Heredity

Question What is heredity? tap to flip ↻ Answer Heredity is the transmission of characters from parents to offspring. Question What are variations? tap to flip ↻ Answer Variations are differences in characteristics among individuals of a species. Question Why are variations important for a species? tap to flip ↻ Answer Variations help a species adapt to environmental changes and survive. Question What is a gene? tap to flip ↻ Answer A gene is a segment of DNA that codes for a specific protein or trait. Question What is an allele? tap to flip ↻ Answer An allele is one of two or more alternative forms of a gene. Question Define dominant trait. tap to flip ↻ Answer A dominant trait is a trait that is expressed even when only one copy of the allele is present. Question Define recessive trait. tap to flip ↻ Answer A recessive trait is a trait that is expressed only when two copies of the recessive allele are present. Question What is genotype? tap to flip ↻ Answer Genotype is the genetic makeup of an organism, e.g., TT, Tt, or tt. Question What is phenotype? tap to flip ↻ Answer Phenotype is the observable physical or biochemical characteristics of an organism. Question State Mendel's Law of Dominance. tap to flip ↻ Answer In a cross between two pure breeding contrasting traits, the F1 generation shows only the dominant trait, while the recessive trait reappears in the F2 generation. Question State Mendel's Law of Segregation. tap to flip ↻ Answer Alleles segregate during gamete formation, so each gamete receives only one allele of a gene. Question What is the phenotypic ratio in the F2 generation of a monohybrid cross? tap to flip ↻ Answer 3:1 (dominant:recessive). Question What is the genotypic ratio in the F2 generation of a monohybrid cross? tap to flip ↻ Answer 1:2:1 (homozygous dominant:heterozygous:homozygous recessive). Question In a monohybrid cross between pure tall (TT) and pure dwarf (tt) pea plants, what is the phenotype of the F1 generation? tap to flip ↻ Answer All tall (Tt). Question What is a dihybrid cross? tap to flip ↻ Answer A cross between two individuals that differ in two pairs of contrasting traits. Question What is the phenotypic ratio in the F2 generation of a dihybrid cross? tap to flip ↻ Answer 9:3:3:1. Question What is sex determination in humans? tap to flip ↻ Answer Sex in humans is determined by the sex chromosomes: females have XX and males have XY. Question Who determines the sex of a child in humans? tap to flip ↻ Answer The father determines the sex of the child because the mother always contributes an X chromosome, while the father can contribute either an X or a Y. Question What are the chances of a boy or a girl in humans? tap to flip ↻ Answer 50% chance of a boy and 50% chance of a girl. Question What is evolution? tap to flip ↻ Answer Evolution is the gradual change in the characteristics of a population over generations. Question What is a fossil? tap to flip ↻ Answer A fossil is the preserved remains or traces of ancient organisms. Question How do fossils provide evidence for evolution? tap to flip ↻ Answer Fossils show the sequence of organisms over time and help trace evolutionary relationships. Question What is homologous organs? tap to flip ↻ Answer Homologous organs are organs that have the same basic structure but perform different functions, indicating common ancestry. Question Give an example of homologous organs. tap to flip ↻ Answer Forelimbs of humans, birds, and whales. Question What are analogous organs? tap to flip ↻ Answer Analogous organs are organs that perform similar functions but have different structures, indicating convergent evolution. Question Give an example of analogous organs. tap to flip ↻ Answer Wings of insects and birds. Question What is natural selection? tap to flip ↻ Answer Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce. Question Who proposed the theory of natural selection? tap to flip ↻ Answer Charles Darwin. Question What is genetic drift? tap to flip ↻ Answer Genetic drift is a random change in allele frequencies in a small population. Question What is speciation? tap to flip ↻ Answer Speciation is the formation of new species from existing ones. Question What is a species? tap to flip ↻ Answer A species is a group of organisms that can interbreed and produce fertile offspring. Question What is the role of variation in evolution? tap to flip ↻ Answer Variations provide the raw material for evolution by natural selection. Question What is the significance of DNA in heredity? tap to flip ↻ Answer DNA carries genetic information and is responsible for the transmission of traits from parents to offspring. Question What is a monohybrid cross? tap to flip ↻ Answer A cross between two individuals that differ in one pair of contrasting traits. Question What is the F1 generation? tap to flip ↻ Answer The first filial generation, the offspring of the parental generation. Question What is the F2 generation? tap to flip ↻ Answer The second filial generation, the offspring of the F1 generation. Question What is a Punnett square? tap to flip ↻ Answer A Punnett square is a diagram used to predict the genotypes of offspring from a cross. Question What is the genotype of a tall pea plant if it is heterozygous? tap to flip ↻ Answer Tt. Question What is the genotype of a dwarf pea plant? tap to flip ↻ Answer tt. Question What is the phenotypic ratio of a cross between two heterozygous tall pea plants (Tt x Tt)? tap to flip ↻ Answer 3 tall : 1 dwarf. Question What is the genotypic ratio of a cross between two heterozygous tall pea plants (Tt x Tt)? tap to flip ↻ Answer 1 TT : 2 Tt : 1 tt. Question What is the probability of a dwarf offspring from a cross between two heterozygous tall pea plants (Tt x Tt)? tap to flip ↻ Answer 1/4 or 25%. Question What is the probability of a tall offspring from a cross between two heterozygous tall pea plants (Tt x Tt)? tap to flip ↻ Answer 3/4 or 75%. Question What is the genotype of the F1 generation in a cross between pure tall (TT) and pure dwarf (tt) pea plants? tap to flip ↻ Answer Tt (heterozygous tall). Question What is the phenotype of the F1 generation in a cross between pure tall (TT) and pure dwarf (tt) pea plants? tap to flip ↻ Answer All tall. Question What is the genotype of the F2 generation in a monohybrid cross between pure tall and pure dwarf pea plants? tap to flip ↻ Answer 1 TT : 2 Tt : 1 tt. Question What is the phenotype of the F2 generation in a monohybrid cross between pure tall and pure dwarf pea plants? tap to flip ↻ Answer 3 tall : 1 dwarf. Question What is the law of independent assortment? tap to flip ↻ Answer The law states that alleles of different genes assort independently of one another during gamete formation. Question What is the significance of Mendel's experiments? tap to flip ↻ Answer Mendel's experiments established the fundamental laws of inheritance. Question What is the difference between acquired and inherited traits? tap to flip ↻ Answer Acquired traits are acquired during lifetime and not passed to offspring; inherited traits are genetically passed from parents to offspring. Question Why are acquired traits not inherited? tap to flip ↻ Answer Acquired traits do not cause changes in the DNA of germ cells, so they are not passed to the next generation. Question What is the role of germ cells in inheritance? tap to flip ↻ Answer Germ cells carry genetic information from parents to offspring. Question What is the significance of sex chromosomes? tap to flip ↻ Answer Sex chromosomes determine the sex of an individual. Question What are the sex chromosomes in human males? tap to flip ↻ Answer XY. Question What are the sex chromosomes in human females? tap to flip ↻ Answer XX. Question What is the probability of a child being a boy if the father contributes a Y chromosome? tap to flip ↻ Answer 100% (if the father contributes Y, the child will be a boy). Question What is the probability of a child being a girl if the father contributes an X chromosome? tap to flip ↻ Answer 100% (if the father contributes X, the child will be a girl). Question What is the evolutionary significance of homologous organs? tap to flip ↻ Answer Homologous organs indicate common ancestry and divergent evolution. Question What is the evolutionary significance of analogous organs? tap to flip ↻ Answer Analogous organs indicate convergent evolution due to similar functions. Question What is the role of fossils in studying evolution? tap to flip ↻ Answer Fossils provide direct evidence of past organisms and help in tracing evolutionary history.