1What is meiosis used for?
It is used for sexual reproduction to create gametes
2Explain the process of meiosis
-the cell duplicates DNA
-the chromosome pairs line up in the centre of the cell
-the pairs are pulled apart, so each new cell only has one copy of each chromosome. one mothers, one fathers
-then the chromosomes line up again in the centre of the cell and divide again
- 4 gametes each with a single set of chromosomes
3What is a haploid?
a cell with one set of chromosomes
4What is a diploid?
a cell that contains both sets of chromosomes
5Is meiosis haploid or diploid?
diploid cells turn to haploid to then make a diploid fertilised egg
6What is DNA?
genetic material
7What's the structure of DNA?
two strands foiled to form a double helix
Sugar phosphate backbone with base bonding. Each base attaches to the sugar
A, T, C, G bases
8What base does base A attach to?
base T
9What base does base C attach to?
base G
10What base does the base T attach to?
base A
11What base does base G attach to?
base C
12Define genome
The whole of the genetic information of an organism
13Define gene
segment of DNA that codes for a specific protein
14How can DNA be extracted from fruit?
1. Mash up a kiwi and add salt and washing up liquid
2. Heat at 60 degrees for 5 minutes
3. Filter this
4. Cool the liquid and add ethanol
15Define allele
Different forms of a gene
16Why are there different inherited characteristics?
People have different alleles, dominant or recessive
17Define chromosome
carriers of genetic information that are copied and passed to new cells
18Define dominant allele
an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state
19Define recessive allele
an allele that only has an effect on the phenotype when present in the homozygous state
20Define homozygous
having two identical alleles of a gene
21Define hetrozygous
having two different alleles of a gene
22Define genotype
genetic makeup of an organism
23Define phenotype
physical characteristics of an organism
24Define gamete
a haploid male or female cell that unites with another of the opposite sex in sexual reproduction to form a zygote.
25Define zygote
a diploid cell resulting from the fusion of two haploid gametes; a fertilized egg
26What is monohybrid inheritance?
The inheritance of a single gene
27What is a punnett square?
A chart that shows all the possible combinations of alleles
28How is sex determined?
The egg always has an X chromosome.If the sperm has an X chromosome it will be a girl if it has a Y chromes, it will be a boy
29How are phenotypes determined?
by which alleles are present in the gene (multiple genes rather then just a single gene)
30What's influences the phenotype?
Genetic variation and environmental variation
31What's genetic variation?
Differences in characteristics as a result of mutation and sexual reproduction
32What's environmental variation?
different characteristics caused by the environment e.g nutrition
33What was the human genome project?
When hundreds of scientists came together to find out the sequence of base pairs in a man and a women
34What did the Human Genome Project allowed us to do?
to search for teens linked in inherited diseases and therefore their treatment, trace human migration patterns from the past
35What is genetic variation?
differences that occur in individuals within a species usually from mutations
36What are mutations?
changes in the genetic material
37Do mutations always affect the phenotype?
most have no effect on phenotype
some will have a small effect
rarely, others determine phenotype