Comprehensive Biology: Cell Structures, Processes, and Ecosystem Dynamics

A comprehensive vocabulary review of cell structures, organelles, biological macromolecules, transport mechanisms, plant tropisms, and ecological dynamics based on the lecture notes.

Prokaryotic cell

A type of cell that lacks a nucleus and membrane-bound organelles, typically smaller and simpler than eukaryotic cells.

Eukaryotic cell

A type of cell that has a nucleus and membrane-bound organelles, allowing for more complex structures and functions.

Prokaryotic Cell vs. Eukaryotic Cell

A comparison showing the simpler organization of a prokaryotic cell (containing a nucleoid, capsule, cell wall, and flagella) contrasted with a eukaryotic cell (featuring a membrane-bound nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus).

Nucleus

The control center of the cell, housing the cell's DNA and coordinating activities such as growth, metabolism, and reproduction.

Mitochondria

The powerhouse of the cell, responsible for producing ATP through cellular respiration.

Endoplasmic reticulum (ER)

An organelle involved in the synthesis of proteins and lipids, which also plays a role in the transport of materials within the cell.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Lysosomes

Organelles containing enzymes that break down waste materials and cellular debris, acting as the cell's waste disposal system.

Ribosomes

The sites of protein synthesis, translating messenger RNA into polypeptide chains.

Chloroplasts

Organelles found in plant cells that conduct photosynthesis, converting light energy into chemical energy.

Cell membrane

A semipermeable barrier that regulates the movement of substances in and out of the cell, maintaining homeostasis.

Cell wall

A rigid layer that provides structural support and protection to plant cells, maintaining their shape.

Carbohydrates

Macromolecules made of sugar molecules that provide energy and structural support in cells.

Lipids

Macromolecules that include fats, oils, and phospholipids, serving as energy storage and structural components of cell membranes.

Nucleic acids

Macromolecules, such as DNA and RNA, that store and transmit genetic information.

Proteins

Macromolecules made of amino acids that perform a variety of functions, including catalyzing biochemical reactions and providing structural support.

Active transport

The movement of substances across a cell membrane against their concentration gradient, requiring energy.

Passive transport

The movement of substances across a cell membrane without the use of energy, typically along the concentration gradient.

Osmosis

The diffusion of water molecules across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Diffusion

The process by which molecules move from an area of higher concentration to an area of lower concentration.

Facilitated diffusion

The process by which molecules pass through a cell membrane via a channel protein, moving from high to low concentration without energy.

Sodium-potassium pump

An active transport mechanism that moves sodium ions out of the cell and potassium ions into the cell, crucial for maintaining cellular homeostasis.

Endocytosis

A cellular process in which substances are brought into the cell by engulfing them in a membrane-bound vesicle from the external environment.

Exocytosis

The process by which a cell expels materials in vesicles that fuse with the cell membrane, releasing their contents outside the cell.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll, converting carbon dioxide and water into glucose and oxygen.

Cellular respiration

The process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

Photosynthesis vs. Cellular Respiration Reactions

The chemical relationship showing photosynthesis as an endothermic reaction storing energy in glucose ($6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$) and cellular respiration as an exothermic reaction releasing energy from glucose ($C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O$).

Virus

A microscopic infectious agent that can only replicate inside the living cells of an organism, lacking cellular structure and metabolism.

Virus vs. Cell Comparison

A Venn diagram framework contrasting viruses (simpler, smaller, protein capsid, needs a host, no organelles, no metabolism) with cells (complex, larger, cell membrane, reproduces independently, has organelles, uses energy), while sharing genetic information.

Plant Tropisms

Growth responses of plants to directional stimuli, including phototropism (growth towards light), thigmotropism (growth in response to touch), geotropism/gravitropism (growth in response to gravity), and hydrotropism (growth towards water).

Aquaporins

Channel proteins that facilitate the rapid transport of water across the cell membrane, crucial for maintaining osmotic balance and homeostasis.

Equilibrium in cells

A state reached when the concentration of molecules is equal on both sides of the membrane, providing balanced solute and solvent concentrations that support homeostasis.

Steps of cellular respiration in order

1. Glycolysis, 2. Krebs Cycle, 3. Electron Transport Chain.

Steps in protein synthesis and transport

1. Nucleus sends DNA instructions, 2. Ribosome builds the protein, 3. Endoplasmic reticulum transports the protein, 4. Golgi apparatus modifies and packages the protein, 5. Vesicle carries the protein to the cell membrane.

Hypertonic solution effects

Water moves out of the cell, causing animal cells to shrink and plant cells to become plasmolyzed.

Isotonic solution effects

Water movement is balanced, resulting in animal cells remaining normal and plant cells maintaining stability.

Hypotonic solution effects

Water moves into the cell, causing animal cells to burst and plant cells to become turgid.

Phospholipid bilayer structure

A double-layered membrane featuring hydrophilic heads that face outward and hydrophobic tails that face inward, creating a selective barrier that allows certain molecules to pass while blocking others.

Seasonal flooding effects on the Amazon Basin

Replenishes nutrients in the soil, supports plant growth, and enhances biodiversity, although excessive flooding can disrupt species balance.