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Folded, 3-D structure of ribonuclease A. Anfinsen's dogma, also known as the thermodynamic hypothesis, is a postulate in molecular biology.It states that, at least for a small globular protein in its standard physiological environment, the native structure is determined only by the protein's amino acid sequence. [1]
Advanced Placement (AP) Biology (also known as AP Bio) is an Advanced Placement biology course and exam offered by the College Board in the United States. For the 2012–2013 school year, the College Board unveiled a new curriculum with a greater focus on "scientific practices".
They hold the eggs internally for several weeks, providing nutrients, and then lay them and cover them like birds. Like marsupial " joeys ", monotreme " puggles " are larval and fetus-like, [ 9 ] as like them they cannot expand their torso due to the presence of epipubic bones, forcing them to produce undeveloped young.
The mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web. [42] [14] In a simple predator-prey example, a deer is one step removed from the plants it eats (chain length = 1) and a wolf that eats the deer is two steps removed from the plants (chain length = 2).
The percentage of students scoring a grade of "5" was only 7.0% in the 2021 testing administration. It remains one of the lowest "5" scoring AP Exams to this date right under AP Art History, AP English Literature & Composition, AP English Language & Composition, and AP World History. The AP Environmental Science exam was first administered in 1998.
Bateman attributed the origin of the unequal investment to the differences in the production of gametes: sperm are cheaper than eggs. A single male can easily fertilize all of a female's eggs; she will not produce more offspring by mating with more than one male. A male is capable of fathering more offspring if he mates with several females.
The egg cell is generally asymmetric, having an animal pole (future ectoderm). It is covered with protective envelopes, with different layers. The first envelope – the one in contact with the membrane of the egg – is made of glycoproteins and is known as the vitelline membrane (zona pellucida in mammals).
Adult fish also prey on fish eggs and larvae. For example, haddock were observed satiating themselves with herring eggs back in 1922. [14] Another study found cod in a herring spawning area with 20,000 herring eggs in their stomachs, and concluded that they could prey on half of the total egg production. [17] Fish also cannibalise their own eggs.