Definitions Flashcards
Anticodon
An anticodon is 3 bases on tRNA molecule that are complementary to the mRNA codon.
Codon
A codon is 3 consecutive bases on the mRNA strand that codes for an amino acid.
Deletion Mutation
A deletion mutation is a mutation on the DNA where a base(s) is deleted from the DNA sequence resulting in a frameshift.
DNA
DNA is a large molecule which is a double-stranded helix shape, where A joins with T and C joins with G.
Enzyme
An enzyme is a folded protein that acts as a biological catalyst to speed up the rate of a chemical in an organism/cell.
Frameshift mutation
After a mutation, all the triplets are incorrect as they are not ‘read’ in their correct threes.
Gene
A gene is a piece of DNA that codes for a particular trait or characteristic.
Gene expression
Gene expression is the process where the instructions on our DNA are converted into a functional protein, this includes transcription, translation, and protein folding.
Genotype
A genotype is the genetic makeup of an organism for a feature
Insertion mutation
where a base is inserted into the DNA sequence resulting in a frameshift
Metabolic pathway
A metabolic pathway is a series of enzyme-controlled reactions, where the product of one reaction becomes the substrate of the next.
Missense mutation
Missense mutations are changes of the base on the DNA which codes for a different amino acid. This may or may not alter the shape of the protein and therefore its function
mRNA
mRNA is the messenger RNA, which is made during transcription in the nucleus. This carries the instructions to the ribosome to make a polypeptide chain. contains codons.
Mutagen
An Environmental factor like radiation or chemical substance that causes the mutation.
Mutation
A mutation is a permanent change in the bases of the DNA, they are the ultimate source of variation because they can create new alleles.
Non-sense mutation
A non-sense mutation is a change of the base on the DNA which changes the instructions, so a STOP codon occurs in the wrong place. Protein is greatly affected
Peptide Bond
The bond joining amino acids to each other in a polypeptide chain during translation
Phenotype
The phenotype is the physical appearance of a feature
Point mutation
A point mutation is a change of only one or a few bases in the DNA
Protein
A molecule containing long strings of amino acids joined together by peptide bonds
Redundancy
The fact that multiple codons code for the same amino acid - eg : CCU, CCC, CCA, and CCG all code for the amino acid Pro
RNA
RNA is short and single-stranded, where U bonds with A, and G bonds with C. There are 3 types of RNA tRNA, mRNA, and rRNA
Silent Mutation
A silent mutation is a mutation that is neither favourable nor harmful, that remains in a population
Start codon
A start codon is the start signal on the mRNA which initiates translation. This is always AUG
Stop codon
These 3 codons on the mRNA (UAA, UAG,UGA) do not code for an amino acid therefore telling the ribosome where to stop translation
Substitution mutation
A substitution mutation is a mutation where the base(s) on the DNA are swapped
Transcription
making an mRNA copy of DNA with the help of enzymes including RNA polymerase
Translation
mRNA is read by ribosome to produce a particular sequence of amino acids
Triplet
A triplet is 3 consecutive bases on the DNA that code for an amino acid
tRNA
tRNA is the transfer RNA. this carries an amino acid to the ribosome, 3 bases on the mRNA = an anticodon
Allele
Alleles are alternative forms of genes
Alpha Helix
A secondary structure in proteins where there is coiling of the polypeptide chain
Amino Acid
Amino Acids are organic molecules that are the building blocks of proteins
Beta pleated sheets
common in the secondary structure of proteins that is a twisted, pleated sheet of several stands.
Chromatid
A chromatid is one-half of a replicated chromosome.
Chromatin fibre
when DNA is being read for protein synthesis it exists as chromatin fiber not tightly wound in chromosomes
Coding strand
The coding strand is the strand of DNA that is not used for transcription and is identical in sequence to mRNA, apart from the mRNA having U, not T.
Deoxyribose
the sugar component in the side chains of DNA
Double Helix
The twisted ladder shape of DNA with a phosphate sugar backbone.
Nucleotide
The subunit of DNA, made of a sugar-phosphate and a nitrogenous base
Polypeptide chain
A long chain of amino acids joined by peptide bonds
Purine
Double ring structure bases G & A
Pyrimidine
Single ring structure bases C, U, & T
Ribose
The suagr component in the single stands of RNA
Ribosome
The site of protein synthesis. Made of rRNA
Missense mutation
Different amino acid
same sense mutation
same amino acid
nonsense mutation
stop codon
substrate
Molecule/substance that binds with an enzyme in a chemical reaction
template strand
The strand of DNA that the RNA polymerase uses as a guide to build complementary mRNA
Uracil
A base found in RNA instead of thymine pairs with adenine
Enzymes are a type of
protein
