Introduction to Biology: Key Concepts and Principles

What is science?

The systematic study of the structure and behavior of the physical and natural world through observation and experimentation. (1.5)

How do researchers study biology at different levels?

By examining levels ranging from molecules to ecosystems. (1.5)

Distinguish between discovery-based science and hypothesis testing.

Discovery-based science focuses on collecting data without a hypothesis, while hypothesis testing follows the scientific method. (1.5)

List the steps of the scientific method.

Observation, hypothesis formation, experimentation, data analysis, conclusion. (1.5)

Explain the difference between a control group and an experimental group.

A control group does not receive the experimental treatment, while the experimental group does. (1.5)

What differentiates a scientific theory from a hypothesis?

A theory is a well-supported explanation of phenomena, while a hypothesis is a testable prediction. (1.5)

Describe the chemical basis of life.

Life depends on chemical reactions involving elements like carbon, hydrogen, oxygen, and nitrogen. (2.1)

Define atomic structure.

Atoms consist of protons, neutrons, and electrons, with protons and neutrons in the nucleus and electrons in orbitals. (2.1)

Define orbital, electron shells, and valence electrons.

Orbitals are regions where electrons are likely to be found. Electron shells are levels of orbitals, and valence electrons are in the outermost shell. (2.1)

Calculate the total number of subatomic particles if given atomic number and atomic mass.

Add the number of protons (equal to the atomic number) and neutrons (atomic mass minus atomic number). Electrons equal protons in a neutral atom. (2.1)

List the elements that make up most of the mass of all living organisms.

Carbon, hydrogen, oxygen, and nitrogen. (2.1)

Compare polar and nonpolar covalent bonds.

Polar covalent bonds have unequal sharing of electrons, while nonpolar covalent bonds share electrons equally. (2.2)

Discuss water's critical properties.

Water is cohesive, has a high heat capacity, and acts as a solvent, essential for life. (2.3)

Define acidic and basic conditions.

Acids release H+ ions, bases release OH− ions. Buffers help maintain stable pH levels. (2.4)

Why is carbon important?

Carbon forms the backbone of organic molecules, enabling diverse structures and functions. (3.1)

What are macromolecules?

Large molecules like carbohydrates, proteins, lipids, and nucleic acids, formed by polymerization. (3.2-3.7)

Contrast prokaryotic and eukaryotic cells.

Prokaryotes lack a nucleus and organelles, while eukaryotes have both. (4.3)

Compare the structure of plant and animal cells.

Plant cells have cell walls, chloroplasts, and large vacuoles; animal cells lack these but have centrioles and lysosomes. (4.3)

What are the four interacting systems of a eukaryotic cell?

Nucleus, cytosol, endomembrane system, and semiautonomous organelles. (4.4-4.8)

Describe the structure and function of the plasma membrane.

The plasma membrane is a phospholipid bilayer with embedded proteins that control substance passage. (5.1-5.6)

Compare simple diffusion, facilitated diffusion, and active transport.

Simple diffusion moves molecules down a gradient without energy; facilitated diffusion uses proteins; active transport requires energy. (5.4)

Define osmosis.

The diffusion of water across a selectively permeable membrane, affecting cell structure. (5.4)

List the stages of cellular respiration.

Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation. (7.1-7.7)

What are the inputs and outputs of cellular respiration?

Inputs: Glucose, oxygen. Outputs: ATP, CO2, H2O. (7.2-7.6)

Describe the processes involved in each stage of cellular respiration.

Glycolysis: Glucose → pyruvate. Pyruvate oxidation: Pyruvate → acetyl-CoA. Citric acid cycle: Acetyl-CoA → CO2 + NADH. Oxidative phosphorylation: NADH → ATP. (7.2-7.6)

Compare light reactions and the Calvin cycle.

Light reactions produce ATP and NADPH; the Calvin cycle uses them to synthesize glucose. (8.1-8.2, 8.4)

Define photosystem.

A protein-pigment complex that captures light energy during photosynthesis. (8.2)

Briefly describe the differences between linear and cyclic electron flow.

Linear flow produces ATP and NADPH; cyclic flow only produces ATP. (8.2)

What are the four key criteria for genetic material?

Information, replication, transmission, and variation. (11.1)

Outline the phases of mitosis.

Prophase, metaphase, anaphase, telophase. (16.2)

Compare mitosis and meiosis.

Mitosis produces identical cells; meiosis produces genetically diverse gametes. (16.3)

What is the difference between the cell cycle and cell division?

The cell cycle includes all stages of growth and division; cell division refers specifically to mitosis and cytokinesis. (16.1)

What are Mendel's two laws?

Law of Segregation and Law of Independent Assortment. (17.1)

Solve a one-trait genetics problem.

Use a Punnett square to predict offspring genotypes and phenotypes. (17.7)

Outline the Central Dogma.

DNA → RNA → Protein. (12.1)

What is transcription?

The process of synthesizing RNA from DNA. (12.2)

What is translation?

The process of synthesizing a protein using mRNA, tRNA, and ribosomes. (12.6)

Explain how the RNA molecule is modified.

RNA is capped, spliced, and given a poly-A tail. (12.3)

Define evolution.

The change in allele frequencies in a population over time. (22.1)

What is natural selection?

The process where advantageous traits increase an organism's reproductive success. (22.1)

Summarize evidence for evolutionary change.

Includes studies of natural selection, the fossil record, biogeography, convergent traits, selective breeding, and homologies. (22.2)

What are the processes for evolutionary change?

Genetic drift, gene flow, mutation, nonrandom mating, and natural selection. (23.1)

Define genetic drift and compare bottleneck and founder effects.

Genetic drift is a random change in allele frequency; bottleneck occurs when population size decreases, founder effect occurs when a new population is established. (23.4)

Describe the Hardy-Weinberg equilibrium.

A state where allele frequencies remain constant if no evolution occurs. (23.1)