Biology flashcards, generated for you.

Homeostasis is the maintenance of stable internal conditions (temperature, pH, osmotic balance) within an organism despite external environmental changes, achieved through negative feedback mechanisms.

Genotype is the organism's genetic makeup (alleles present); phenotype is the observable physical or biochemical characteristic. Phenotype results from genotype + environmental factors: Phenotype = Genotype + Environment.

ATP (adenosine triphosphate) is the primary energy currency of cells. When the phosphate bond breaks (ATP → ADP + Pi), energy is released and used to power active transport, muscle contraction, protein synthesis, and other cellular work.

Negative feedback detects deviation from a set point, then triggers a response that opposes the change and returns the system to normal. Example: High blood glucose → pancreas releases insulin → glucose taken up by cells → blood glucose decreases back to normal.

Mitosis produces 2 identical diploid daughter cells (2n → 2n); used for growth and repair. Meiosis produces 4 unique haploid daughter cells (2n → n); used for sexual reproduction. Meiosis includes two divisions; mitosis is one.

Passive transport moves substances across a membrane without energy (ATP), along the concentration gradient from high to low concentration. Example: Oxygen diffusion into cells or water movement via osmosis through aquaporins.

Enzyme catalysis is acceleration of a chemical reaction by an enzyme (protein catalyst). Enzymes lower activation energy by stabilizing the transition state, allowing reactions to proceed at body temperature without heat. This increases reaction rate without being consumed.

Photosynthesis captures light energy in chlorophyll and converts it to chemical energy in glucose. Light-dependent reactions (thylakoids): light → ATP + NADPH + O₂. Light-independent reactions/Calvin cycle (stroma): ATP + NADPH → glucose from CO₂.

Genetic variation in populations allows individuals to differ in traits. Heritable traits are passed to offspring. Individuals with advantageous traits survive/reproduce better (differential survival/reproduction), increasing those allele frequencies in the population over generations.

Central dogma: DNA → RNA → Protein. DNA is transcribed to mRNA in the nucleus. mRNA is translated at ribosomes into proteins using tRNA to match codons with amino acids. This explains how genetic information controls organism traits and function.