Consider again the discussion of "properties of life" and describe at least three distinct reasons why viruses are not classified as living organisms.
What will be an ideal response?
Answers may vary. The basic unit of life is the cell and all cells come from pre-existing cells. Cells are metabolically active, acquiring, transforming, and using energy. A virus does not qualify as living because it is acellular. Viruses can best be described as nucleic acid surrounded and protected by a protein shell. Cells reproduce either sexually or asexually to form new cells and/or new organisms. Viral components are synthesized during the biosynthesis phase and then assembled in the maturation phase of a virus life cycle. A whole virus does not divide to become new viruses, nor are sex cells produced. Viruses are metabolically inactive unless inside of a host cell. Once inside, nucleic acid replication, transcription and translation may occur, as the host cell's machinery is commandeered by the virus.
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All atoms possess the ability to do work. The term that is defined as the ability to do work is:
A. matter B. energy C. molecules D. space
Which of the following is TRUE of cell cleavage?
A. It involves consecutive cycles of cell division without cell growth. B. It forms a blastula. C. It is a rather slow event of embryonic development. D. It involves consecutive cycles of cell division without cell growth and forms a blastula. E. It is a rather slow event of embryonic development involving consecutive cycles of cell division.
Carbon-12 has six protons and six neutrons in its nucleus. Carbon-14 has six protons and eight neutrons in its nucleus and is radioactive. Carbon-14 is an example of a(n) ________.
Fill in the blank(s) with the appropriate word(s).
When blood glucose levels rise, insulin signals cells to take up glucose, removing it from the blood. Diabetes mellitus is a disorder caused by a dysfunction in the insulin signaling system. There are two types of diabetes
People with type 1 diabetes must take insulin regularly, usually through injection. People with type 2 diabetes are not helped by supplemental insulin. What does this tell you about where the defect might be in these two disorders? A) Type 1 diabetes is probably caused by defective insulin receptors. B) Type 2 diabetes is probably caused by underproduction of insulin. C) Type 1 diabetes is probably caused by underproduction of insulin. D) Type 2 diabetes is probably caused by overproduction of insulin.