*14.1 meiosis, Medelian inheritance
*14.3 population genetics
*14.7 food chains and webs
*14.9 carbon and nitrogen cycles
He noticed pea plants were either full sized (tall) or very short (dwarf)
He used self fertilisation to find PURE BREEDING PLANTS
Then produced offspring by FERTILISATION
All plants grew tall
So he took the offspring and crossed them with each other.
The offspring were ÃÂ¾ Tall and ÃÂ¼ Dwarf
Each plant has 2 genes
Genes give instructions to organisms-'grow tall' 'grow short'
If a plant has both type of gene the GROW TALL gene is DOMINANT the GROW SHORT is RECESSIVE
To show crosses we use symbols P-parents T-grow tall t-grow short
GAMETES: T & T x t & t
F1: Tt all offspring are TALL
2nd cross Tt x Tt
GAMETES: T t x T t
F2: TT, Tt, Tt, tt ÃÂ¼ will be DWARF
1.Mendel's experiment (second part) using PUNNETT SQUARES
2.Showing CODOMINANCE-Feather colour in chickens is controlled by CODOMINANT ALLELES C -allele for white feather C -allele for black
3.Showing MULTIPLE ALLELES-Blood group is controlled by a gene which has 3 alleles- I & I are co dominant and I is recessive
4.SEX LINKAGE- X chromosomes are LARGE, y chromosomes are SMALL-Male humans XY Women XX
5.DIHYBRID INHERITANCE-All previous examples dealt with the inheritance of a single characteristic e.g. MONOHYBRID INHERITANCE-With DIHYBRID INHERITANCE we are looking at the inheritance of a pair of characteristics.
Illustration of the process by which a single parent diploid cell (Both homologous chromosomes) divides to produce four daughter haploids cells (One homologous chromosome of the pair).
Meiosis is the type of cell division by which germ cells (eggs and...