General Biology 2

• A virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called a capsid
• Viruses have no nucleus, organelles, cytoplasm, or cell membrane, which is why they do not belong to any kingdom
• Viruses have either DNA or RNA but not both. Viruses with RNA that transcribe into DNA are called retroviruses
• Viruses are parasites, depending entirely upon another living organism (a host) for their existence in a way that harms the host
• Prions are nonviral particles that have protein only, no DNA or RNA, causing diseases like mad cow disease and Creutzfeldt-Jakob disease in humans
• Replication is how a virus spreads. A virus cannot reproduce by itself; it must invade a host cell, take over the cell activities, and eventually cause destruction of the cell
• Certain viruses can only attack specific cell types, matching their surface markers with receptor sites on cells
• Viruses are harmful as they cause diseases, disrupt the body's normal equilibrium, and can only be prevented with vaccines, not treated with antibiotics
• Viruses possess one characteristic of life: genetic material. They are not considered living organisms
• A special reproductive structure with seeds-works

  Leaves
• It is an accessories structure which not found in all viruses

  Envelo
• This is found in every soft part of plants

  Parenchyma
• A vascular tissue that carries food in the leaves and to all part of plants

  Phloem
• It is a disease producing agent

  Patgogen
• Phloem:

  • Vascular tissue that carries food made in the leaves to all other parts of the plant
• Chlorophyll:

  • Green pigment responsible for photosynthesis
  • Essential for photosynthesis
• Chloroplast:

  • Organelles responsible for photosynthesis
• Schlerenchyma:

  • Found in pitules libes and young (ground tissue)
  • Provides protective covering around nuts and seeds
• Xylem:

  • Vascular tissue that carries water and nutrients up from the roots through the stems to the leaves
• Oxygen:

  • By-product of photosynthesis
• Respiration:

  • Process
• Photosynthesis:

  • Process by which plants make their food
• False statements:

  1. Bacteria can be prevented with vaccines but not treated by antibiotics

  2. Viruses are not considered living organisms

  3. Viruses with RNA that transcribe into DNA are called (the true meaning is "a virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called Capsid), hence it's FALSE
• Nervous System:

  • Rabies is an infection that affects the respiratory system