Cell Structures and Functions

Cell Types and Structures

• Prokaryotes are unicellular organisms lacking a nucleus or membrane-bound organelles
• Eukaryotes are multicellular organisms containing a nucleus and membrane-bound organelles
• Cells are composed of organelles that assist with various functions
• Organelles present in all cells include a plasma membrane, cytoplasm, vacuoles, and ribosomes

Organelles and Their Functions

• The nucleus stores DNA in eukaryotic cells
• Mitochondria generates chemical energy in the form of ATP (adenosine triphosphate) for biochemical reactions
• The Golgi body receives proteins, lipids, and other molecules from the endoplasmic reticulum, separates, modifies, and packages them into vesicles
• Chloroplasts are organelles found primarily in plants and facilitate photosynthesis

Cell Division

• Mitosis is a nuclear division process that results in two identical daughter cells, requiring DNA doubling
• Meiosis is a process that produces haploid cells (gametes) from diploid cells for sexual reproduction

Cellular Processes

• Cellular respiration converts chemical energy from food and nutrients into ATP
• Photosynthesis converts carbon dioxide, water, and light energy into glucose and oxygen, occurring in two stages: the Calvin Cycle and Light Dependent Reactions
• In the Calvin cycle, carbon dioxide is fixed to ribulose bisphosphate (RuBP) to form glyceraldehyde 3-phosphate, utilizing ATP and NADPH from light reactions

Bacteria and Antibiotics

• Bacteria are single-celled organisms reproducing via binary fission
• Common bacteria strains encompass Escherichia coli (E. Coli), Salmonella, and Staphylococcus aureus
• E. Coli is a rod-shaped gut bacteria from the Escherichia genus
• Antibiotics combat bacteria, but antibiotic resistance leads to "superbugs"
• Penicillin, the first commercial antibiotic, was derived from mold and discovered by Alexander Fleming

Viruses and HIV

• Viruses are noncellular infectious particles with a protein capsid and genetic material (DNA or RNA), lacking metabolic processes
• HIV weakens the immune system, leading to AIDS, and infects helper T cells as a retrovirus

Disease prevention

• Vaccines help prevent viral diseases by injecting weakened virus forms to build immunity

Biomes

• Tundra is characterized by treeless plains, cold temperatures, and permafrost
• Deserts lack water and are found at specific latitudes with warm, dry air
• Tropical forests occur along the equator, receiving high rainfall and housing complex trees
• Taiga is found in the mountains of the Northern Hemisphere, receiving heavy snowfall and characterized by coniferous forests

Genetics and Heredity

• Genes are the functional units of heredity
• Gregor Mendel discovered trait inheritance mechanisms through experiments with pea plants
• DNA encodes genetic information and helps code structure and function
• DNA structure consists of nucleotides with a phosphate group, 5-carbon sugar (deoxyribose), and nitrogenous bases (adenine, thymine, guanine, cytosine), arranged in a double helix
• Amino acids are protein building blocks

Additional Molecules

• RNA is a molecule with a 6-carbon ribose sugar and nitrogenous bases (uracil, adenine, guanine, cytosine)
• Genetic mutations result in genetic disorders such as Down Syndrome (extra chromosome-21) and sickle cell anemia

Evolution

• Evolution is the change in heritable traits of species over generations
• Charles Darwin outlined evolution by natural selection in "On the Origin of Species" after observing finches in the Galapagos
• Natural selection favors species members with differential reproductive success based on phenotype, also known as "survival of the fittest"

Taxonomy

• Kingdom is the highest taxonomic rank
• Kingdoms are Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria
• Fungi are decomposers, like mushrooms
• Phylum is the classification after Kingdom
• Important phyla are chordata, porifera, cnidaria, nematoda, and arthropoda
• Non-vascular plants lack vascular tissue
• Vascular plants have vascular tissue
• Gymnosperms produce seeds not enclosed in a chamber
• Angiosperms produce flowers and fruit seeds
• Leaves are the site of photosynthesis
• Roots maximize water uptake
• Invertebrates lack a backbone
• Mollusks have a muscular foot, soft body, and a mantle that produces shell
• Arthropods have a segmented body, exoskeleton, and jointed appendages
• Cnidarians have radial symmetry and a cnidocyte

Anatomy

• The digestive system digests food
• The esophagus carries food to the stomach
• The stomach uses gastric juice to break down food
• Calories measure food energy
• The respiratory system uses lungs to breathe
• The nervous system controls thoughts, actions, and perceptions
• The central nervous system includes the brain and spinal cord
• Neurons compose the spinal cord and brain
• The cardiovascular system transports oxygen and nutrients
• The heart circulates blood
• Skin is the largest organ
• Livers produce bile, detoxify blood, and become inflamed in hepatitis
• Kidneys filter blood to produce urine
• Parasites benefit from hosts

Atomic Structure and Bonds

• Atoms comprise matter, containing protons, neutrons, and electrons
• Protons possess a positive charge and 1 amu mass, located in the nucleus
• Neutrons lack charge and possess 1 amu mass, located in the nucleus
• Electrons possess a negative charge, negligible mass, and reside in clouds outside the nucleus
• Elements in the periodic table list the atomic number of protons per atom
• Molecules consist of two or more elements chemically bonded
• Covalent bonds form through electron sharing
• Ionic bonds form through attraction of oppositely charged ions
• Hydrogen bonds are weak attractions between partially positive hydrogen and negative nitrogen, oxygen, or fluoride atoms

Chemical Elements

• Russian chemist Dmitri Mendeleev invented the periodic table to organize elements by atomic mass and chemical reactivity
• The modern table is organized by increasing atomic number, with rows named periods and columns named groups
• Elements in the same group share chemical properties.
• Hydrogen (H) with atomic number 1 is the lightest and most abundant element
• Helium (He) with atomic number 2 is a colorless, inert noble gas with a low boiling and melting point
• Oxygen (O) with atomic number 8 is essential for respiration, produced by photosynthesis. Water consists of two hydrogen atoms bonded to an oxygen atom
• Nitrogen (N) with atomic number 7 constitutes most of Earth’s atmosphere
• Mercury (Hg) with atomic number 80 is the sole metal that is a liquid at room temperature and it was used in thermometers

Additional Elements and Compounds

• Sulfur (S) with atomic number 16 commonly exists as the S8 (octasulfur) molecule. It makes sulfur dioxide (SO2), used for sterilizing fruit as well as hydrogen sulfide (H2S), utilized to mark dangerous gases
• Iron (Fe) with atomic number 26 is the primary component of steel
• Carbon (C) with atomic number 6 forms four covalent bonds, allowing for allotropes like diamond, graphite, and fullerenes. Carbon-14 is used to date artifacts
• Lithium (Li) with atomic number 3 is used in rechargeable batteries
• Uranium (U) with atomic number 92 has isotopes utilized to measure time
• Aluminum(Al) with atomic number 13 is the most abundant metal found in the lithosphere
• Calcium (Ca) with atomic number 20, is part of the alkaline earth metals
• Silicon (Si) with atomic number 14, has a wide array of industry applications
• Phosphorous (P) with atomic number 15 is a variety of allotropes, but commonly exists as Phosphate in rocks
• Water has components of two hydrogen and one oxygen molecules

Chemical and Physical States

• Carbon dioxide (CO2) is released by the burning of fossil fuels.
• Coal is a combustible, sedimentary black rock utilized as fuel
• Alloys contain more than one metal
• Solids possess a fixed volume and shape
• Liquids possess a fixed volume
• Gases lack a fixed volume and shape
• Plasma consists of ions and is abundant

Reaction Types

• Endothermic reactions have products with higher energy than the reactants which causes a positive change in enthalpy
• Exothermic reactions have reactants with higher energy than the products and causes a negative change in enthalpy
• In evaporation, liquid changes to a gas which causes an ice forming
• In melting, a solid changes to liquid
• Freezing converts a liquid to solid.
• Condensation converts a gas to a liquid

Chemical Conditions

• Boiling happens when the liquid equals the pressure being exerted on it
• Sublimation converts a solid to a gas
• Pressure equals the force on an oject per unit area
• Avogadro’s law states at a constant temperature and pressure, the volume is proportional
• Acids have a ph less than 7
• Bases have a ph greater than 7
• A catalyst lowers the activation energy
• Entropy is the disorder of a compound/molecule

Physics

• The first law of thermodynamics states that the change in internal energy equals the heat added minus the amount of work done
• The second law of thermodynamics states that the total entropy of a system will never decrease
• Silicates are common minerals silicon and oxygen
• Non-silicates are similar but no oxygen or silicon
• Crystals possess an organized structure
• The Mohs Hardness Scale measures the hardness of a mineral
• Rocks can either be igneous, sedimentary, or metamorphic
• Felsic is an igneous rock
• Obsidian is another felsic rock
• Mafic rock is usually rich in magnesium and iron

Geology Timescales

• Radiometric Dating helps date materials based on radioactive decay
• Carbon dating finds the age via using the decay of carbon-14
• Half life is how long an isotope is decayed by half of its original state
• The Precambrian Era was the starting formation of earth from planetesimals and other objects
• The Mesozoic Era consisted of dinosaurs and the breakup of the landmass Pangea
• The C-T Extinction killed 80% of animals
• The Holocene Epoch showcases the start of the human species

Geology

• Plate tectonics is a theory by Alfred Wegener explaining how continents drifted
• The Mid-ocean ridge is a mountain system in the sea floor
• Sea floor spreading reveals tectonic plates being split
• The lithosphere is the rocky layer with felsic rocks that can be cooled
• The Mantle is the layer above the core
• Earthquakes result from the sudden shaking of the collision of tectonic plates
• The focus indicates where an earthquake originates
• P waves travel the fastest
• S waves travel through solids but will be slower than P waves
• The shadow zone is where there are no P waves

Math and Science Quantities

• The Mercalli Intensity Scale measures he density of P waves, and ranges from 1 to 12
• The Richter scale measures the Earth’s magnitude from 1 through 9
• Clouds mass release water
• Ocean Currents are directed water flows across the ocean
• Glaciers are typically large moving masses of ice
• The Sun is at the center of the solar system
• Mercury is the smallest planet in our solar system
• Venus is the second closest planet to the Sun
• Mars is the planet with planet sized storms

Space

• Jupiter is the largest planet
• Asteroids are astronomical bodies that orbit the Sun
• Comets are icy orbiters named Halle-Bopp and Halley’s
• The speed of light is 300 million meters per second
• A supernova explodes
• The big bang is the theory of the universe expanding through a point
• The Apollo Program is a plan by NASA and astronauts to get to the moon

Measuring systems

• Levers are simple machines that rely on force over longer distances
• Pulleys lift objects but are simple machines
• Gravity is the weak force that pulls object down
• Electronegativity is the measure of an atoms ability to attract photons
• Mass can be measured in kilograms
• Voltage measures an electric potential difference

Laws of Physics

• Inertia measures the way a moving object can stay in motion
• Momentum is a product of mass and velocity
• Friction is a force that opposes motion
• Kinetic energy is the moving energy over two times the object

Other concepts

• Photons that measure visibile light
• Electrical resistance opposes electric force
• Electric circuits allow electricity to flow
• Density measures mass/volume and determines objects floating
• Circles are 2D and can be measured with Pi
• Standard Deviation measures the set of data
• Irrational number cannot be determined
• Perfect numbers sum of other primes
• calculus involves integration and derivatives

Historical Scientist

• Rene Descartes created a philosophy stating “I think therefore I am”
• Stephen Hawking was a physicist who was confined to a wheelchair
• Galileo supports heliocentrism
• Edwin Hubble names the 1990 telescope
• Thomas Edison had the lightbulb
• Alan Turing with AI
• Euclid is the father of geometry
• Schrödinger with his cat

Scientists

• Marie Curie with radioactivity
• Louie Pasture had a vaccine
• Einstein with equations