Exam 1 – Study Guide (Chapters 1–3)

A comprehensive set of Q&A flashcards covering Chapter 1 through Chapter 3 content from the notes, designed to review concepts, definitions, and key processes for Exam 1.

What are the characteristics of living organisms?

Organized, require materials and energy, respond, reproduce, maintain homeostasis, and adapt.

What are the levels of biological organization from simplest to most complex?

Atom, molecule, cell, tissues, organs, organ system, organism, population, community, ecosystem, biosphere.

What is an atom?

The smallest unit of an element composed of electrons, protons, and neutrons.

What is a molecule?

A union of two or more atoms of the same or different elements.

What is a cell?

The structural and functional unit of all living organisms.

What are tissues?

A group of cells with a common structure and function.

What are organs?

Structures composed of tissues that function together for a specific task.

What is an organ system?

A group of organs working together.

What is an organism?

An individual; a complex organism contains organ systems.

What is a population?

Organisms of the same species interacting in a particular environment.

What is a community?

Interacting populations in a particular environment.

What is an ecosystem?

A community plus the physical environment.

What is the biosphere?

Regions of Earth’s crust, waters, and atmosphere inhabited by living organisms.

What is metabolism?

All chemical reactions in a cell.

What does food provide?

Nutrients and energy.

What is energy?

The capacity to do work.

What is a nutrient?

The building blocks for growth, metabolism, and other processes.

What is homeostasis?

Maintenance of internal conditions within certain boundaries despite external changes.

How do organisms pass genetic information to the next generation?

Through their DNA.

What is an adaptation?

A change due to the external environment that allows an organism to function better in its environment.

What is meant by chemicals cycle and energy flows in ecosystems?

Chemicals cycle: nutrients are recycled through populations; energy flows from the sun through photosynthesis and food chains.

What is taxonomy?

Classification: identifying, naming, and grouping organisms; branch of biology; founded by Carolus Linnaeus.

What are the taxons in the hierarchical system from most inclusive to most exclusive (as noted)?

Domain, Phylum, Class, Order, Family, Genus, Species.

What are the rules of binomial nomenclature?

Two-part name; 1st word is genus (capitalized), 2nd word is species (lowercase); both underlined or italicized; Latin.

What are the 3 domains and what does each contain?

Bacteria: unicellular prokaryotes; all environments. Archaea: unicellular prokaryotes in harsh environments. Eukarya: unicellular or multicellular eukaryotes.

What are the four kingdoms under the domain Eukarya and their general characteristics?

Protista: absorbs, photosynthesizes, or ingests; algae, protozoans, slime molds, water molds. Fungi: absorbs food; molds, mushrooms, yeast, ringworm. Plantae: photosynthesis; mosses, ferns, conifers, flowering plants. Animalia: ingests food; sponges, worms, insects, fishes, frogs, turtles, birds, mammals.

What does 'prokaryotic' mean?

Without membrane-bound nucleus.

What does 'eukaryotic' mean?

With membrane-bound nucleus.

How do prokaryotic cells compare to eukaryotic cells?

Prokaryotic cells lack a membrane-bound nucleus; eukaryotic cells have a membrane-bound nucleus.

What are the steps of the scientific method?

Observation, hypothesis, predictions and experiments, data collection, conclusion.

What is the independent (experimental) variable?

The variable being tested.

What is the dependent (responding) variable?

The result or outcome measured in the experiment.

What is a test group?

Exposed to the independent variable.

What is a control group?

Not exposed to the independent variable.

What is the Cell Theory?

All organisms are composed of cells, and new cells come only from preexisting ones.

What is the Homeostasis Theory?

The internal environment stays relatively constant within a range that protects life.

What is the Evolution Theory?

All living organisms have a common ancestor, but each is adapted to a particular way of life.

What is matter?

Anything that takes up space or has mass.

Which elements make up living organisms?

Carbon, Hydrogen, Nitrogen, Oxygen, Sulfur, Phosphorus.

What is an atom?

The smallest part of an element that displays properties of that element.

What is a proton, neutron, and electron, and where are they located?

Proton: positively charged; in the nucleus. Neutron: no charge; in the nucleus. Electron: negatively charged; orbits around the nucleus.

What is the atomic number and atomic weight?

Atomic number: number of protons in the nucleus. Atomic weight: number of protons and neutrons in the nucleus.

How do you determine the number of neutrons in an atom?

Neutrons = Atomic Mass − Atomic Number.

What is the Octet Rule?

First shell holds up to 2 electrons; outer shells up to 8.

What does inert mean in this context?

Valence shell is not full (not reactive).

What are reactants and what are products in a chemical equation?

Reactants are the starting substances on the left; products are the formed substances on the right.

What is the valence shell and why is its electron count important?

The outermost shell; its electron count determines many chemical properties.

What is covalent bonding? Ionic bonding? Polar covalent bonding? Hydrogen bonding?

Covalent: sharing of electrons. Ionic: transfer of electrons forming ions. Polar covalent: unequal sharing. Nonpolar covalent: equal sharing. Hydrogen bonding: bond between a weak hydrogen and a slightly negative atom.

What are endergonic and exergonic reactions?

Endergonic: require energy. Exergonic: release energy.

List five properties of water.

High heat capacity, high heat of evaporation, good solvent, cohesive and adhesive, less dense when frozen.

What do hydrophobic and hydrophilic mean?

Hydrophobic: water-fearing. Hydrophilic: water-loving.

What is dissociation?

Breaking into smaller parts such as atoms or ions.

What is an acid and what is a base?

Acid: dissociates in water and releases H+. Base: accepts H+ and releases OH-.

What is the pH scale?

A scale to measure relative strengths of acids and bases.

Which pH values are acidic, neutral, and basic?

Acidic: 0–6. Neutral: 7. Basic: 8–14.

What element do organic molecules always contain?

Carbon and Hydrogen.

What are the characteristics of carbon?

Atomic number 6; 4 electrons in outer shell; covalent strong bonds; can form single, double, triple bonds and ring structures.

What is a functional group?

Clusters of specific atoms attached to carbon skeletons; determine reactivity and polarity; always react the same way.

What are isomers?

Organic molecules with identical molecular formulas but different arrangements.

What are monomers and polymers?

Monomers are small units that bond to form polymers, which are large macromolecules made of repeating monomers.

What reaction joins monomers?

Dehydration (condensation) reaction; removes a water molecule.

What reaction breaks down polymers?

Hydrolysis reaction; adds a water molecule to break bonds.

What are the four groups of organic molecules?

Carbohydrates, Lipids, Nucleic Acids, Proteins.

What are examples of carbohydrates and their classifications?

Monosaccharides: glucose, fructose, ribose, deoxyribose. Disaccharides: maltose, sucrose, lactose. Polysaccharides: starch, glycogen, chitin, cellulose.

What are the functions of carbohydrates?

Energy source and structural role.

What is the molecular formula ratio for carbohydrates?

1 carbon: 2 hydrogen: 1 oxygen (C:H:O = 1:2:1).

What is the monomer of carbohydrates?

Monosaccharides.

Where are structural carbohydrates found and what are they?

Cellulose in plant cell walls; Chitin in fungal cell walls and exoskeletons of insects and crustaceans.

What are the two polysaccharides used for energy storage and where are they found?

Starch in plants; Glycogen in animals.

What is a lipid and what are some examples?

Nonpolar, insoluble in water (hydrophobic). Examples: fats and oils, phospholipids, steroids, and waxes.

What are the functions of lipids?

Long-term energy storage, structural components, heat retention, cell communication/regulation, and protection.

How do lipids behave in water?

They are insoluble (hydrophobic).

What is the structure of a fat or oil?

Glycerol backbone with three fatty acids.

What is the difference between saturated and unsaturated fats?

Saturated fats have no double bonds, straight chains, solid at room temp; unsaturated fats have one or more double bonds, kinked chains, liquid at room temp.

What is a phospholipid and how is it different from a fat/oil? Where is it found?

Phospholipids have a phosphate group instead of three fatty acids; they form the cell membrane; found in cell membranes of all living organisms.

How are phospholipids oriented in membranes and why?

Hydrophilic heads face water (inner and outer surfaces), hydrophobic tails face inward.

What are proteins and their functions?

Complex molecules made of amino acids; perform vital roles, including structural support.

What are the monomers of proteins?

Amino acids.

What are the parts of an amino acid?

Amino group, carboxyl group, R group, and a hydrogen.

How many amino acids are there?

20.

What are the four levels of protein structure?

Primary (linear amino acid sequence), Secondary (folding into helices/sheets), Tertiary (3D shape), Quaternary (more than one polypeptide).

What is denaturation and what causes it?

Loss of proper shape; caused by certain chemicals, pH changes, and high temperature.

What are nucleic acids and what are some examples and their functions?

DNA stores genetic information; RNA functions in protein synthesis and gene expression; ATP stores energy for cellular reactions.

What are the monomers of nucleic acids?

Nucleotides.

What are the components of a nucleotide?

Phosphate group, pentose sugar, and a nitrogen-containing base.

What nitrogen bases are found in DNA?

Cytosine, Thymine, Adenine, Guanine.

What nitrogen bases are found in RNA?

Cytosine, Uracil, Adenine, Guanine.

What are the characteristics of DNA?

Double-stranded; held together by hydrogen bonds; forms a double helix; bases A-T and G-C; stores genetic information.

What are the characteristics of RNA?

Single-stranded; bases A-U and G-C; involved in protein synthesis and gene expression.

What is ATP and what is it composed of?

Adenosine Triphosphate; adenine (nitrogen base), ribose (pentose sugar), and three phosphate groups.

What reaction forms ATP, according to the notes?

Dehydration synthesis (condensation) reaction.

What reaction releases energy from ATP and what is it used for?

Hydrolysis: ATP → ADP + P + energy; used for cellular processes, signaling, muscle contraction, nerve impulses, etc.