What is meiosis?
Is a type of cell division that creates sex cells with half the genetic info in each
What happens in meiosis?
-The chromosomes in the cell copy and attach to eachother
-the cells then divides into 2 with half of the genetic info in each
-The cells then divides again this time into 4 each with half the genetic info and go on to become gametes
What is the difference between haploid and diploid cells?
Haploid has a single set of chromosomes where as a diploid cell has 2 complete sets of chromosomes
Describe the structure of Dna
Dna is found in the nucleus in long stands called chromosomes. There are 2 stands of chromosomes which twist to for a double helix shape. In the backbone of the dna bases guanine and cytosine and bases adenine and thymine are bonded together with weak hydrogen bonds and are called complementary bases these bases are connected to sugars and phosphate of the dna forming a dna strand.
What do nucleotides consist of?
Sugars, bases and phosphate
What is an allele
Alleles are a variation of a gene
What does phenotype genotype, homozygous and heterozygous mean?
Phenotype is what the organisms look like
Genotype is the alleles an organsim had
Homozygous is when the alleles are same
Heterozygous is when the alleles are different
Heterozygous
What chromosomes do males have?
Xy chromosomes
What chromosomes do females have?
Xx
What is a mutation?
A mutation is a change in the dna sequence of an organism
What are Some causes of mutations?
Radiation,cell division and drugs
What was the human genome project?
It was a scientific project aimed to map and understand the genes in human dna
What does the human genome project allow doctors to do?
It allows doctors diagnose genetic disorders and give the right medication
What is genetic variation?
Variation resulting from different genes Eg hair,bloodtype
What is environmental variation?
Variation caused by the environment eg. Length of plant height and weight
describe the extraction of DNA practical
- first we combine salt and washing up liquid into a beaker this solution breaks down cell surface membranes
- next we mash some strawberries and add this to the solution then we filter the combined solution
- once filtered add 2 drops of protease enzyme to break down the proteins
- finally pour cold ethanol into the filtered solution to form a precipitate this is shown as a gooey layer forming
