monohybrid crosses and punnet squares (1 Viewer)

[cowamooners]

Hey everyone. Just wondering whether anyone could help me out on these punnet sqaure problems, any revelant answers to these questions would be most appreciated (referencing punnett squares;

how could u dtermine if an organism displaying a dominant characteristic is homozygous or heterzygous?

briefly explain he implications of thie technique and knowledge for society, ie, decision making about issues that concern people

breifly describe how medels work influenced the direction and nature of scientific thinking

comment on any patterns of inheritance you have detected whilst completly the problems.

 

[rooeys2]

Hey everyone. Just wondering whether anyone could help me out on these punnet sqaure problems, any revelant answers to these questions would be most appreciated (referencing punnett squares;

how could u dtermine if an organism displaying a dominant characteristic is homozygous or heterzygous?

briefly explain he implications of thie technique and knowledge for society, ie, decision making about issues that concern people

breifly describe how medels work influenced the direction and nature of scientific thinking

comment on any patterns of inheritance you have detected whilst completly the problems.

very broad questions =/. homozygous if when you have a pair of identical alleles, so if an organism is said to be homozygous dominant, thus it must be purebred. eg. homozygous dominant for blue eyes. BB (B-blue eyes dominant)
heterzygous is a pair of different alleles, one dominant, one recessive, if b=brown eyees recessive, then a heterozygous would have the genotype Bb. (it still has blue eyes, but carries a recessive blue eye gene)
i have no idea what u mean by the 'technique'?!

about mendel's work, he performed the experience on purebred pea plants, this means that he started out with homozygous parents. his discovery of dominance was significant as he also established the monohybrid ratio 3:1 (monohybrid = 1 characteristic)
eg. he studied the tallness in pea plants, purebred plants for two years, crossed purebred tall plant with purebred short plant TT * tt
all F1 offspring were tall plants of genotype (Tt)
he then self pollinated the offsprings and crossed them with each other:
Tt * Tt
produced simple ratio of 3tall:1short, this shows TALLNESS IS DOMINANT TO SHORTNESS
overall, mendel's work was significant as it allowed the scientific society to realise that in simple genetics, one allele is dominant and the other recessive, it explains a great deal of the occurance in phenotype&genotypes in the organisms present today.
hope that helps

 

[Undermyskin]

1. Depends but easy: Cross it with a homozygous organism with the recessive gene. If A is homo, F1 gives all offsprings with same dominant chracteristic. If hetero, you get 50:50. Use punnett Square: Aa*aa gives 2Aa:2aa. AA*aa gives 4Aa (Mendel's first principle of segregation).

2. Owing to my poor English, I can't comprehend what you mean. It's just too concise. You should explain more what you want. Decision made that concerns people? ... The implication of pedigree and family tree, I suppose? Because this dominant/recessive phenomenon has either the implication to find out the structure of chromosomes (but figured out already by Sutton and Boveri and only concerns scientists mostly. The pedigree helps trace the inheritance of certain diseases such as albino, epilepsy, etc.

3. It's the recognition of genetic characteristics that set the foundation and resources for further investigation such as in 1902 Hugo de Cries and another 2 (can't remember their names. Damn) who gave credits to Mendel's experiments. Thusly, we understand the mechanism of genetic inheritance from simple level to more complex ones relating to meiosis, the difference between it and mitosis, the chromosomes, structure of DNA coiled by Crick and Watson in 1950s, etc. It's basically the initial trigger for researches on the genes field. Without Mendel's work, it didn't mean people wouldn't figure out this mechanism but it would occur much later until the beginning of 20th century. Imagine it could have taken the same period to reach current knowledge and enlightenment, I don't think we could understand DNA as clearly like now, maybe our grandchildren would!

4. Which problem? Genes or er... factors? OK, from Mendel's works, we can see that factors occur in pairs. They separate suring the formation of gametes (this term is coiled much later). During fertilisation, the zygote cell formed is a hybrid of one chromosome of mommy and another from daddy.

That's about it.