Biology; Chemistry; Physics: Post your doubts here!

[luckywang]

40 Two heterozygotes are crossed. Some of the offspring show the recessive characteristic.

What is the probability that one of these offspring that shows the recessive characteristic is
homozygous?

Please anwer this with expalnation

answer is B? two heterozygous crossed will produce offspring with ratio 3(dominant characteristic):1(recessive characteristic)... so the probability is 1/4= 0.25?

 

[Dukeofwin]

answer is B? two heterozygous crossed will produce offspring with ratio 3(dominant characteristic):1(recessive characteristic)... so the probability is 1/4= 0.25?

I came up with same reasoning but its wrong! the correct answer is D)1

 

[ashiqbal]

Firstly it asks for recessive so it should be 0.25(becuase its 1 in 4)
However the correct answer from Marking scheme is D)1

sorry didnt read the question properly !
the genetic diagram will be same:
Aa * Aa
A---a__*__A---a
AA---Aa---Aa---aa
only aa shows recessive characteristic.
genotype of those with recessive characteristics is only aa
Therefore, the probability of the recessive being homozygous is 1/1 as heterozygous will only show dominant trait.

 

[luckywang]

C 0.50
draw genetic diagram
Aa * Aa
A---a__*__A---a
AA---Aa---Aa---aa
AA and aa are homozygous.
prabability = 2/4 =0.5

question wan homozygous with recessive characteristic?

 

[ashiqbal]

question wan homozygous with recessive characteristic?

yes. probability.

 

[luckywang]

sorry didnt read the question properly !
the genetic diagram will be same:
Aa * Aa
A---a__*__A---a
AA---Aa---Aa---aa
only aa shows recessive characteristic.
genotype of those with recessive characteristics is only aa
Therefore, the probability of the recessive being homozygous is 1/1 as heterozygous will only show dominant trait.

oh! i got it! this question is quite tricky!

 

[Dukeofwin]

sorry didnt read the question properly !
the genetic diagram will be same:
Aa * Aa
A---a__*__A---a
AA---Aa---Aa---aa
only aa shows recessive characteristic.
genotype of those with recessive characteristics is only aa
Therefore, the probability of the recessive being homozygous is 1/1 as heterozygous will only show dominant trait.

It asked for recessive which is 1 in 4! So the answer should be 0.25 right?
Its shows only 1 but is actually out of 4!

 

[luckywang]

physic syllabus 8(e), they wan the whole process or just wan what energy convert to what energy?

 

[Dukeofwin]

oh! i got it! this question is quite tricky!

okay, take it another way.
If it had asked for dominant than would your answer be 1 (3/3) or 0.75?

 

[luckywang]

It asked for recessive which is 1 in 4! So the answer should be 0.25 right?
Its shows only 1 but is actually out of 4!

read the question one more time! offspring that shows the recessive characteristic is
homozygous?

 

[Dukeofwin]

sorry didnt read the question properly !
the genetic diagram will be same:
Aa * Aa
A---a__*__A---a
AA---Aa---Aa---aa
only aa shows recessive characteristic.
genotype of those with recessive characteristics is only aa
Therefore, the probability of the recessive being homozygous is 1/1 as heterozygous will only show dominant trait.

okay, take it another way.
If it had asked for dominant than would your answer be 1 (3/3) or 0.75?

 

[luckywang]

okay, take it another way.
If it had asked for dominant than would your answer be 1 (3/3) or 0.75?

dominant homozygous or heterozygous or dominant characteristic is
homozygous?

 

[Dukeofwin]

read the question one more time! offspring that shows the recessive characteristic is
homozygous?

yes!! but the homozygous is 1 out of 4! which means its 0.25!

 

[Dukeofwin]

dominant homozygous or heterozygous or dominant characteristic is
homozygous?

yes or no or yes is no?

 

[luckywang]

physic syllabus 8(e), they wan the whole process or just wan what energy convert to what energy?

help me on this pls....

 

[luckywang]

yes or no or yes is no?

.... u making me confused....

 

[SilverCrest]

guess pastpapers or exact past papers...... just click this link sis...
http://www.xtremepapers.com/papers/

u got it?sis?

GUESS papers..not past papers..​

​

 

[SilverCrest]

but souldnt we FIND ANSWER of acc. in kilometres per hour^2?

i dont know..the question didnt specify..eitherway the standard is m/s^2 ..right???

 

[Dukeofwin]

.... u making me confused....

Right back at you, anyone could get confused by "dominant homozygous or heterozygous or dominant characteristic is
homozygous?" Doesn't seem a question nor does it look like an answer

 

[ashiqbal]

i dont know..the question didnt specify..eitherway the standard is m/s^2 ..right???

k