Answer: Substances that are protein based cannot cross the lipid cell membrane, but can exert their effect by binding to the proteins based receptors present on the lipid bilayer.
Explanation:
Hormones such as calcitonin , Parathyroid hormone and pituatry horomones are proteins and water soluble.They cannot cross lipid bilayer but can bind to ligand binding protein receptors.
These receptors are protein macromolecules that are specific in nature for specific hormones.
After binding to the receptors, these hormone-recpetor complexes activate second messengers and regulate the downstream effects.
Answer/Explanation:
The DNA in all living organisms is made up of 4 bases, adenine, thymine, guanine, cytosine. The RNA replaces thymine with uracil, making 5 types of nucleotide. The number of nucleotide pairs in a genome can range from half a million up to 100,000 million - meaning there are an exponential number of combinations of these 4 bases.
Imagine an organism exists that has only 2 nucleotides (<u><em>this is over 200,000x smaller than even the smallest bacterial genome</em></u>). If we allow any nucleotide at each of the 2 positions, then we have 4x4 (4²) or 16 possible combinations of sequences. For a nucleotide length of 4, the total number of possible combinations are 4⁴ or 256.
Since we are dealing with many millions of nucleotides, there are essentially infinite combinations of nucleotides, giving rise to the variation that produces over 20 million organisms on the planet.
Ohhh I know this! Number 1 is saturated fats, Number 2 is unsaturated
Carbon is exchanged, or "cycled" among Earth's oceans, atmosphere, ecosystem, and geosphere. All living organisms are built of carbon compounds. It is the fundamental building block of life and an important component of many chemical processes.
Spanish:
El carbono se intercambia o se "cicla" entre los océanos, la atmósfera, el ecosistema y la geosfera de la Tierra. Todos los organismos vivos están construidos con compuestos de carbono. Es el componente fundamental de la vida y un componente importante de muchos procesos químicos.
Rapid defibrillation is important because it contributes greatly to the survival of sudden cardiac arrest patients by eliminating abnormal hearth rhythm. Research has shown that the only proven, effective treatment for sudden heart attack is prompt defibrillation which is applied within the first few minutes of attack.
