Bee hummingbird, zunzuncito or Helena hummingbird (Mellisuga helenae) is a species of hummingbird which is the world's smallest bird and the smallest known dinosaur. It is native to Cuba.
Answer:
F-actin is a double helical filament as opposed to G-actin,which is a globular protein .Each actin filament has two ends,called the plus and
the minus ends, which makes it recognizable from each other.This gives the structure a distinct polarity.
Explanation:
Actin is the most abundant protein that is found in almost all eukaryotic cells.Its a most important part cytoskeleton as its a monomeric subunits(size 42kDa) of two types of filaments i.e. microfilaments and thin filaments in cells. Actin is essentially required to maintain stability and morphogenesis of cell.It is involved in numerous significant processes such as endocytosis,cell division and migration.Actin is present in two forms:
•G-actin
•F-actin
The two forms of actin are different structurally.
G- actin is a globular shaped protein,usually present in free form(a monomer),having a tight binding site for another actin monomer.Each monomer has ATP. Upon polymerization of G-actin monomers, a polymer called F-actin filaments is form. This process is driven by hydrolysis of ATP.
Answer:
In many species, females choose the male they will mate with. For their part, males try to be chosen as mates. They show females that they would be a better mate than the other males. To be chosen as a mate, males may perform courtship behaviors. These are special behaviors that help attract a mate. Male courtship behaviors get the attention of females and show off a male’s traits. These behaviors are often observed as direct competition between males. Different species have different courtship behaviors.
Explanation:
The primary goal of technological advancement should be to increase people's efficiency so that they have more leisure time.
