18/09/2018
S30 Unit A: Biology
Mutations and Genetic Technologies
A recap so far:
In each ______(body) cell is a nucleus, and in each nucleus is _____ pairs of chromosomes, each containing one very long strand of DNA.
When all of these chromosomes are ordered, we have a ______.
The autosomal cells replicate via ______, which follows these general steps (from your notes) you should know...and the gametes (sex cells) replicate via ______, which follows these general steps (from your notes) you should know.
Chromosomes are broken into smaller chunks of DNA which control a various trait, called genes. Genes have different variations, called ______.
Punnett Squares and Pedigree Charts track how specific genes are passed down from generation to generation.
The actual DNA itself is chemically made up of three different molecules: a ______, a ______and a ______base.
There are four nitrogen bases (___denine, ____hymine, ___uanine and ___ytosine) in DNA which always form pairs (______and ______).
Getting three of these bases together gives the instructions for forming one type of ______, which in turn form proteins, which in turn make up your body.
We can decode some strands of DNA using the Data Booklet table.
DNA is self-replicating, and will "unzip" along the base pairs where ______bonds break, allowing fresh ______nucleotides to come in and make two identical copies of DNA.
When an change is made in the sequence of DNA bases, we get a ______.
Most mutations occur naturally, and each change is carried to next generation and inherited by offspring.Mutations increase variability and lead to ______, both beneficial and harmful.
Beneficial:
- Mutations can allow for adaptation to the environment; brighter flower color, camouflage coloring, etc.
- Allows for more chances to breed = more offspring with adaptation.
- Genetic inheritance is the key to ______.
Non - Beneficial:
Mutations usually occur in chromosomal regions where they do not affect the protein; thus body can ______some mutations.
Some mutations cause gene to stop working or alter function. This can lead to health problems.
Each disease occurs because of a mutation on 1 of the chromosomes in the parent and can be caused by recessive or dominant genes.
Mechanism of Mutation
______agents can also cause mutations:
- High energy electromagnetic radiation (X-rays, Gamma Rays)
- ______are mutagens that are known to cause cancer (uncontrolled cell growth): X-rays, cigarette smoke, pesticides…
Types of Mutations
There are 3 types of mutations:
- ______mutations (substitution of 1 base for another).
- ______mutations (deleting/adding a base during replication).
- Non-______(chromosomes do not properly separate during meiosis)
Common Genetic diseases include:
Hemophilia
- absence of a certain protein, which is required for blood clotting
- traced to a single defective gene (X-chromosome)
Cystic fibrosis
- deletion of the nitrogen bases on chromosome 7
- Lung secretions are thick and block airways
There are more down-sides to mutation...
- Antibiotic ______bacteria have adapted and mutated so they are not killed by antibiotics.
- Every time the bacteria is exposed to an antibiotic, more become resistant: pass on to the new bacteria.
Although bacteria do not reproduce sexually, they do have the ability to incorporate free DNA into themselves through the process of ______.
This allows the genetic info of one bacterium to be passed onto another.
The little bits of DNA that get transferred form circles called ______.
If the plasmid has info containing resistance to an antibiotic drug, then the bacterium that absorbs that plasmid gains that resistance.
Genetic Technologies
- Used to identify, treat and prevent hereditary disease; develop medicine, solve crimes and identify individuals.
- Ethical issues arise with this new technology.
DNA fingerprinting
- DNA fingerprinting test was developed in the mid-1980s.
- Particular segments of DNA are ______arrangements of nitrogen bases
- Only identical twins share same N base arrangements in these sections, but blood-family relationships can also be determined.
Transgenetics
- Genes from 1 species are transferred and ______into the DNA of another species.
- Results in agenetically modified organism (______).
- Used to create food,medicine or materials that will improve results.
- Crops with naturallyproducing pesticides.
- Bacteria that canproduce insulin.
- Pig organs that areclosely related to humans.
Gene Therapy
- Using genes to treat or cure a disease.
- Using an altered ______/______to deliver needed gene to individual’s cells.
The bacterium/virus is used like a ______man to introduce the DNA into the body's cells.
1. Scientists use enzymes to cut healthy DNA into pieces.
2. They then isolate desired gene and place it into a ______. This new DNA is called ______DNA; DNA with genes from 2 or more organisms.
3. They insert the plasmid into a bacteria/virus, which implants the new DNA.
On the diploma exam:
The following perspectives will be used:
-Societal: deals with society as a whole
-Cultural: Behaviors and beliefs of a group of people.
-Environmental: Ecology and human effects on the environment
-Ethical: Moral principles (right and wrong).
-Economic: money