Biology : Ultimate Review Guide

Qualitative Data

Characteristics that cannot be easily counted or measured, such as color, texture, and smell.

Quantitative Data

Characteristics that are counted or measured, such as temperature, weight, length, and time.

Hypothesis

The predicted outcome of an experiment or proposed explanation.

Independent Variable

The variable that is intentionally changed in an experiment.

Dependent Variable

The variable that is observed or measured in an experiment.

Controlled Variable

A variable that is kept constant between groups in an experiment.

Control Group

Groups used as a baseline/comparison for 'normal' in an experiment.

Line Graph

A graph where data points are related to each other, representing continuous data.

Bar Graph

A graph where data points are unrelated to each other, representing discrete data.

Mean

The average value calculated by adding all numbers and dividing by the count of numbers.

Median

The middle value when a set of numbers is listed from least to greatest.

Mode

The most common value in a set of data.

Cell Theory

The theory that states all living things are composed of cells, the cell is the basic unit of life, and all cells come from pre-existing cells.

Eukaryotic Cells

Cells with membrane-bound organelles that may be multicellular or unicellular.

Prokaryotic Cells

Cells without membrane-bound organelles, all are unicellular.

Phospholipid Structure

A molecule composed of a hydrophilic phosphate group (head) and a hydrophobic lipid tail.

Nucleolus

A dense region in the nucleus where ribosome production begins.

Vesicles

Transport sacs that move materials throughout the cell.

Mitochondria

Organelles that convert energy stored in glucose into ATP through cellular respiration.

Chloroplasts

Organelles that perform photosynthesis, converting sunlight, carbon dioxide, and water into glucose.

Cytoplasm

The fluid and most organelles in a cell except for the nucleus.

Denaturation

The unfolding of a protein due to changes in temperature, pH, or salt concentration, preventing it from performing its function.

Alleles

Variations of a gene that can influence traits.

Gametes

Haploid cells used for sexual reproduction, such as sperm and eggs.

Homozygous

Having two identical alleles for the same trait.

Heterozygous

Having two different alleles for the same trait.

Transcription

The process of making an mRNA copy of a DNA gene.

Translation

The process of making a protein from an mRNA copy of a gene.

Adaptation

Inherited characteristics that increase an organism's chance for survival and reproduction.

Natural Selection

The process in which individuals with favorable traits are more likely to survive and reproduce.

Fossils

Preserved remains or traces of organisms from the past.

Phenotype

The physical characteristics or traits of an organism.

Evolution

The gradual process by which the heritable characteristics of biological populations change over successive generations. These changes may include alterations in morphology, physiology, behavior, and genetics.

Biology

The scientific study of life and living organisms, encompassing their structure, function, growth, origin, evolution, distribution, and taxonomy. It explores molecular mechanisms within cells up to the diversity of ecosystems.

Phylogenetic Tree

A visual representation that depicts the evolutionary relationships among different biological species or other entities based on inherited characteristics. These trees classify organisms into groups based on the recency of their last common ancestor.

Photosynthesis

The biochemical process used by plants, algae, and certain bacteria to convert light energy into chemical energy. It involves capturing sunlight and using it to convert carbon dioxide and water into glucose and oxygen.

Cellular Respiration

A set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate (ATP), and then release waste products.

Osmosis

The net movement of water across a selectively permeable membrane driven by differences in solute concentrations on either side of the membrane. Water moves from an area of lower solute concentration to an area of higher solute concentration to equalize the osmotic pressure.

Gene

A segment of DNA that contains the instructions for making a specific protein or performing a particular function. Genes are the basic units of heredity and are responsible for transmitting traits from parents to offspring.

Genotype

The genetic constitution of an individual organism, typically with reference to a specific trait. It describes the specific alleles inherited for a particular gene, which collectively influence the phenotype.

Genome

The complete set of genes or genetic material present in a cell or organism, including both coding and non-coding regions. It represents all the hereditary information encoded in DNA (or RNA for some viruses).

Species

A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. Species are generally considered the fundamental unit of biodiversity.

Qualitative Data

A type of data that describes qualities or characteristics. It is descriptive and conceptual, often gathered through observations or interviews.

Quantitative Data

A type of data that can be measured and expressed numerically. It is objective and can be analyzed statistically.

Hypothesis

A testable statement about the relationship between two or more variables. It is a tentative explanation or prediction that can be supported or refuted through experimentation or observation.

Independent Variable

The variable that is deliberately changed or manipulated by the researcher in an experiment. It is the presumed cause in a cause-and-effect relationship.

Dependent Variable

The variable that is measured or observed in an experiment to determine the effect of the independent variable. Its value is 'dependent' on the changes made to the independent variable.

Controlled Variable

Variables that are kept constant or unchanged during an experiment to prevent them from influencing the results. This ensures that any changes observed in the dependent variable are due to the independent variable alone.

Control Group

A group in an experiment that is not exposed to the independent variable. It serves as a baseline against which to compare the effects of the treatment given to the experimental groups.

Line Graph

A type of graph used to represent continuous data points connected by line segments. It is useful for showing trends and changes over time or across different values.

Bar Graph

A type of graph that uses rectangular bars to represent data. It is suitable for comparing discrete categories or groups.

Mean

A measure of central tendency calculated by adding all the values in a dataset and dividing by the number of values. It is the arithmetic average.

Median

A measure of central tendency that represents the middle value in a dataset when the values are arranged in ascending or descending order. It divides the dataset into two equal halves.

Mode

A measure of central tendency that represents the most frequently occurring value in a dataset. A dataset can have one mode, multiple modes, or no mode.

Cell Theory

A fundamental principle in biology stating that all living organisms are composed of cells, cells are the basic structural and functional units of life, and all cells arise from pre-existing cells.

Eukaryotic Cells

Complex cells that contain membrane-bound organelles, including a nucleus. These cells can be either unicellular (e.g., protists) or multicellular (e.g., animals, plants, fungi).

Prokaryotic Cells

Simple cells that lack membrane-bound organelles and a defined nucleus. These cells are typically unicellular and include bacteria and archaea.

Phospholipid Structure

A lipid molecule composed of a hydrophilic phosphate head and two hydrophobic fatty acid tails. Phospholipids are major components of cell membranes, where they form a bilayer.

Nucleolus

A structure in the nucleus where ribosomal RNA (rRNA) is transcribed and ribosomes are assembled. It is essential for protein synthesis.

Vesicles

Small, membrane-bound sacs or compartments that transport materials within the cell. They can bud off from other organelles or the cell membrane.

Mitochondria

Organelles responsible for generating energy in the form of ATP through cellular respiration. They have a double-membrane structure and contain their own DNA.

Chloroplasts

Organelles found in plant cells and algae that conduct photosynthesis. They contain chlorophyll and other pigments to capture light energy.

Cytoplasm

The gel-like substance that fills the cell, excluding the nucleus and other organelles. It is composed of water, ions, enzymes, and other molecules necessary for cell function.

Denaturation

The process by which a protein loses its native shape and function due to environmental stress such as changes in temperature, pH, or salt concentration. It disrupts the non-covalent interactions stabilizing the protein structure.

Alleles

Different forms of a gene that can occupy the same locus on a chromosome and control the same trait. Organisms inherit one allele from each parent.

Gametes

Haploid reproductive cells (sperm in males, eggs in females) that fuse during sexual reproduction to form a diploid zygote.

Homozygous

Having two identical alleles for a particular gene, resulting in a purebred trait.

Heterozygous

Having two different alleles for a particular gene, resulting in a hybrid trait.

Transcription

The process by which an RNA copy of a gene sequence is made from a DNA template. This mRNA molecule carries the genetic information from the nucleus to the cytoplasm for protein synthesis.

Translation

The process by which the information encoded in mRNA is used to assemble a protein. This occurs on ribosomes in the cytoplasm or endoplasmic reticulum.

Adaptation

A genetically inherited trait or characteristic that enhances an organism's ability to survive and reproduce in a particular environment.

Natural Selection

The differential survival and reproduction of individuals due to differences in phenotype. Individuals with advantageous traits are more likely to survive and pass on their genes to the next generation.

Fossils

The preserved remains or traces of ancient organisms. They provide evidence of past life forms and the evolutionary history of organisms.

Phenotype

The observable characteristics or traits of an organism, resulting from the interaction of its genotype with the environment.

Biome

A group of ecosystems that share similar climates and dominant plant communities. Major terrestrial biomes include forests, grasslands, deserts, and tundra.

Community

An ecological community including all of the interacting populations of organisms in a given area.

Autotroph

An organism that makes its own food through photosynthesis or chemosynthesis.

Heterotroph

An organism that cannot produce its own food and obtains nutrients by consuming other organisms.

Evaporation

The process by which water is converted from its liquid form into vapor and released into the atmosphere.

Condensation

The process by which water vapor in the atmosphere changes into liquid or solid form.

Precipitation

Any form of water, such as rain, snow, sleet, or hail, that falls from the atmosphere to the Earth's surface.

Directional Selection

The process by which traits become more or less common in a population due to consistent environmental effects in a population.

Disruptive Selection

A mode of natural selection in which extreme values for a trait are favored over intermediate values

Stabilizing Selection

A mode of natural selection by which selection pressures select against extremes