Question

Can someone please help me with these 5 questions please?
Why are many of the same genes found in almost all living organisms?

Similar genes arose independently under similar conditions.
There are limited macromolecules involved in DNA synthesis.
All living organisms likely originated from a common ancestor.
Any similarities among genes of different species are due to random chance.

Answer 1

I think it would be c. all living organisms likely originated from a common ancestor.
None of the others makes sense.

Answer 2

I think so too ( common ancestor). You know, evolution and stuff 😀

Answer 3

exactly!! :)

Answer 4

When scientists say they share a universal genetic code it means that all organisms it can mean either:

-DNA as the main source of hereditary information in all life forms we know of

or more likely

that all organisms we know of use a three base pair code for the synthesis of proteins, DNA produces mRNA this mRNA is read three base pairs at a time by a ribosome, this is called the genetic code.

Here is the genetic code, each three letter code represents three nucleotide bases and each three letter codes for an amino acid, note there is redundancy in the code.
http://www.mun.ca/biology/scarr/MGA2-03-28.jpg

Please be aware that this code is not really universal as we have discovered organisms that deviate from this code. For example an organism might see UUU and read that as a Leucine instead of a proline. So the code isn't really universal.

Also please be aware of the fact that only a small portion of DNA actually codes for proteins and also proteins are not the only product DNA produces, it also produces many types of RNA that doesn't code for protein that serve various functions inside the cell for example: snRNA and tRNA, rRNA

Answer 5

The first reason is that we all came from a common ancestor.The second reason has to do with what DNA does. And the fact that all living things have lots in common with each other, but not exactly similar.