2.3 nucleotides and nucleic acid definitions Flashcards
Adenosine triphosphate (ATP)
A nucleotide consisting of a molecule of ribose joined to the nitrogenous base adenine and three phosphate groups
Degenerate (genetic code)
A term used to describe the fact that some amino acids can be coded for by multiple different codons
Deoxyribonucleic acid (DNA)
double helix composed of two polynucleotides joined together by hydrogen bonds between complementary bases that contains the genetic material of an organism and is made up of deoxyribonucleotide monomers joined together by phosphodiester bonds
components of a DNA nucleotide
The monomer that makes up DNA and consists of deoxyribose, a nitrogenous base (organic bases adenine, cytosine, guanine or thymin) and a phosphate group.
DNA polymerase
An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new DNA strand.
RNA polymerase
An enzyme that catalyses the formation of phosphodiester bonds between nucleotides during the synthesis of a new RNA strand
Helicase
An enzyme that catalyses the unwinding and unzipping of DNA in many processes like replication and transcription
Messenger RNA (mRNA)
A type of RNA that carries genetic information from the DNA in the nucleus to the ribosomes for translation
Non-overlapping (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.
Nucleotide
The monomer from which nucleic acids are made that consists of a pentose sugar, nitrogenous base and phosphate group
Phosphodiester bond
A type of bond that joins nucleotides together to create polynucleotides.
Purines
A class of nitrogenous bases which are made up of two rings that adenine and guanine. (smaller ones)
Pyrimidines
A class of nitrogenous bases which are made up of a single ring that cytosine, thymine and uracil. (larger ones)
Ribosomal RNA (rRNA)
A type of RNA that makes up ribosomes.
components of a RNA nucleotide
The monomer that makes up RNA and consists of ribose, a nitrogenous base (organic bases adenine, cytosine, guanine or uracil) and a phosphate group
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. meaning that genetic information is passed on from one generation from the next.
Transcription
The process of synthesising a new mRNA strand from a molecule of DNA.
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.
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
Triplet (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.
Universal (genetic code)
A term used to describe the fact that the same codons code for the same amino acids in all organisms.
what happens when ATP is hydrolysed
Energy is released to form ADP and a phosphate
molecule. This process is catalysed by ATP hydrolase
what can an inorganic phosphate be used for
used to phosphorylate other compounds, as a
result making them more reactive.
Condensation of ADP and inorganic phosphate produces what
produces ATP during photosynthesis and respiration when catalysed by ATP synthase
what are the steps of semi conservative replication of DNA
1) The double helix unwinds and the hydrogen bonds between the complementary bases break using DNA helicase thus separating the two strands of DNA.
2) Both strands are used as templates and complementary base pairing occurs between the template strands and free nucleotides.
3) Adjacent nucleotides are joined by phosphodiester bonds formed in condensation reactions using DNA polymerase.
what is the genetic code
The order of bases on DNA
what does the genetic code consist of
triplets of bases - each triplet of bases codes for a particular amino acid and is known as a codon
how are amino acids joined
by peptide bonds and form a polypeptide chain
what is a gene
a sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain
not all the genome codes for proteins - what are non-coding sections of DNA called
introns
what are the coding regions of DNA called
exons
Features of the genetic code
non-overlapping and degenerate
what does degenerate mean
more than one triplet codes for the same amino acids reducing the phenotypic effect of mutations
what are mutations in the genetic code
mistakes in the base sequence such as base deletion, insertion or substitution
what does a change in the base sequence of DNA lead to
may alter the amino acid sequence and the
protein therefore cause mutations which leads to production of sticky mucus and causes cystic fibrosis or sickle cell anaemia in which a mutated form of haemoglobin distorts the shape of red blood cells
what does the genetic code contain
start and stop codons which either start or stop protein
synthesis
