🔬 9th grade Science: how to help at home

What each unit covers

1. 🧫Cells from Cells

   How cells copy their DNA and divide by mitosis, the stages in order, why cells divide for growth and healing, and what can go wrong when cell growth isn't controlled.

2. 🌱Reproduction

   How organisms reproduce with one parent or two, why sexual reproduction creates variety, the parts of a flower, and the strengths and weaknesses of each approach.

3. 🦠Microbes & the Immune System

   What makes something alive, helpful and harmful micro-organisms, how the immune system defends the body, how vaccines and antibiotics work, and the impact of epidemics and pandemics.

4. 🦠Infectious Disease

   Practices pathogens, vaccines, antibiotics and antibiotic resistance, mutations and strains, waning immunity, and public health measures that limit the spread of disease.

5. 🦎Evolution & Selection

   Practices variation, adaptation, natural and artificial selection, mutations, the evidence for evolution from fossils and rock layers, and how new species can form.

6. 🌿Photosynthesis & Respiration

   The reactants, products and location of photosynthesis and cellular respiration, why they are complementary, and how they link plants, animals and the carbon cycle.

7. 🧬Biomolecules & Enzymes

   Practices the four kinds of biomolecules (carbohydrates, lipids, proteins and nucleic acids), their building blocks and jobs in the cell, and how enzymes speed up cellular reactions and are affected by temperature and pH.

8. 🔬Cell Types, Transport & Specialization

   Practices comparing prokaryotic and eukaryotic cells, how cells keep homeostasis by moving molecules (diffusion, osmosis, active transport), how cells specialize through differentiation, and how a disrupted cell cycle can lead to cancer.

9. 🧬DNA, RNA & Proteins

   Practices the parts of DNA and how base sequences code for traits, transcription and translation (DNA to RNA to protein), kinds of mutations and their effects, and molecular technologies such as PCR, gel electrophoresis and genetic engineering.

10. 🧮Genetic Crosses

    Practices predicting the outcomes of monohybrid and dihybrid crosses with Punnett squares, and non-Mendelian inheritance: incomplete dominance, codominance, sex-linked traits and multiple alleles.

11. 🦴Evidence & Mechanisms of Evolution

    Practices the evidence for common ancestry (the fossil record, biogeography, and anatomical, molecular and developmental homologies), explanations for different rates of change in the fossil record (gradualism, abrupt appearance, stasis), how natural selection can lead to speciation, and mechanisms other than selection: genetic drift, gene flow, mutation and recombination.

12. 🫀Systems in Animals & Plants

    Practices how animal systems interact for regulation (nervous and endocrine), nutrient absorption (digestive and circulatory), reproduction and defense (immune and skin), and how plant structures carry out transport (xylem and phloem), reproduction (flowers, pollination) and response (tropisms).

13. 🦌Ecosystem Stability

    Practices how predation, parasitism, commensalism, mutualism and competition affect ecosystem stability, energy flow through trophic levels, carrying capacity, and how human activity and disturbances change biodiversity, with Texas examples such as Gulf Coast wetlands and invasive species.

14. ♻️Carbon & Nitrogen Cycles

    Practices the steps of the carbon cycle (photosynthesis, respiration, decomposition, combustion) and the nitrogen cycle (fixation, nitrification, assimilation, denitrification), why they matter to ecosystem stability, and the consequences of disrupting them, such as fertilizer runoff and burning fossil fuels.