Biology Midterm

Levels of Organization in Biology

Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere.

Properties of Life

Order, Growth, Reproduction, Homeostasis, Response to Stimuli, Energy Processing, Evolution.

Prokaryotes

Cells without a nucleus; simple in structure; includes bacteria and archaea.

Eukaryotes

Cells with a nucleus and organelles; includes plants, animals, fungi, and protists.

Control Group

A standard for comparison in experimental design to isolate the effects of the experimental variable.

Theory vs. Hypothesis

A theory is a well-supported explanation, while a hypothesis is a testable prediction.

Three Domains of Life

Bacteria (prokaryotes), Archaea (prokaryotes), and Eukarya (eukaryotes).

Atoms & Subatomic Particles

Protons (+, in nucleus), Neutrons (0, in nucleus), Electrons (-, in orbitals).

Isotopes

Atoms that have the same number of protons but different numbers of neutrons.

Covalent Bonds

Chemical bonds formed by sharing electrons between atoms.

Ionic Bonds

Chemical bonds formed by the transfer of electrons from one atom to another.

Hydrogen Bonds

Weak attractions between molecules, important for properties of water.

Cohesion vs. Adhesion

Cohesion is water sticking to itself, while adhesion is water sticking to surfaces.

Acids and Bases on the pH Scale

Acids have more H+ ions, while bases have fewer H+ ions.

Macromolecules

Large biological molecules that include carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Organic compounds like glucose that consist of monosaccharides.

Proteins

Polymers made up of amino acids, differing by their R-groups.

Lipids

Not polymers; includes fats and phospholipids, which make up cell membranes.

Cell Theory

States that all living things are made of cells, cells are the basic unit of life, and cells come from preexisting cells.

Light Microscope

Microscope with less detail that can view live cells.

Electron Microscope

High-resolution microscope used for viewing dead cells only.

Animal vs. Plant Cells

Plant cells contain chloroplasts, cell walls, and a central vacuole; animal cells do not.

Chloroplast Function

Site of photosynthesis in plant cells.

Mitochondria Function

Produces ATP, the energy currency of the cell.

Golgi Apparatus

Organelle responsible for protein modification and packaging.

Nucleus

Organelle that stores the cell's DNA.

Endoplasmic Reticulum (ER)

Involved in protein and lipid synthesis; includes smooth and rough types.

Peroxisome Function

Organelle involved in detoxification processes.

Phospholipid Structure

Molecule with a hydrophilic head and hydrophobic tail, forming bilayers in water.

Exergonic Reactions

Chemical reactions that release energy.

Endergonic Reactions

Chemical reactions that require energy input.

Anabolic Pathways

Metabolic pathways that build molecules.

Catabolic Pathways

Metabolic pathways that break down molecules.

Enzymes

Biological catalysts that speed up chemical reactions by lowering activation energy.

Competitive Inhibitor

Inhibitor that blocks the active site of an enzyme.

Non-competitive Inhibitor

Inhibitor that binds to an allosteric site, changing the enzyme's shape.

Cellular Respiration

Aerobic process occurring in mitochondria that converts glucose to ATP.

Glycolysis

Initial step in cellular respiration that occurs in the cytoplasm and produces ATP and pyruvate.

Citric Acid Cycle

Mitochondrial cycle that produces NADH and FADH₂.

Electron Transport Chain

Mitochondrial process that uses a hydrogen ion gradient to produce ATP.

Fermentation

Anaerobic process of energy production, including alcoholic and lactic acid fermentation.

Obligate Anaerobes

Organisms that cannot survive in the presence of oxygen.