Introduction to Science

Introduction to Science

• Science is the way of learning about the natural world through observation, experimentation, and analysis to understand how it works.
• The scientific method has steps to follow in investigations
  • Make observations
  • Define a problem/question
  • Research background information
  • Formulate testable hypotheses
  • Design an experiment (including variables: controlled, independent, and dependent)
  • Test hypotheses/conduct investigation
  • Generate data (qualitative and quantitative)
  • Conduct numerous trials
  • Draw conclusions from results
  • Communicate findings to the community
  • Verification from peers
  • Establish models, laws, or theories
• Quantitative data are numerical values (e.g., height, weight).
• Qualitative data are descriptive observations (e.g., color, texture).
• Accuracy refers to closeness to the true value.
• Precision refers to consistency of measurements.
• Independent variable is the manipulated factor, cause.
• Dependent variable is the measured factor, effect.
• Control variable remains constant.

Qualitative & Quantitative Data

• Quantitative data is numerical, like measurements (height, weight).
• Qualitative data is descriptive, like characteristics (color, texture).

Accuracy and Precision

• Accuracy is how close a measurement is to the actual value.
• Precision is how consistent the measurements are.

Independent and Dependent Variables & Control Group

• Independent variable: Changed or manipulated variable.
• Dependent variable: Measured variable that changes due to the independent variable.
• Control group: Used for comparison; variable is not manipulated.

Graphs

• Bar graphs: Compare categories/groups.
• Line graphs: Show changes over time.
• Pie charts: Show proportions of a whole (percentages).

Metric System (SI Units)

• Length: Meter (m)
• Mass: Kilogram (kg)
• Volume: Liter (L)
• Temperature: Kelvin (K) or Celsius (°C)
• Time: Seconds (s)
• Energy: Joules (J)

Scientific Notation

• A way to write very large or small numbers using powers of 10.
  • a × 10ⁿ
    • a is a number between 1 and 10
    • n is an integer (positive or negative)

Biology

• The study of living organisms and how they work.

Macromolecules

• List and describe types of bonds found in water.
  • Covalent Bonds: Atoms share electrons to form water molecules.
  • Hydrogen Bonds: Weak bonds form between hydrogen of one water molecule and the oxygen of another, partially charged.
• Adhesion: Water molecules sticking to other surfaces (e.g., water climbing up a paper towel or plant stem)
• Cohesion: Water molecules sticking to other water molecules and creating surface tension(e.g., water forms drops)
• Specific Heat: The amount of heat needed to raise the temperature of 1 gram of water by 1°C (water has high specific heat).
• Heat of Vaporization: The amount of heat needed to turn 1 gram of water from liquid to gas.

Enzymes

• Enzymes are proteins that speed up chemical reactions by lowering activation energy.
• Activation energy is the energy needed to start a chemical reaction.
• Denaturing is when an enzyme loses its shape and stops working.
• Factors that affect enzymes include temperature, pH, substrate concentration, and inhibitors.
• ATP releases energy by hydrolysis, where one phosphate group is released (ATP  ADP+Pi)
• Dehydration synthesis makes ATP from ADP +Pi.

Origin of Life

• Chemical evolution: Abiotic synthesis of organic molecules in early Earth's conditions
• Abiogenesis: Formation of life from non-living matter
• Biogenesis: Life comes from pre-existing life

Cells

• Light microscopes: inexpensive, view live cells
• Electron microscopes: high resolution, but cannot view live cells
• Dissecting microscopes: study larger objects in 3D.
• Cell theory: all living things are made of cells, cells are the basic unit of structure and function in life, all cells come from pre-existing cells
• Prokaryotic cells (Bacteria and Archea): lack a nucleus, membrane-bound organelles
• Eukaryotic cells (Plants, animals, fungi, protists): contain a nucleus and membrane-bound organelles.

Differences between Plant and Animal Cells

• Features of plant cells: Rigid cell wall, chloroplasts, large central vacuole, usually have less centrioles
• Features of animal cells: Flexible cell membrane, lack chloroplasts and large central vacuole, usually have centrioles.

The Cell: Organelles

• Nucleus: Control center, holds DNA, surrounded by nuclear envelope, has nucleolus
• Endoplasmic reticulum (rough and smooth): Protein synthesis/processing (rough), lipids (smooth)
• Ribosomes: Protein synthesis
• Mitochondria: Powerhouses of the cell, ATP production
• Chloroplast: Site of photosynthesis in plants
• Golgi apparatus: Packages and ships proteins/lipids
• Lysosomes: Break down waste.
• Vacuoles and vesicles: Storage sacs for water, nutrients, and waste in the cell

Cell Wall

• The rigid outer layer of plant cells, fungi, and bacteria. Provides support.

Cell Transport

• Passive transport: substances move from high to low concentration (no energy required); Diffusion (simple, facilitated), osmosis, ion channels.
• Active transport: substances move against the concentration gradient (energy required); Active transport, endocytosis, exocytosis.

Cellular Respiration

• The process of breaking down glucose to produce ATP.
• Steps: Glycolysis, Pyruvate oxidation, Krebs cycle, electron transport chain.

Photosynthesis

• Capturing light energy to convert carbon dioxide and water into glucose.
• Steps: Light dependent reactions, Calvin cycle.

Mitosis

• Cell division for growth and repair (somatic cells).
• Phases: Prophase, metaphase, anaphase, telophase, cytokinesis

Meiosis

• Cell division for sexual reproduction (gametes).
• Two rounds of division: Meiosis I, Meiosis II
• Result: 4 haploid cells.

Genetics

• Heredity: Transmission of traits from parents to offspring
• Allele: Different forms of a gene.
• Dominant allele: Trait is expressed even in presence of recessive allele
• Recessive allele: Trait is expressed only when two copies of the allele are present
• Homozygous: two same alleles
• Heterozygous: two different alleles

DNA

• DNA: Deoxyribonucleic acid, genetic material
• Genes: Segments of DNA that code for proteins
• Replication: Process of copying DNA, semi-conservative
• DNA structure: Double helix, A-T, C-G base pairs
• RNA: Ribonucleic acid, involved in protein synthesis
• Differences between DNA and RNA: Structure difference, different sugar, different nitrogen bases

Mutations

• Changes in DNA sequence that can lead to genetic variation.
• Germline mutations: inherited from parents
• Somatic mutations: not inherited

Other topics

• Incomplete dominance
• Codominance
• Polygenic Traits
• Multiple Alleles
• Sex-linked traits
• Epistasis
• Punnett Squares

Explore the fundamentals of science through the scientific method. This quiz covers crucial concepts including observations, hypothesis formulation, and the difference between qualitative and quantitative data. Test your understanding of how scientific investigations are designed and conducted.