Biology - Semester 2 Final Exam Review (2024)

• Interphase


  Grows and DNA replicates
• Mitosis


  Actually begins separating cells
• Cell cycle


  • Series of growth and division stages
• Reasons for mitosis in somatic/body cells

  • Growth
  • Replacement
  • Heal and regenerate
• DNA is duplicated during interphase before mitosis
• Cell cycle checkpoints


  Make sure the cell is dividing correctly and no mistakes or mutations occurred
• Cancer


  Blows past cell cycle checkpoints and speeds up the cell cycle
• Processes in meiosis that create genetic variation

  • Crossing Over (Prophase 1)
  • Independent Assortment (Metaphase 1)
  • Random Fertilization
• A dog's sperm cell would have 39 chromosomes
• Genotype and phenotype percentages for offspring of heterozygous widow's peak parent

  • 50% Aa (widow's peak)
  • 50% aa (no widow's peak)
• Genotype


  The DNA trait, not visual
• Phenotype


  The physical, visible trait
• Allele


  Different versions of a given gene
• Heterozygous


  Both dominant and recessive alleles
• Homozygous


  Same alleles, one dominant, one recessive
• Dominant


  The trait that if one is present, will always be the overpowering one
• Genotype and phenotype percentages for offspring of Gg x Gg cross

  • 25% GG (grey)
  • 50% Gg (grey)
  • 25% gg (black)
• Genotype and phenotype percentages for offspring of Bb x bb cross

  • 50% Bb (long beak)
  • 50% bb (short beak)
• Chromosome


  A thread-like structure composed of DNA and proteins that carries genetic information
• This organism has 16 total chromosomes in 8 pairs
• Most animals have an even number of total chromosomes because they inherit one set from each parent, resulting in pairs of homologous chromosomes
• Genotypic and phenotypic probabilities for offspring of III.6 and III.7

  • 25% AA
  • 50% Aa
  • 25% aa
• Adaptation


  Inherited traits or behaviors that increase an organism's chances of survival in their environment
• Types of adaptation


  • Morphological (physical features)
  • Physiological (body chemistry)
  • Behavioral (actions or behaviors)
• Selective pressure


  An evolutionary force that causes a particular phenotype to be more favorable in certain environmental conditions
• The selective pressure acting on the brightness of the poison dart frogs' skin is predation
• The selective pressure that caused the evolution of predators to avoid the brightest frogs is the toxicity of the frogs
• Types of reproductive isolation

  • Geographic
  • Behavioral
  • Temporal
• Ways genetic variation arises

  • Mutation
  • Recombination
  • Independent Assortment
• Genetic variation is essential for the survival of a species because it allows them to adapt to changing environments
• Requirements for natural selection

  • Variation
  • Inheritance
  • Time
  • Differential Survival & Reproduction
• Natural selection leads to antibiotic resistance through variation in bacteria, exposure to antibiotics killing non-resistant bacteria, and the resistant bacteria multiplying and passing on their resistance
• Zone of inhibition


  Area around an antibiotic where bacteria are unable to grow
• Levels of organization in the ecosystem image

  • Water weeds (producer)
  • Snail (primary consumer)
  • Frog (secondary consumer)
• The organisms that make energy usable for all the others in this ecosystem are the producers (algae)
• No agents on disk = nothing to provide resistance
• Ecosystem Homeostasis


  • Sun
  • Water weeds
  • Fish
  • Snal
• Biotic components


  • Fish
  • Frog
• Abiotic components


  • water
• Producer


  Organisms that make energy usable for all others in this ecosystem