Honors Biology Final Exam Vocabulary

Flashcards covering key vocabulary terms for the Honors Biology Final Exam, Second Semester 2025, focusing on genetics, human impact, protein synthesis, genetic engineering, and evolution.

Heredity

The process by which traits are passed on from parents to their offspring. This transmission of genetic information ensures continuity of characteristics across generations.

Genotype

The complete genetic makeup of an organism, including all the genes and alleles it carries. It represents the hereditary information that influences the phenotype.

Phenotype

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

F1 plants

The first filial generation of plants resulting from a cross between two parental plants. These plants are studied to understand inheritance patterns.

Hybrids

Offspring resulting from crosses between parents with different traits. Hybrids often display a mix of characteristics inherited from both parents.

Homozygous

Having two identical alleles for a specific gene. This results in a predictable expression of the trait associated with that gene.

Heterozygous

Having two different alleles for a specific gene. The interaction between these alleles determines the expressed trait.

Dominant

An allele that masks the presence or expression of another allele (recessive) in a heterozygous individual. The dominant trait is the one observed in the phenotype.

Recessive

An allele that is masked by the presence of a dominant allele in a heterozygous individual. The recessive trait is only expressed when an individual is homozygous for the recessive allele.

Gamete

A haploid sex cell (sperm or egg) that contains only one set of chromosomes. Gametes fuse during sexual reproduction to form a diploid zygote.

Nondisjunction

The failure of chromosomes to separate properly during meiosis, leading to an abnormal number of chromosomes in the resulting gametes.

Plasmid

A small, circular DNA molecule found in bacteria and some other microscopic organisms, often used in genetic engineering.

Genes

A unit of heredity that is transferred from a parent to offspring and determines some characteristic of the offspring. Genes are segments of DNA that encode proteins.

Cystic Fibrosis

A genetic disorder that primarily affects the lungs and other organs, caused by a mutation in the CFTR gene.

Sickle-cell anemia

A genetic disorder that affects red blood cells, causing them to become rigid and sickle-shaped, leading to various health complications.

Huntington disease

A genetic disorder that causes nerve cells in the brain to break down over time, leading to progressive decline in motor and cognitive abilities.

Down syndrome

A genetic disorder caused by the presence of an extra copy of chromosome 21, leading to intellectual disability and characteristic physical features.

Karyotype

A visual display of an individual's chromosomes, used to identify chromosomal abnormalities, such as aneuploidy or structural rearrangements.

Pedigree

A chart that shows the inheritance of a particular trait or genetic disorder within a family, used to trace patterns of inheritance.

Mutation

A change in the nucleotide sequence of DNA, which can result in altered protein function and phenotypic effects.

Homologous organs

Structures in different species that have a common evolutionary origin but may have different functions, indicating divergent evolution.

Analogous organs

Structures in different species that have similar functions but different evolutionary origins, indicating convergent evolution.

Vestigial organs

Organs or structures in an organism that have lost their original function over evolutionary time, providing evidence of evolutionary history.

Adaptation

Any heritable trait that enhances an organism's survival and reproduction in a particular environment, increasing its fitness.

Species

A group of organisms that can interbreed in nature and produce fertile offspring, representing a fundamental unit of biological classification.

Reproductive isolation

The inability of two species to interbreed and produce fertile offspring, leading to the maintenance of distinct species boundaries.

Genetic drift

A random change in the allele frequencies of a population, often occurring in small populations, that can lead to loss of genetic diversity.

Adaptive radiation

The divergence of a single ancestral lineage into many different forms, each adapted to a different ecological niche.

Divergent evolution

The process by which two or more related populations become more dissimilar over time, often due to different environmental pressures.

Convergent evolution

The process by which unrelated organisms evolve similar characteristics due to similar environmental pressures or ecological niches.

Gradualism

The theory that evolution occurs slowly and gradually over long periods of time, with small incremental changes.

Punctuated equilibrium

The theory that evolution occurs in bursts of rapid change, separated by long periods of stasis or equilibrium.

Gene pool

The total collection of genes, including all the different alleles, present in a population.

Geographic isolation

The separation of two populations by a physical barrier, such as a mountain range or body of water, leading to reproductive isolation and potential speciation.

Temporal isolation

When two or more species reproduce at different times of day or year, preventing interbreeding and maintaining reproductive isolation.

Ecological isolation

When two species occupy different habitats within the same geographic area, reducing the likelihood of interbreeding.

Fitness

A measure of the ability of an organism to survive and reproduce in its environment, often quantified by the number of offspring produced.

Natural selection

The process by which organisms with traits better suited to their environment survive and reproduce more successfully, leading to adaptation over time.

Gene flow

The movement of genes from one population to another through migration and interbreeding, which can introduce new alleles and increase genetic diversity.

Evolution

A change in the genetic makeup of a population over time, resulting in the adaptation of organisms to their environment.

Microevolution

Evolution on a small scale, affecting a single population, such as changes in allele frequencies.

Macroevolution

Evolution on a large scale, affecting changes in species across populations, such as the formation of new species or major evolutionary trends.

Speciation

The formation of new and distinct species in the course of evolution.

Character displacement

The phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur,but are minimized or lost where the species' distributions do not overlap. This pattern arises from natural selection favoring individuals in each species that compete less with the other species.

Allele

Different forms of a gene, which arise by mutation and are found at the same place on a chromosome.

Autosome

Any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes.

Sex Chromosome

A chromosome involved with determining the sex of an organism, typically X and Y in mammals.

Polygenic Trait

A trait controlled by two or more genes, resulting in a range of phenotypes. Examples include height and skin color.

Codominance

A condition in which both alleles for a gene are fully expressed, resulting in a phenotype that shows both traits simultaneously.

Incomplete Dominance

A condition in which one allele is not completely dominant over the other, resulting in a blended phenotype in heterozygous individuals.

Multiple Alleles

Genes that have more than two alleles in the population, although each individual can only carry two alleles.

Epistasis

A gene at one locus alters the phenotypic expression of a gene at a second locus. One gene masks or modifies the expression of another gene.

Pleiotropy

One gene having multiple effects on an organism, influencing several seemingly unrelated traits.

Genetic Engineering

The process of modifying an organism's DNA to introduce desirable traits or remove undesirable ones.

Gene Therapy

The process of inserting genes into a patient's cells to treat a disease, correcting genetic defects.

Cloning

The process of creating a genetically identical copy of an organism or cell.

Biotechnology

The use of living organisms or their products to develop or improve products, processes, and technologies.

Transgenic Organism

An organism that contains genes from another organism, often created through genetic engineering.

Gel Electrophoresis

A technique used to separate DNA fragments by size, allowing for analysis and comparison of genetic material.

Restriction Enzymes

Enzymes that cut DNA at specific sequences, used in genetic engineering to manipulate DNA fragments.

DNA Ligase

An enzyme that joins DNA fragments together, used in genetic engineering to create recombinant DNA molecules.

Polymerase Chain Reaction (PCR)

A technique used to amplify a specific DNA sequence, creating