Unit 3 Part 1 Flashcards
Mutations and gene editing
Mutations?
Any change to RNA or DNA base sequence of cell
What’s involved in DNA replication?
Enzymes
Transcription
Synthesis of RNA using DNA as template
What transcribes DNA to RNA?
Enzyme RNA polymers
Translation
Synthesis of polypeptides by ribosomes
What do ribosomes need to synthesize polypeptides?
mRNA and tRNA
What do mRNA and RNA do in translation?
mRNA
- Brings genetic code to ribosomes
RNA
- Brings amino acids to the ribosomes
Gene mutations
Change in nucleotide sequence of a gene
Types of gene mutations
Point mutations
- Changes one base in DNA sequence
Substitutional mutations
- When one or more nucleotide(s) in DNA sequences are replaced by another nucleotide
Insertion mutations
- When one or more nucleotide(s) are added to the DNA sequence
Deletion mutation
- Happens when one or more nucleotides are removed from DNA sequences
Single nucleotide polymorphism
Happens when a single nucleotide in a gene changes resulting in different amino acids in a protein
Allele
Gene in the population
- A mutation that creates a single nucleotide polymorphism produces and alternative version of an allele
Polymorphism
Occurrence of 2 different phenotypes w/in a population
What are the results of single nucleotide based solutions?
single nucleotide polymorphisms
Base substitution mutations
Single base substitution mutation changes the nucleotide sequence for 1 codon w/in a gene
Why could base substitution mutation not be able to change amino acid sequences?
Due to degeneracy of genetic code
- Genetic code is degenerate b/c 1 acid can be coded by more then 1 codon
How is a different protein sequence produced?
When a codon mutates to code for a different amino acid or a stop codon
Insertion mutation
Adds 1 or more nucleotides(s) to a gene
- Changes many codons as they are triplets of nucleotides
- All codons are changed after insertion
- Insertion mutation will release protein w/multiple different amino acids
Deletion mutation
Removes 1 or more nucleotide(s) from gene
- Changes many codons as they are triplets of nucleotides
- All codons are changed after deletion
- Deletion mutation will release protein w/multiple different amino acids
Frame shift mutation
Results from insertion/ deletion of nucleotides that are not in multiples of 3
- Changes all codons after mutation
Point Mutation
Changes 1 nucleotide in single codon
- Could change a singular amino acid in a protein
Frame shift mutation features
- Insertion/ deletions disrupt reading of codons in gene
- Polypeptides created by FSM are unlikely to function as many codons have different sequences of amino acids
Causes of gene mutation?
Naturally through DNA replication or in repair of damaged DNA
Mutagens
Agents that cause permanent, heritable changes to DNA of cells
High energy radiation of mutagens?
- High energy electromagnetic radiation like ultraviolet light
- x-rays, gamma lights = mutagens
Radioactive isotopes of elements release alpha and beta particles (mutagens)
How are mutagens chemicals?
B/c they react w/ and damage DNA
- Alkylciting agents used in chemo = mutagens
- Tobacco smoke = has many mutagens ( polycyclic chromatic hydrocarbons) formed when lighted up
Why are mutations random?
They happen anywhere w/in genome but vary according to nucleotide and have no natural mechanisms for deliberate mutation, creating new allele for gene, and changing a trait
Cytosine
Nitrogen base/ highest probability of mutating
Consequences of mutations
Can be neutral, beneficial, or harmful
- Most are neutral b/c they occur w/in noncoding sections of DNA that have no function or b/c of the degeneracy of genetic code
- Many are harmful but could be beneficial for survival and reproduction reasons
Germ Cells
Develops into gamets
What happens if the gamete that the Germ cell is developing into has mutilated cell?
The allele will be present in zygote after fertilization
Somatic cells
Any cell that is not reproductive meaning mutations are not passed off to offsprings
Natural selection
Differential survival due to inheritance of traits that make an individual more likely to survive and reproduce w/ alleles and are made by mutagens
Natural selection traits
Causes evolution of species overtime
- Genetic variation is required for evolution
Mutations are a key source of variation for natural selection
Gene knockout
Technique where the targeted gene is inactivated/ removed from an organism
- Allows scientists to study the impact on an organism of removing a gene
Gene Knockout organisms
Mice
- Created for nearly all of the mice coded genes
Fruit fly
- Cover most of the fruit by genome
Zebrafish
- Developed to study ventelorcte development + diseases
