Diploid/Haploid, 2n=20, I am confused?

[Dencology]

Guys, i still don't get particular problem. i don't get the difference or the similarity of these two questions and more importantly, i don't know how to approach them. i wanted to know if any of you can explain to me how i should be looking that these problems and how to attack them. thanks.


1. The maximum number of chromosome combinations among the gametes of a diploid organism is

(2n=10) asn. is 32

a. 2
b. 4
c. 6
d. 16
e. 32


2. A diploid cell (2N=20) has how many tetrads

a. 0
b. 10
c. 20
d. 40
e. 80

ans. 10

would you explain for both questions. thanks

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[Svart Aske]

1. 10 chromosomes, 5 homologous pairs.
2^5 = 32

2. A tetrad consists of a chromosome pair, 20 chromosomes will result in 10 tetrads.

Hope this is correct.

 

[Dencology]

1. 10 chromosomes, 5 homologous pairs.
2^5 = 32

2. A tetrad consists of a chromosome pair, 20 chromosomes will result in 10 tetrads.

Hope this is correct.

I still don't understand the first question. how would the answer be 32. i mean i understand that 2<5 is 32 but what does it have to do with this question? thanks.

 

[steelrfan8]

I still don't understand the first question. how would the answer be 32. i mean i understand that 2<5 is 32 but what does it have to do with this question? thanks.

2n = 10 diploid which means there are 10 PAIRS of chromosomes in the organism. This would be analogous to you having 46 chromosomes where you got 23 from mom and 23 from dad. Keep in mind the question is talking about combos in GAMETES which is haploid odds, not diploid.

So a 2n=10 diploid organism is n=5 haploid meaning there are 5 chromosomes each parent can donate to make a diploid organism...... so lets say we have chromosome 1 2 3 4 5 from mom and chromosome 6 7 8 9 10 from dad; when they donate to make a diploid organism mom can deliver xsome 1 and dad xsome 6, or 2 and 9, or 5 and 7 etc etc.......... so you take 2 chromosomes total which the zygote would have and figure out different combos of 5 xsomes mom and dad can deliver so it would be 2X2X2X2X2 or 2^5 which is 32 different combos.

I'm not sure if the above is a 100% correct explanation but thats what makes sense to me; if anyone can verify or correct a mistake in logic I made it would be appreciated.

 

[Dencology]

2n = 10 diploid which means there are 10 PAIRS of chromosomes in the organism. This would be analogous to you having 46 chromosomes where you got 23 from mom and 23 from dad. Keep in mind the question is talking about combos in GAMETES which is haploid odds, not diploid.

So a 2n=10 diploid organism is n=5 haploid meaning there are 5 chromosomes each parent can donate to make a diploid organism...... so lets say we have chromosome 1 2 3 4 5 from mom and chromosome 6 7 8 9 10 from dad; when they donate to make a diploid organism mom can deliver xsome 1 and dad xsome 6, or 2 and 9, or 5 and 7 etc etc.......... so you take 2 chromosomes total which the zygote would have and figure out different combos of 5 xsomes mom and dad can deliver so it would be 2X2X2X2X2 or 2^5 which is 32 different combos.

I'm not sure if the above is a 100% correct explanation but thats what makes sense to me; if anyone can verify or correct a mistake in logic I made it would be appreciated.

all right. i get it now. but what about the second question? WOuld you explain that as well. thanks.

 

[steelrfan8]

all right. i get it now. but what about the second question? WOuld you explain that as well. thanks.

A tetrad is TWO homologous chromosomes at metaphase when they have already duplicated right before the split so they look like: X

So we got a 2n=20 diploid organism which means it has 20 chromosomes (10 from mom, 10 from dad... which is irrelavent for this quesiton but might help you get a better mental picture of whats going on).

So imagine we got 10 DUPLICATED (look like X) chromosomes lined up in one row, and 10 lined up in the other row at metaphase:

X X
X X
X X
X X
X X
X X
X X
X X
X X
X X

A tetrad is 4 chromatids so 1 row above in form X X is a tetrad. We got 10 rows, so we got 10 tetrads. If you count the chromosomes, you got 20 total which makes 2n=20 diploid true.

The explanation for the 1st question I posted is a little off, I just read it with a semi fresh head and caught a few errors but the general logic is correct... so if you figured it out, you probably have the right idea so I won't bother fixing it.