ss biology semester 1 final exam

Biology

Scientific study of life.

Scientific Method

Process used to answer questions through testing and observation.

Observation

Information gathered using senses or tools.

Hypothesis

Testable prediction, usually written as an "If…then…" statement.

Experiment

Procedure used to test a hypothesis.

Data Collection

Recording observations and results.

Conclusion

Final explanation based on the data.

Theory

Widely accepted explanation supported by evidence.

Law

Describes a pattern or relationship that always occurs in nature.

Independent Variable

“I change” in an experiment

Dependent Variable

The thing factor that is measured in an experiment.

Control Variable

Factor kept the same in all groups.

Experimental Group

Receives the independent variable.

Control Group

Does not receive the independent variable.

Meter (m)

Metric unit for length.

Liter (L)

Metric unit for volume.

Gram (g)

Metric unit for mass.

Autotroph

Makes its own food using sunlight or chemicals.

Heterotroph

Gets energy by consuming other organisms.

Homeostasis

Maintaining stable internal conditions.

Heredity

Passing genes from parents to offspring.

Sexual Reproduction

Reproduction involving two parents; increases variation.

Asexual Reproduction

Reproduction involving one parent; produces identical offspring.

Stimulus

Environmental change that causes a response.

Metabolism

All chemical reactions occurring in an organism.

Characteristics of Life

Organization, growth, reproduction, heredity, homeostasis, response to stimuli, energy use, and evolution.

Unit 2: Chemistry

Matter

Anything that has mass and takes up space.

Atom

Smallest unit of an element.

Molecule

Two or more atoms bonded together.

Element

Pure substance made of one type of atom.

Compound

Two or more elements chemically combined.

Proton

Positive particle found in the nucleus.

Neutron

Neutral particle found in the nucleus.

Electron

Negative particle found in energy levels.

Atomic Number

Number of protons in an atom.

Atomic Mass

Total number of protons and neutrons.

Isotope

Atom of the same element with a different number of neutrons.

Energy Level

Region where electrons are found.

Valence Shell

Outermost electron shell.

Valence Electrons

Electrons in the outermost shell.

Electron Arrangement

First shell holds 2, second 8, third 8.

Chemical Reaction

Process that changes reactants into products.

Reactants

Starting materials in a reaction.

Products

Substances formed in a reaction.

Electronegativity

Attraction an atom has for electrons.

Ionic Bond

Bond formed by electron transfer.

Covalent Bond

Bond formed by electron sharing.

Polar Covalent Bond

Unequal sharing of electrons.

Nonpolar Covalent Bond

Equal sharing of electrons.

Ion

Charged atom formed by gaining or losing electrons.

Heat

Total kinetic energy of particles.

Temperature

Average kinetic energy of particles.

Carbon (C)

4 valence electrons.

Oxygen (O)

2 valence electrons.

Hydrogen (H)

1 valence electron.

Nitrogen (N)

3 valence electrons.

pH Scale

Measures acidity or basicity (0–14).

Acid

Donates H⁺ ions; pH below 7.

Base

Accepts H⁺ ions; pH above 7.

Buffer

Resists changes in pH.

Cohesion

Attraction between water molecules.

Adhesion

Attraction between water and other substances.

Surface Tension

Resistance of water's surface to breaking.

High Heat Capacity

Water absorbs lots of heat before changing temperature.

Expansion Upon Freezing

Water becomes less dense when frozen.

Polar Molecule

Unequal distribution of charge.

Nonpolar Molecule

Equal distribution of charge.

Water

Polar molecule that dissolves ionic and polar substances.

Unit 3: Biological Molecules

Macromolecule

Large biological molecule.

Monomer

Small building block molecule.

Polymer

Large molecule made of repeating monomers.

Dehydration Synthesis

Builds polymers by removing water.

Hydrolysis

Breaks polymers by adding water.

Functional Group

Group of atoms that affects molecule properties.

Carbohydrate

Provides quick energy and structure.

Monosaccharide

Carbohydrate monomer.

Polysaccharide

Carbohydrate polymer.

Examples of Carbohydrates

Starch, glycogen, cellulose, chitin.

Lipid

Long-term energy storage and cell membranes.

Examples of Lipids

Fats, oils, waxes, steroids, phospholipids.

Protein

Performs most cell functions.

Amino Acid

Protein monomer.

Polypeptide

Protein polymer.

Examples of Proteins

Enzymes, hemoglobin, collagen.

Nucleic Acid

Stores genetic information.

Nucleotide

Nucleic acid monomer.

DNA

Stores hereditary information.

RNA

Helps make proteins.

Four Major Macromolecules

Carbohydrates, lipids, proteins, nucleic acids.

Unit 4: DNA

Griffith

Discovered transformation.

Transformation

One bacterium changes into another form.

Avery, McCarty, MacLeod

Showed DNA is the transforming factor.

Hershey & Chase

Confirmed DNA carries genetic information.

Chargaff

A = T and C = G.

Rosalind Franklin

Used X-ray diffraction; showed DNA is helical.

Watson & Crick

Built DNA double-helix model.

Meselson & Stahl

Proved semiconservative replication.