The Nature of Life Quiz 1

Relevancy of taking biology for non-science majors

Reshapes understanding, accurate information and advancement of knowledge, also helps prepare the to interact with scientific information in the real world.

What was the main purpose of the Java Report: Caffeine Study?

To determine whether drinking caffeinated coffee prevents the typical daily decline in memory performance among adults over age 65.

What was the independent variable in the Java Report: Caffeine Study?

The type of coffee consumed, caffeinated coffee (experimental group) vs. decaffeinated coffee (control group).

What was the dependent variable in the Java Report: Caffeine Study?

Memory performance, measured by comparing morning and afternoon memory test scores.

What treatment did the control group receive in the Java Report: Caffeine Study?

The control group drank 12 oz. of decaffeinated coffee 30 minutes before each memory test.

What treatment did the experimental group receive in the Java Report: Caffeine Study?

The experimental group drank 12 oz. of caffeinated coffee 30 minutes before each memory test.

What was the outcome of memory performance in the control group for the Java Report: Caffeine Study?

The control group showed a decline in memory performance, with afternoon scores lower than morning scores.

What was the outcome of memory performance in the caffeinated group for the Java Report: Caffeine Study?

The caffeinated group showed no decline in memory performance; afternoon scores remained equal to morning scores.

What conclusion did the researchers draw from the Java Report: Caffeine Study?

Caffeinated coffee prevented the usual afternoon decline in memory performance in this population of adults over age 65.

Who is the experimental group of the Java Report: Caffeine Study?

The participants who drank caffeinated coffee before taking the memory tests.

Who is the control group of the Java Report: Caffeine Study?

The participants who drank decaffeinated coffee before taking the memory tests.

What overall pattern did the Parkinson’s study find between coffee intake and Parkinson’s disease?

The study found a strong correlation where people who drank less coffee had a higher incidence of Parkinson’s disease, while those who drank more coffee had a lower incidence.

What was the relationship between nondrinkers and Parkinson’s incidence?

Nondrinkers showed the highest cumulative incidence of Parkinson’s disease compared to all coffee‑consuming groups.

How did high coffee consumption (20–24 oz/day or 28+ oz/day) relate to Parkinson’s incidence?

Individuals who drank 20-24 oz/day or 28+ oz/day had the lowest incidence of Parkinson’s disease in the study.

 Does the study prove that drinking coffee prevents Parkinson’s disease?

No. The study shows correlation, not causation. It cannot prove that coffee prevents Parkinson’s disease.

What is one alternative explanation for the correlation between coffee and Parkinson’s disease?

People who are at higher risk for Parkinson’s disease may naturally avoid drinking coffee.

What is another possible explanation for the lower Parkinson’s rates in coffee drinkers?

Coffee may mask early symptoms of Parkinson’s disease, delaying diagnosis and making incidence appear lower.

Why can’t the Parkinson study’s results be generalized to everyone?

The study was conducted on Japanese‑American men, so the findings may not apply to other populations.

 What key scientific principle does the Parkinson’s Study illustrate?

Correlation does not imply causation; even strong correlations require controlled experiments to determine cause.

Who was the experimental group for the Parkinson’s study?

Everyone who drank coffee (any amount).

Who was the control group for the Parkinson’s study?

The nondrinkers, people who consumed 0 oz/day of coffee

What is a placebo in an experiment?

A placebo is a treatment with no active ingredient, given to participants to compare against the real treatment and measure psychological or expectation-based effects.

What is the placebo effect?

The placebo effect occurs when participants experience changes in symptoms or behavior simply because they believe they are receiving a real treatment, even though the treatment has no active ingredient.

Which group receives the placebo in an experiment?

The control group receives the placebo. This allows researchers to compare their results with the experimental group receiving the actual treatment.

Why do researchers use a placebo in controlled experiments?

 Researchers use a placebo to isolate the true effect of the treatment by controlling for participants’ expectations or psychological responses.

How does the placebo effect help strengthen experimental results?

It helps researchers determine whether improvements are due to the actual treatment or simply the participants’ belief that they are being treated.

 What is the independent variable in the Java Report: Caffeine & Memory Study?

The independent variable is the type of coffee consumed, caffeinated vs. decaffeinated.

What is the dependent variable in the Java Report: Caffeine & Memory Study?

The dependent variable is memory performance, measured by comparing morning and afternoon memory test scores.

What is the independent variable in the Parkinson’s & caffeine study?

The independent variable is the amount of coffee consumed per day (0 oz, 4-8 oz, 12-16 oz, 20-24 oz, 28+ oz).

What is the dependent variable in the Parkinson’s & caffeine study?

The dependent variable is the cumulative incidence of Parkinson’s disease in each coffee‑intake group.

What is the first step of the scientific process?

Making an observation, noticing something in the natural world that raises a question.

 What is the second step of the scientific process?

Asking a question, identifying what you want to understand or explain.

What is the third step of the scientific process?

 Forming a hypothesis, creating a testable, educated prediction about what will happen.

What is the fourth step of the scientific process?

Conducting an experiment, testing the hypothesis using controlled methods and variables.

 What is the fifth step of the scientific process?

Collecting and analyzing data, recording results and determining whether they support the hypothesis.

What is the sixth step of the scientific process?

Drawing a conclusion, deciding whether the hypothesis was supported or rejected based on the data.

What is the seventh step of the scientific process?

 Communicating results, sharing findings through reports, graphs, presentations, or publications.

 Why is repetition important in the scientific process?

Repeating experiments increases reliability and ensures results are consistent and not due to chance.

What is a testable hypotheses?

supported or rejected by carefully designed experiments or nonexperimental studies

What is a falsifiable hypotheses?

Can be ruled out by data.

What is a theory?

A scientific theory is a well-supported, evidence-based explanation of a natural phenomenon that has been repeatedly tested and confirmed through observation and experimentation.

What happens during a peer review?

Other experts in the field examine the study’s methods, data, and conclusions to check for accuracy, reliability, and scientific quality before it is published.

What is a peer review?

A peer review is a process where scientists evaluate another scientist’s research to ensure it meets scientific standards and is valid and trustworthy.

What is the conclusion of a peer review?

Reviewers decide whether the study should be accepted, revised, or rejected based on the strength of its methods, data, and conclusions.

What is correlation?

Correlation is a relationship where two variables change together in a predictable pattern, but the cause of the relationship is unknown.

What is causation?

Causation means one variable directly produces a change in another variable.

Why doesn’t correlation prove causation?

 Because two things can be related due to coincidence, hidden variables, or other factors that were not controlled for.

 Give an example of correlation from the caffeine studies.

Higher coffee intake is correlated with lower incidence of Parkinson’s disease.

Why can’t the Parkinson’s study claim causation?

It was an observational study, so researchers could not control all variables or prove that coffee directly caused the lower incidence.

What type of study is usually required to prove causation?

A controlled experiment where the independent variable is manipulated and all other variables are controlled.

What is the Curiosity rover?

Curiosity is a NASA robotic rover sent to Mars to explore the planet’s surface and study whether Mars could have ever supported microbial life.

When did Curiosity land on Mars?

Curiosity landed on Mars on August 6, 2012, inside Gale Crater.

What is the main mission of the Curiosity rover?

Its main mission is to determine whether Mars ever had the environmental conditions necessary to support life.

What are the five functional traits of life?

Growth, Reproduction, Homeostasis, Sense and response to stimuli, Metabolism

What is the growth trait of life?

Living things increase in size or number of cells over time.

What is the reproduction trait of life?

Living things can produce new individuals, either sexually or asexually.

What is homeostasis?

The ability of an organism to maintain a stable internal environment despite external changes.

 What does it mean to sense and respond to stimuli?

Living things detect changes in their environment and react to them.

What is metabolism?

Metabolism is the ability to obtain and use energy to power cellular processes.

Why are mules considered an exception to the traits of life?

Mules cannot reproduce, but they are still considered living because they meet all other traits of life.

Why is fire NOT considered alive even though it grows and uses energy?

 Fire lacks cells, cannot reproduce biologically, and does not maintain homeostasis.

Why are viruses considered exceptions to the traits of life?

Viruses cannot reproduce on their own or perform metabolism; they require a host cell, so they are not considered fully alive.

What makes prions an exception to the traits of life?

Prions are infectious proteins with no cells, no metabolism, and no ability to reproduce independently; they are not alive.

 Why are bacteria considered fully alive?

Bacteria have cells, grow, reproduce independently, maintain homeostasis, respond to stimuli, and perform metabolism.

Why is possible Mars life (if discovered) important for defining life?

It may show different or borderline traits of life, challenging our Earth‑based definitions.

What is a covalent bond?

A covalent bond is a chemical bond formed when two atoms share electrons to become more stable.

Where can covalent bonds be found?

Covalent bonds are found in water, gases like O₂ and CO₂, and nearly all biological molecules such as proteins, DNA, sugars, and fats.

 What are the three subatomic particles?

Protons, neutrons, and electrons

What are the charges of protons, neutrons, and electrons?

Protons are positive (+), neutrons are neutral (0), and electrons are negative (–).

What is an atom?

The smallest unit of an element, made of protons, neutrons, and electrons.

What is an element?

A pure substance made of only one type of atom.

 What is a molecule?

 A molecule is formed when two or more atoms bond together.

What is a macromolecule?

A large molecule made of smaller building blocks called monomers.

What is a polymer?

A polymer is a large molecule made of repeating monomers, such as carbohydrates.

What is a monomer?

A monomer is a small building block that forms polymers, such as sugars.

What are examples of monomers and polymers?

Monomer: monosaccharides; Polymer: polysaccharides (carbohydrates).

What makes a molecule organic?

It contains a carbon backbone and C-H bonds.

What are the four major types of organic macromolecules?

Carbohydrates, proteins, nucleic acids, and lipids.

What is the difference between organic and inorganic molecules?

Organic molecules contain C-H bonds; inorganic molecules do not.

Carbohydrates are made of what?

Sugars

Proteins are made of what?

Amino Acids

Nucleic Acid is made of what?

 Nucleotides

Lipids are made of what?

Fats

What does the atomic number represent?

The atomic number is the number of protons in an atom

What does atomic mass represent?

Atomic mass is the total number of protons and neutrons in the nucleus.

What is the cell membrane made of?

A phospholipid bilayer, two layers of phospholipids.

Why does the cell membrane form a bilayer?

 Hydrophilic heads face water while hydrophobic tails hide from water, forming two layers.

What does hydrophobic mean?

Hydrophobic means “water-fearing”; repels water.

 What does hydrophilic mean?

Hydrophilic means “water-loving”; attracted to water.

 What is a solvent?

 The substance that does the dissolving, such as water.

 What is a solute?

The substance being dissolved, such as salt or sugar.

 Rank the strength of bonds from strongest to weakest.

1. Ionic bonds 2. covalent bonds 3. hydrogen bonds.

What is a polar molecule?

A molecule with unequal sharing of electrons, creating partial charges.

 What is an ion?

An atom that has gained or lost electrons, becoming charged.

 What is an ionic bond?

A bond formed when electrons are transferred between atoms, creating charged ions.

What is a hydrogen bond?

A weak attraction between the slightly positive hydrogen of one molecule and the slightly negative atom of another.

Why is water a good solvent?

Water is polar, so it can dissolve ionic and polar substances.

Why is water considered “sticky”?

Because of hydrogen bonding, which causes cohesion and adhesion.

What is cohesion?

Water sticking to other water molecules.

What is adhesion?

Water sticking to other surfaces.