The OG Blueprint
This is what DNA stands for
What is Deoxyribonucleic acid?
The process of using DNA as a template to make RNA, such as messenger RNA (mRNA).
What is Transcription?
The process in which a ribosome reads mRNA codons and joins amino acids to make a polypeptide
What is translation?
A permanent change in the base sequence of DNA
What is a mutation?
An organisms observable characteristics, resulting from its genotype and environmental influences
What is a phenotype?
A section of DNA containing the information needed to produce a functional product, like a protein
What is a gene?
Transcription occurs in this part of a eukaryotic cell
What is the Nucleus?
What is the ribosomes in the cytoplasm?
Three common types of gene mutations
What is Substitution, Insertion and Deletion?
These are the building blocks of proteins
What is an amino acid?
These are the four Nitrogenous Bases found in DNA
What is Adenine (A), Thymine (T), Cytosine (C), and Guanine (G)?
This enzyme builds the RNA strand during transcription
What is RNA Polymerase?
A sequence of three nucleotides on mRNA that specifies an amino acid or a stop signal.
What is a codon?
A mutation that does not change the amino acid encoded by a codon, so the primary amino acid sequence remains unchanged
What is a Silent Mutation?
A proteins specific shape allows it to interact with particular molecules and carry out its function. Changes in shape can alter its function
Why does the shape of a protein matter?
A gene is a section of DNA associated with a particular product or characteristic. Alleles are different versions of the same gene, resulting from differences in DNA sequence.
What is the difference between a gene and an allele?
A DNA template strand has the sequence TAC GGA CTT. What is the complementary mRNA sequence?
AUG CCU GAA. RNA uses uracil (U) instead of thymine (T).
What is the role of tRNA during translation?
Each tRNA carries a specific amino acid and has an anticodon that pairs with a complementary mRNA codon, helping put amino acids in the correct order.
Why can an insertion or deletion of one nucleotide have a greater effect on a protein than a substitution?
A one-nucleotide insertion or deletion can cause a frameshift, changing the grouping of bases into codons from that point onwards. This can alter many amino acids and may introduce an early stop codon.
Explain how a gene can influence a characteristic such as eye colour.
The gene's DNA sequence provides instructions for making a protein involved in pigment production or distribution. The protein's activity influences the pigment present in the iris, contributing to eye colour, alongside other genes and factors.
Why can nearly all cells in an organism contain the same DNA but have different structures and functions?
Different cell types express different sets of genes. This means they produce different RNA and proteins, leading to different structures and functions despite having largely the same DNA.
A mutation changes one base in the DNA sequence of a gene that codes for an enzyme. The mutation causes a different amino acid to be incorporated into the protein.
Explain how this mutation could affect gene expression, the enzyme's function and the phenotype of the organism. Your answer must link the DNA sequence, transcription, translation, protein structure and biological function.
The mutation changes the DNA base sequence. During transcription, this can result in a different mRNA codon. During translation, the altered codon may cause a different amino acid to be incorporated into the polypeptide. This changes the protein's primary structure and may affect how it folds into its three-dimensional shape. If the enzyme's active site changes, its substrate may bind less effectively or not at all, reducing the rate of the reaction. The resulting change in cell function may cause a change in phenotype. The effect is not guaranteed: some amino acid changes have little or no effect on protein function.
Explain how the sequence of bases in a gene determines the primary structure of a protein.
The DNA base sequence is transcribed into a complementary mRNA sequence. The ribosome reads mRNA codons, and tRNAs bring the corresponding amino acids. These amino acids are joined by peptide bonds in a specific order, forming the protein's primary structure.
A mutation changes a codon so that a different amino acid is added to a protein. Explain how this could change the organism's phenotype.
The altered amino acid sequence may change how the protein folds and its three-dimensional shape. This can alter the protein's function, affecting cell processes and potentially the organism's observable characteristics. The effect depends on where the change occurs and the protein's role.
Two people have the same allele for a gene, but environmental differences cause different levels of gene expression. Explain how their phenotypes could differ.
Environmental factors can affect whether, when or how strongly a gene is expressed. Different amounts of mRNA and protein may be produced, changing the effect on cells and potentially causing differences in phenotype even when the allele is the same.