Biology 138 Spring Semester Final Review

These flashcards cover vocabulary and key concepts from the Biology 138 Spring Semester Final Review guide, including DNA structure, genetics, evolution, and ecology.

Watson and Crick

The scientists credited with the discovery of the structure of DNA.

Rosalind Franklin

The scientist who discovered Photo 51, the picture of a DNA structure.

Chargaff's Rule

The discovery of base pairings where DNA contains equivalent amounts of Adenine/Thymine and Guanine/Cytosine; represented as $A=T$ and $G=C$.

Genes

A section of DNA that codes for a specific trait.

DNA Structure

A parallel and double-stranded double helix.

Nucleotide

The monomer for nucleic acids like DNA and RNA, consisting of a phosphate, a sugar, and a nitrogenous base.

Helicase

The enzyme that unzips DNA before replication by breaking hydrogen bonds.

DNA Polymerase

An enzyme that reads and synthesizes a new complementary strand by adding DNA nucleotides; it also performs proofreading.

Messenger RNA (mRNA)

The molecule that sends a message from the DNA to the ribosome to indicate what gene to code for.

Transfer RNA (tRNA)

The molecule that brings amino acids and anticodons to the ribosome.

Central Dogma

The process describing the flow of genetic information: DNA replication $\rightarrow$ Transcription (RNA) $\rightarrow$ Translation (Protein).

Somatic Cell Mutations

Mutations that affect the body's cells and can lead to cancer but are not passed down to offspring.

Sex Cell Mutations

Mutations that occur in gametes and can be passed down to offspring.

Nondisjunction

The failure of chromosomes to separate properly, which can cause genetic diseases.

Karyotype

A visual representation of an individual's chromosomes used to identify genetic abnormalities.

Homozygous

A genotype consisting of two of the same alleles (e.g., BB or bb).

Heterozygous

A genotype consisting of two different alleles (e.g., Bb).

Incomplete Dominance

A form of inheritance where the heterozygous phenotype is a blend of the two homozygous phenotypes (e.g., red and white flowers producing pink offspring).

Codominance

A form of inheritance where both alleles are expressed equally in the phenotype (e.g., a circle with a star eye shape).

Cell Differentiation

The process by which a cell becomes specialized in order to perform a specific function.

Adaptation

Beneficial traits that increase an organism's fitness in its environment.

Adaptive Radiation

An evolutionary pattern where a single ancestral species evolves into several distinct species.

Analogous Structures

Structures that have similar functions but different origins and structures, such as a butterfly's tongue and a possum's tongue.

Homologous Structures

Structures that share a common evolutionary origin but may have different functions, such as the appendix in humans and zebras.

Vestigial Structures

Remnants of organs or structures that had a function in an early ancestor but no longer serve a purpose.

Hardy-Weinberg Equilibrium

A principle stating that allele frequencies in a population will remain constant unless evolutionary forces act upon them; defined by the equation $p^2 + 2pq + q^2 = 1$.

Biotic Factors

The living components of an ecosystem, such as plants, animals, and bacteria.

Abiotic Factors

The non-living components of an ecosystem, such as moisture, temperature, and wind.

Carrying Capacity

The maximum population size of a species that a particular environment can normally and consistently support.

Keystone Species

A species that has an unusually large effect on its ecosystem; its removal significantly decreases biodiversity.

Commensalism

A symbiotic relationship in which one organism benefits while the other is neither helped nor harmed.

Mutualism

A symbiotic relationship in which both organisms benefit.

Parasitism

A symbiotic relationship in which one organism benefits by harming the other.

Population Density

A measurement of the number of individuals per unit of area, calculated as $D = N/A$.

Density-Dependent Limiting Factors

Factors that affect a population more strongly as the population density increases, such as competition and predation.

Density-Independent Limiting Factors

Factors that affect a population regardless of its density, such as natural disasters or weather.

Frameshift Mutation

A mutation caused by the insertion or deletion of a nucleotide that shifts the 'reading frame' of the genetic message.

Purine

Nitrogenous bases consisting of Adenine (A) and Guanine (G).

Pyrimidine

Nitrogenous bases consisting of Cytosine (C) and Thymine (T).