AP Bio Ch 8 Test
Based on the data in Figure 1, for each strain describe the relationship between the number of colonies observed and the likely mutation rate of the strain.
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State the null hypothesis for the experiment whose data are graphed in Figure 2. Provide evidence to support or refute the scientists' claim that more colonies grew in strains C3 and C6 than in the other strains because the genes for proteins that are normally targeted by the toxic chemical contain nucleotides with incorrect bases in the C3 and C6 cells. The scientists additionally determined that the C3 and C6 strains had no decrease in virulence (disease-causing ability) in comparison with the virulence of the other clinical isolate strains and concluded that these two strains have mutator phenotypes. Explain why mutator phenotypes were found only among clinical isolate strains and not among environmental strains.
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A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?
Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
A researcher claims that different metabolic pathways allow bacteria to use different molecules as sources of matter and energy. Which of the following statements best helps justify the researcher's claim by providing a relevant example?
E coli bacteria reproduce in liquid media containing either glucose or galactose
Describe why DNA replication is said to be a semiconservative process. Explain how random mutations such as those in pathogens with a mutator phenotype may arise in the DNA of an organism.
DNA replication is semi-conservative because each helix that is created contains one strand from the helix from which it was copied. The replication of one helix results in two daughter helices each of which contains one of the original parental helical strands. A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke. Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation.
Identify a dependent variable in the experiments. Identify the reasoning of the scientists when they tested the number of colonies produced by strains C3-PBB and C6-PBB . The scientists also analyzed the number of colonies produced from each of the environmental and clinical isolate strains when the strains were plated on a growth medium lacking the toxic chemical. Justify this analysis.
Dependent variable is the outcome that is measured. This is the number of colonies produces by the clinical Isolate strain. Without the growth media the strain cannot thrive or reproduce hence their dependent on the media for survival. While independent variable is the treatment that is varied in an experiment. It usually not dependent on any variable and can stand on it own. The growth media that is lacking in chemical is the independent variable because it stands on it own and it can be carried depending on the experimental design it could be a chemical based growth media or no chemical like the one used in this experiment
A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. Which of the following observations provides the best evidence to support the claim?
Elysia chlorotica grows when exposed to light in the absence of other food sources. as the reaction proceeds is also labeled with 18O.
Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result, the color of cyanobacteria cultures can vary significantly based on the relative amount of each pigment produced.A researcher placed a culture of cyanobacteria under green lights. Within a few weeks, the appearance of the cyanobacteria changed from green to red. The researcher claimed the color change in the culture was the result of an adaptation allowing greater photosynthesis.Which of the following provides the best reasoning to justify the researcher's claim?
In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis.
In chloroplasts, ATP is synthesized from ADP plus inorganic phosphate (Pi) in a reaction catalyzed by ATP synthase molecules that are embedded in the thylakoid membrane. Which of the following statements provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane?
No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane.
Which of the following best supports the claim that the species is better adapted to environmental changes and other photosynthetic species are?
The additional pigments allow the species containing them to harvest energy from wavelength of light that the other photosynthetic species cannot use