DNA, Cell Division And Genetics Flashcards
Chromosomes
Genetic structures that occur in functional pairs in the nucleus of cells (except gametes)
Gene
A short section of DNA (chromosome) that codes for a particular characteristic
Genome
The entire genetic material found in an organism
What shape Is DNA folded into?
A double Helix
How are Base Sequences Read?
In sets of 3. Each group of 3 bases is called a Base Triplet. Each Base Triplet codes for a particular Amino Acid. The AA then combine to form Proteins
Mitosis
A type of cell division that produces cells genetically identical to the parent cell and to each other
Meiosis
A type of cell division that produces cells (gametes) that have half the normal chromosome number
Mitosis (key info)
Takes place throughout the body.
Important for growth/repair of cells.
Ensures the new ‘Daughter’ cells have exactly the same chromosome arrangement
Meiosis (key info)
Occurs in Sex organs (testes + ovaries)
Produces Gametes
Reduction Division
One cell produces 4 genetically different, haploid cells in 2 divisions
Independent Assortment
A process that takes place during meiosis, in which chromosomes are reassorted in the formation of gametes. (Causes variation in Individuals)
Allele
A particular form of a gene ( E.g Brown eye or Blue eye )
Homozygous
Both alleles of a gene are the same
Heterozygous
The 2 alleles of a gene are different
Genotype
Paired symbols showing the allele arrangement in an individual . E.g Rr
Phenotype
Outward appearance of an individual. E.g Blue eyes
What are Punnet Squares used for?
Genetic Crossing
Who is Gregor Mendel
The founder of Genetics (monk who carried out monohybrid crosses on peas)
Male Sex Chromosomes Vs Female Sex Chromosomes
M = XY , F = XX
The Y chromosome in males doesn’t contain?
Any Alleles
Genetic Conditions
Are a genetic fault (which can be inherited)
Haemophilia (inherited)
Condition caused by a problem with the blood clotting mechanism. Sufferers are at risk of excessive bleeding.
Cystic Fibrosis (inherited)
Frequent lung infections and problems with food digestion.
Huntingtons Disease (inherited)
Progressive Brain deterioration. Becomes apparent in middle ages. It is fatal and has no cure.
Down Syndrome ( mistake during gamete formation - not inherited)
Caused by the presence of an extra chromosome so that affected individuals have 47 chromosomes rather than 46.
What can Genetic Screening be used for?
Identifying the presence of genetic conditions (in a foetus)
What can Genetic Screening be used for?
Used to testa foetus (or person) for the presence of harmful alleles or other genetic abnormalities
How can you test for down syndrome?
Amniocentesis (taking foetal cells and growing them in a laboratory to check how many chromosomes each has).
Genetic Engineering
The deliberate modification of the DNA in an organism to introduce desirable characteristics.
Bacteria are Genetically engineered to make human insulin. How does this happen?
Special enzymes (restriction enzymes) cut the human gene in such a way as to leave overlapping strands of DNA.the same enzymes cut the bacterial plasmid (DNA) in the same way to leave complementary sticky ends. The sticky ends make it easy for the human and bacterial DNA to join through base pairing.
How is Genetically Engineered bacteria formed?
In large Fermenters that provide optimum conditions for growth and reproduction (and producing insulin)
Following the production of insulin, what then happens to it? And what is this called?
It is extracted, purified and packaged in a process called downstreaming
Advantages of producing insulin by Genetic engineering?
1) Before it, the amount of insulin available was limited (many animals would have needed to be killed)
2) Human insulin is slightly different in Structure (than animals so it would have been less effective)
3) Risk of Spreading Viruses (when transferring insulin from animals)
