When determining the number of base pairs in a genome of an organism, do you count the basepairs for both/all chromosomes in a set or just one of the chromosomes per set?

Question

For example, rice has 430 Mbp across 12 chromosomes. Rice is diploid so in total there are 24 chromosomes. Would that mean **on average** there is 430/12 Mbp per set of chromosome? Which would mean there is **an average of 430/24 Mbp per chromosome.

Please explain it like I’m a baby because I’m well confused

Edit:
Or is genome summed based on one chromosome (haploid) set?

In: 2

Answer 1

It is a bit confusing, because the definition of genome is sometimes misleading.

Genome refers to the haploid chromosome set. When someone says the genome of rice has 430 Mbp, he means there are 430 Mbp on the haploid chromosome set, which is 12.

If you would take all DNA of a rice cell and count the base pairs, you would get 860 Mbp.

The same logic applies to genes. Maybe it is better understandable. If not, ignore it:
Lets say a diploid cell has 5 genes on chromosome 3. If I would ask you to count for me those genes, you would have a total count of 10.
Why?
First you search for the chromosome 3. Because the cell is diploid you have 2 of them. So you start counting to 5 and then move to the next one and get 10.
Because there are 2 copies of the same gene, you would agree with me, that we can ignore the copies and say there are 5 genes.

Back to your average example:
The average basepair per chromosome in rice is 430/12 Mbp, respectively 860/24

I hope it helped.