Answer options:
- extraction and observation of DNA
- identification of ribose and deoxyribose
- recognition of RNA as DNA’s messenger
- construction of an accurate DNA model
Answer:
- identification of ribose and deoxyribose
Explanation:
Phoebus Levene was an American biochemist who studied the structure of DNA and RNA. He was able to isolate the sugars (ribose and deoxyribose) from the nucleic acids, which are an important part of their structure.
He also determined how the nucleic acid components combine to form the nucleotides, the basic building blocks of nucleic acids, and how the nucleotides combine in chains to form the polymer.
1.underground stem -- for storage of food ex. potato , ginger.
2.spines for protection ex. citrus , bougainvillea
Answer:
Interphase is the portion of the cell cycle that is not accompanied by gross changes under the microscope, and includes the G1, S and G2 phases. During interphase, the cell grows (G1), replicates its DNA (S) and prepares for mitosis (G2). ... In interphase, the cell gets itself ready for mitosis or meiosis.
Explanation:
Answer:
The lytic cycle.
Explanation:
<u>HIV is a retrovirus</u> that has a special enzyme called transcriptase reverse, which can synthesize DNA using RNA as a template. This replication system is particularly useful for the virus because the DNA synthesized from the RNA viral genome can be then integrated into the human chromosomes and stay inactive for years. This is called a lysogenic cycle and is characterized by a latency of the virus and an integration to the host DNA.
When there is a triggering event, <u>this latent virus can be excised from the human chromosome and start producing copies of itself using the host machinery.</u> <u>Then the virions are assembled and after that they lyse the host cell and release new infective units that can then infect neighboring cells. </u>This is called the lytic cycle of the virus and is the reproduction cycle that occurs when a person moves into the acquired immunodeficiency syndrome (AIDS) stage of HIV infection.
Cancerous cells go through interphase so fast, that they are constantly multiplying in mitosis.
