Living Environment Regents Review: Part 2

Introduction

• Series of videos for NYS Regents Exam in Living Environment
• Can be used as a basic biology refresher
• Encouragement to take notes and subscribe for more content

Key Ideas 4-7: Standard 4

Reproduction

• Asexual Reproduction: Genes from one parent, identical copies.
• Sexual Reproduction: Half genetic info from each parent (haploid cells combine).
• Cloning: Making identical genetic copy (e.g., Dolly the sheep).
• Meiosis: Produces gametes (eggs/sperms), half genetic info.
  • Genetic Variation: Independent assortment, crossing over (prophase I), random fertilization.
  • Mutations: Important source of variation.
• Fertilization: Fusion of egg and sperm to form diploid zygote.
• Mitosis: Division to grow embryo, cell differentiation.
• Influence Factors: Hormones (testosterone, estrogen, progesterone), environment, gene expression.

Hormonal Regulation

• Female Cycle: Hormone changes for uterus and ovaries to support pregnancy.
• Gonads: Ovaries (eggs, fallopian tubes, uterus), testes (sperm, urethra).
• Placenta: Nutrient provider via umbilical cord.
• Embryonic Growth: Essential organ development, impact of negative conditions (alcohol, tobacco).

Photosynthesis

• Occurs in chloroplasts, converts sunlight to glucose (organic compounds), produces ATP.
• Inputs: Sunlight, CO2, H2O
• Outputs: Glucose, O2
• Organic Compounds: DNA, proteins, carbohydrates, fats.

Cellular Respiration

• Aerobic Respiration: Glucose + O2 = CO2 + H2O + ATP (36 ATP)
• Anaerobic Respiration: Glycolysis, less efficient (2 ATP), no mitochondria needed, no O2 required.
• Relation to photosynthesis (products feed each other).

ATP and Homeostasis

• ATP used for material transport, energy transformation, waste elimination.
• Homeostasis Mechanisms: Heart rate, respiratory rate, sweating, insulin release.
• Active Transport: Utilizes ATP for cell functions.
• Disease: Pathogens (viruses, bacteria, fungi) disrupt homeostasis.
• Immune System: Defense against pathogens, produces antibodies, memory cells, vaccines.
  • Diseases: AIDS (damages immune system), allergic reactions, environmental diseases, cancer.

Ecosystems

• Energy from the sun; matter cycles (carbon, hydrogen, nitrogen, oxygen).
• Organisms Interaction: Mutualism, parasitism, commensalism, predator-prey.
• Ecosystem Progression: Primary and secondary succession to stable ecosystem.
• Human Impact: Invasive species, pollution, resource depletion, habitat loss, climate change.
  • Global Warming: Caused by fossil fuels combustion, greenhouse gases, not related to ozone depletion.
  • Ozone Layer Depletion: Caused by CFCs, increases UV radiation, separate from global warming.

Conclusion

• Review of key ideas 4-7 in standard 4, focus on topics for regents exam
• Encouragement to subscribe for more content