AKS 8 Microorganisms

The list shows some characteristics of microscopic algae.

found in freshwater and salt water ecosystems can perform photosynthesis do not have roots, leaves, or stems are a food source for marine organisms

Which two arguments support the claim that microscopic algae are beneficial?

• Microscopic algae create oxygen for the atmosphere.

• Microscopic algae keep fish populations under control.

• Microscopic algae can be found in different ecosystems.

• Microscopic algae prevent decaying matter from building up.

• Microscopic algae are a source of energy for other organisms.

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2. The list describes some characteristics of the bacteria called Clostridium botulinum, which can cause a disease called botulism.

The bacteria are found naturally in many places. The bacteria creates spores which help it to survive. The spores of the bacteria can create a dangerous toxin. The toxin created by the spores can affect human nerves if it is eaten. The bacteria thrive in an environment with low or no oxygen.

Which argument best supports the claim that some microorganisms are harmful?

• Clostridium botulinum bacteria are harmful because they occur naturally in many places.

• Clostridium botulinum bacteria are harmful because they create spores that help them to survive.

• Clostridium botulinum bacteria are harmful because they can create spore toxins that negatively affect humans.

• Clostridium botulinum bacteria are harmful because they are able to survive in conditions that other bacteria cannot.

Read the passage about the Escherichia coli bacteria.

Escherichia coli, also called E. coli, is a bacteria that is too small to see with the naked eye. Many strains of the bacteria are found in the intestines of humans and animals. Most of the strains are harmless, and some of the strains are helpful because they aid in digestion. A few of the strains found in meat are dangerous and can make a person sick if these strains are eaten. Except for extreme heat, E. coli bacteria can survive in many conditions.

Which argument best supports a claim that some strains of the E. Coli bacteria can be harmful?

• E. Coli bacteria are harmful because they are found in the intestines of humans and animals.

• E. Coli bacteria are very small and can only be observed using a high-powered microscope.

• E. Coli bacteria can make a person sick if they eat meat that has not been been cooked at a high temperature.

• E. Coli bacteria are harmful because they break down food in the intestines of humans and animals and take away the nutrients.

The pictures show Kiegan's fish tank before and after she added a population of microorganisms called rotifers. Keegan claims that the microorganisms were beneficial to the fish in the tank. Which claim can Kiegan support by looking at the tank?

• The rotifers created more water for the tank.

• The rotifers caused the fish population to grow

• The rotifers increased the temperature of the water.

• The rotifers cleaned the tank by eating waste matter.

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Some forests have trees that shed their leaves every year and grow new ones in the spring. Which argument best describes how some bacteria are beneficial to these forests?

• Bacteria prevent the trees from losing leaves.

• Bacteria develop into new leaves for the trees.

• Bacteria provide food for the leaves on the ground

• Bacteria break down fallen leaves to release nutrients.

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Some yeasts help plants to rapidly divide their cells in their roots. Which argument supports the claim that some yeasts are beneficial to plants?

• Plants use more sunlight with a larger root system.

• Plants need less nutrients with a larger root system.

• Plants make brighter flowers with a larger root system.

• Plants can absorb more water with a larger root system.

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Read the passage about antibiotics.

The human body is filled with many different kinds of good bacteria. Sometimes, people need to take an antibiotic to kill harmful bacteria that are causing diseases in their bodies. Unfortunately, antibiotics kill all of the bacteria, not only the harmful bacteria. Some people will develop a stomach problem with their antibiotics.

Which argument best supports the idea that some bacteria is helpful?

• When antibiotics kill the good bacteria that aid in food digestion, a person may start to feel better.

• When antibiotics kill the good bacteria that aid in food digestion, a person may get an upset stomach.

• When antibiotics cause the growth of harmful bacteria in the stomach, a person may start to feel better.

• When antibiotics cause the growth of harmful bacteria in the stomach, a person may get an upset stomach.

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Read the passage about Alexander Fleming.

In 1928, Alexander Fleming was studying a common, harmful bacteria that he grew in petri dishes. After returning from a vacation, he noticed that an uncovered petri dish had been left by an open window. The petri dish had become contaminated by mold. He noticed that the bacteria surrounding the mold had died. This discovery would lead other scientists to develop penicillin, a medicine that would go on to save many lives.

Which argument supports the claim that some microorganisms are beneficial?

• The mold that Fleming discovered developed from the harmful bacteria.

• The mold that Fleming discovered had properties that could kill harmful bacteria.

• The mold that Fleming discovered could change harmful bacteria into helpful bacteria.

• The mold that Fleming discovered could prevent people from being around harmful bacteria.

What term refers to an organism that causes a disease?

• a protein

• a protein

• a protein

• a pathogen

What are disease-causing agents?

• predators

• pathogens

• interferons

• antibodies