midterm explanations

ecological hierarchy

• ecosystem: community + abiotic factors

• community: all different living species interacting with each other in the river but excluding non-living surroundings

• population: group of individuals of the same species living somewhere

• biosphere: global sum of all ecosystems; the entire zone of life on Earth

• population → community → ecosystem → biosphere (smallest to largest)

standard taxonomic hierarchy

• smallest to largest

• Dear King Philip Came Over For Good Soup

• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

independent variable

• the cause

• this variable changes or manipulates

dependent variables

• the effect

• factor being measured or observed to see how it responds to the independent variable

energy flow through an ecosystem

• almost all ecosystems get their initial energy from the sun in the form of light energy, captured by plants and other photosynthetic organisms

• as organisms. use this energy to live, grow and move, a lot is converted into mechanical energy and metabolic processes

  • significant amount is lost to the environment as heat energy

• energy flows one way and must be constantly replenished

• nutrients are continously recycled within an ecosystem

atomic number

• number of protons in the nucleus of an atomc

atomic mass

• atomic mass = protons + neutrons

• measured in Daltons (Da)

valence electrons

• 1st and innermost shell: 2 electrons

• 2nd shell: 8 electrons

• 3rd shell: 18 electrons

bonding capacity

• bonding capacity = shell - valence electrons

• number of covalent bonds it can form to achieve stability

hydrogen bonds + surface tension

• property of the surface of a liquid that allows it to resist an external force

• happens in water because of cohesion

• hydrogen bond: H₂O is polar molecule and causes neighbouring water molecules to attract one another, forming weak electrical attachments

• at the surface: creates tight, compressed skin of molecules at the surface, giving water its exceptionally high surface tension

Big Six

• CHNOPS

• Carbon, Hydrogen, Nitrogen, Oxygen, Potassium, Sulfur

• make up over 97% of the mass of the living organisms

serine functional groups

• hydroxyl group: (-OH)

• amino group: left side of central carbon (-NH₂)

• carboxyl group: right side of the central carbon (-COOH)

• methyl group: (-CH₃)

amino acid polarity

• if it ends -OH, -NH₂, or O, it’s polar, or charged

  • these heteroatoms are electronegative powerhouses that create dipoles and love interacting with water

• if it consists only of carbons and hydrogens (-CH₂,-CH₃), it’s non-polar

  • hydrocarbons share electrons equally, meaning they’re hydrophobic

• serine is a polar, uncharged amino acid because -OH

amino acid and position

• polarity at the absolute tip, it will always face outward toward the aqueous cellular solvent or reach out to bind with other molecules

  • functions as an environmental sensor

• polarity close to the central carbon, it spends its time forming tight, local hydrogen bonds to fold and stabilize the protein’s internal backbone architecture

  • movement is restricted

unsaturated fatty acids

• unsaturated hydrocarbon chain contains fewer than the max possible number of hydrogen atoms

  • one or more pairs of carbon atoms share a double bond

• these double bonds introduce a rigid kink or bend into the fatty acid chain

• only generally saturated fats are solid at room temp and unsaturated fats are liquid

glycogen

• large, highly branched polysaccharide that animals use to store glucose

• animal equivalent of starch

• found in animals, mostly stored in the liver and skeletal muscle tissue

source of starch

• plant-based foods

• they store their excess glucose in the form of startch

  • and build their cell walls out of cellulose

prokaryotes cells

• don’t have a membrane-bound nucleus to house their DNA

• genetic material is loosely coiled up in a specific, open region of the cytoplasm called nucleoid

eukaryotic cells

• plants and animal cells

• larger and more complex compared to prokaryotes

• still share several basic cellular features with prokaryotes

• both cells need: ribosome, plasma membrane and cytosol

endomembrane system

• coordinated network of internal

electron transport chain in the cellular respiration

• at the end of the electron transport chain, the electrons have dropped down their energy gradient and must be removed so the chain doesn’t get backed up

• water: product of the final step

• glucose: original electron source at the beginning

• ETC complex 4: final protein complex in the chain passing the electrons off to oxygen

• ATP synthase: enzyme channel that uses the proton gradient to manufacture and doesn’t transport or accept electrons from the chain

cellular respiration

• the cell breaks down glucose and harvests high-energy electrons using two specific coenzymes as molecular shuttles

• NAD+/NADH: primary electron shuttle used throughout glycolysis, pyruvate oxidation and the critic acid cycle

  • NAD+ picks up two electrons and one hydrogen ion, it’s reduced to ADH

• FAD/FADH₂: shuttle used during the citric acid cycle

  • FAD picks up two electrons and two protons, it’s reduced to FADH₂

• they travel to the inner mitochondrial membrane to drop their electrons off at the electron transport chain

photorespiration

• wasteful metabolic pathway that occurs when the enzyme Rubisco accidentally binds to O₂ instead of CO₂

  • the plant destroys stored carbon and wastes energy to clean byproduct, reducing photorespiration and standard mesophyll cells

• decreased yield: C3 plants

  • have no specialized mechanism to prevent photorespiration

  • they close their stomata to save water on hot days, so oxygen gas builds instead the lead while CO₂ runs out.

    • reduces potential photosynthetic yield by up to 25% or more