Mastering Biology: Chapter 1

What is the molecule that is responsible for both the unity and the diversity of life?

DNA *The uniformity of coding in DNA is virtually universal. Life's variety arises from variations in the nucleotide sequences of inherited DNA molecules, the substance of genes.

Which of the following is true of a scientific theory? It is a method or device that applies scientific knowledge for some specific purpose. It is formulated by many scientists over drinks at a convention. It is only accepted after the person who came up with it has died. It generates testable hypotheses, is supported by a large body of evidence, and is broad in scope. It must demonstrate the effect of one variable by testing control groups and experimental groups.

It generates testable hypotheses, is supported by a large body of evidence, and is broad in scope. A scientific theory is more than an interesting idea. It must stand up to constant scrutiny from skeptical researchers.

Which of the following is (are) true of natural selection?

It requires genetic variation, results in descent with modification, and involves differential reproductive success.

Which of the following statements most clearly demonstrates inductive reasoning?

If the animals observed require organic molecules as nutrients, then it can be concluded that all animals require organic molecules as nutrients.

Which example illustrates a property that emerges at the community level?

Metabolic cooperation between prokaryotic cells forms a biofilm that allows bacterial colonies to transport nutrients and wastes. Biofilms may damage industrial equipment or cause tooth decay. *This emergent property emerges at the community level, due to the interactions among prokaryotic species forming the biofilm. Read about levels of biological organization in and emergent properties.

Which of the following can best be considered a biological system? a pond a single liver cell the biosphere a salmon's cardiovascular system

A system is a combination of components that function together. It can be defined at any scale.

Can you label this diagram showing how nutrients and energy flow in an ecosystem?

a. sunlight b. producers c. chemical energy d. consumers e. heat f. CO2 g. O2

Experimentation is only one part of the process of scientific inquiry, but it is a very important step because it __________.

allows rejection of hypotheses *Experimentation is important because hypotheses can be rejected when contradictory evidence emerges.

Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope?

archaean

With evolution as the core theme of biology, we can explain traits shared by organisms as evidence of __________ and traits that differ among organisms as evidence of __________.

common ancestor ... adaptation through natural selection *Many shared traits have been derived from common ancestry. The modifications to those shared traits can usually be attributed to adaptive evolution by natural selection.

What is the correct order for the hierarchy of biological organization from the least to the most complex?

molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem *Each level of biological structure builds on the level before it.

A localized group of organisms that belong to the same species is called a _____.

population

Protists and bacteria are grouped into different domains because:

protists have a membrane-bounded nucleus, which bacterial cells lack

In the process of science, which of these is tested?

a hypothesis

The phylogenetic tree below _____.

depicts the three major domains of life

Emergent properties of living systems are properties that __________.

are due to the arrangement and interactions of parts as complexity increases *Emergent properties are novel properties not present at the level of biological organization just below. Emergent properties arise from the arrangement and interactions of parts as complexity increases.

In an ecosystem, nutrients __________ and energy __________.

are recycled ... flows through *Nutrients are always recycled. Energy flows through the system, typically entering as solar energy and leaving as heat.

In comparison to eukaryotes, prokaryotes _____.

are smaller

A scientific theory is __________.

a well-supported concept that has broad explanatory power

Which of the following is the fundamental unit of structure and function in living organisms?

cell *The cell is the fundamental structural and functional unit of both single-celled and multicellular organisms.

A team of scientists has devised a new chemical fertilizer that its members believe will increase crop yields. The team planted three garden plots with corn. The soil was similar in each, and equal amounts of water were applied to each plot. One plot was treated with a common commercial fertilizer, another was treated with the new fertilizer, and the third plot was not given any fertilizer. The experimenters measured yields as bushels of corn from each plot. The plot that did not receive fertilizer was the __________.

control plot

No amino acid molecule by itself can speed up or catalyze reactions between other molecules; however, when amino acids are joined together to make a protein with catalytic properties, the new structure (enzymatic protein) can speed up the rate of a specific chemical reaction. What does this illustrate?

emergent properties *A molecule such as a protein has attributes not exhibited by any of its component parts (e.g., amino acids). Therefore, novel properties are emerging that were not present at a simpler level of organization.

The best method for determining whether bean plants require sodium is to __________.

grow bean plants with and without sodium *In hypothesis-based scientific inquiry, the experiment must have an experimental group and a control group. In this case, growing bean plants with sodium would constitute the experimental group, and growing bean plants without the addition of sodium would constitute the control group.

At which point in a study is a scientific investigator most likely to use deductive reasoning?

in establishing a test of a hypothesis *In deduction, reasoning flows from the general to the specific. Deductive testing would take the form of "if ... then" logic.

How does DNA (deoxyribonucleic acid) encode information?

in the sequence of nucleotides.

The best experimental design _____.

includes a large sample size and a control, and alters only one condition between the controls and the experimental condition

A controlled experiment _____.

includes at least two groups, one of which does not receive the experimental treatment

Repetition of an experiment _________.

is necessary before concluding that a given set of results is correct *Repetition of tests is crucial to the process of science. Only when a result is repeatable can it be considered correct.

Which of these provides evidence of the common ancestry of all life?

near universality of the genetic code

Which of the following is not an observation or inference on which Darwin's theory of natural selection is based?

poorly adapted individuals never produce offspring

What is the appropriate term for an interacting group of individuals of a single type occupying a defined area?

population *Only the organisms of a given species that have the opportunity to interact with one another are considered to be within the same population.

A controlled experiment is one that:

tests experimental and control groups in parallel

A company was testing a new drug it thought would help decrease the risk of transmission of viruses from mother to fetus. In an experiment to test the compound, an investigator gave 400 pregnant female rats a small dose of the experimental drug and inoculated each with a type of virus known to cause disease in rats. At the same time, 400 other pregnant rats were given only the virus. Of the rat pups born to the females that received both the virus and the drug, 197 showed no symptoms of the disease; 205 rat pups born to the virus-only females showed symptoms. From these data, we can best conclude __________.

that the drug seems to have little effect on viral transmission at the dosage given *Approximately equal numbers of pups were affected in both groups (experimental group = 197, control group = 205), suggesting that the drug was probably not effective at the dosage given.

In the diagram below, "A" is _____ ; "B" is _____.

the common ancestor of all life; the last common ancestor of Archaea and Eukarya

Which of the following best demonstrates the unity among all the organisms?

the structure and function of DNA

The energy used by most organisms for metabolism and growth ultimately comes from __________.

the sun *Energy for most living things ultimately comes from the light energy of the sun, used to drive the synthesis of energy storage molecules by photosynthetic organisms.

Which of the following attributes is common to both prokaryotic cells and eukaryotic cells?

the use of DNA as the information storage molecule All cells (discovered so far) use DNA to store information.

Which of the following is NOT an attribute of living things?

All living things require oxygen.

The universal genetic language of DNA is common to virtually all organisms on Earth, however diverse. What is the best explanation for this fact?

All living things share a common genetic language of DNA because they share a common ancestry. *The genetic code is arbitrary, at least to some extent. The fact that all organisms share a single genetic code is due to their common ancestry. Read about the core theme of biology: Evolution accounts for the unity and diversity of life.

Which of the following systems does NOT display emergent properties? a drop of water a colony of bees a calculator an organ

All of the listed answers are examples of emergence. Emergence is not restricted to biological systems.

Prokaryotes are classified as belonging to two different domains. What are the domains?

Bacteria and Archaea

Which of these is an example of inductive reasoning?

Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic.

Which taxonomic domain includes multicellular photosynthetic organisms?

Eukarya *Plants and certain algae are multicellular photosynthetic organisms included in the kingdom Plantae of the domain Eukarya.

Competition is central to the theory of natural selection. Why does competition occur?

Organisms typically produce too many offspring, and resources are limited. *Resource competition is one of the main ingredients for natural selection. Organisms must compete for limited resources, and only the best adapted will survive and reproduce.

Drag the terms to their correct location in the paragraph.

The scientific study of life, called [biology], can be organized around several themes. As the biological hierarchy builds from molecules on up to ecosystems, each level has [emergent properties] that result from interactions among component parts. Life's basic unit of [structure and function] is the cell, which occurs in two basic forms--prokaryotic and eukaryotic. As organisms interact with the environment, [chemical nutrients] cycle within an ecosystem, while [energy] flows one way from sunlight->chemical energy->heat. According to the core theme of [evolution], all of life is related by common descent. Life has diversified as [natural selection] has led to the gradual accumulation of adaptions that fit populations to the environment.

Which of the following statements best describes the phenomenon of "emergence"?

The whole is greater than the sum of the parts.

Should an experiment test only one variable at a time? Why or why not?

Yes, an experiment should test only one variable at a time. This ensures that the experimental outcome is clearly due to one identifiable factor.

Can you organize these terms that describe key ideas about evolution?

a. diversity b. natural selection c. living species d. ancestral species e. heritable variations in a population f. greater reproductive success g. evolutionary adaptions

Radon is a radioactive gas that seeps into homes from the soil. It is thought to be a cause of lung cancer. A research team investigates this hypothesis. The members of the team gather large amounts of data on basement radon concentrations and lung cancer rates and conclude that the more radon there is in a home, the more likely are people living in the home to develop lung cancer. After the study is published, other researchers criticize it by asserting that the studied neighborhoods with higher radon concentrations also have a higher percentage of older people and a higher percentage of cigarette smokers than the low-radon neighborhoods. Both advanced age and cigarette smoking increase the risk of lung cancer. This criticism, if correct, shows that the radon study suffered from __________.

uncontrolled variables *An important feature of the scientific process is to control for as many variables as possible. Ideally, the control and experimental groups should differ only in the one variable the study is designed to test.