General revision (Nucleic acids, DNA + plant Transport) Flashcards
(45 cards)
Define a gene mutation
A change in the sequence of base pairs in a DNA molecule
What is an insertion mutation?
When a nucleotide is randomly added into the DNA sequence
What is it called when a new base is removed or added? (For the rest of the DNA)
Frameshift
Describe a deletion mutation
Where a nucleotide is randomly removed from a DNA sequence
Describe a substitution mutation
When a base in the DNA sequence is randomly swapped for a different one
What are the three type substitution mutation?
- silent mutation
- missense mutations
- nonsense mutation
Describe a silent mutation
The mutation does not alter the amino acid sequence of the polypeptide
Describe a missense mutation
Mutation changes a single amino acid in the chain
Describe a nonsense mutation
The mutation creates a premature stop codon. The polypeptide chain is left incomplete and affects the final protein structure
Describe inversion in a gene section
- the DNA of a single gene is cut in two places
- the cut portion is inverted 180’ and rejoined to the same place
- a large section of the gene is read backwards and multiple amino acids are affected
Describe duplication of a gene (as a mutation)
- a section of a gene is duplicated so two copies appear on one chromosome
- mutation isn’t harmful and original gene remains intact
What gene mutation is responsible for evolutionary change?
Duplication mutation
Describe translocation of a gene (mutation)
- section of a gene is cut off and attaches to a separate gene
- both genes are likely non-functional
What is a factor that increases the likelihood of mutations?
Mutagen/mutagenic agent
What is the equation for photosynthesis?
Carbon dioxide + water = glucose + oxygen
Why did scientists doubt that DNA was the store of genetic information?
- because of the simplicity of the DNA molecule
What is the formula to calculate how many different codons are possible?
Different codon possibilities = number of different bases ^(number of nucleotides)
What is the function of a ribosome during translation (2 marks)
- to assemble amino acids into specific proteins
- by facilitating tRNA binding
What is the sediment that forms at the bottom tube during centrification?
A pellet
What is the centrifuged liquid called?
Supernatant
What is a locus?
A locus is the position of a gene on a chromosome
