)?
A nucleotide consisting of a molecule of ribose joined to the nitrogenous base adenine and three phosphate groups.
What does ‘degenerate’ mean in the context of the genetic code?
A term used to describe the fact that some amino acids can be coded for by multiple different codons.
What is deoxyribonucleic acid (DNA)?
A double stranded polynucleotide that contains the genetic material of an organism and is made up of deoxyribonucleotide monomers joined together by phosphodiester bonds.
What is a DNA nucleotide?
The monomer that makes up DNA and consists of deoxyribose, a nitrogenous base and a phosphate group.
What is the function of DNA polymerase?
An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new DNA strand.
What is the role of RNA polymerase?
An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new RNA strand.
What does helicase do?
An enzyme that catalyses the unwinding and unzipping of DNA in many processes like replication and transcription.
What is messenger RNA (mRNA)?
A type of RNA that carries genetic information from the DNA in the nucleus to the ribosomes for translation.
What does ‘non-overlapping’ mean in the genetic code?
A term used to describe the fact that each base is only part of one codon and that each codon is read one at a time in order.
What is a nucleotide?
The monomer from which nucleic acids are made that consists of a pentose sugar, nitrogenous base and phosphate group.
What is a phosphodiester bond?
A type of bond that joins nucleotides together to create polynucleotides.
What are purines?
A class of nitrogenous bases which are made up of two rings that adenine and guanine are members of.
What are pyrimidines?
A class of nitrogenous bases which are made up of a single ring that cytosine, thymine and uracil are members of.
What is ribosomal RNA (rRNA)?
A type of RNA that makes up ribosomes.
What is an RNA nucleotide?
The monomer that makes up RNA and consists of ribose, a nitrogenous base and a phosphate group.
What is semi-conservative replication?
The replication of DNA to produce two new DNA molecules which both contain one new strand and one old strand from the original DNA molecule.
What is transcription?
The process of synthesising a new mRNA strand from a molecule of DNA.
What is transfer RNA (tRNA)?
A type of RNA that has three hairpin loops, an anticodon for attachment to the mRNA codon and an amino acid binding site and is used to carry amino acids to the ribosome.
What is translation?
The process of protein synthesis where complementary tRNAs carrying amino acids are brought to each codon in an mRNA molecule as it moves through a ribosome.
What does ‘triplet’ mean in the genetic code?
A term used to describe the fact that DNA is grouped into three base long codons that are read together and code for an amino acid.
What does ‘universal’ mean in the context of the genetic code?
A term used to describe the fact that the same codons code for the same amino acids in all organisms.
