Keywords in Genetics 🧬 🧬 🧬
In I/GCSE Biology, you would need to familiar with the keywords in genetic listed as below so that you can answer the question precisely.
DNA - The molecule which contains genes. It's shaped like a double helix (a spiral)
Chromosomes - Found in the cell nucleus: X-shaped things made up of long coils of DNA
Chromatids - The separate arms of the chromosomes
Centromere - Area at centre of chromosome where the separate arms meet
Gene - Section of DNA molecule
Allele - A gene, but there are two types of alleles
Homozygous - An organism with two alleles the same for a particular gene (e.g. HH or hh)
Heterozygous - An organism with two alleles that are different (e.g. Hh)
Dominant - An allele/gene that determines the characteristics in the organism (dominant over the recessive allele)
Recessive - Does not usually affect the phenotype of the organism
Genotype - The description of the GENES you have (e.g. MM or Hh etc...)
Phenotype - The description of your PHYSICAL ATTRIBUTES (e.g. hair colour)
Mitosis - Cell division - one cell splits into two identical cells
Meiosis - Cell division - produces haploid cells (the sperm / egg cells)
Diplod - Describes a cell with the full number of chromosomes (46 for humans)
Haploid - Describes a cell with half the full number of chromosomes
Zygote - A newly formed life just after fertilisation of the egg by the sperm
Gamete - A sperm / egg cell (both haploid)
Inheritance 🤱
Multiple and missing alleles 👨👨👧
genetic variation – different characteristics as a result of mutation and sexual reproduction
environmental variation – different characteristics caused by an organism’s environment (acquired characteristics)
That's the end of the topic!
Drafted by Joey (Biology)