Comprehensive Biology Review: Lab Safety, Cell Structure, Macromolecules, Enzymes, and Photosynthesis

Vocabulary flashcards covering key terms and definitions across lab safety, biological safety levels, microscopy, organic macromolecules, chemical indicators, cell organelles, passive membrane transport, tonicity, enzyme kinetics, and photosynthesis.

BSL-1

A biosafety level assigned to basic lab settings conducting research on nonlethal agents that pose a minimal potential threat, such as E. coli.

BSL-2

A biosafety level assigned to laboratories working with pathogenic or infectious agents associated with human disease that pose a moderate health hazard.

BSL-3

A biosafety level for research on microbes that can cause serious or potentially lethal disease through inhalation, such as yellow fever, West Nile virus, or tuberculosis bacteria.

BSL-4

A biosafety level for working with highly dangerous, fatal microbes that lack available treatments and vaccines.

Resolution (Resolving Power)

The closest distance between two points or objects at which they can still be distinguished as separate and distinct.

Total Magnification

The overall magnification calculated by multiplying the ocular lens magnification (typically $\text{10}\times$) by the objective lens magnification.

Image Inversion

The optical property where microscope lenses bend light so that the specimen image appears inverted both top-to-bottom and left-to-right.

Depth of Field

The vertical thickness or amount of a specimen that remains in clear focus when focused on a single plane ($\text{3D}$ focus).

Field of View

The total area on the slide observable without moving the stage, which is inversely proportional to objective lens magnification.

Parfocal

The property of a microscope where once an object is in focus under one objective lens, switching to a higher magnification objective requires focusing adjustments using only the fine focus knob.

Dehydration Reaction

A chemical reaction that synthesizes polymers by removing a water molecule ($\text{H}_2\text{O}$) to form a new covalent bond.

Hydrolysis

A chemical reaction that breaks covalent bonds within a polymer by adding a water molecule ($\text{H}_2\text{O}$).

Benedict's Solution

A chemical reagent used to test for monosaccharides and reducing sugars, changing from light blue (negative) to orange (positive).

Lugol's Iodine

A reagent used to test for polysaccharides, turning blue-black in the presence of starch and blue-brown in the presence of glycogen (amber when negative).

Beta Carotene

A lipid-staining reagent used to visualize fats in emulsions or aqueous solutions, forming a confluent orange solution when positive.

Biuret's Solution

A reagent used to test for proteins, turning from light blue (negative) to violet or dark purple (positive).

Nucleus

A membrane-bound organelle that houses $\text{DNA}$ molecules for cellular regulation and produces ribosomal subunits in the nucleolus.

Rough Endoplasmic Reticulum

A membrane-bound organelle studded with ribosomes that synthesizes proteins for secretion, plasma membrane incorporation, or lysosomal enzymes.

Smooth Endoplasmic Reticulum

A membrane-bound organelle that functions in lipid synthesis, carbohydrate metabolism, and the detoxification of drugs, alcohol, and poisons.

Golgi Apparatus

An organelle composed of flattened cisternae that modifies, packages, sorts, and ships proteins moving from its cis-face to its trans-face.

Mitochondrion

A double-membrane organelle termed the "powerhouse of the cell" that digests organic molecules to produce $\text{ATP}$ by aerobic cellular respiration.

Lysosome

A membrane-bound organelle containing digestive enzymes that break down endocytosed materials, damaged organelles (autophagy), and dead cells (autolysis).

Peroxisome

A membrane-bound organelle containing oxidative enzymes to detoxify harmful substances and perform beta oxidation of fatty acids into acetyl $\text{CoA}$.

Ribosome

A non-membrane-bound organelle composed of large and small subunits that serves as the site of protein synthesis.

Cytoskeleton

A structural cellular network of microfilaments, intermediate filaments, and microtubules that maintains cell shape, organizes organelles, and aids in cell division and movement.

Centrosome

A non-membrane-bound structure containing centrioles that organizes microtubules and directs mitotic spindle formation during cell division.

Diffusion

The passive movement of a solute from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

Isotonic Solution

A solution with the same solute concentration as the cytosol, resulting in no net movement of water into or out of the cell.

Hypotonic Solution

A solution with a lower concentration of non-penetrating solutes than the cytosol, causing water to flow into the cell.

Hypertonic Solution

A solution with a higher concentration of non-penetrating solutes than the cytosol, causing water to flow out of the cell.

Plasmolysis

The process in plant cells where the plasma membrane pulls away from the rigid cell wall when placed in a hypertonic environment.

Turgor Pressure

The internal fluid pressure exerted by water against the plant cell wall when the cell expands in a hypotonic solution.

Crenation

The shriveling or shrinking of red blood cells (erythrocytes) when exposed to a hypertonic solution.

Hemolysis

The swelling and rupture of red blood cells (erythrocytes) when exposed to a hypotonic solution.

Catalyst

A chemical agent that speeds up the rate of a reaction without being consumed or permanently altered by the reaction.

Enzyme

A biological catalyst (usually a protein) that accelerates chemical reactions by lowering the activation energy ($E_A$).

Substrate

The specific reactant molecule upon which an enzyme binds and acts.

Active Site

The specific catalytic region on an enzyme where the substrate binds to form an enzyme-substrate complex.

Activation Energy ($E_A$)

The initial investment of energy required to start a chemical reaction.

Denaturation

The structural unfolding of an enzyme or protein causing it to lose its shape and catalytic activity, often triggered by extreme temperature or pH.

Photosynthesis

The metabolic process by which photoautotrophs convert light energy, carbon dioxide ($\text{CO}_2$), and water ($\text{H}_2\text{O}$) into sugars ($\text{C}_6\text{H}_{12}\text{O}_6$) and oxygen ($\text{O}_2$).

Photoautotroph

An organism (such as a plant, alga, or cyanobacterium) that produces its own food using energy from sunlight.

ATP (Adenosine Triphosphate)

The primary energy carrier molecule used to store and transfer chemical energy in living cells.

Chloroplast

The plant cell structure containing thylakoids and stroma where photosynthesis takes place.

Thylakoid

A flattened, disc-like membrane structure inside a chloroplast containing chlorophyll that absorbs light energy during photosynthesis.

Grana

Stacks of disc-like thylakoid membranes within a chloroplast.

Chlorophyll

A pigment located within the thylakoid membrane that absorbs red and blue light energy while reflecting green light to drive carbohydrate synthesis.

Stroma

The fluid-filled region surrounding the grana inside a chloroplast where the Calvin cycle occurs.

Light-Dependent Reactions

The first stage of photosynthesis occurring in the thylakoid membrane that uses light energy to split $\text{H}_2\text{O}$, release $\text{O}_2$, and generate $\text{ATP}$ and $\text{NADPH}$.

Calvin Cycle

The light-independent stage of photosynthesis occurring in the stroma that utilizes $\text{ATP}$ and $\text{NADPH}$ to fix $\text{CO}_2$ into three-carbon sugars ($\text{G3P}$).

G3P (Glyceraldehyde-3-phosphate)

A three-carbon sugar molecule produced during the Calvin cycle of photosynthesis.