DNA (B2) Flashcards
What are chromosomes?
a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
What is a gene?
(in informal use) a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
(in technical use) a distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell (or virus) may synthesize.
Explain why almost everyone’s DNA is unique.
Everyone’s DNA is different because everyone gets a random mix of the genes from their mother and father, and that random mix is never the same.
Even identical twins have tiny differences in their DNA, because during our development and lifetime we all get a few tiny mutations and those are different in different people.
What are the advantages and disadvantages of a genetic database?
ARGUMENTS FOR:
A DNA database covering the whole population and every visitor to the UK, as advocated by Lord Justice Sedley, would save massive amounts of police time and help clear up crimes faster.
Those who do nothing wrong have nothing to fear and should be reassured.
The current system - the DNA of all those arrested for recordable offences, guilty or not, is retained - is selective and inefficient.
Current practice is unfair: ethnic minorities and young people are over-represented, creating resentment and anti-police feeling. Two-in-five black men have their DNA on record, as against fewer than one-in-ten whites.
The world has changed: international mobility means that potential terrorists can come and go, often on false papers.
ARGUMENTS AGAINST:
It would be the ultimate step on the road to a ‘Big Brother’ state: Britain would become ‘a nation of suspects’.
Whatever the utility of DNA samples, there is something inherently disturbing about entering every baby on a database at birth.
A national DNA bank would be massively expensive and bureaucratic.
It would be damaging to the image of the UK - ‘Welcome to Britain: now provide a mouth swab’.
DNA information could be abused by corrupt police and others illegally passing information to unauthorised people.
What are the similarities and differences between mitosis and meiosis?
Meiosis and mitosis are both preceded by one round of DNA replication; however, meiosis includes two nuclear divisions. The four daughter cells resulting from meiosis are haploid and genetically distinct. The daughter cells resulting from mitosis are diploid and identical to the parent cell.
What are stem cells? What are the advantages and disadvantages of their use?
Advantages
It provides medical benefits in the fields of therapeutic cloning and regenerative medicine.
It provides great potential for discovering treatments and cures to a variety of diseases including Parkinson’s disease, schizophrenia, Alzheimer’s disease, cancer, spinal cord injuries, diabetes and many more.
Limbs and organs could be grown in a lab from stem cells and then used in transplants or to help treat illnesses.
It will help scientists to learn about human growth and cell development.
Disadvantages
The use of embryonic stem cells for research involves the destruction of blastocysts formed from laboratory-fertilized human eggs. For those people who believe that life begins at conception, the blastocyst is a human life and to destroy it is immoral and unacceptable.
Like any other new technology, it is also completely unknown what the long-term effects of such an interference with nature could materialize.
Embryonic stem cells may not be the solution for all ailments.
According to a new research, stem cell therapy was used on heart disease patients. It was found that it can make their coronary arteries narrower.
A disadvantage of most adult stem cells is that they are pre-specialized, for instance, blood stem cells make only blood, and brain stem cells make only brain cells.
