Free NY Regents Life Science: Biology Exam Flashcards

A biological structure is shaped for what it does. A receptor's shape affects signaling, a red blood cell's shape supports transport, and a root hair's shape increases absorption.

Most body cells contain the same genome, but different genes are turned on or off. Different gene expression leads to different proteins and specialized cell functions.

Homeostasis is maintaining a stable internal environment despite external change. It depends on monitoring conditions and responding when values move away from a normal range.

Negative feedback reverses a change and supports stability, such as insulin lowering blood glucose. Positive feedback amplifies a change until an endpoint, such as contractions during birth.

Enzymes lower activation energy by helping reactants fit and react. Their shape matters, so high heat or extreme pH can reduce enzyme function.

Water moves into the cell by osmosis because the outside solution is hypotonic. Without a cell wall, the cell can swell and burst.

Vaccines expose the immune system to a safe antigen, causing memory cells to form. Later exposure triggers a faster, stronger immune response.

Mitosis produces genetically identical body cells for growth, repair, and replacement. It preserves chromosome number in the daughter cells.

Photosynthesis converts light energy into chemical energy stored in glucose. Carbon dioxide and water become glucose and oxygen in chloroplasts.

Cellular respiration breaks down food molecules to make ATP, the short-term energy carrier used for cell work.

Matter atoms are recycled through ecosystems, such as carbon and nitrogen cycles. Energy flows one way, entering mostly as sunlight and leaving as heat.

Organisms use much of the energy they take in for metabolism, movement, growth, and heat loss. Only a fraction becomes biomass available to the next level.

Arrows show the direction of energy transfer, from the organism being eaten to the organism that eats it. They do not point toward the food source.

Decomposers break down dead organisms and wastes, returning matter to the environment. Without them, nutrients would remain locked in dead biomass.

Working muscles need more oxygen and glucose and produce more carbon dioxide. Faster breathing and circulation help deliver materials and remove wastes.

Carrying capacity is the population size an environment can support over time with available resources and limiting factors. It can change when conditions change.

A limiting factor is any biotic or abiotic condition that restricts population growth, such as food, water, space, disease, predators, or nesting sites.

Greater biodiversity provides more roles, genetic variation, and alternate pathways in food webs. A diverse ecosystem is often more resilient after disturbance.

Predation benefits the predator and harms prey. Competition harms both by using the same limited resource. Mutualism benefits both interacting species.

It may lack natural predators, face little competition, reproduce rapidly, or use resources efficiently. Its spread can reduce biodiversity and alter food webs.

Runoff can cause algal blooms. When algae die, decomposers use oxygen while breaking them down, leaving less dissolved oxygen for aquatic organisms.

Succession is the gradual change in community composition after disturbance or on new surfaces. Species replace one another as conditions change.

Identify axes, units, trend, peaks, and timing. Then connect the pattern to a cause such as resource limits, disturbance, migration, or disease.

DNA contains genes. Genes are instructions for making RNA and proteins. Proteins help produce traits by building structures, enzymes, and signals.

Transcription makes RNA from a DNA template. Translation reads mRNA codons at a ribosome to assemble a chain of amino acids into a protein.

Mitosis makes identical body cells with the same chromosome number. Meiosis makes genetically varied gametes with half the chromosome number.

Crossing over exchanges chromosome segments, and independent assortment shuffles homologous chromosomes into gametes. Fertilization adds another source of variation.

Genotype is the allele combination. Phenotype is the observable trait or function, which can be influenced by genotype, environment, and gene expression.

It shows possible offspring genotypes and expected probabilities from parent alleles. It does not guarantee the exact outcome for a small number of offspring.

Nondisjunction is a chromosome-separation error during meiosis. It can produce gametes with extra or missing chromosomes.

A mutation in a body cell affects that individual but is usually not inherited. A mutation in a gamete can be passed to offspring.

Environmental conditions can affect gene expression and development. Traits often result from interaction between genes and environment, not genes alone.

Natural selection is differential survival and reproduction caused by heritable variation. Traits that improve reproductive success can become more common in a population.

No. Individuals may survive, die, or change during life, but evolution is a change in heritable trait frequencies in a population across generations.

An adaptation is an inherited trait that improves survival or reproduction in a particular environment. A trait can be helpful in one environment and harmful in another.

Some individuals already have heritable resistance. Treatment kills susceptible individuals, resistant survivors reproduce, and the resistance trait becomes more common.

Shared DNA sequences, homologous structures, embryological patterns, fossils, and consistent branching patterns in phylogenetic trees can support common ancestry.

Genetic drift is random change in allele frequencies, strongest in small populations. Bottlenecks and founder events can reduce genetic diversity by chance.

Separated populations stop interbreeding and face different mutations, selection pressures, and drift. Over time they may become reproductively isolated species.

Photosynthesis removes carbon dioxide and releases oxygen. Over long time scales, photosynthetic organisms changed atmospheric oxygen levels and carbon cycling.

Combustion moves carbon from fuels or biomass into the atmosphere as carbon dioxide, increasing the atmospheric carbon pool.

Temperature, precipitation, seasons, and habitat conditions affect survival and reproduction. Species may move, decline, or expand as suitable conditions shift.

A feedback loop occurs when a change triggers responses that either reduce the change or amplify it. Biology, climate, carbon, and habitat can interact in loops.

The independent variable is changed or compared by the investigator. The dependent variable is measured as the response and is often shown on the y-axis.

Controlled variables keep other conditions constant so the observed effect can be linked more confidently to the independent variable.

Reliable evidence comes from appropriate controls, repeated trials, accurate measurements, enough data, and methods that reduce bias or random error.

It should state a claim, cite specific data or observations as evidence, and explain the biological mechanism that connects the evidence to the claim.

Ask what the model represents well, what it leaves out, what assumptions it makes, and whether its predictions match data.

Criteria define what a successful solution should accomplish. Constraints are limits such as cost, time, materials, safety, or effects on other species.

A solution can improve one outcome while creating costs or side effects elsewhere. Strong answers compare benefits, constraints, and evidence for each option.