TEKS Presentation

By: Justin Sharma and Chaitanya Kalathuru

TEKS 4A

What are the basic structures of bacteria?


  • The structures found in bacteria are unique to only bacteria; they are not found in eukaryotes or in archaea
  • Bacteria is prokaryotic, so it does not contain any features that are exclusive to eukaryotes
  • They come in various sizes, but the most common shapes are spherical, rod-like, and spiral
  • Since bacteria do not have a nucleus, their genetic material is found in the cytoplasm.
  • Bacteria have a cell wall, cell membrane, cytoplasm, and ribosomes.

  • Some bacteria have flagella, which helps the bacteria move
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TEKS 11B

What is the basic structure of an endospore?

The basic structure of an endospore from inside to outside consists of the core, cell wall, inner membrane, outer membrane and the coat. The outer coat surrounding the spore provides much of the chemical resistance. Beneath the coat resides a very thick layer called the cortex. Proper cortex formation is needed for dehydration of the spore core, which helps in resistance to high temperature. A germ cell wall resides under the cortex. This layer will become the cell wall of the bacterium after the endospore germinates. The inner membrane, under the germ cell wall, is a major permeability barrier against damaging chemicals. The center of the endospore, the core, exists in a very dehydrated state and houses the cell's DNA, ribosomes and large amounts of dipicolinic acid. This endospore-specific chemical can comprise up to 10% of the spore's dry weight and appears to play a role in maintaining spore dormancy.

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What is the function/purpose of endospores, and how does it help bacteria?

  • Endospores are small, round, thick-walled structure that contain the bacteria's genetic materials.
  • Endospores are very resistant and can protect a bacteria's genetic material from freezing, drying, and heating.
  • They are also resistant to gamma radiation, desiccation, starvation, and chemical disinfectants.
  • They are the reason for the resilience of bacteria

What do helpful bacteria do for humans and animals?

Bacteria...

  • helps the body digest food.

  • decomposes and recycles dead organisms

  • is used to create various foods such as cheese, sausage, and sauerkraut

  • is used in the production of antibiotics
  • is helpful in the decomposition of petroleum, and is used in the cleaning of oil spills
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TEKS 4B

What kind of toxins do bacteria produce, give examples?

  • Bacteria creates toxins that can be named as exotoxins or endotoxins
  • Exotoxins are toxins created by bacteria, and the bacteria release the toxin from the cell
  • Endotoxins are toxins that contain lipids, and it is within the cell
  • Humans or animals get toxins in their bodies by consuming foods that are contaminated by bacteria
  • Common examples of bacteria that create toxins are Staphylococcus aureus and Clostridium botulinum
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How do medicines such as penicillin treat infections and kill bacteria? What is their process?

  • Medicines such as penicillin are used to treat bacterial infections caused by gram-positive organisms.

  • Penicillin was the first drug to be effective against an array of diseases.

  • Penicillin kills bacteria by blocking the ability to synthesize the cell wall. The bacteria is able to stretch, but not divide. This causes the weak cell wall to eventually rupture, killing the bacteria.

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What are binary fission and conjugation?

  • Binary fission is a form of asexual reproduction in which the organism divides into two equal organisms

  • Conjugation is a form of sexual reproduction in which two organisms join together, exchange nuclear material, and split using binary fission.

  • Conjugation helps bacteria be durable.
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TEKS 4C

What does the immune system do to prevent viruses?

  • The immune system was created to recognize threats, and find ways to eradicate them

  • It uses white blood cells to get rid of viruses. However, if the virus is strong it uses white blood cells called T and B lymphocytes.

  • The B lymphocytes creates antibodies, which binds to the virus and stops it from creating more viruses.

  • After the threat is taken care of, the immune system registers it in its system, and is prepared to get rid of the same virus in the future.
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What is the lytic cycle?

  • The lytic cycle is a cycle of viral reproduction in which the virus takes over a cell and uses it for replication

  • It is a five-stage cycle

    • Attachment – the virus attaches to receptors on the host

    • Penetration – the nucleic acid moves across the cell membrane into the host cell

    • Replication and Synthesis – the virus degrades the host nucleic acid and uses the host to make new viral components.

    • Assembly – viral components are assembled into new viruses.

    • Release / Lysis – fully assembled viruses are released when the host cell bursts
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How do viruses spread within the body?

Viruses can enter the human body through any of its openings, but most often they use the nose and mouth. Once inside, the virus attaches itself to the outside of the kind of cell it attacks, called a host cell. For example, a rhino virus attacks cells in the nose, while an enterovirus binds to cells in the stomach and intestines. Then the virus works its way through the host cell's outer membrane.


After entering the cell, the virus begins making identical viruses from the host cell's protein. These new viruses may make their way back out through the host cell's membrane, sometimes destroying the cell, and then attacking new host cells. This process continues until the body develops enough antibodies and other defenses to defeat the viral invaders.

What aren't viruses affected by antibiotics? What makes them different from bacteria in this way?

Viruses aren't living, because in order for an organism to be living it must be made up of cells. Antibiotics are made up of dead bacteria so that your body knows how to fight it and learns to get rid of it. Because viruses aren't living in the first place, you can't kill them, and antibiotics won't work. The symptoms, however, can be treated.
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