ACT Science : Biology

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #611 : Biology

Eukaryotic cells, cells that contain membrane-bound organelles and generally reside within multicellular organisms, contain DNA, or deoxyribonucleic acid, which is organized into chromosomes. DNA is a double-stranded nucleic acid that forms a double helix. The bases found within a DNA molecule are adenine (A), thymine (T), guanine (G), and cytosine (C). DNA is organized into functional units, called genes, that encode the basic traits and characteristics of living organisms. DNA can be replicated within the nucleus prior to cell division to ensure each daughter cell receives an identical copy of DNA. The central dogma of molecular biology states that DNA is transcribed to RNA which is then translated into protein. RNA, or ribonucleic acid, is a nucleic acid found in all cells that serves a messenger to carry the genetic code from DNA to produce a functional molecule, the protein. RNA is a single-stranded nucleic acid and consists of the bases adenine (A), uracil (U), guanine (G), and cytosine (C). RNA is translated into amino acids on the ribosome to produce a polypeptide chain, or a protein. There are two general hypotheses for the original evolutionary molecule. The “RNA world” hypothesis states that the original genetic molecule is RNA, and RNA was able to be translated into protein and reverse transcribed to produce DNA. Alternatively, the “DNA, RNA, and Protein World” suggests that DNA was the original genetic molecule and was responsible for subsequent production of RNA and protein.

The central dogma of molecular biology supports which hypothesis?

Possible Answers:

RNA world

DNA, RNA, and protein world

Translation

Transcription

Correct answer:

DNA, RNA, and protein world

Explanation:

The central dogma of molecular biology states that DNA is transcribed into RNA which is translated into protein. This model starts with DNA as the genetic building block which supports the "DNA, RNA, and protein world" hypothesis.

Example Question #612 : Biology

Eukaryotic cells, cells that contain membrane-bound organelles and generally reside within multicellular organisms, contain DNA, or deoxyribonucleic acid, which is organized into chromosomes. DNA is a double-stranded nucleic acid that forms a double helix. The bases found within a DNA molecule are adenine (A), thymine (T), guanine (G), and cytosine (C). DNA is organized into functional units, called genes, that encode the basic traits and characteristics of living organisms. DNA can be replicated within the nucleus prior to cell division to ensure each daughter cell receives an identical copy of DNA. The central dogma of molecular biology states that DNA is transcribed to RNA which is then translated into protein. RNA, or ribonucleic acid, is a nucleic acid found in all cells that serves a messenger to carry the genetic code from DNA to produce a functional molecule, the protein. RNA is a single-stranded nucleic acid and consists of the bases adenine (A), uracil (U), guanine (G), and cytosine (C). RNA is translated into amino acids on the ribosome to produce a polypeptide chain, or a protein. There are two general hypotheses for the original evolutionary molecule. The “RNA world” hypothesis states that the original genetic molecule is RNA, and RNA was able to be translated into protein and reverse transcribed to produce DNA. Alternatively, the “DNA, RNA, and Protein World” suggests that DNA was the original genetic molecule and was responsible for subsequent production of RNA and protein.

A new organism is identified and the only nucleic acid contained within its cells is RNA. Which hypothesis would be supported by such a finding?

Possible Answers:

Transcription

DNA, RNA, Protein World

The Central Dogma

RNA World

Correct answer:

RNA World

Explanation:

The RNA World hypothesis states that RNA was the first genetic material. Idenitifying and organism that contains RNA but not DNA suggests that organisms can survive without DNA, supporting the idea that RNA may have been the first sole genetic information.

Example Question #613 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

Which of the following is a valid summary of Scientist II's argument against Scientist I?

Possible Answers:

Just because we did not see an event occur does not mean it did not happen

There is insufficient experimental evidence to prove spontaneous generation

Maggots do not appear on rotting carcasses

Not all plants come from seeds

Correct answer:

Just because we did not see an event occur does not mean it did not happen

Explanation:

Scientist II argues that just because we have not witnessed something does not mean it does not exist. He suggests that an unseen animate object is responsible for the growth and reproduction of organisms in an area that previously appeared to have no life.

Scientist II does not dispute that maggots appear on rotting carcasses or that some plants do not come from seeds. He also does not argue that the first scientist has insufficient experimental evidence. Rather, he gives an alternative explanation for the experimental results cited by Scientist I.

Example Question #614 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

On which point do both scientists agree?

Possible Answers:

Animate objects cannot come from inanimate objects

Organisms can spontaneously appear under the right circumstances

Maggots are incapable of sexual reproduction

Some bacteria can only sexually reproduce in broth

Correct answer:

Animate objects cannot come from inanimate objects

Explanation:

Both scientists agree that living organisms cannot come from non-living organisms. Scientist I suggests that living organisms can spontaneously generate, coming from neither a living source, nor a non-living source. Scientist II disagrees with the idea of spontaneous generation. Neither scientist discussed sexual and asexual reproduction in depth.

Example Question #615 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

An experiment is performed in which a bowl of broth containing bacteria is boiled and then left in the open air. After a day, the broth is observed to be cloudy. How might Scientist I explain this result?

Possible Answers:

The cloudiness is part of a natural cycle of the clarity of liquids

The bacteria did not necessarily come from the broth itself

The broth was insufficiently boiled and the original bacteria in it were not killed

The bacteria spontaneously generated in the broth, given the proper combination of nutrients and air

Correct answer:

The bacteria spontaneously generated in the broth, given the proper combination of nutrients and air

Explanation:

Scientist I argues that organisms can spontaneously appear. He would likely suggest that the live bacteria spontaneously generated in the broth after it was left to sit.

The argument that the bacteria did not come from the broth is the viewpoint of Scientist II. Neither scientist discussed the clarity of the liquid or the idea of boiling liquids to remove bacteria.

Example Question #616 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

An experiment is performed in which a rotting carcass is vacuum sealed. After several weeks, no maggots are observed. The rotting carcass is removed from the vacuum seal, and several days later maggots are observed. Which theory does this best support?

Possible Answers:

Both theories are supported

Scientist II

Neither theory is supported

Scientist I

Correct answer:

Scientist II

Explanation:

Scientist II would use this as proof that spontaneous generation cannot exist; otherwise maggots would have developed inside of the vacuum seal. Scientist I's theory would not work because the maggots did not appear until after the carcass was removed from the seal.

Example Question #617 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

Fungal spores are placed on a slice of melon. After a certain amount of time, the only fungi that appear on the melon are the same species as the spores. What conclusion would Scientist II draw from this experiment?

Possible Answers:

Fungi grow more slowly on melons

The fungi came from the spores, not from spontaneous generation

The fungus would have appeared on the melon regardless of the initial spores added

The experimental species of fungus can only grow on melon

Correct answer:

The fungi came from the spores, not from spontaneous generation

Explanation:

Scientist II would use this result as further proof that fungi do not come from spontaneous generation, but from the spores themselves. The spores would allow reproduction of only the same species. If spontaneous generation occurred, we may expect to see several species on the melon.

Example Question #618 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

Why does Scientist I mention that some plants come from seeds, while some come from asexual reproduction?

Possible Answers:

We do not fully understand the reproductive system

To remind the reader that animate objects can be generated by means other than sexual reproduction

Not all plants bear seeds or spores

Maggots and bacteria do not bear seeds

Correct answer:

To remind the reader that animate objects can be generated by means other than sexual reproduction

Explanation:

Scientist I argues that spontaneous generation is possible. He acknowledges the possibility for sexual reproduction, and then points out that this not the only way for creatures to reproduce. He does not argue that we do not understand the reproductive system, nor does he discuss plants bearing seeds or maggots bearing seeds.

Example Question #619 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

In order to create sourdough bread, the baker leaves the dough exposed. After a certain amount of time, the baker observes that the dough has begun to rise due to the addition of yeast. How would Scientist I explain this?

Possible Answers:

The yeast was in the air and reproduced in the dough

Yeast is not an organism

The dough must have a chemical reaction inside of it that causes yeast to be created

It is unclear how the yeast came into the dough

Correct answer:

The dough must have a chemical reaction inside of it that causes yeast to be created

Explanation:

Scientist I argues for spontaneous generation, so the correct answer will be the one that implies the yeast came from something within the dough. Scientist I does not believe that the yeast needed to enter through the air. Yeast is a small eukaryotic organism that is capable of asexual reproduction.

Example Question #620 : Biology

Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.

Scientist I

Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.

Scientist II

Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.

If true, which of the following statements would disprove Scientist II's theory?

Possible Answers:

Bacteria require oxygen to reproduce

Maggots are fly larvae that are laid in rotting carcasses

Some single-celled bacteria have been observed to appear in inanimate objects spontaneously

When bacteria reproduce in broth, the broth has a tendency to froth

Correct answer:

Some single-celled bacteria have been observed to appear in inanimate objects spontaneously

Explanation:

Scientist II's theory could only be disproved by something that proves spontaneous generation is possible. The correct answer shows an example of an animate object spontaneously arising in an area where only inanimate objects previously exist.

The answer about maggots would prove Scientist II correct. The other two answer choices do not relate directly to Scientist II's theory.

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