Comprehensive Biology Review: Scientific Method, Characteristics of Life, and Biochemistry

Flashcard set for reviewing scientific method, characteristics of living organisms, biosphere hierarchy, basic chemical bonding, macromolecules, enzymes, and properties of water.

What is the main goal of science according to the lecture notes?

To collect evidence through observation, experimentation, and data collection to learn how the world and universe work.

What two essential criteria must a scientific hypothesis meet?

It must be testable (able to be tested) and falsifiable (testing can show it to be either correct or incorrect).

How do the independent variable and dependent variable differ in a controlled experiment?

The independent variable is the single factor that is different between groups at the start of the experiment, while the dependent variable is the measurable difference between the groups at the end.

What is cognitive bias, and what is the Dunning-Kruger effect?

Cognitive bias involves trusting one's gut over data or misinterpreting results without asking if they make sense. The Dunning-Kruger effect is the inverse relationship between confidence and actual knowledge.

How are biotic and abiotic factors defined?

Biotic factors are things that are alive or were once living (including dead matter and products of living organisms), whereas abiotic factors are non-living and were never alive.

What does the acronym O.R.A.N.G.E. stand for regarding the characteristics of life?

Organized (made of cells & DNA, structured), Reproduce (making offspring), Adjusts as needed (response to stimuli & homeostasis), Growth & Development, and Energy (metabolism).

How do sexual and asexual reproduction differ?

Sexual reproduction requires two parent cells combining genetic material to create a new organism, whereas asexual reproduction requires a single parent producing genetically identical offspring (cloning).

What is homeostasis?

The ability of an organism to keep a stable internal environment even when external conditions change.

What is the correct sequence of structural organization in the biosphere from smallest to largest?

Atom, Molecule, Macromolecule, Organelle, Cell, Tissue, Organ, Organ system, Organism, Population, Community, Ecosystem, Biome, Biosphere.

What are emergent properties in chemistry?

Properties that arise when elements combine to form new substances with distinct traits, such as non-toxic table salt forming from explosive sodium metal and poisonous chlorine gas.

How many maximum electrons can be held in the 1st, 2nd, and 3rd energy levels of an atom?

The 1st energy level holds a maximum of $2$ electrons, while the 2nd and 3rd energy levels each hold a maximum of $8$ electrons.

What is the difference between polar-covalent and non-polar covalent bonds?

Polar-covalent bonds involve unequal sharing of electrons, resulting in partial positive and negative charges (e.g., water), while non-polar covalent bonds share electrons equally so charges cancel out (e.g., ethane).

What are the four major classes of biological macromolecules and their primary roles?

1) Proteins: Structural support and metabolic regulation (enzymes/hormones). 2) Carbohydrates: Quick energy and structural support. 3) Lipids: Long-term energy storage, waterproofing, insulation, and hormones. 4) Nucleic Acids: Information storage (DNA/RNA).

What are the key chemical groups attached to the central alpha carbon in a standard amino acid?

An amino group ($\text{H}_2\text{N}$), a carboxyl group ($\text{COOH}$), a hydrogen atom ($\text{H}$), and a variable side chain ($\text{R}$ group).

Why is the three-dimensional shape of a protein so important?

Because shape determines function ( Shape = Function); the specific order of the $20$ different amino acids determines the protein's unique shape and biological job.

How do enzymes function to control metabolism?

Enzymes are specialized proteins that act as biological catalysts to lower the activation energy required to start chemical reactions.

What naming convention do enzymes usually follow, and what is an active site?

Enzyme names almost always end in the suffix '-ASE'. The active site is the specific connection point where an enzyme binds to its specific substrate.

What is the chemical formula for glucose, and what are its two primary ring configurations?

The chemical formula is $\text{C}_6\text{H}_{12}\text{O}_6$. Its two ring forms are $\text{Alpha}$ (found in starches) and $\text{Beta}$ (found in structural fiber like cellulose).

What are the four major polysaccharides (the 'Big 4 Sugars') and their building blocks?

1) Starch: Plant energy storage (built from $\text{alpha}$-glucose). 2) Glycogen: Animal energy storage in liver/muscles (built from $\text{alpha}$-glucose). 3) Cellulose: Plant structural fiber (built from $\text{beta}$-glucose). 4) Chitin: Animal exoskeleton support (built from $\text{beta}$-glucose).

How do saturated fats and unsaturated oils differ in structure and state at room temperature?

Saturated fats have no carbon-carbon double bonds, are typically animal fats, and are solid at room temperature. Unsaturated oils have one or more double or triple bonds, are plant energy storage, and are liquid at room temperature.

What are the main biological roles of triglycerides and phospholipids?

Triglycerides serve as animal fat subunits for long-term energy storage, while phospholipids form the structure of cell membranes.

What is the monomer subunit of nucleic acids and what three components make it up?

The monomer is a nucleotide, which consists of a nitrogenous base, a 5-carbon sugar, and a phosphate linker group.

What are the structural and functional differences between DNA and RNA?

DNA is double-stranded, contains deoxyribose sugar, remains in the nucleus, and stores master protein-building instructions. RNA is single-stranded, contains ribose sugar, can leave the nucleus, and serves as a working copy of the DNA blueprint.

How do hydrogen bonds explain cohesion, adhesion, and surface tension in water?

Polar water molecules form weak magnetic hydrogen bonds with each other. Cohesion is water sticking to water, surface tension is the cohesive resistance at the liquid boundary, and adhesion is water sticking to other hard polar or charged surfaces.

What unique density behavior occurs when water freezes, and what is high specific heat?

Water reaches maximum density at $4^\text{o}\text{C}$; as it freezes at $0^\text{o}\text{C}$, molecules expand into a crystal lattice with 4 hydrogen bonds, causing ice to float. High specific heat means water resists rapid temperature changes.