PRE-COMPREHENSIVE EXAM Study Guide 2025-26 BIOLOGY FINAL DRAFT

This set of flashcards covers essential concepts and vocabulary relevant to the Biology 8 Pre-comprehensive exam.

Observations

Information gathered using the senses or tools.

Inferences

A conclusion or explanation based on observations and prior knowledge.

Hypothesis

A predicted outcome of an experiment, often written in 'If…, Then…' form.

Quantitative Data

Data expressed using numbers or measurements.

Qualitative Data

Descriptive data not easily measured with numbers.

Independent Variable

The variable that is deliberately changed in an experiment.

Dependent Variable

The variable that is measured or observed in response to the independent variable.

Controlled Variables

Variables that are kept the same to ensure a fair, reliable test.

Control Group

The group that does not receive the independent variable and is used for comparison.

Experimental Group

The group that receives the independent variable.

Sample Size

The number of subjects included in a study or experiment.

Line Graph

Used for data that is numerical and continuous from one data point to the next.

Mean

The average value in a data set calculated by adding all values and dividing by the number of values.

Median

The middle value when data is organized from least to greatest.

Mode

The most frequently occurring value in a data set.

Outlier

A data value that is much greater or lower than the rest of the data points.

Cohesion

The tendency of water molecules to stick to each other, due to hydrogen bonds.

Adhesion

The tendency of water molecules to stick to other substances.

Enzyme

A protein that acts as a biological catalyst.

Denaturation

The loss of structure and function of an enzyme or protein.

Macromolecules

Large molecules made up of smaller subunits (monomers) linked together.

DNA

Deoxyribonucleic acid, the molecule that carries genetic information.

RNA

Ribonucleic acid, involved in protein synthesis.

Cell Membrane

The outer barrier of a cell that regulates the flow of materials in and out.

Mitochondria

Organelles that perform cellular respiration to produce ATP.

Chloroplasts

Organelles that convert sunlight into chemical energy via photosynthesis.

Homologous Chromosomes

Pairs of chromosomes, one from each parent, that are similar in shape, size, and genetic content.

Meiosis

A type of cell division that produces gametes with half the number of chromosomes.

Mitosis

A type of cell division that results in two identical daughter cells.

Gene

A segment of DNA that codes for a protein and determines a trait.

Allele

Variations of a particular gene.

Phenotype

The physical expression of a trait determined by genotypes.

Genotype

The genetic makeup of an organism, represented by alleles.

Punnett Square

A diagram used to predict the genotype and phenotype ratios of offspring.

Carbohydrates

Molecules used for energy storage and structural support; composed of carbon, hydrogen, and oxygen (C, H, O).

Lipids

Nonpolar organic molecules, including fats and steroids, used for long-term energy storage and cell membrane structure.

Nucleic Acids

Large molecules that store and transmit genetic information; composed of nucleotide monomers.

Proteins

Macromolecules made of amino acids that perform essential functions such as catalysis, structural support, and transport.

Monosaccharides

The simplest form of carbohydrates (1:2:1 ratio of C:H:O) and the building blocks of polysaccharides.

Fats

A group of lipids primarily used for long-term energy storage, insulation, and protection.

Nucleotides

The building blocks of nucleic acids, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Amino Acids

The subunits (monomers) of proteins, characterized by an amino group and a carboxyl group.

Polysaccharides

Complex carbohydrates made up of many monosaccharides linked together, such as starch or cellulose.

Phospholipids

Lipids that form the core of cell membranes, consisting of a hydrophilic head and two hydrophobic tails.

DNA and RNA

The two primary nucleic acids; DNA stores genetic code, while RNA helps translate it into proteins.

Polypeptides

Long chains of amino acids linked by peptide bonds, which fold to form functional proteins.

Glucose

A common monosaccharide (C{6}H{12}O_{6}) that serves as the primary energy source for cellular respiration.

Steroids

A category of lipids with a carbon skeleton of four fused rings, often functioning as hormones.

Active Site

The specific region of an enzyme where the substrate binds and where the chemical reaction is catalyzed.

Polar

A molecule with an uneven distribution of electrical charge, resulting in distinct positive and negative poles.

Glycogen

An extensively branched polysaccharide used for short-term energy storage in animals.

Substrate

The specific reactant molecule that an enzyme acts upon.

Catalyst

Any substance that speeds up a chemical reaction by lowering its activation energy without being consumed.

Starch

A storage polysaccharide found in plants, composed of long chains of glucose monomers.

Activation Energy

The minimum amount of energy required to jumpstart a chemical reaction (E_{a}).

Nonpolar

A molecule with an even distribution of charge, making it generally hydrophobic.

Cellulose

A structural polysaccharide that makes up the rigid cell walls of plants.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, caused by cohesion.

Chitin

A structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi.

Polarity

The quality of a molecule having opposite charges at either end.

Hydrophobic

Describing substances that repel water and do not dissolve in it.

Hydrophilic

Describing substances that have an affinity for water and dissolve easily in it.

Hydrogen bond

A weak attraction between a slightly positive hydrogen atom and a slightly negative atom (like oxygen or nitrogen).

Covalent bond

A strong chemical bond formed when two atoms share one or more pairs of valence electrons.

pH effects

The influence of acidity or alkalinity on molecular shape, which can lead to the denaturation of enzymes.

Temperature effects

The influence of heat on the rate of kinetic energy and the structural stability of proteins.

Bacteria

A domain of unicellular prokaryotes that typically have cell walls containing peptidoglycan.

Archaea

A domain of unicellular prokaryotes that have cell walls without peptidoglycan and are often found in extreme environments.

Eukarya

The domain that includes all organisms with eukaryotic cells, such as protists, plants, fungi, and animals.

Cyanobacteria

A group of photosynthetic, oxygen-producing bacteria formerly known as blue-green algae.

Cell

The basic structural, functional, and biological unit of all known living organisms.

Prokaryote

A unicellular organism that lacks a nucleus and membrane-bound organelles.

Eukaryote

An organism whose cells contain a nucleus and other membrane-bound organelles.

Nucleoid region

The non-membrane-enclosed region in a prokaryotic cell where the primary genetic material is located.

Cellular respiration

The metabolic process by which cells convert biochemical energy from nutrients into adenosine triphosphate (ATP).

Vacuole

A membrane-bound organelle used for the storage of materials such as water, nutrients, or waste.

Smooth Endoplasmic Reticulum

A tube-like organelle involved in lipid synthesis and detoxification that lacks ribosomes on its surface.

Rough Endoplasmic Reticulum

An organelle involved in protein synthesis and transport, characterized by being studded with ribosomes.

Lysosome

A membrane-bound organelle containing digestive enzymes used to break down macromolecules and cell waste.

Cytoplasm

The jelly-like substance that fills the cell and surrounds the organelles.

Photosynthesis

The process by which plants and other autotrophs use light energy to convert carbon dioxide and water into glucose (C{6}H{12}O_{6}) and oxygen.

Centrosome

An organelle that serves as the main microtubule organizing center and is active during cell division.

Cytoskeleton

A network of protein fibers that helps the cell maintain its shape, secure organelles in place, and allow for movement.

Vesicle

A small, membrane-bound sac that transports materials within, into, or out of the cell.

Endosymbiont theory

The theory that mitochondria and chloroplasts originated as independent prokaryotic cells that were engulfed by a larger host cell.

Cell theory

The fundamental scientific theory stating that all living things are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.

Nucleolus

A dense structure inside the nucleus responsible for the production and assembly of ribosome subunits.

Cell wall

A rigid outer layer found in plants, fungi, and bacteria that provides structural support and protection.

Nucleus

The membrane-bound organelle that acts as the control center of the cell and houses genetic information (DNA).

Characteristics of life

The set of traits shared by all living organisms, including metabolism, reproduction, homeostasis, and response to stimuli.

Ribosome

A small organelle consisting of RNA and protein that serves as the site of protein synthesis.

Virus

A non-living, microscopic infectious agent that consists of genetic material enclosed in a protein coat.

Lytic cycle

A viral replication cycle that results in the quick destruction (lysis) of the host cell to release new viruses.

Lysogenic cycle

A viral replication cycle in which the viral DNA is integrated into the host cell's genome and replicated without immediately killing the host.

Deoxyribose

The five-carbon sugar that is a component of DNA nucleotides.

Nitrogenous base

A molecule that contains nitrogen and has the chemical properties of a base; components of DNA and RNA (A, T, C, G, U).

Phosphate group

A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms; part of the DNA/RNA backbone.

Double helix

The structural shape of a DNA molecule, consisting of two strands of nucleotides coiled around each other.

DNA replication

The process by which a DNA molecule is copied to produce two identical DNA molecules.