Answer:
True. You can get vitamin A as "preformed vitamin A" which is already active and/or you can get vitamin A as carotenoids which the body can turn into active vitamin A.
Explanation:
There are two different types of vitamin A that can be obtained from food:
1. Preformed vitamin A, which is already active, is found in animal products such as beef, fish, poultry and dairy products.
2. Provitamin A, which is the inactive form, is found in plant-based foods, such as fruits and vegetables. The most common type of provitamin A is β-carotene, which is a carotenoid that the body can turn into active vitamin A via an enzyme named β-carotene 15,15'-monooxygenase.
About 37.2 trillion cells present in the body of an adult human.
Answer: Roles of DNA polymerases and other replication enzymes. ... which require a template and a primer (starter) and synthesize DNA in the 5' to 3' direction. ... Topoisomerase also plays an important maintenance role during DNA replication.
Explanation:
hard to explain
Answer: The transcription and translation process allows trna and rrna molecules to be used to synthesize wide variety of polypeptides.
Explanation:
DNA molecule is made up of information for coding proteins. This information is passed on the mRNA during a process known as transcription. Transcription is the first of many steps of DNA based gene expression in which a part of the segment of DNA is copied into RNA (especially mRNA) by the enzyme RNA polymerase.
Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During the process of transcription, a DNA sequence is read by an RNA polymerase, which gives a complementary, antiparallel RNA strand referred to as a primary transcript.
A large diversity among genes is followed by a large amount of various mRNA molecules. However, the ribosomes consist of rRNA, which is included in the process of translation. Translation is the process whereby ribosomes in the cytoplasm or ER synthesize proteins after the process of transcription of DNA to RNA in the cell's nucleus. The overall process is called gene expression.
The smallest of the three types of RNA is tRNA, which has only 75 to 95 nucleotides and has a role in bringing particular amino acids to the growing polypeptide. It can be concluded that mRNA contribute to the diversity of polypeptide molecules due to the fact that it carries an information about their synthesis.
