Q&A - P5 Science

[guchengyouzi]

Thanks.

Interesting fact indeed.
This world is full of stranger things than you can imagine.

[susan88]

Please help to answer the following, thanks.


Extracted from 2012 ACS P5 SA1, Q27:
.
Jerome poured 50g of salt into a container of 100 ml of water.
a) What will happen to the water level in the container? Why?
b) What will happen to water level in the container after Jerome stirs the water until all the salt is completely dissolved? Why?

[guchengyouzi]

susan88:

Please help to answer the following, thanks.


Extracted from 2012 ACS P5 SA1, Q27:
.
Jerome poured 50g of salt into a container of 100 ml of water.
a) What will happen to the water level in the container? Why?
b) What will happen to water level in the container after Jerome stirs the water until all the salt is completely dissolved? Why?

a)Water level increases because salt is solid and occupies space.
b)Water level decreases but not back to the original position because the salt is not solid anymore but has turned into solution which occupies less space.

[Hougangdaddy]

Shouldn’t the nucleus of sperm be label and name as it also contributes to the baby blood group?

[Hougangdaddy]

Include picture for my question above. http://i62.tinypic.com/1zg3o12.png\">

[Hougangdaddy]

http://i61.tinypic.com/fkwp06.png\">


Question : Which of their children is a carrier of the genertic disorder trails?
Answer given : Jolene.
DDs answer : Jolene and Joshua. Why is Joshua not a carrier?

Appreciate your help!

[HFPMAT]

Your DD's answer is correct ,both Jolene and Joshua are carrier of genetic disorder.

Hougangdaddy:

http://i61.tinypic.com/fkwp06.png\">


Question : Which of their children is a carrier of the genertic disorder trails?
Answer given : Jolene.
DDs answer : Jolene and Joshua. Why is Joshua not a carrier?

Appreciate your help!

[Max]

http://i61.tinypic.com/fkwp06.png\">

Jolene is the unaffected carrier daughter while Joshua is the affected son. For a person to have a recessive disorder, it requires two copies of the mutated genes. Males are affected by a single X-linked recessive gene from their mother. This is because they do not have a second X chromosome to override the recessive trait.

In conclusion, a woman who is a carrier of a X-linked recessive disorder has a 25% chance of either having an unaffected son, or having an unaffected daughter, or having having an unaffected daughter who is a carrier, or having an affected son.

The question asked for which of the children is a carrier of the genetic disorder traits. So the correct answer is Jolene only. Joshua is the affected son.

[guchengyouzi]

Hougangdaddy:

http://i61.tinypic.com/fkwp06.png\">


Question : Which of their children is a carrier of the genertic disorder trails?
Answer given : Jolene.
DDs answer : Jolene and Joshua. Why is Joshua not a carrier?

Appreciate your help!

Basically Jolene and Joshua have the bad genes. The difference is that Joshua is suffering from the disease of the bad gene while Jolene isn't. That's why Jolene is called the carrier, appearing normal but has the bad gene.

[guchengyouzi]

But to be more precise, this kind of gene is called recessive gene. If you receive one good and then one bad gene, this recessive gene would not show up as disease. The good gene is strong enough to negate the effect of the bad gene.