Cell Division, Genetics, Evolution, and Ecology

Interphase

Chromosomes replicate to prepare for division.

Mitosis

Process producing two identical daughter cells.

Meiosis

Produces four genetically diverse haploid cells.

Chromosome

Structure carrying genetic information in cells.

Diploid

Cell with two sets of chromosomes (46 total).

Haploid

Cell with one set of chromosomes (23 total).

Chromatid

Identical halves of a duplicated chromosome.

Prophase

Chromosomes condense, spindle fibers form, envelope breaks.

Metaphase

Chromosomes align in the cell's equatorial plane.

Anaphase

Sister chromatids separate and move to poles.

Telophase

Nuclei envelopes around separated chromosomes.

Cytokinesis

Cytoplasm divides, forming two daughter cells.

Punnett Square

Tool for predicting genetic cross outcomes.

Complete Dominance

Dominant allele fully masks recessive allele effect.

Codominance

Both alleles expressed equally in phenotype.

Crossing Over

Exchange of DNA between homologous chromosomes.

Recombinant Chromatids

Chromatids with mixed genetic material from parents.

Homologous Pairs

Chromosomes from each parent that are similar.

Chargaff's Rules

A=T and C=G in DNA base pairing.

Genetic Diversity

Variation in genetic traits within a population.

Asexual Reproduction

Reproduction without the fusion of gametes.

Rosalind Franklin

Produced significant DNA image via x-ray crystallography.

Watson and Crick

Developed 3D model of DNA structure.

Nucleotides

Building blocks of DNA/RNA with bases, sugars, phosphates.

Antiparallel structure

DNA strands run in opposite directions.

DNA vs RNA

DNA is double-stranded; RNA is single-stranded.

DNA function

Stores genetic information and energy.

RNA function

Transcribes amino acids and aids ribosome formation.

Base pairs in DNA

Contains adenine, thymine, guanine, cytosine (ATGC).

Base pairs in RNA

Contains adenine, uracil, guanine, cytosine (AUGC).

DNA replication

Occurs during interphase, producing identical DNA strands.

Semiconservative replication

One original strand retained, new strand synthesized.

DNA Helicase

Unwinds DNA helix during replication process.

DNA Polymerase

Adds nucleotides in 5'-3' direction during replication.

Lagging strand

Synthesized in fragments called Okazaki fragments.

DNA Ligase

Joins Okazaki fragments together on lagging strand.

Transcription

Process of forming RNA from DNA in nucleus.

RNA polymerase

Enzyme that initiates transcription process.

mRNA

Messenger RNA that carries DNA's message.

tRNA

Transfers amino acids to ribosome during translation.

rRNA

Ribosomal RNA, component of ribosomes.

Codon

Three-nucleotide sequence coding for amino acids.

Human Genome Project

Mapped and sequenced entire human genome.

Darwin's natural selection

Mechanism of evolution based on survival of fittest.

Directional selection

One extreme trait is favored over others.

Stabilizing selection

Intermediate trait is favored in population.

Disruptive selection

Both extreme traits are favored over intermediate.

Nondisjunction

Failure to separate chromosomes during meiosis.

Homologous structures

Similar bones in related species indicating common ancestry.

Embryological similarities

Similar embryos suggest shared evolutionary origins.

Molecular similarities

Similar genetic makeup among related species.

Fossil record

Preserved remains showing evolutionary changes over time.

Speciation

Process where populations evolve into distinct species.

Gene pool

Total genetic diversity within a population.

Reproductive isolation

Inability of populations to interbreed.

Geographic isolation

Separation by physical barriers like rivers or mountains.

Behavioral isolation

Different mating behaviors prevent interbreeding.

Mechanical isolation

Incompatible reproductive organs prevent mating.

Temporal isolation

Different mating times prevent interbreeding.

Hybrid inviability

Offspring fail to survive to reproductive age.

Hybrid sterility

Offspring are sterile and cannot reproduce.

Linnaean taxonomy

Hierarchical classification system for organisms.

Binomial nomenclature

Two-part naming system using genus and species.

Three domains of life

Bacteria, Archaea, Eukarya based on cellular structure.

Convergent evolution

Unrelated species develop similar traits due to environment.

Organism

Individual living entity.

Population

Group of same species in a specific area.

Community

Different populations interacting in a shared area.

Ecosystem

Community plus nonliving environmental components.

Biome

Large area with distinct climate and organisms.

Biosphere

Global sum of all ecosystems on Earth.

Energy flow

Energy moves in one direction through ecosystems.

Nutrient recycling

Nutrients are reused within ecosystems.

Nitrogen Cycle

Process of nitrogen conversion in ecosystems.

Nitrogen-fixing Bacteria

Convert nitrogen gases into ammonia for plants.

Nitrogen Fixation

Transformation of nitrogen gas into usable ammonia.

Decomposition

Breakdown of organic matter, returning nutrients to soil.

Abiotic Factors

Nonliving components like temperature and water.

Biotic Factors

Living factors and organisms such as plants, fungi, bacteria

Ecological Niche

Species' role and position in its environment.

Competition

Organisms vying for the same limited resources.

Predation

One organism captures and eats another.

Symbiosis

Close relationship between different species.

Mutualistic Symbiosis

Both species benefit from the relationship.

Commensalistic Relationship

One species benefits, the other is unharmed.

Parasitic Relationship

One organism benefits at the expense of another.

Freshwater Biome

Includes rivers and lakes, no salt content.

Savanna Biome

Tropical grassland with wet and dry seasons.

Freshwater Wetlands

Diverse areas important for breeding and feeding.

Taiga Biome

Cold climate with coniferous forests.

Temperate Forest

Deciduous trees dominate with seasonal changes.

Temperate Grassland

Prairie ecosystem with moderate climate and grazing.

Alpine Biome

Mountainous regions with specific flora and fauna.

Tundra Biome

Cold regions with no trees, near poles.

Permafrost

Soil frozen year-round, limiting plant growth.

Arctic Biome

Cold climate with low flora and fauna diversity.

Chaparral

Warm, dry climate with scrubland vegetation.

Rainforest

High biodiversity biome near the equator.

Desert

Extremely dry climate with temperature extremes.

Exponential Growth

Population increases without resource limitations.