Protein synthesis Flashcards
Define gene
a section of dna/ sequence of nucleotides that form part of a dna molecule ad codes for a particular polypeptide
Define gene mutation
this is a chage in sequence of base pairs that may result in an altered polypeptide
describe rna structure
RNA is a polynuleotide or is made up of may nucleotides linked together forming a long chain. RNA contains the nitrogenous bases adenine, guanine, cytosine and uracil (in place of thymine). Rna contains the pentose sugar ribose (not deoxyrobose). RNA is made up of only one polynucleotide strand and each RNA strand is made up of alternating ribose sugar and phosphate groups that linked together with the nitrogenous bases of eavh nucleotide projting out sideways from the single stranded RNA molecule. the bonds between phosphate groups and sugars are covalent/phosphodiester bonds which form the sugar-phosphate backbone of of the RNA polynucleotide strand
define mRNA
it is a transcript copy of a gene that encodes a specific polypeptide
define codon
it is the triplet of bases
where does transcription and translation occur
transcript: nucleus
translation: cytoplasm
describe the process of transcription
-part of dna unwinds
-exposed gene to be transcribed
a complementary copy of the code from the gene is made by building single stranded nucleic acid molecule known as mRNA
-free activated nucleotides pair up by hydrogrn bonds with their complementary bases on the template strand of the unzipped dna
-the sugar and phosphate groups are bonded together by and enzyme called RNA polymerase forming the sugar-phosphate backbone mRNA molecule
-mRNA leaves nucleaus through nuclear pore
describe the process of translation
-mRNA now attaches to a ribosome
-free molecules of tRNA are found in the cytoplasm
-the tRNA have a triplet of unpaired bases at one end and a region where a specific acid can attach to the other
-there are 20 different tRNA molecules with a specific anticodon and amino acid binding site
-the tRNA molecules bind with their specfic amino acids in the cytoplasm and bring them to mRNA molecule on the ribosome
- the triplet bases (anticodon)von each tRNA with a complementary triplet -codon- on the mRNA
-as trna molecules fit onto the ribosome bringing the amino acid they’re each carrying side by side then a polypeptide is formed and the amino acid chain forms the final polypeptide
-process wwill be stopped by a stop codon
state the 3 tyoes of gene mutation
substitution. deletion and insertion
what are coding and non-coding sequences called
exons and introns
in the chain of amino acids coding for red blood pigmentation which no. of amino acid will undergo s mutation and what disease am i talking about?
amino acid number 6 and sickle cell anaemia
glutamic acid is replaced by valine
a substitution mutation takes place and a T is replaced by an A
state similarities and differences between introns and exons
introns and exons are both transcribed and they both have triplet bases
exons are translated and introns are not translated
exons code for a specific amino acid introns do not code for anything
exons are coding and introns are non-coding
exons remain in the RNA and introns are removed from the RNA moelcule
what is meant by non-overlapping
bases present in one codon are not present in adjacent codons or are not present in the formation of adjacent codons
