Bio Building Blocks Question

[torobcheh21]

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Does anyone have a detailed list (in increasing order) of the the building blocks of DNA. This may seem like a simple question but I keep seeing different things that throw me off. I feel it would be a really good idea to have a general idea of the sizes of things so we can know what's what.

What I'm asking is to rank these building blocks based on size. Including things like histones, nucleosomes, genes, nucleic acids...that kind of thing. Let me know if that makes sense.

Thanks

 

[kc1469]

Does anyone have a detailed list (in increasing order) of the the building blocks of DNA. This may seem like a simple question but I keep seeing different things that throw me off. I feel it would be a really good idea to have a general idea of the sizes of things so we can know what's what.

What I'm asking is to rank these building blocks based on size. Including things like histones, nucleosomes, genes, nucleic acids...that kind of thing. Let me know if that makes sense.

Thanks

In order to answer these questions, the best way to do it is to think of it as, what is composed of what?
So:
Genes are composed of nucleic acids.
Nucleosomes are composed of histones.
In terms of histones or genes, its more difficult because histones are globular while genes are linear. So they wouldn't ask it in terms of that. But your best bet would be, (according to the logical thinking above):
Nucleic Acids, Genes, Histones, Nucleosomes in order of increasing complexity.

 

[torobcheh21]

thanks. i'm hoping for something in more detail..

does anyone have a picture that diagrams this all out? i'm a visual learner and that'll help a lot

 

[aqz]

http://bcs.whfreeman.com/lehninger5...=chapter&i=24020.01&s=24000&n=00020&o=|11000|

Histone -> Nucleosome -> 30 nm fiber -> Rosettes -> 2x chromatids that make up a chromosome

 

[torobcheh21]

thanks

 

[torobcheh21]

What I'm looking for is for someone to break it down in a largest to smallest type of way...like amino acids are the building blocks of nucleic acids which are the building blocks of DNA. That type of thing.

So the way I see it is: histone>nucleosome>chromatids>chromosomes>DNA but where do amino acids and nucleic acids fit into this? Don't know why this is so confusing

 

[aqz]

Histone is a protein...meaning it contains amino acids.

DNA is a nucleic acid.

DNA is wrapped around histones. If you want some biochem tossed in too, about 150 base pairs wrap around the histone and they bind through hydrogen bonding between histone AA side chains and DNA phosphate backbone.

 

[Troyvdg]

What I'm looking for is for someone to break it down in a largest to smallest type of way...like amino acids are the building blocks of nucleic acids which are the building blocks of DNA. That type of thing.

So the way I see it is: histone>nucleosome>chromatids>chromosomes>DNA but where do amino acids and nucleic acids fit into this? Don't know why this is so confusing

1. nucleotides (A,T,C,G or U if in RNA)
2. a polymer of nucleotides is a nucleic acid. At this point, it is called DNA (DNA-deoxribonucleic acid)
2. histones are attracted to the negative phosphate sugar backbone of DNA-->condense into nucleosomes
3. linker histones bind condensing nucleosomes into the 30m chromatin fiber
4. chromatin fiber is bound to a protein scaffold to form chromatids
5. 2 chromatids make up a chromosome (i.e. what you are used to seeing DNA as during metaphase)

in summation:
nucleotide<nucleic acid<nucleosome<chromatin<chromatid

 

[torobcheh21]

I found this to be pretty helpful for why I was confused. I thought amino acids and nucleic acids were components of the other. Now I know the difference...so the two aren't related at all really.

And amino acids makes proteins and polypeptides and nucleic acids are completely separate, they are the building blocks of DNA (obviously)...this is where I was confused. I thought amino acids were precursors to nucleic acids for some reason

"An amino acid is a substance of the form:

(NH2)-CH(COOH)(R)

That is a carbon atom with an amino group (NH2), a hydrogen atom (H), a carboxyl group (COOH) and a side residue R covalently bound to the carbon and arrange in the shape of a tetrahedron.

The amino and carboxyl groups can ionise to NH+ and COO- depending on the pH of the environment.

The side residue R varies. There are 20 naturally occurring amino acids. When R is H the amino acid is glycine. For all other types of R, the amino acid can exist is two mirror image isomers called the L and D type. The L type is naturally occurring. It is difficult to type the structure for a lot of the other 19 types of R. One is -CH2 - SH and this makes L-cysteine.

Amino acids combine to male polypeptides and proteins.

Nucleic acids are totally different molecules. There are two types: deoxyribonulceic acid (DNA) and ribonucleic acid (RNA).

Each consist of a phosphate-sugar back-bone with various types of base attached to each sugar molecule. In DNA the sugar is deoxyribose and in RNA the sugar is ribose.

In DNA the four types of base are adenine, guanine, cytosine and thymine. In RNA uracil replaces thymine."

 

[torobcheh21]

Another point of confusion I'm having from some practice tests is the wording of Protein Structure...meaning primary, secondary, tertiary, quaternary. Sometimes the problem words it in a way that's tricky, but can someone breakdown the definitions that way i don't have to second guess myself.

For example, does 3D shape begin with secondary structure or tertiary? Chad says tertiary in his videos, but technically aren't alpha helices and beta sheets 3D? What's what...

 

[hasanein4u]

Another point of confusion I'm having from some practice tests is the wording of Protein Structure...meaning primary, secondary, tertiary, quaternary. Sometimes the problem words it in a way that's tricky, but can someone breakdown the definitions that way i don't have to second guess myself.

For example, does 3D shape begin with secondary structure or tertiary? Chad says tertiary in his videos, but technically aren't alpha helices and beta sheets 3D? What's what...

Primary: the amino acid sequence. Ex: Alanine-Glycine-Serine....
Secondary: Alpha-Helics and Beta-Sheet (Attraction between the backbone peptide links due to hydrogen bonding)
Tertiary: 3d structures (like have disulfide bonds)
Quaternary: the assembly of several protein subunits (ex: hemoglobin)

Hope this helps