Biology and the Concept of Life Lecture Notes

Flashcards covering the concept of life, biological classifications, metabolism, homeostasis, and acellular agents based on the lecture transcript.

Vegetative Soul (anima vegetativa)

Aristotle's term for the life principle in organisms, such as plants, that can grow, take in nutrients, and reproduce, but lack movement and thought.

Sensitive Soul (anima sensitiva)

The life principle in animals that grants them sentience, mobility, the capacity to feel emotions, and the ability to process sensory information.

Rational Soul (anima intellectiva)

The life principle unique to humans that adds the capacity for logic, abstract thought, and moral choice to basic physical and sensory functions.

2nd Law of Thermodynamics

A law stating that the total entropy of an isolated system must always increase over time during any spontaneous process; changes in the entropy of the universe can never be negative.

Entropy in Living Organisms

Living things maintain a highly-organized, low-entropy state as open systems that obtain energy from surroundings and release heat and waste, thus not violating the 2nd Law of Thermodynamics.

Prokaryotic

Small, simple, single cells that lack a nucleus.

Eukaryotic

Larger, more complex cells that contain a nucleus and membrane-bound parts.

Cell

The basic building block and unit of life that makes up plants, animals, and humans.

Tissue

A group of similar cells that work together to perform a specific job.

Organ

A group of different tissues that work together to perform a specific job.

Organism

A spatially discrete unit of life.

Bioinks

Specialized formulations of living cells mixed with a fluid, gel-like biomaterial used in bioprinting.

Bioprinting

A process that uses living cells, proteins, and nutrients to build $3D$ tissue structures layer by layer.

E. coli O157:H7

A dangerous prokaryotic strain spread through dirty food or water that produces Shiga toxin, causing kidney failure and hemorrhagic colitis.

Shiga toxin

A powerful poison produced by E. coli O157:H7 that causes severe abdominal cramps and bloody diarrhea.

Acanthamoeba

A free-living, single-celled eukaryotic amoeba found in soil and water that can cause severe infections of the eye, skin, and central nervous system.

Trichophyton

A group of eukaryotic fungi that eat keratin and cause infections such as athlete’s foot, jock itch, and ringworm.

Allium cepa

The onion; a multicellular eukaryotic plant cell consisting of specialized cells with membrane-bound nuclei.

Human glomerulus

A tiny ball of specialized blood vessels in the kidney that serves as a biological filter to clean blood and remove waste to produce urine.

Metabolism

The sum of all chemical reactions in an organism that obtain, convert, and use energy and materials to sustain life.

Catabolism

Metabolic reactions that break down molecules into smaller units, either to release energy ($PE \rightarrow KE$) or for use in anabolic reactions.

Anabolism

Metabolic reactions that construct molecules from smaller units, requiring an input of energy ($KE \rightarrow PE$).

Ketosis

A metabolic state occurring when the body burns fat for energy instead of glucose.

Leaf Sheep

An organism that eats algae and uses sunlight to produce energy like a plant.

Binary Fission

The primary asexual method of reproduction for prokaryotes that results in exponential population growth.

Katakataka plant

A plant that reproduces asexually through vegetative propagation, growing baby plantlets along the edges of its leaves.

Parthenogenesis

A reproductive process in Komodo dragons where a female fertilizes her own eggs without a male, producing only male offspring.

Tropisms

Slow and irreversible plant movements where the direction of movement is determined by the direction of the stimulus (e.g., phototropism).

Nastic Movements

Quick and reversible plant movements that occur independent of the direction of the external stimuli.

Homeostasis

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

Contractile vacuole

A specialized structure in Paramecium used to collect and pump out extra fresh water to maintain osmotic pressure.

Negative Feedback Loop Components

The system consisting of a receptor (notifies changes), a control center (defines normal balance), and an effector (causes a reaction to correct imbalance).

Insulin

A hormone released by the pancreas when blood sugar is high to signal cells to take up glucose.

Glucagon

A hormone released by the pancreas when blood sugar is low to signal the liver to break down glycogen and release glucose into the blood.

Natural Selection

The process by which traits that enhance survival and reproduction are passed on, as seen in the color changes of the Peppered moth.

Disk Diffusion Assay

A standardized technique used to determine the susceptibility of bacteria to antimicrobial agents.

Sukunaarchaeum mirabile

A single-celled archaeon that exists between living and nonliving because it is extremely dependent on other organisms for metabolic processes.

Viruses

Acellular infectious agents composed of nucleic acid inside a protein coat; rabies ($\sim 99\%$ fatality) and ebola ($\sim 90\%$ fatality) are examples.

Viroids

The smallest infectious agents, composed only of circular, single-stranded RNA, which exclusively infect plants.

Prions

Acellular agents made of misfolded proteins with no genetic material that cause $100\%$ fatal brain diseases like Mad Cow Disease.

Apoptosis

An orderly, programmed process of cell death used to remove old or damaged cells without harming surrounding tissues.

Necrosis

Premature, unprogrammed cell death caused by external factors such as injury, toxins, or infection.

Biological Death

The permanent death of brain cells and body tissues due to lack of oxygen, where cells begin to digest themselves.

Brain Death

The complete, permanent, and irreversible loss of all brain activity, including the cerebral cortex and brainstem; medically and legally defined as dead.