Introduction to Science Fundamentals

Exam Format

• The exam is digital, administered via Respondus Lockdown Browser on Canvas.
• It consists of 35 questions, including MCQs, matching, short answer, and short essay/free response types.
• The exam is worth 70 points in total.
• One handwritten index card is allowed as a resource, to be submitted after the exam.

What is Science?

• Abiotic refers to non-living factors, while biotic refers to living factors in an ecosystem.
• Living things share characteristics like reproduction, response to stimuli, adaptation, growth, order/organization, energy utilization, and homeostasis.
• Homeostasis is the maintenance of a stable internal environment, for example, body temperature regulation.
• A scientific hypothesis is a testable explanation for an observed phenomenon, while a prediction is a specific outcome expected if the hypothesis is supported.
• The independent variable (IV) is the factor manipulated by the researcher, while the dependent variable (DV) is the factor being measured.
• Controlled variables are factors kept constant during an experiment.
• An experimental group is exposed to the independent variable, while the control group does not receive the treatment.
• Quantitative data involves numerical measurements, while qualitative data involves descriptive observations.
• Quantitative data is preferred to collect in biological studies when possible due to ease of statistical analysis.
• Claim-Evidence-Reasoning (CER) is a framework for analyzing data and drawing conclusions

Ecology

• The levels of ecological organization are connected, with each level building upon the previous one (individual, population, community, ecosystem, biome, biosphere).
• Abiotic factors are non-living components, while biotic factors are living components of an ecosystem.
• Abiotic factors influence living things by affecting their growth, distribution, and survival.
• The four ecological spheres are the atmosphere (air), lithosphere (land), hydrosphere (water), and biosphere (living organisms).
• Climate is long-term weather patterns, while weather is short-term atmospheric conditions.
• Climate data is most helpful when studying trends in global warming.
• Weather data includes temperature, precipitation, wind speed, and humidity.
• Climate data includes average temperature, precipitation patterns, and frequency of extreme weather events.
• The greenhouse effect is the trapping of heat in the Earth's atmosphere by greenhouse gases, which is a good thing because it maintains a habitable temperature on earth
• Human activities, such as burning fossil fuels, are increasing the concentration of greenhouse gases, leading to global warming.
• Natural climate change patterns include annual seasons and ice ages.
• Scientists collect data on temperature, ice core samples, sea levels, and carbon dioxide levels to understand climate change.
• Human activities like deforestation, burning fossil fuels, and industrial processes contribute to accelerated climate change.
• Albedo is the measure of how much light that hits a surface is reflected without being absorbed.
• Decreased albedo contributes to accelerated climate change.
• Darker surfaces have lower albedo and absorb more heat, while lighter surfaces have higher albedo and reflect more heat.
• The melting of glaciers decreases the Earth's albedo because ice reflects more sunlight than water or land.
• Energy moves through ecosystems via food chains, with producers capturing energy and consumers obtaining energy by eating other organisms.
• Producers (autotrophs) create their own food (e.g., plants), consumers (heterotrophs) obtain energy by consuming other organisms (e.g., animals), and decomposers/detritivores break down dead organic matter (e.g., fungi, bacteria).
• The ultimate source of energy in nearly all ecosystems is the sun.
• Autotrophs are organisms that produce their own food, while heterotrophs obtain food from other organisms.
• Carnivores eat meat, herbivores eat plants, omnivores eat both meat and plants, and decomposers break down dead organic matter.
• Arrows in a food web represent the flow of energy, pointing from the organism being eaten to the organism that is eating it.
• Approximately 10% of energy is passed from one trophic level to the next in a food chain.

Reproductive Anatomy

• The testes produce sperm in the male reproductive system.
• Puberty is a period of physical and hormonal changes leading to reproductive maturity.
• The female reproductive system includes the ovaries, which produce eggs, and the uterus, which supports fetal development.
• Menstrual cycles involve the monthly maturation and release of an egg, along with changes in the uterine lining.

Biochemistry

• Atoms consist of protons, neutrons, and electrons.
• The atomic number indicates the number of protons in an atom.
• The number of neutrons can be determined by subtracting the atomic number from the mass number.
• The first electron shell holds up to 2 electrons, and the second and third shells hold up to 8 electrons each.
• The valence shell is the outermost electron shell and is important for chemical bonding.
• The three types of chemical bonds are ionic, covalent, and hydrogen bonds.
• Covalent bonds share electrons, ionic bonds involve the transfer of electrons, and hydrogen bonds are weak attractions between polar molecules.
• In Biology, covalent bonds are the strongest, and hydrogen bonds are the weakest.
• Atoms become ions when they gain or lose electrons.
• Electronegativity is the ability of an atom to attract electrons in a chemical bond.
• Polar molecules have an uneven distribution of charge, such as water.
• Water Properties:
  • Cohesion is the attraction between water molecules.
  • Adhesion is the attraction between water molecules and other substances.
  • High specific heat is the ability to absorb a lot of heat without changing temperature.
  • Versatile solvent is the ability to dissolve many substances.
• A monomer is a small building block molecule, while a polymer is a large molecule made of repeating monomer units.
• Dehydration reactions link monomers together to form polymers by removing water.
• Hydrolysis breaks polymers down into individual monomers by adding water.
• Carbohydrates contain carbon, hydrogen, and oxygen.
• Lipids contain carbon, hydrogen, and oxygen.
• Proteins contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
• Nucleic acids contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.
• The monomer of carbohydrates is monosaccharides (e.g., glucose). example polymers are starch, glycogen, and cellulose.
• The monomers of lipids are glycerol and fatty acids, example polymers are triglycerides and phospholipids.
• The monomer of proteins are the amino acids, example polymers are polypeptides and proteins.
• The monomer of nucleic acids are nucleotides, example polymers are DNA and RNA.
• Saturated lipids have no double bonds and are solid at room temperature, while unsaturated lipids have one or more double bonds and are liquid at room temperature.
• A nucleotide consists of a sugar, a phosphate group, and a nitrogenous base, creating nucleic acids.
• An amino acid consists of an amino group, a carboxyl group, a hydrogen atom, and a variable R group.
• The 20 different naturally occurring amino acids differ in their R groups.
• Four Levels of Protein Structure:
  • Primary structure is the sequence of amino acids.
  • Secondary structure is the local folding patterns (alpha helix, beta sheet).
  • Tertiary structure is the overall 3D shape of a single polypeptide.
  • Quaternary structure is the arrangement of multiple polypeptide subunits.
• Carbohydrates provide energy and structural support.
• Lipids store energy, insulate, and form cell membranes.
• Proteins perform many functions, including enzymes, structural components, and transport.
• Nucleic acids store and transmit genetic information.
• Reactants are the starting materials in a chemical reaction, while products are the end results.
• Endergonic reactions require energy input, while exergonic reactions release energy.
• Activation energy is the energy required to start a chemical reaction.
• Enzymes are proteins that catalyze (speed up) chemical reactions by lowering activation energy.
• A substrate molecule is acted upon by an enzyme during a chemical reaction.
• The active site is the region of an enzyme where the substrate binds.
• Denaturation is the loss of a protein's native shape due to environmental factors, such as changes in temperature or pH.
• The Lock and Key Model is a specific substrate fitting into the specific active site.
• Enzymes have an optimal temperature range; if it gets too hot the shape will change and the enzyme will stop working.

Cell: Structure & Function, Cell Membrane, & Transport

• Magnification refers to enlarging the apparent size of an object, while resolution refers to the clarity of the image.

• Steps to Use a Microscope:

  • Start with the lowest power objective lens
  • Place the slide on the stage and secure it with the clips.
  • Use the coarse adjustment knob to bring the specimen into approximate focus.
  • Use the fine adjustment knob to sharpen the focus.
  • Adjust the light intensity with the diaphragm.
  • Increase magnification by switching to a higher power objective lens.

• A wet mount is a temporary slide preparation where the specimen is placed on a slide with a drop of liquid and covered with a coverslip.

• Prokaryotic cells (e.g., bacteria) lack a nucleus, while eukaryotic cells (e.g., plant and animal cells) have a nucleus.

• Plant cells have chloroplasts, a cell wall, and a large central vacuole, while animal cells do not.

• Cell type studied for any project should be noted.

• Key Organelles:

  • Nucleus stores DNA and controls cell activities.
  • Ribosomes synthesize proteins.
  • Endoplasmic reticulum (ER) synthesizes and transports proteins and lipids.
  • Golgi apparatus modifies, sorts, and packages proteins and lipids.
  • Mitochondria generate ATP (energy) through cellular respiration.
  • Lysosomes contain enzymes for breaking down waste materials.
  • Chloroplasts (in plant cells) perform photosynthesis.
  • Cell wall (in plant cells) provides support and protection.
  • Vacuoles store water, nutrients, and waste products.

• Phospholipids are unique from other lipids because they have a polar head and nonpolar tails.

• Cell membranes mainly consist of phospholipids and proteins.

• Proteins in cell membranes facilitate transport, act as receptors, and provide structural support.

• Cholesterol helps maintain membrane fluidity.

• Cell Membrane Structure:

  • A phospholipid bilayer with proteins embedded within.
  • Hydrophilic (polar) heads face outward, interacting with water.
  • Hydrophobic (nonpolar) tails face inward, avoiding water.

• The primary job of the cell membrane is to regulate the movement of substances in and out of the cell.

• Passive transport does not require energy input.

• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

• A concentration gradient is the difference in concentration of a substance across a space.

• Simple diffusion is the movement of molecules across the cell membrane without the help of transport proteins

• Facilitated diffusion is the movement of molecules across the cell membrane with the help of transport proteins.

• Small, nonpolar molecules (e.g., oxygen, carbon dioxide) cross the cell membrane via simple diffusion.

• Large, polar molecules (e.g., glucose, amino acids) cross the cell membrane via facilitated diffusion.

• Osmosis is the diffusion of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.

• Aquaporins are transport proteins used for osmosis.

• Hypertonic: higher solute concentration, hypotonic: lower solute concentration, isotonic: equal solute concentration.

• Water moves from hypotonic to hypertonic solutions.

Explore the fundamentals of science. Key topics include the characteristics of living things, the definition of homeostasis, and the difference between a hypothesis and a prediction. Also covered variable types in scientific experiments.