G10 Genetic Mutation Flashcards
When a cell divides and makes a copy of its DNA, there are times that the copy is not perfect. This imperfect copy is called a _
mutant
change in the original DNA sequence is called a
mutation
occurs when there is a disruption in the complementary base pairing of the DNA
Genetic mutation
Some mutations cause the DNA sequence to change which results in amino acids that make up the protein assembled in a different order. When the incorrect sequence of amino acids is folded into proteins such as enzymes, the proteins may be defective.
Defective proteins then disrupt metabolic processes.
classification of genetic mutation
hereditary or somatic
a type of mutation inherited from a parent and is present throughout a person’s life in every cell of the body
Hereditary mutation
Hereditary mutation is a type of mutation inherited from a parent and is present throughout a person’s life in every cell of the body.
It is also called _ _ because it is present in germ cells or reproductive cells.
germline mutation
People with porphyria are characterized by their ability to produce high levels of porphyrin. Porphyrins are molecules needed to create hemoglobin, a protein present in your red blood cells responsible for capturing and transporting oxygen throughout your body.
occurs at a point in a person’s lifetime. It occurs only in specific cells
Somatic mutation or acquired mutation
It is commonly caused by _ _, such as exposure to radioactivity. It does not affect the egg and the sperm cell. Thus, it is not inherited from a parent and is also not passed onto offspring.
external factors
Mutations that occur in a somatic cell in the bone marrow can damage the cell, make the cell cancerous, or kill the cell. This mutation is not passed on to descendants.
These type of genetic changes happen not during fertilization but during the developmental stages of embryo where it starts to produce somatic cells.
mosaicism
Somatic mutations may lead to cancer, while mutations in the germ cells may lead to birth defects. In a worse case scenario, severe mutations may lead to immediate death.
Not all mutations are harmful. Sometimes, mutations tend to be useful and beneficial. When the mutation is beneficial, they are even incorporated to the normal gene pool and help organism evolve!
Human beings have a mutated gene that produces a mutated type of protein known as the _ which enables us to deliver complex speech and understand languages properly!
“forkhead box protein P2” (FOXP2
(GMOs)
genetically modified organisms
Another example of a useful mutation is the production of genetically modified organisms (GMOs).
Crops such as soybean, corn, and potatoes are genetically modified to increase pest resistance and produce more yield. Some carrots are engineered to increase their capacity to absorb calcium and other nutrients.
occurs when one DNA base is replaced by another, resulting in a change of codon in the RNA sequence
Point mutation
It is caused by _ _ such as transition and transversion.
base substitution
purine
guanine
adenine
pyrimidine
cytosine
thymine
a change from a purine to another purine or a pyrimidine to another pyrimidine
transition
occurs when a purine changed into pyrimidine
transversion
This type of genetic mutation can change a codon to one with a different amino acid sequence.
Transversion
point mutation classification
nonsense
missesnse
silent
occurs when a stop codon is gained or lost upon mutation
Nonsense mutation
A nonsense mutation which gains a stop codon is called a
stop-gain mutation
A nonsense mutation which loses a stop codon is called a
stop-loss mutation
A nonsense mutation which gains a stop codon is called a stop-gain mutation. Since a stop codon is gained, it prematurely terminates translation which results in an abnormally short polypeptide.
A nonsense mutation which loses a stop codon is called a stop-loss mutation. Since a stop codon is lost, it allows the translation to proceed further resulting in an abnormally long polypeptides.
codes for a different amino acid which may affect the integrity and function of the resulting polypeptide
Missense mutation
The amino acid change may not drastically affect the polypeptide, especially if the mutated amino acid and the original amino acid are of the same property and size.
Mutations that involve amino acids that are highly different from one another in terms of chemical property and size may lead to function loss which eventually cause severe diseases
codes for the same amino acid.
Silent mutation
Silent mutation codes for the same amino acid.
The resulting codon still codes for the same amino acid. This does not affect the protein’s structure and function. This is possible because there are 61 codons that translate to 20 amino acids
occurs when the mutation changes a reading frame of RNA
Frameshift mutation
classification of frameshift mutation
insertion
deletion
occurs when one or more DNA pairs are lost
Deletion
Deletion occurs when one or more DNA pairs are lost. It causes a frameshift that results in a completely different DNA sequence.
When this happens, enzymes are not produced, or if they are produced, they do not function properly.
An example of a disorder caused by this genetic mutation is cystic fibrosis.
Cystic fibrosis occurs when three nucleotides are deleted. This deletion results in a loss of amino acid phenylalanine at the 508th position of the protein.
In cystic fibrosis, the person produces thicker mucus, which causes the lungs to be congested.
occurs when one or more DNA pairs are added
Insertion
Insertion occurs when one or more DNA pairs are added.
The insertion of an extra base can completely alter the sequence of amino acids.
The frameshift may alter the position of the stop codon so the polypeptide chain may be shorter than the normal.
Huntington’s disease is an example of a genetic disorder brought about by insertion mutation. Here, trinucleotide repeats are inserted into the DNA sequence.
