Module 6 - Miss Estruch

• What is a mutation in genetics?

  Change in base sequence of DNA
• When do gene mutations most likely occur?

  During DNA replication
• What increases the likelihood of random mutations?

  Exposure to mutagenic agents
• Name a type of mutagenic agent.

  High energy radiation
• What is a base substitution mutation?

  One base is replaced by another
• What is a base deletion mutation?

  One base is removed from the sequence
• What happens to the codons after a base deletion?

  All subsequent codons change
• Why can a base substitution be silent?

  It may still code for the same amino acid
• What is the effect of a frame shift mutation?

  It alters all subsequent amino acids
• How do mutations affect protein structure?

  They can change the amino acid sequence
• What happens when a transcription factor binds to DNA?

  Transcription of the gene begins
• What is the role of transcription factors?

  They initiate transcription of genes
• How do eukaryotes control transcription?

  Through specific transcription factors
• What is an operon?

  A group of controlled genes
• Where is the lac operon found?

  In E. coli
• What is the function of the lac operon?

  Aids in lactose digestion
• What happens when glucose is absent?

  Lactose is digested instead
• What does the LacI gene code for?

  A repressor protein
• What occurs when lactose is present?

  Lactose binds to the repressor
• What is cAMP's role in the lac operon?

  Increases transcription rate
• What is pre-mRNA?

  Newly synthesized mRNA before modification
• What is splicing?

  Removal of introns from pre-mRNA
• What is alternative splicing?

  Reordering of exons to create proteins
• What happens during post-translational changes?

  Proteins are modified after translation
• What are homeobox genes?

  Genes that regulate body development
• What is the significance of symmetry in body development?

  It indicates proper body part positioning
• What are Hox genes responsible for?

  Correct body development in animals
• What is mitosis?

  Increase in number of cells
• What is apoptosis?

  Programmed cell death
• How is the cell cycle controlled?

  By genes regulating cell division
• What do tumor suppressor genes do?

  Stop the cell cycle from continuing
• What are proto-oncogenes?

  Genes that initiate the cell cycle
• What is genotype?

  Genetic constitution of an organism
• What is phenotype?

  Expression of genes and environment interaction
• What does homozygous mean?

  Same alleles for a single gene
• What does heterozygous mean?

  Two different alleles for a single gene
• What is a recessive allele?

  Expressed only if no dominant allele present
• What is a dominant allele?

  Always expressed in phenotype
• What does codominant mean?

  Both alleles expressed in heterozygous
• What are multiple alleles?

  More than two alleles for a single gene