In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. based on this information alone, we can conclude that sickle-cell hemoglobin exhibits:
altered primary structure.
altered secondary structure.
altered tertiary structure.
altered quaternary structure.
altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

Altered primary structure.

Explanation:

Proteins are formed by chains of amino acids, which constitutes their primary structure. In sickle-cell disease, there is a single amino acid exchange. Therefore, the primary structure of the protein is altered, and because of this hemoglobin form long fiber that clog arteries.

explanation:

1 rosales   order

2 eurarya   domain

3 rosaceae   family

4 cania - genus

5 plantae - kingdom

6 magnoliopsida - class

7 rosa - species

8 magnoliophyta - phylum

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure