Answer:
Please find the explanation below
Explanation:
Our nucleus is made up of a genetic material called deoxyribonucleic acid (DNA), which is a double-helical structure that stores the genetic information needed for the optimal functioning of any organism. DNA, alongside RNA are nucleic acids that are composed of NUCLEOTIDES subunits. The nucleotide consists of a pentose sugar (deoxyribose in DNA and ribose in RNA), nitrogenous base and a phosphate group.
However, the genetic information stored in the DNA molecule needs to be expressed in order to form useful products (proteins). This genetic expression is done in two stages viz: transcription and translation. Transcription, which is catalyzed by an enzyme called RNA polymerase is the process whereby the information stored in the DNA is used to synthesize a mRNA molecule. However, this mRNA molecule is considered pre-mature until it is processed. RNA processing occurs in three stages viz: 5' capping, polyadenylation, and splicing.
5' capping involves adding a 5' cap to the marks molecule. Polyadenylation involves adding a poly(A) tail to the mRNA molecule while splicing is the removal of introns (non coding regions) with the aid of Spliceosomes and joining of the exons (coding region). After processing, the mRNA becomes matured and ready to be translated.
Translation is the process whereby the mRNA transcript is used to synthesize a protein molecule. It occurs in the ribosomes (organelles for protein synthesis, a complex of rRNA and proteins) where the mRNA is read in a group of three nucleotides called CODON. The reading is done by the Anticodon of a transfer RNA (tRNA), which is complementary to the codon.
Translation occurs in three stages: initiation, elongation and termination. The mRNA attaches to the P site of the ribosomes (initiation) where it is attached to by a tRNA's anticodon complementary to it. The anticodon carries the amino acid corresponding the codon and shifts to the A-site. The addition of amino acid to the polypeptide chain continues (elongation) until a stop codon is encountered, which signals the end of the translation process i.e. termination. This causes the polypeptide (protein) to be released from the E-site.
The synthesized protein undergoes packaging and modification in the Golgi apparatus.
Answer:
Fossil record is used to study macro evolution.
Explanation:
Macroevolution may be defined as the change above the species level. Fossils are the impressions of dead plants and animals buried under the surface of rocks.
Fossils provide the direct evidence of macroevolution. For example : Paleozoic era was dominated by trilobites, crinoids and brachiopods. Rocks that one part of paleozoic era are now contains the fossils of trilobites, crinoids and brachiopods. These species may either extinct or not common in today's world. Thus, fossil record can be used to study macroevolution.
<span>Human activities can alter an ecosystem and bring about the extinction of a species. Such activities include any of these except assuring a habitat remains unaltered.
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This photo shows the differences between phloem and xylem/functions of stems
description of root: is the organ of a plant that typically lies below the surface of the soil.
function of roots: absorption of water
storage of food and nutrients
description of leaves: organ of a vascular plant
function of leaves: gas exchange occurs here!!!
1) leaves have large SA for fast diffusion
2) contain many stomata to allow movement of gases into and out of the leaf.
