New Technology Flashcards
What are alleles?
Different forms of the same gene.
Name the type of allele that will produce a characteristic in an organism.
Dominant allele
How many copies of a recessive allele are needed for it to be expressed?
Two.
Can characteristics be predicted?
Yes, scientists able to predict what an organisms offspring will look like by carrying out a genetic cross. They often do so by using a punnet square.
If a mother has blue eyes (bb) and a father has brown eyes (Bb) what are the chances of the child having blue eyes?
2/4- 50%
What is a genetically inherited disorder?
A condition passed from parents to their offspring in their genes.
State what is meant by a carrier.
A carrier is a person who has one copy of a dominant allele and one copy of a recessive allele. They only show the characteristics of the dominant allele.
What is polydactyly?
A disorder that results in a child being born with extra digits on their hands or feet. They can be small stumps of soft tissue or extra fingers or toes.
It is caused by a dominant allele, therefore even if only one allele for this disorder is present, the person will have the disorder.
What is cystic fibrosis?
A disorder that causes sufferers to produce lots of thick sticky mucus, blocking their air passages and making it difficult to breath. It can lead to chest infections, and the excess mucus also causes difficulty in food being absorbed.
What is selective breeding?
A method of breeding organisms to produce offspring with desired characteristics.
What are the steps of selective breeding?
- Decide which characteristic(s) of the species is most important.
- Select parents that show high levels of this characteristic.
- Breed these individuals.
- Select the best offspring and breed again.
- Repeat for many generations.
Describe a disadvantage of selective breeding.
Leads to a reduced gene pool, and may cause the accidental loss of useful genes. For example, if a new disease occurs, an organism may not exist that contains the gene for resistance to this disease and could result in a species becoming extinct.
State the effect of selective breeding on variation.
Selective breeding reduces a species gene pool and therefore reduces variation within a species.
What is genetic engineering?
A technique where scientists insert foreign genes unto organisms to change their characteristics.
State an advantage of genetic engineering.
It is a very precise process, as single genes can be targeted.
State an advantage of using genetic engineering to create organisms with desired characteristics over selective breeding.
Genetic engineering can happen in one generation so is a much quicker process than selective breeding.
It is definite that the desired characteristics will be achieved, as single genes can be targeted, unlike using selective breeding, where useful characteristics may sometimes be bred out.
Where is DNA found?
In the nucleus of almost all do our cells.
Describe the steps of genetic engineering.
- Certain gene is removed from the DNA in a certain cell.
- Loop of bacterial DNA is cut open and the chosen gene is inserted into it.
- The loop of bacterial DNA is placed into a host bacteria which is now genetically modified.
- The genetically modified bacteria is placed into a fermenter.
- Bacteria multiply in the fermenter.
- The large number of genetically modified bacteria in the fermented produce the chosen characteristic.
- The product is extracted from the fermenter and used.
Give an example of genetic engineering.
- Genetically engineering bacteria to produce medicinal drugs (eg insulin)
- producing frost resistant tomatoes by inserting flounders fish antifreeze gene into the cell of a tomato plant.
- genetically modifying corn to produce fixings that kill insects.
How can you alter an organisms genes?
In order to create an organism with a desired characteristic, genes are taken from another organism that shows the desired characteristic. These are known as foreign genes. The foreign genes are put into plant or animal cells say a very early stage of the organisms development. As the organism develops, it will display rue characteristics of the foreign gene.
What is a clone?
An organism that is genetically identical to its parent.
What is asexual reproduction?
Reproduction using only one parent.
Give examples of plants that can reproduce asexually.
Potato plants- produce many tubers, each or which can grow into a new plant.
Strawberry plants- produce long stems with tiny plants on the end (plantlets)
Daffodils- at the end of each growing season a new bulb is formed from which next years flower grows.
