Genetics Test Study Sheet
Where Heredity Goes Wrong
Mutation
-A sudden change in the gene or chromosome
Types of Mutation
1. Gene mutations
-Point mutation
-Mutation of single gene on a chromosome
-Involves one or two nucleotides
-Generally occur during replication
Ex/ Cystic fibrosis, sickle cell, Huntington’s
a) Substitution
-An incorrect nucleotide is substituted in place of the correct one
-Only one protein affected
CTGGAG
CTGGGG
b) Insertion
-One base is inserted from the sequence
CTGG AG
CTGG TGG AG
c) Deletion
-One base is deleted from the sequence
CTGGAG
CTAG
Insertions and deletions can be really harmful since adding or deleting a nucleotide
shifts the whole reading of the codons. It is also known as frame shift mutations.
2. Chromosome mutations
-Involves changes in number or structure of chromosomes
-Usually a failure in separation during meiosis
a) Deletion
-Loss of all or part of the chromosome
b) Duplication
-Extra copy of all or part of chromosome
c) Inversion
-Reverses parts of a chromosome
d) Translocation
-When part of one chromosome breaks off and attaches to another
e) Nondisjunction
-Failure of chromosomes to separate during meiosis
Bacterial Transformation
Biotechnology
-Application of technological process to living organisms
1) Production of medicine
2) Gene therapy/ treating diseases
3) Insect/ herbicide resistant crops
-Use gel electrophoresis to find certain genes
Transformation
-When one bacteria is changed by the gene from another strain of bacteria
Recombinant DNA
-DNA produced by combining DNA from different sources
-Makes it possible to change the genetic composition of an organism
Plasmids
-Separate circular DNA found in bacteria
-Widely used in recombinant DNA
1) Use restriction enzymes to cut the DNA and the plasmid so both have “sticky ends”.
2) Insert DNA into the plasmid.
3) Then, re-insert the plasmid into a bacterial cell which can rapidly divide
Studying the Human Genome
Restriction Enzymes
-Produced by bacteria
-Used to cut DNA molecules into restriction fragments
-Each enzyme cuts a specific DNA
Gel Electrophoresis
-Separates and analyzes restriction fragments which is stained
-Run DNA through a gel using electric current
-DNA (Neg. charged) will move to the opposite end of the gel (Pos. charged)
-Smaller fragments will move faster and farther
-Bands of varying lengths are visible
Human Genome Project
-International effort to sequence all 3 billion base pairs of human DNA and identify
all the genes.
-Pinpointed genes of many diseases and disorders
-Identified 3 million locations where single-base DNA differences occur in humans
What’s the Point?
1) Can lead to better, less expensive and more nutritious food.
a) GM food
-Produce higher yield of crops
-Are modified to be resistant to bugs and herbicides
-Growth hormones injected into certain animals
-Hoping to clone animals to increase food supply and save endangered species
2) Human health can be improved
a) Preventing disease
b) Medical research
c) Treating disease Ex/ Gene therapy
-Process of changing a gene to treat medical disorder
-Replacing faulty gene with normal one
d) Diagnosing disease Ex/ Genetic testing
Selective Breeding
-Allowing animals with wanted characteristics to breed
Inbreeding
-Continued breeding of individuals with similar characteristics
-Offspring has an increased chance of genetic defect
Hybridization
-Crossing different individuals to bring together the best of both organisms
-Offspring usually stronger than the parents
Finding Something Wrong
Karyotype:
-Way to organize a set of chromosomes.
-Used to see if there’s anything abnormal.
*Know how to determine if a person has a genetic disorder or not*