Mutations (lesson ten) Flashcards
how many cells does your body make in a day
Your body makes billions of cells in a day
Mutations
- sometimes, your body may make mistakes or the environment may cause errors to happen during division
- These mistakes that can be made are called mutations
impact of mutations
These errors in the “code” may have a positive or negative impact or no effect on the individual at all
how can mutations be caused?
They can be caused by chemicals, environmental factors, radiation, etc.
What Causes a Spontaneous Mutation to Occur?
- Spontaneous mutations are those that happen in nature by accident
- These are a result of incorrect copying of DNA during the replication of chromosomes in mitosis and meiosis
What Causes an Induced Mutation to Occur?
- Induced mutations are a result of exposure to a physical or chemical agent
- This would include mutations that are a result of exposure to UV radiation, cigarette smoke, chemicals in processed foods, etc.
Point Mutations
- A point mutation is a failure by the replicating cell to copy the genetic information accurately
-This may be the result of a: - Base-pair substitution
- Base-pair insertion
- Base-pair deletion
Chromosome Mutations
- Chromosome mutations involve a mutation involving an entire chromosome or large part of it
- Non-disjunction would be an example of a chromosome mutation that can happen in meiosis
- This can result in genetic disorders if it happens in gametogenesis or early in development during mitosis
- Some examples can be seen Lesson 10 slide 10
Inheriting Mutations
- Mutations can occur as the DNA in an organism’s cell is copied
- most mutations occur in the parts of DNA that do NOT code for genes
- Also, many mutations that DO occur in the coding regions are immediately corrected during the replication process
what happens to mutations as an organism ages?
As organisms age, there is a greater likelihood that these mutations (or “mistakes” that occur during mitosis) can lead to more devastating effects (i.e. diseases - like the development of cancer)
somatic cells
Mutations that occur in somatic cells (body cells/autosomes) are not passed onto offspring so therefore, they do not affect future generations
can mutations occur in the formation of gametes
yes mutations can occur in the formation of gametes
mutations that occur in the formation of gametes (sex cells)
- mutations that occur in the formation of gametes (sex cells) become part of the DNA of the zygote
- This means that the offspring/new individual will have a copy of the mutation in every cell of its body, including its sex cells, and will be able to pass it on to future generations
Lactose Intolerance
- Lactose intolerance is a very common trait in which an individual is not able to digest lactose, the common sugar in milk
- This is caused by a deficiency of the enzyme lactase (which breaks down lactose)
- If these individuals consume a lot of dairy, the undigested lactose will be metabolized by the intestinal bacteria which can cause bloating, cramping, and diarrhea
Sickle-Cell Anemia (SCA)
Sickle Cell Anemia is an example of a mutation which can be seen as both helpful and harmful
- This is caused by a single nitrogenous base substitution
- Single adenine base is substituted by a thymine
- This causes red blood cells to NOT be healthy and round, but instead, are c-shaped and less effective at moving oxygen around the body via the blood (as their shape does not allow for proper travel through the vessels)
- It also is associated with causing pain and an increased risk of infection
