BIOL106 Exam 1 Study Guide: Key Concepts and Questions

Posted on May 2, 2024 in Biology

BIOL106 Exam 1 Study Guide

Key Concepts

Genetics and Heredity

Induction: Using observations and facts to formulate hypotheses (specific to general).

Deduction: Making predictions based on hypotheses (general to specific).

Replication: Duplication of DNA for daughter cells.

Gene: A unit of heredity; a sequence of nucleotides coding for a protein.

Allele: A form of a gene.

Dominant Allele: Expressed in heterozygotes.

Recessive Allele: Suppressed in heterozygotes.

Genotype: The pair of alleles at a locus.

Phenotype: Observable properties resulting from genetics and environment.

Homozygote: Has the same alleles on both homologous chromosomes.

Heterozygote: Has different alleles on homologous chromosomes.

Gamete: Sexual reproductive cell (egg/sperm).

Diploid (2n): Two copies of chromosomes (e.g., human somatic cells).

Haploid (n): One copy of each chromosome (e.g., gametes).

Evolution

Genetic Drift: Random changes in allele frequencies over generations.

Bottleneck Effect: A large population reduced to a small size, leading to changes in allele frequencies.

Founder Effect: Changes in allele frequencies in a new, smaller population.

Biogeography: Study of the distribution of living organisms.

Natural Selection: Differential survival and reproduction based on traits.

Sexual Selection: Selection based on mating preferences.

Experimental Design

Dependent/Response Variable: The variable being explained or predicted.

Independent/Explanatory Variable: The variable used to explain or predict the response variable.

Continuous Variable: Varies quantitatively (e.g., height, speed).

Categorical/Discrete Variable: Varies qualitatively (e.g., species, color).

Questions and Answers

Genetics and Heredity

  1. Induction and deduction are complementary processes in scientific inquiry. Induction leads to hypotheses, while deduction tests those hypotheses through predictions.
  2. A scientific control is a variable held constant in an experiment to isolate the effects of the independent variable.
  3. Mitotic cell divisions occur in different phases depending on the organism: diploid in animals, haploid in fungi, and both in plants.
  4. Meiosis differs from mitosis by reducing chromosome number from diploid to haploid, increasing genetic diversity through crossing over, and involving two nuclear divisions.
  5. Hardy-Weinberg equilibrium describes a non-evolving population where allele and genotype frequencies remain constant.

Evolution

  1. Evolution by natural selection requires overproduction of offspring, variation among individuals, heritable variation affecting reproductive success, and heritability of traits.
  2. Biogeographical patterns, such as vestigial traits, homologous structures, and DNA sequencing, support the theory of evolution.
  3. Artificial selection involves human intervention in breeding, while natural selection occurs without human influence.
  4. Allele frequency is the proportion of each allele in a population, while genotype frequency is the proportion of each genotype.
  5. Frequency-dependent selection and heterozygote advantage maintain genetic diversity by favoring rare or heterozygous genotypes.

Phylogeny and Speciation

  1. Phylogeny is the evolutionary history of a group of organisms.
  2. A clade is a group containing an ancestor and all its descendants.
  3. Speciation is the process of forming new species.
  4. Allopatric speciation occurs with geographic isolation, while sympatric speciation occurs without it.
  5. Reproductive isolation mechanisms prevent gene flow between species.

Prokaryotes

  1. Prokaryotes and eukaryotes share fundamental characteristics like cell membranes, ribosomes, and DNA as genetic material.
  2. Archaea and bacteria are distinct domains of prokaryotic life.
  3. Gram staining differentiates bacteria based on cell wall structure.
  4. Archaea often inhabit extreme environments.
  5. Viruses are considered non-living but have biological origins and evolve rapidly.

Additional Notes

  • Molecular clocks estimate divergence times based on DNA sequence differences.
  • Earth’s history is divided into geological eras, each marked by significant events.
  • Plate tectonics and other geological processes have influenced evolution and extinction.