What is Mendel's Law of Segregation?	The two alleles for each gene separate during gamete formation so each gamete carries only one allele.
What is Mendel's Law of Independent Assortment?	Genes on different chromosomes are inherited independently because homologous pairs orient randomly during meiosis I.
What is the phenotypic ratio of a monohybrid cross (Aa x Aa) with complete dominance?	3:1 dominant to recessive (genotypic ratio 1 AA : 2 Aa : 1 aa).
What is codominance?	Both alleles are fully expressed in the heterozygote (e.g., AB blood type expresses both A and B antigens).
What is incomplete dominance?	The heterozygous phenotype is intermediate between the two homozygotes (e.g., red x white snapdragons produce pink).
What is a test cross?	Crossing a dominant-phenotype individual with a homozygous recessive to determine if the dominant parent is homozygous or heterozygous.
What is semi-conservative DNA replication?	Each parent strand serves as a template, so each daughter molecule has one original strand and one new strand.
What does DNA helicase do?	Unwinds the double helix by breaking hydrogen bonds at the replication fork, creating single-stranded templates.
Why does DNA replication require an RNA primer?	DNA polymerase cannot initiate a new strand; it needs a free 3'-OH group provided by a short RNA primer laid down by primase.
How do the leading and lagging strands differ?	The leading strand is synthesized continuously toward the fork; the lagging strand is synthesized in short Okazaki fragments away from it.
What is transcription?	RNA polymerase synthesizes mRNA from a DNA template. In eukaryotes it occurs in the nucleus.
What are the three post-transcriptional modifications in eukaryotes?	5' methylguanosine cap, 3' poly-A tail, and RNA splicing (introns removed, exons joined by the spliceosome).
What is translation?	Ribosomes synthesize a polypeptide from mRNA in the cytoplasm; tRNA delivers amino acids matched to codons via anticodons.
What is a codon?	A three-nucleotide mRNA sequence encoding one amino acid or a stop signal. 64 codons encode 20 amino acids plus 3 stops (redundant code).
What are the three types of point mutations?	Silent (no amino acid change), missense (different amino acid), and nonsense (premature stop codon).
What is epistasis?	One gene's expression masks or modifies another gene at a different locus (e.g., coat color in Labrador retrievers).
Why are males more affected by X-linked recessive disorders?	Males have only one X chromosome, so a single recessive allele is expressed. Females need two copies to show the trait.
What is polygenic inheritance?	A trait controlled by two or more genes with additive effects, producing continuous variation (e.g., height, skin color).
What is the central dogma of molecular biology?	DNA is transcribed to RNA, which is translated to protein (DNA -> RNA -> Protein).
What is a frameshift mutation?	An insertion or deletion (not a multiple of three) that shifts the reading frame, altering all downstream amino acids and usually producing a nonfunctional protein.
What is the difference between genotype and phenotype?	Genotype is the allele combination an organism carries (e.g., Bb); phenotype is the observable trait expressed, influenced by genotype and environment.
What is a Punnett square used for?	A diagram that predicts offspring genotypic and phenotypic ratios by combining one allele from each parent per grid box.
How does the lac operon regulate gene expression?	When lactose is absent, a repressor blocks transcription. When present, allolactose binds the repressor, releasing it so RNA polymerase transcribes the genes.
What are linked genes?	Genes close together on the same chromosome that tend to be inherited together; crossing over can separate them at a rate proportional to their distance.
What is Hardy-Weinberg equilibrium?	Allele frequencies stay constant when there is no selection, mutation, gene flow, or genetic drift, and mating is random.