2.3 Nucleic Acids Flashcards
genes
a sequence of nucleotide bases that codes for one (or more) polypeptides
polypeptide
a larger polymer molecule made by many amino acids joined by peptide bonds
human genome
25,000 genes, most found on the linear chromosomes within the nucleus, each gene occupies a specific locus on the chromosome, DNA in chromosome associated with histone proteins
the genetic code
the sequence of nucleotide bases on a gene provides a code, with instructions for the construction of a polypeptide or protein
DeoxyriboNucleic Acid (DNA)
contains instructions on how to build proteins used in the body, found in cell nucleus, codes for individual proteins, made up from chain of sugar-phosphates and one of four bases
protein
polymer of units linked by peptide bonds, built up from 20 amino acids, created in ribosomes, perform nearly all biological functions
messenger RNA
an intermediary form that dna uses to build protein in ribosomes outside the nuclear envelope as molecules are too large to escape the nucleus
where are the nucleotides in transcription from
there are free dna nucleotides in the nucleoplasm and free rna nucleotides in the nucleolus
base triplet
a triplet of bases on a dna molecule
codon
a triplet of bases on a length of mRNA
anticodon
a triplet of bases on a tRNA molecule complementary to the mRNA codon
nucleotides
biological molecules that participate in nearly all biochemical processes
RNAs nucelotide pentose sugar
ribose
DNAs nucleotide pentose sugar
deoxyribose
phosphodiester bond
covalent bond formed between sugar residue and phosphate group in nucleotide of DNA formed when polynucleotides synthesise
examples of a purine (nitrogenous base)
adenine
guanine (2 rings)
examples of a pyrimidine (nitrogenous base)
thymine
cytosine (1 ring)
how bonds in DNA are formed
2 antiparallel DNA strands joined by hydrogen bonds between the nitrogenous bases
semi-conservative replication
a product of 2 DNA molceules, identical to each and parent, containing 1 old strand and 1 new strand
precipitation
when salty DNA becomes undissolved as it comes into contact with alcohol (DNA normally stays dissolved in water)
in DNA what does Adenine pair with
Thymine
in DNA what does Guanine pair with
Cytosine
in DNA what does Thymine pair with
Adenine
in DNA what does Cytosine pair with
Guanine
how many hydrogen bonds between A and T
2
how many hydrogen bonds between G and C
3
the 5’ end
where the phosphate group is attached to the 5th carbon molecule on the five-carbon sugar (deoxyribose)
the 3’ end
where the phosphate group is attached to the 3rd atom of the sugar (deoxyribose)
function of gyrase
an enzyme that catalyses the process of the double helix untwisting a bit at a time to unwind each DNA molecule
function of helicase
enzyme that catalyses breaking of hydrogen bonds between the nucleotide bases to unzip DNA molecule
double helix
shape of DNA molecule, due to coiling of the 2 sugar-phosphate backbone strands into a right-handed spiral configuration
polynucleotide
large molecule containing many nucleotides
DNA polymerase
enzyme that catalyses formation of DNA from activated deoxyribose nucleotides using single-stranded DNA as a template
transcription
the process of making messenger RNA from a DNA template
translation
formation of a protein(polypeptide) by assembling amino acids into a particular sequence at ribosomes-
according to the coded instructions carried from DNA by mRNA
the starter codon of a polypeptide chain
AUG
bond between 2 adjacent amino acids
peptide
bond between codons and anticodons
hydrogen
