There are two kingdoms of bacteria. They are
1. Eubacteria and
2. Archaea
The members of these two kingdoms appear similar in shape and appearance, even under the extreme magnification of the electron microscope . However, they are very different from each other in a number of molecular and biochemical aspects. It is these differences that have resulted in the microorganisms being grouped into separate kingdoms.
For example, eubacteria contain the rigid, stress-bearing network known as the peptidoglycan . The only exceptions are the bacteria from the genera Mycoplasma and Chlamydia. Archaebacteria do not contain peptidoglycan. Instead, they contain a different structure that is called pseudomurein.
The common bacteria belongs to Eubacteria kingdom.
A cytoskeleton acts as a frame that gives a cell its shape, protects it to an extent, and helps with cellular motion.
Right ventricle (which pumps blood to the lungs), pulmonary artery (which carries blood to the lungs), and left atrium (which receives blood from the lungs) are involved directly in pulmonary circulation.
In flowering plants one sperm nucleus fertilizes the egg and the other sperm nucleus fuses with two other nuclei found within the ovule, thus forming triploid endosperm.
Hence, double fertilization is unique to flowering plants.
Heritable variation is one of the four most important factors that affect whether natural selection can occur. These factors include
1) Heritable variation
2) Descent with modification
3) Struggle for survival, and necessarily if the others are satisfied
4) Survival of the fittest.
Heritable variation allows for possibly beneficial, negative, or even neutral mutations to get filtered during each generation by natural selection--weeding out negative mutations, passing on positive and neutral ones. Without heritable variation, species would quickly fall victim to parasites who take advantage of identical genetic material in a population and evolution would not occur.
Variation is the raw material of evolution.
DNA is a very long chain polymer made up of thousands of repeating units called nucleotides.
Nucleotide Unit is composed of a phosphate group, a pentose sugar, and a nitrogenous base.
The sides of the DNA ladder are made up of alternating deoxyribose sugar -- phosphate group units.
A nitrogenous base, or nitrogen-containing base, is an organic molecule with a nitrogen atom that has the chemical properties of a base. The main biological function of a nitrogenous base is to bond nucleic acids together. A nitrogenous base owes its basic properties to the lone pair of electrons of a nitrogen atom.
In DNA, four bases have been found. They are
1. Adenine (A),
2. Guanine (G),
3. Cytosine (C) and
4. Thymine (T).
The first three of these bases are found in RNA also but the fourth which is Uracil (U) is absent in it.
RNA contains cytosine and uracil as pyrimidine bases while DNA has cytosine and thymine.
Translation occurs in the cytoplasm whereas transcription occurs in the nucleus.
Transcription and Translation:
Terms transcription and translation in biology are generally related to the DNA and its properties. Human cells replicate. In order to do that, they have to produce the same constituents for the new cell that is to be made. The only way to do that is by producing proteins.
The proteins are produced in the process that is called protein synthesis. The first step is in the nucleus where a particular gene is being expressed so it enables all protein factors to come and to replicate that part of a chromosome. This is finished when mRNA, the same single-stranded genetic code of a particular gene, is formed. This is transcription.
Right after that, the mRNA enters the cytoplasm through nuclear pores. There, it could be translated into proteins by ribosomes. This process is called translation.
Arteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation (usually veins carry deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood as well).
The fimbriae of the uterine tube, also known as fimbriae tubae, are small, fingerlike projections at the end of the fallopian tubes, through which eggs move from the ovaries to the uterus.
The fimbriae are connected to the ovary.
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