Alleles and Phenotypes Flashcards
How is genotype different from phenotype?
A gene encodes a type of protein, an allele is a different gene sequence that codes for a different version of the protein
How is gene different from allele?
Genotype is the genetic information (DNA) in
cells, phenotypes are observable characteristics that arise from those genotypes
What creates new alleles?
Mutations (caused by replication errors or replication of damaged DNA)
What types of mutations are more likely to result in proteins with altered functions?
Mutations that significantly alter protein structure, such as a nonsense or frameshift mutation
2 reasons why most mutations do not affect phenotypes
Reason 1:
Reason 2:
Reason 1: If the mutation occurs in between genes
Reason 2: If the mutation occurs in an intron
2 reasons why most mutations do not affect phenotypes:
Reason 3:
Reason 4:
Reason 3: If a mutation does not alter the amino acid (synonymous mutation)
Reason 4: For organisms with two copies of most chromosomes, a mutation will not show a phenotype so long as one good copy remains
Process | that performs | sequence(s)
| the process | control each
| | process
———————————————-
Transcription| |
| |
| |
Primary enzyme | Relevant
RNA polymerase, Promoter and terminator
Process | that performs | sequence(s)
| the process | control each
| | process
———————————————-
RNA | |
processing | |
| |
Primary enzyme | Relevant
Splicing enzymes, Exons and introns
Process | that performs | sequence(s)
| the process | control each
| | process
———————————————-
Translation | |
| |
| |
Ribosome
Start codon, Stop codon
Process | that performs | sequence(s)
| the process | control each
| | process
———————————————-
DNA | |
replication | |
| |
DNA polymerase, origin of replication
Mutations that affect whether and how much transcription is occurring:
Mutations occurring in the promoter, enhancer, or silencer sequences that affect RNA polymerase and/or transcription factor binding
Mutations that affect the sequence or length of the mRNA:
Mutations to exons (whether translated or not)
Mutations that affect whether and how much translation is occurring:
Mutations to UTRs of proteins or that affect capping or poly(A) tail addition
Mutations that affect the sequence or length of the protein:
Mutations to translated regions of exons
The blood type gene encodes an enzyme that adds…
Sugars to proteins on the
surface of red blood cells
