General Biology 1: Themes, Chemistry, Biomolecules, and Cell Structure

Flashcards reviewing key concepts, definitions, processes, and comparisons across Chapters 1-5 of General Biology.

What is the biological definition of organization?

The arrangement of biological structures from smaller, simpler levels to larger, more complex levels.

What are emergent properties in biological systems?

New properties that arise at each successive level of biological organization due to the specific arrangement and interactions of lower-level components.

What is the difference between reductionism and systems biology?

Reductionism breaks down complex biological systems into simpler components to study them easily, whereas systems biology studies how those components interact and function together as a whole.

What is the correct sequence of the biological hierarchy of organization from smallest to largest?

Atoms $\rightarrow$ Molecule $\rightarrow$ Organelle $\rightarrow$ Cell $\rightarrow$ Tissue $\rightarrow$ Organ $\rightarrow$ Organ System $\rightarrow$ Organism $\rightarrow$ Population $\rightarrow$ Community $\rightarrow$ Ecosystem $\rightarrow$ Biosphere.

How do population, community, and ecosystem differ from one another?

A population is a group of individuals of the same species in an area; a community includes all populations of different species in that area; an ecosystem consists of the community plus the nonliving physical environment.

How do energy and matter move differently through an ecosystem?

Energy flows through an ecosystem in a one-way direction (entering as light and exiting as heat), while matter cycles and is continuously reused and recycled within an ecosystem.

What are the primary differences between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus, have DNA not enclosed in a membrane, lack membrane-bound organelles, and are smaller and simpler; eukaryotic cells have a membrane-bound nucleus enclosing their DNA, contain membrane-enclosed organelles, and are larger and more complex.

What are the three domains of life and their cell types?

Domain Bacteria (prokaryotic), Domain Archaea (prokaryotic), and Domain Eukarya (eukaryotic).

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

Protons have a positive charge ($+$) and are located in the nucleus; neutrons have no charge ($0$) and are located in the nucleus; electrons have a negative charge ($-$) and reside in electron clouds surrounding the nucleus.

How do you calculate the number of neutrons in an atom?

$$\text{Number of Neutrons} = \text{Mass Number} - \text{Atomic Number}$$

What defines an isotope versus an ion?

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons (varying mass numbers); ions are atoms or molecules that have gained or lost electrons, gaining a net electric charge.

What are the key differences between covalent, ionic, and hydrogen bonds?

Covalent bonds involve the sharing of electron pairs between atoms; ionic bonds involve the transfer of electrons creating charged ions that attract; hydrogen bonds are weak attractions between a partially positive hydrogen atom and a negative atom in polar molecules.

How does a 2-unit change in pH affect the concentration of hydrogen ions ($\text{H}^+$)?

Because the pH scale is logarithmic, a 2-unit change represents a $10 \times 10 = 100$\text{-fold}$change in$\text{H}^+$$ concentration.

What is the function of a chemical buffer in biological systems?

A buffer resists drastic changes in pH by accepting $\text{H}^+$ ions when the solution becomes too acidic and donating $\text{H}^+$ ions when it becomes too basic.

Why can carbon form a vast variety of complex organic molecules?

Carbon has 4 valence electrons, allowing it to form 4 covalent bonds with other atoms in straight chains, branched chains, or ring structures.

What chemical functional group is represented by $\text{-COOH}$ and what property does it confer?

The carboxyl group ($\text{-COOH}$), which acts as an acid because it can donate an $\text{H}^+$ ion.

How do dehydration synthesis and hydrolysis reactions differ?

Dehydration synthesis removes a molecule of water to covalent join two monomers together into a polymer; hydrolysis adds a molecule of water to break the bond between monomers in a polymer.

What is the structural difference between saturated and unsaturated fatty acids?

Saturated fatty acids have no carbon-carbon double bonds ($\text{C=C}$) in their hydrocarbon chains, forming straight structures that are solid at room temperature; unsaturated fatty acids have one or more $\text{C=C}$ double bonds that create kinks, remaining liquid at room temperature.

What are the four levels of protein structure?

Primary (linear sequence of amino acids), Secondary (local coiling or folding into $\alpha$-helices or $\beta$-pleated sheets via hydrogen bonds), Tertiary (overall 3D shape formed by R group interactions), and Quaternary (association of multiple polypeptide chains).

What is protein denaturation, and what structures are affected?

Denaturation is the process where a protein loses its native shape and function due to factors like high temperature or extreme pH, disrupting secondary, tertiary, and quaternary structures while leaving primary structure intact.

Why are cells limited to a small size by the surface area-to-volume ratio?

As a cell grows, its volume increases much faster than its surface area, causing the surface area-to-volume ratio to decrease and making it difficult to exchange sufficient materials and waste across the plasma membrane.

What is the function of the nucleolus inside the eukaryotic nucleus?

The nucleolus produces ribosomal RNA (rRNA) and assembles ribosomal subunits.

What is the transport pathway for a protein destined for secretion out of the cell?

Nucleus $\rightarrow$ Rough ER $\rightarrow$ Transport Vesicle $\rightarrow$ Golgi Apparatus $\rightarrow$ Secretory Vesicle $\rightarrow$ Plasma Membrane $\rightarrow$ Outside Cell.

What is the Endosymbiont Theory?

The theory that mitochondria and chloroplasts originated as free-living prokaryotes that were engulfed by an ancestral eukaryotic cell and evolved into permanent, mutually beneficial organelles.

How does cholesterol regulate cell membrane fluidity at different temperatures?

At moderate temperatures, cholesterol restrains movement of phospholipids to reduce fluidity; at low temperatures, it prevents tight packing of phospholipids to stop the membrane from solidifying.

Which types of molecules cross the selectively permeable phospholipid bilayer most easily without proteins?

Small, hydrophobic (nonpolar) molecules, such as oxygen ($\text{O}_2$) and steroid hormones.

What is the difference between simple diffusion, facilitated diffusion, and active transport?

Simple diffusion moves substances high to low concentration without ATP or proteins; facilitated diffusion moves substances high to low using transport proteins without ATP; active transport moves substances low to high (against gradient) using transport proteins and ATP.

What happens to animal and plant cells placed in a hypotonic solution?

Water enters the cell; the animal cell swells and lyses (bursts), while the plant cell becomes turgid (firm and healthy due to cell wall counterpressure).

What happens to animal and plant cells placed in a hypertonic solution?

Water leaves the cell; the animal cell shrivels, while the plant cell undergoes plasmolysis (plasma membrane pulls away from the cell wall).

What is dynamic equilibrium in cellular transport?

A state where molecules continue to move randomly across a membrane in both directions at equal rates, resulting in no net change in concentration.