NY Regents Life Science: Biology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Cell Theory

The principle that all living organisms are composed of one or more cells, that the cell is the basic unit of structure and function, and that all cells arise from existing cells.

Selective Permeability

A property of the cell membrane allowing some substances to pass through while blocking others, controlled by the phospholipid bilayer and embedded transport proteins.

Mitochondrion

A membrane-bound organelle where aerobic cellular respiration occurs, converting glucose and oxygen into ATP energy, carbon dioxide, and water.

Chloroplast

A plant-cell organelle containing chlorophyll that captures light energy to convert carbon dioxide and water into glucose and oxygen during photosynthesis.

Enzyme Active Site

The region of an enzyme where substrate molecules bind; its specific shape determines which reactions the enzyme can catalyze and is affected by temperature and pH.

Cell Differentiation

The process by which unspecialized cells develop into distinct cell types with specific structures and functions, allowing multicellular organisms to form specialized tissues and organs.

DNA Base Pairing

The complementary pairing rule in DNA where adenine bonds with thymine and cytosine bonds with guanine, holding the two strands of the double helix together.

Transcription

The process in which a DNA sequence is copied into messenger RNA in the nucleus, carrying genetic instructions to ribosomes for protein synthesis.

Translation

The process at ribosomes where messenger RNA codons are read and matched to transfer RNA to assemble amino acids into a protein chain.

Mutation

A change in the DNA nucleotide sequence that may alter the protein produced; effects range from none to harmful or occasionally beneficial.

Allele

One of two or more alternative forms of a gene that occupy the same position on homologous chromosomes and influence the same trait.

Meiosis

A cell division producing four haploid gametes with half the chromosome number, generating genetic variation through crossing over and independent assortment.

Genotype

The genetic makeup of an organism, describing the specific combination of alleles for a trait, such as homozygous dominant, heterozygous, or homozygous recessive.

Phenotype

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

Natural Selection

The process by which individuals with heritable traits better suited to their environment survive and reproduce more, increasing those traits in later generations.

Homologous Structures

Body parts in different species that share similar underlying structure due to common ancestry, though they may serve different functions, such as human arms and bat wings.

Speciation

The formation of new species when populations become reproductively isolated and accumulate genetic differences over time, often after geographic separation.

Genetic Drift

A random change in allele frequencies in a population, especially pronounced in small populations, which can reduce genetic variation independent of natural selection.

Binomial Nomenclature

The two-part scientific naming system for organisms using the genus name capitalized and the species name lowercase, both italicized or underlined.

Fitness

An organism's ability to survive and reproduce in its environment, measured by the relative contribution of offspring to future generations.

Trophic Level

A feeding position in a food chain or web, such as producer, primary consumer, or secondary consumer, with energy decreasing at each higher level.

Carrying Capacity

The maximum population size that an ecosystem can sustain indefinitely given available food, water, space, and other limiting resources.

Mutualism

A symbiotic relationship in which both participating species benefit from the interaction, such as bees obtaining nectar while pollinating flowers.

Primary Succession

The gradual establishment of an ecosystem on bare rock or newly formed land lacking soil, beginning with pioneer species such as lichens and mosses.

Keystone Species

A species whose influence on community structure is disproportionately large relative to its abundance; its removal can cause major ecosystem changes.

Decomposer

An organism such as bacteria or fungi that breaks down dead organic matter, recycling nutrients such as carbon and nitrogen back into the ecosystem.

Eutrophication

Nutrient runoff, especially nitrogen and phosphorus, causes excessive algal growth, then oxygen depletion when algae die, harming aquatic organisms.

Biological Magnification

The increasing concentration of certain toxins in organisms at successively higher trophic levels, because toxins accumulate faster than they are eliminated.

Greenhouse Effect

The trapping of heat in Earth's atmosphere by gases such as carbon dioxide and methane, which absorb and re-emit infrared radiation from the surface.

Invasive Species

A non-native organism introduced to a new environment where it spreads rapidly, outcompetes native species, and disrupts existing food webs.

Independent Variable

The factor deliberately changed or manipulated by the researcher in an experiment, whose effect on the dependent variable is being tested.

Control Group

The group in an experiment that does not receive the experimental treatment and serves as a baseline for comparison with the experimental group.