Biology Chapter 18

Front 1

The number one infectious agent in the world that causes death in adults is __________.

Back 1

Tuberculosis

Front 2

Antibiotics, chemicals used for treatment of infections such as tuberculosis, were not used until the __________.

Back 2

1940’s

Front 3

Antibiotics were discovered in 1928 by __________.

Back 3

Alexander Fleming

Front 4

Bacteria were first observed by Anton van Leeuwenhock in 1673 when he fashioned the first __________.

Back 4

Microscope

Front 5

Plants and animals are composed of __________ cells.

Back 5

Eukaryotic

Front 6

Bacterial cells are examples of __________ cells.

Back 6

Prokaryotic

Front 7

Large amounts of waste dumped into rivers causes some microbes to grow to huge numbers, which depleted the dissolved __________ in the water.

Back 7

Oxygen

Front 8

Mitochondria and chloroplasts are prokaryotic cells that were taken up and now reside in eukaryotic cells as organelles, a process known as __________.

Back 8

Endosymbiosis

Front 9

Of all the biomass in the ocean, it is estimated that __________% is microbial.

Back 9

90

Front 10

Archaebacteria, a group of organisms that can survive in extreme conditions, are also known as __________.

Back 10

Extremophiles

Front 11

Microbes can be used to extract metals from ore, a process known as __________.

Back 11

Bioleaching

Front 12

Briefly explain the history of tuberculosis throughout human history.

Back 12

Evidence from Egyptian mummies suggests that tuberculosis was common in humans as long as 5000 years ago. It has also been shown that tuberculosis infected Native Americans as early as 2000 B.C. During the 18th and 19th centuries tuberculosis was responsible for countless deaths and today remains the leading infectious cause of death adults.

Front 13

Briefly explain the 2 stop process of tuberculosis infection.

Back 13

The first stage of infection, or the primary phase, is when the bacteria enters the lung and causes a mild, often asymptomatic infection. Only 10% of all tuberculosis infections enter the second stage of infection, where dormant bacteria in the lungs come alive, multiply and gradually damage the lungs to the point of causing respiratory failure.

Front 14

How does multi-drug antibiotic resistance develop in bacteria such as tuberculosis?

Back 14

Multi-drug antibiotic resistance develops in a multi-step process where one antibiotic is given to kill most of the bacteria, but then a second antibiotic is given to kill some of the remaining cells, and then a third must be given to kill those cells resistant to the first or second antibiotics. If a patient fails to take all of the prescribed antibiotics, those resistant bacteria that survive reproduce and pass on their resistance to their descendants.

Front 15

Compare and contrast eukaryotic cells and prokaryotic cells. How do they differ and how are they similar?

Back 15

Prokaryotic and eukaryotic cells are similar in that they both have cell membranes, ribosomes and DNA as their genetic material. However, eukaryotic cells are compartmentalized and much more complex that prokaryotic cells, containing such structures as a membrane bound nucleus and organelles such as chloroplasts, lysosomes and mitochondria.

Front 16

Explain how dumping sewage and waste into rivers and streams damages the ecosystems of those bodies of water.

Back 16

When sewage and waste is dumped into these bodies of water, it provides nutrients for the microbes in the ecosystem. These microbes begin to reproduce to unusually high numbers and they begin to consume all the oxygen in the water, leaving none for the plants and animal life such as fish. When the fish and plants die, the entire river ecosystem collapses and many other organisms die as well.

Front 17

How have microbes been used to speed up the decomposition processes in landfills?

Back 17

Most of the waste in landfills takes 40 to 50 years to completely decompose because there isn’t enough water and oxygen present for microbial growth. Some researches found that microbes can be used to speed this process up. If water and air is pumped into the waste in a landfill, the growth of larger numbers of microbes is facilitated. These microbes then degrade the waste in a much shorter amount of time. What once took 50 years only takes a few years with the help of microbes.

Front 18

What was the purpose of the Biosphere 2 project, how did microbes bring it down, and what insight did its failure give us into the role of microbes in the Earth’s ecosystems?

Back 18

The purpose of the Biosphere 2 project was to build a self contained environment that could sustain 8 people for two years through complete recycling of everything including waste, water, air and food. The goal was to demonstrate that long term colonization of planets such as Mars was theoretically possible. After a few months of successful functioning, oxygen levels in the Biosphere began to plummet and many plants began to die. It was discovered that the microbes in the compost heap for degrading biological waste were growing out of control. These huge amounts of bacteria began consuming all of the biosphere’s oxygen and oxygen eventually had to be pumped in from the outside. This failure demonstrated how crucial microbes are to the balance that is Earth’s ecosystems. If bacterial growth were to go unchecked on the planet, we too would run out of oxygen and die.