Chapter 1

Question 1

List the 7 characteristics of life.

Answer 1

• Contains DNA/RNA & biomolecules
• Composed of cells
• Grows & reproduces
• Requires energy & raw materials (metabolism)
• Responds to stimuli
• Maintains homeostasis
• Populations evolve via adaptive traits

These characteristics differentiate living organisms from non-living matter.

Question 2

Give an everyday example for DNA characteristic of life.

Answer 2

Paternity test

DNA testing can determine biological relationships.

Question 3

Give an everyday example for cells characteristic of life.

Answer 3

Cheek-swab microscopy

Microscopy allows observation of cells in human tissue.

Question 4

Give an everyday example for growth characteristic of life.

Answer 4

Child → adult

Shows the developmental process of organisms.

Question 5

Give an everyday example for metabolism characteristic of life.

Answer 5

Digesting lunch → ATP

Metabolism converts food into usable energy.

Question 6

Give an everyday example for response characteristic of life.

Answer 6

Pupils constrict to bright light

This reaction protects the eyes from excessive light.

Question 7

Give an everyday example for homeostasis characteristic of life.

Answer 7

Sweating cools body

Sweating is a physiological response to regulate body temperature.

Question 8

Give an everyday example for evolution characteristic of life.

Answer 8

Antibiotic-resistant bacteria

Evolution can lead to traits that enhance survival in changing environments.

Question 9

What 2 abilities are required for organisms to respond to the environment?

Answer 9

• Detection of a stimulus (sensory receptors)
• Effector mechanism to act (nerves, muscles, hormones)

These abilities allow organisms to react appropriately to their surroundings.

Question 10

Define adaptive trait & link it to natural selection.

Answer 10

Heritable feature that increases survival/reproduction in a given environment; individuals with the trait leave more offspring, increasing trait frequency through natural selection.

Adaptive traits enhance the fitness of organisms in specific environments.

Question 11

Example of an adaptive trait driving evolution.

Answer 11

Peppered-moth dark coloration became common in polluted forests

This change illustrates natural selection in response to environmental changes.

Question 12

Name & describe the 3 domains of life.

Answer 12

• Bacteria – unicellular, prokaryotic, diverse habitats
• Archaea – unicellular, prokaryotic, extreme environments
• Eukarya – cells with nuclei & organelles; includes Protists, Fungi, Plants, Animals

These domains categorize all living organisms based on cellular structure.

Question 13

Order the levels of biological organization from atom to biosphere.

Answer 13

Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ system → Organism → Population → Community → Ecosystem → Biosphere

This hierarchy illustrates the complexity of biological systems.

Question 14

Which level is more inclusive: community or population?

Answer 14

Community

A community includes all interacting species’ populations.

Question 15

Purpose of the scientific method in biology.

Answer 15

Systematic logic for answering testable questions & minimizing bias when building knowledge

The scientific method is essential for rigorous scientific inquiry.

Question 16

List the classic steps of the scientific method.

Answer 16

• Observation
• Question
• Hypothesis
• Prediction
• Experiment/Observation
• Conclusion
• (Revise & repeat)

Following these steps ensures thorough investigation and validation of scientific ideas.

Question 17

Define independent vs. dependent variable.

Answer 17

• Independent = factor researcher changes
• Dependent = response measured that depends on the independent variable

Understanding these variables is crucial for experimental design.

Question 18

What is a confounding variable & why does it matter?

Answer 18

Uncontrolled factor that changes with the independent variable; can mislead cause-and-effect conclusions

Confounding variables can obscure the true relationship between variables.

Question 19

Essential features of a well-designed experiment.

Answer 19

• Random assignment
• Control group
• Single independent variable
• Blinding if possible
• Sufficient sample size
• Repeatability

These features enhance the reliability and validity of experimental results.

Question 20

Control group versus experimental group.

Answer 20

• Control receives no treatment (or placebo)
• Experimental group gets the independent variable treatment

This distinction helps assess the effect of the treatment.

Question 21

Why use a placebo?

Answer 21

To mimic treatment without active ingredient, controlling for participants’ expectations

Placebos help isolate the psychological effects of treatment.

Question 22

Why perform a double-blind study?

Answer 22

Neither subjects nor researchers know group assignments, preventing expectation bias on both sides

Double-blind studies enhance the integrity of the results.

Question 23

Define statistical significance (p < 0.05).

Answer 23

Probability that observed difference is due to chance is less than 5%; results considered unlikely random

This threshold is commonly used to determine the reliability of findings.

Question 24

How does a hypothesis differ from a theory?

Answer 24

• Hypothesis = narrow, testable explanation
• Theory = broad, well-supported framework integrating many hypotheses & data

Theories are more comprehensive and are supported by substantial evidence.

Question 25

Describe inductive reasoning, give an example.

Answer 25

Specific observations lead to a general conclusion. Example: Repeatedly seeing swans that are white leads to inferring 'all swans are white.' ## Footnote Inductive reasoning is often used in forming hypotheses.

Question 26

Describe deductive reasoning, give an example.

Answer 26

General principle leads to a specific prediction. Example: If all mammals have hair and a whale is a mammal, then whales have hair. ## Footnote Deductive reasoning is used to test hypotheses.

Question 27

Clinical trial Phase I goal.

Answer 27

Assess safety & dosage in less than 100 healthy volunteers ## Footnote Phase I trials focus on determining safe levels of treatment.

Question 28

Clinical trial Phase II goal.

Answer 28

Test effectiveness & short-term side effects in a few hundred patients with target disease ## Footnote Phase II trials evaluate the treatment's efficacy and safety.

Question 29

Clinical trial Phase III goal.

Answer 29

Compare to standard treatments in thousands of patients; monitor efficacy & rare adverse events ## Footnote Phase III trials are crucial for assessing the overall benefit-risk ratio.

Question 30

Role of informed consent in trials.

Answer 30

Participants acknowledge risks/benefits in writing before enrollment ## Footnote Informed consent is essential for ethical research practices.

Question 31

Value & limitation of epidemiological studies.

Answer 31

Can reveal correlations in large populations when experiments are impossible; cannot prove causation, subject to confounders ## Footnote Epidemiological studies are important for public health insights but have inherent limitations.

Question 32

Difference between correlation & causation (example).

Answer 32

Ice-cream sales correlate with drowning deaths (both increase in summer) but do not cause drownings ## Footnote Understanding this distinction is critical in interpreting data.

Question 33

Metabolism – concise definition.

Answer 33

Sum of all chemical reactions that acquire & use energy ## Footnote Metabolism encompasses both anabolic and catabolic processes.

Question 34

Homeostasis – concise definition & exemplar.

Answer 34

Active maintenance of stable internal conditions; e.g., glucose regulation by insulin/glucagon ## Footnote Homeostasis is vital for the proper functioning of living organisms.

Question 35

Define eukaryote & contrast with prokaryote.

Answer 35

Eukaryote: organism whose cells possess a nucleus & organelles; Prokaryotes lack these structures ## Footnote This distinction is fundamental in biological classification.

Question 36

Define atom & molecule.

Answer 36

* Atom: smallest unit of an element with chemical identity * Molecule: two or more atoms bonded together ## Footnote Atoms and molecules are the building blocks of matter.

Question 37

Define tissue, organ, and organ system with examples.

Answer 37

* Tissue: group of similar cells (e.g., cardiac muscle) * Organ: structure of ≥2 tissues (e.g., heart) * Organ system: coordinated organs (e.g., circulatory system) ## Footnote These definitions are essential for understanding biological organization.

Question 38

Explain why 'population' is a genetic unit.

Answer 38

Evolution acts on allele frequencies within a population, not on individuals ## Footnote This concept is crucial for understanding evolutionary dynamics.

Question 39

Key reason confounding variables must be controlled.

Answer 39

They create alternative explanations, preventing clear attribution of effects to the independent variable ## Footnote Controlling confounding variables is essential for valid experimental conclusions.

Question 40

Example of theory evolution over time.

Answer 40

Cell theory refined as microscopy improved, e.g., recognition of organelles & cell lineage ## Footnote Scientific theories evolve with advancements in technology and knowledge.

Question 41

Quick checklist for critically evaluating information.

Answer 41

* Source credibility * Evidence consistency * Proper scientific method * Clear data interpretation * Alternative explanations considered * Distinction between correlation & cause ## Footnote This checklist can help assess the reliability of scientific claims.