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Cell Chapter 2
| Term | Definition |
|---|---|
| reactions are always ocurring, we cannot exist without them; ex. homeostasis, making and breaking of energy | Why are we studying chemistry in a biology class? |
| anything that takes up space and has mass | matter |
| matter | what are organisms composed of? |
| atoms (not subatomic particles) | What are nature's building materials? |
| each specific type of atom; substance that cannot be broken down to other substance by chemical reactions | Chemical Element |
| elements | What makes up matter? |
| substance consisting of two or more elements in a fixed ratio; has emergent properties | compound |
| composed of molecules of one type of atom | Pure Elements |
| natural: atomic mass is not a whole number because it has isotopes; artificial: atomic mass is a whole number because no isotopes | What is the difference between naturally occurring elements and artificial elements? |
| high-speed particle accelerator | How are artificial elements made? |
| 118, 92 | How many elements are there on the periodic table and how many are naturally ocurring? |
| elements you cannot survive without; nitrogen, carbon, hydrogen, oxygen | Basic Elements of Life |
| must have 5.1% quantity; elements needed by an organism to live a healthy life and reproduce (calcium for bones, sodium proline for brain and nerves) | Essential Elements |
| 0.01% quantity; required in only minute quantities (iron, enzymes need zinc and cobalt) | Trace Elements |
| the smallest unit of matter that still retains the properties of any other element; neutral | atom |
| protons, electrons, and neutrons | subatomic particles |
| positively charged subatomic particle located in the nucleus | protons |
| negatively charged subatomic particle | electrons |
| subatomic particle with no electric charge located in the nucleus | neutrons |
| very simple model based on the solar system; nucleus is the sun, electrons are the orbiting planets | Niel Bohr's atomic model |
| equal | Ratio of protons to electrons in an atom |
| number of protons in an atom (not based on electrons because they move) | atomic number |
| number of protons plus the number of neutrons | mass number |
| the amount and arrangement of electrons determine the chemical characteristics of an element, as well as the volume of an atom | What do electrons determine for an atom? |
| path taken by an electron | orbit |
| the area around the nucleus where there is the highest probability of finding an electron; each orbital only contains 2 electrons | orbital |
| sharp (s) - sphere, principle (p) - dumbbell. diffuse (d) - , fundamental (f) - | What are the four types of orbitals and their shapes? |
| areas around the nucleus where you find electrons with certain potential to store energy (lowest energy potential electrons ware in the first shell, increases further from the nucleus) | energy shell |
| K(1), L(2), M(3), N(4) | What are the four energy shells? |
| 1s2, 2 electrons | What are the orbitals in the K shell? How many electrons in the K shell? |
| 2s2, 2p6, 8 electrons | What are the orbitals in the L shell? How many electrons in the L shell? |
| 3s2, 3p6, 3d10, 18 electrons | What are the orbitals in the M shell? How many electrons in the M shell? |
| 4s2, 4p6, 4d10, 4f14, 32 electrons | What are the orbitals in the N shell? How many electrons in the N shell? |
| 1s2, 2s2, 2p3, 3 electrons | What is the orbital configuration of nitrogen? How many electrons does it need to fulfill the octet rule? |
| the arrangement of its electrons | How can you determine the reactivity of an atom? |
| Your weight may change as your gravity strength changes on different planets (earth, moon, neutron star), but your mass never changes | Describe the difference between mass and weight. |
| measure of the force of gravity on any substance | Weight |
| the mass of the neutrons and protons; atom's total mass that can be approximated by the mass number | atomic mass |
| universally accepted method to indicate an atom's mass relative to another atom's mass; ex. atomic mass of hydrogen is 1/12th of carbon | atomic mass scale |
| want a 1% sodium chloride solution; i just fill up a container with 99% water and 1% sodium chloride by weight | Example of determining weight |
| forms of an element with the same atomic number and different masses (different number of neutrons); chemical properties of isotopes are identical but physical properties change; unstable | isotopes |
| isotopes that decay spontaneously, release energy in the form of radioactive energy and particles; ex. Carbon-12 is stable but Carbon-13 and -14 will release radioactive energy to try to break down into element with smaller atomic number | radioactive isotopes |
| time taken for 1/2 of a compound to break down; ex. C-14's is 5730 years (carbon-dating) | Half-Life |
| helpful: radiation therapy, medical applications; harmful: UV radiation on DNA, radiation targets DNA and phospholipids | Applications of Radioactivity |
| capacity to do work/ability to make change | energy |
| kinetic, chemical, heat, light | examples of energy |
| They all produce heat and can be converted to heat | What do all sources of energy have in common? |
| energy that matter has because of its location and structure; changes in potential energy occur in steps of fixed amounts | potential energy |
| distance from nucleus | What is the potential energy of electrons based on? |
| average distance from nucleus | What does an electron's energy level correlate too |
| increase | Do the energy levels of energy shells increase or decrease with distance from nucleus? |
| periodic table | Where can you find the electron distribution of each element? |
| moving pockets of light with unique packets of energy | photon |
| It absorbs it, excites from ground state until potential energy is reached, unstable so it releases photons to return to ground state from excited state | What happens when a photon hits an electron? |
| Dimitri Mendelev | Who created the periodic table? |
| originally by atomic mass, now by atomic number | How has the periodic table been organized? |
| same number of valence electrons, identical chemical characteristics | Groups/Columns in periodic table |
| gradual increase in electrons and change in chemical properties | Period/Rows in periodic table |
| chemical behavior of an atom depends mostly on the number of electrons in the valence shell; capacity of elements to react or become non-reactive | octet rule |
| outermost shell | valence shell |
| electrons in the outermost shell | valence electrons |
| All elements with 8 valence electrons (except hydrogen and helium) | Which elements are non-reactive or inert? |
| presence of one or more unpaired electrons in the valence shell | How does reactivity arise? |
| atoms with incomplete valence shells can share or transfer their valence electrons with certain other atoms | What leads to attractions called chemical bonds? |
| force that brings atoms together | bond |
| a measure of the capacity of an atom to attract bonded (shared) electrons; move towards the right of the periodic table and it increases; does not equal polarity, unequal electronegativity leads to polarity | electronegativity |
| the sharing of a pair of valence electrons by two atoms; the shared electrons count as part of each atom's valence shell; very strong bond | covalent bond |
| equal sharing of electrons between atoms (C-H, H-H) | non-polar covalent bond |
| formed because of atoms of unequal electronegativity sharing electrons unequally causing a partial charge separation in the compound (partial +ive and -ive) | polar covalent bond |
| tetrahedral shape, need a bond angle of 109.5 but partial charges apply a pressure that reduces it to 104.5; shape gives water all of its properties | water as a polar molecule |
| two or more atoms held together by covalent bonds | molecule |
| single bond is one pair of shared electrons represented by one line, double bond is two pairs of shared electrons represented by two lines | single bond and double bond in a structural formula |
| must supply energy | How can i break a covalent bond? |
| covalent compounds (equal sharing between nuclei of atoms is involved) | Which compounds store the most energy in their bonds? |
| weak forces of attraction which arise (originate) from the hydrogen of a polar compound to another charge compound or a polar compound | hydrogen bond |
| dotted line | structural formula of hydrogen bond |
| good because they break easily | hydrogen bonds between taste receptors and food |
| weak when there's only a few, stronger with more all together, but overall weaker than covalent | strength in numbers of hydrogen bonds |
| many hydrogen bonds hold the two nucleotide chains together; need a lot of energy to break but if they were covalent you'd need more | example of hydrogen bonds in DNA |
| they are like seagulls; if you put sodium chloride in water is pulled apart by hydrogen bonds | hydrogen bonds and solubility |
| umbrella term for intermolecular forces between two molecules that are present in close proximity to each other (Van der Waal's radius); a weak force of attraction compared to hydrogen bonds | Van der Waals interactions |
| Electrons may distribute asymmetrically in molecules or atoms because atoms are constantly moving; the resulting regions of positive or negative charge enable all atoms and molecules to stick to one another (positive region to negative region) | how are van der waals interactions formed? |
| london dispersion, dipole-dipole, induced-dipole | which forces are included under van der waals interactions? |
| gecko's two hairs and a wall surface; large number of van der waal forces breaking and reforming quickly | Example of strength of van der waals forces |
| force of attraction between cations and anions (never between nuclei) | ionic bonds |
| positively charged ion | cation |
| negatively charged ion | anion |
| Tom Holland walks through door, we switch focus to him; but if Zendaya then walked through the door, we would all forget him and go to her; Atoms look for which has a greater force of attraction (while covalent bonds do not move) | Tom Holland and Zendaya example for ionic bonds |
| T- only ions | T/F: no atoms are involved in ionic bonds |
| compounds formed by ionic bounds; found in nature as crystals | ionic compounds/salts |
| Atoms want to fill their octet so they will donate/accept electrons and become ions to become stable (Na donates its one valence electron to Cl which has seven valence electrons; Both ions fulfill their octets and this forms a bond between them) | How are ionic bonds created? |
| They are flexible and constantly changing shape; made of atoms held together by bonds that rotate around their axis bond angles between atoms; changing shape and reacting is necessary to sustain life | What allows molecules to react? |
| The function of the cell and how biological molecules recognize and respond to one another; molecules with similar shapes can have similar biological functions | What does molecular shape determine? |
| an adaptive mechanism the body does when it experiences stress; molecules with one atom that has one unpaired electron; this electron has the capacity to grab unpaired electrons of perfectly balanced compounds to generate new families of free radicals | Free Radicals |
| one dot that represents the unpaired electron | How are free radicals denoted? |
| producing superoxide anion as a free radical when exposed to radiation; targets one of the four nitrogenous bases guanine, is completely susceptible to them; it converts to octoguanine; undergoes point mutation and will fail to bond with adenine | What is a negative impact of free radicals? |
| Hydrogen peroxide sold in stores is not at a concentration harmful to humans but it kills infective agents in cuts and scrapes | What is a positive effect of free radicals? |
| Antioxidants! Darkly pigmented molecules in dark vegetables act as antioxidants; provide electron to the free radical without become free radicals themselves; antioxidants help prevent free radicals | How can you prevent free radicals? |
| DNA and phospholipids | What do free radicals target? |
| breaking old bonds and making new bonds | chemical reaction |
| starting molecules of chemical reactions | reactants |
| final molecules of chemical reactions | products |
| • Heat is necessary; allows reactants to move, break old bonds and form new ones | What is necessary for a chemical reaction? |
| you need enzymes to bind to substrates to increase the rate of reaction | What is necessary for chemical reactions in your stomach? |
| optimal | What must conditions be for a reaction to occur? |
| when forward and reverse rates of reaction are equal | equilibrium |
| products of forward react become reactants for the reverse reaction | Reversible reaction |
| No, they need an aqueous environment | Can chemical reactions occur without water? |
| water, water | all organisms are made of mostly ___ and live in an environment dominated by ___ |
| 60-70%, 95% | what percent of human cells are water? what percent of plant cells are water? |
| capacity to exist in 3 states of matter: most stable in liquid, high temp in vapor, cold temp in ice | most essential aspect of water |
| polarity | What property of water allows it to exist with all of its characteristics? |
| Cohesion/adhesion, high specific heat, high heat of vaporization, lower density of ice, colligative properties, surface tension, solubility, hydrophobic exclusion | What are the eight properties of water? |
| hydrogen bonds cause water molecules to be attracted to other polar or charged species | cohesion/adhesion |
| capacity of water to attract itself (little energy); ex. capillary action: leaves pull water upward from the roots with little energy because water sticks to xylem cells which are mostly water | cohesion |
| capacity of water to react with other compounds (much energy); every part of the body contains water; ex. water covering your hand when you wash them | adhesion |
| amount of energy required to increase the temperature of 1 gram of a substance to 1 degree (not calorie, which is 1 gram of water); Hydrogen bonds absorb heat when they break and release heat when they form, minimizing temperature changes (homeostasis) | high specific heat |
| amount of energy needed to convert one mole of a liquid to gas at equal pressure; running and lots of H bonds are broken, water evaporates, then vapor meets atmospheric pressure/temp and it condenses into sweat to cool body | high heat of vaporization |
| High specific heat and high heat of vaporization | what are two properties of water that help the body maintain homeostasis? |
| when a compound releases energy at a freezing temp forming fewer H bonds with fewer H2O molecules resulting in the formation of less dense ice; preserves aquatic life in winter | lower density of ice: molar heat of solidification |
| capacity of water to absorb energy and convert from solid to liquid form (ice cannot stay ice for long; ice melting in cup with water) | high heat of fusion |
| capacity of a compound to stretch its physical properties such as freezing/boiling point so that life can sustain; ex. insects in volcano/ice secrete compounds whose concentrations stretch boiling/freezing point; antifreeze stretches freezing point | colligative properties |
| property of water caused by cohesion; surface of H2O is concave because of immense cohesive forces between H2O molecules; form a space which allows gasses to mix/reactions to occur (trachea isn't blocked, spider can walk on water) | surface tension |
| water can easily dissolve hydrophilic compounds (charged/polar) but cannot dissolve hydrophobic compounds (non-polar/lipids); when drink non-polar substances (alcohol) need water to solublize the -philic compounds the liver breaks them down into | solubility: water as an (almost universal solvent) |
| any substance that can be mixes or dissolved in a liquid medium | solute |
| any liquid medium that is used to react or dissolve or react with a substance | solvent |
| NaCl + H2O, sugar + H2O, salt + H2O (all of these solutes are hydrophilic) | Examples of solutes and solvents |
| water fearing, ex. oil in water, phospholipid layer | hydrophobic exclusion |
| substance with an affinity for water | hydrophilic |
| substance that does not have an affinity for water | hydrophobic |
| hydrophilic and hydrophobic components within it; ex. phospholipid layer (philic head, phobic tails); soap (philic acid, phobic oil) | amphoteric |
| sum of all masses of all atoms in a molecule; 1 mole of a substance is the amount of the substance in grams equal to its molecular mass (NaCl = 58.44 g/L = 1M of solution) | molecular/atomic mass |
| number of particles in one mole; 6.02x10^23 | Avogadro's number |
| avogadro's number | 1 mole |
| 6.02 x 10^23 = 1 gram | avogadro's number and the unit dalton |
| gold! but they have the same amount of particles | Is one mole of gold or one mole of feathers heavier? |
| number of moles of solute per liter of solution (water) | molarity (M) |
| split into equal concentrations of H+ and OH- ions | pure water can ionize |
| -log(H+); the negative logarithm of hydrogen ion concentration to the base 10; the more H+, the more acidic, the lower the pH | pH |
| pH 8 has 10 fold more H+ than pH 9 | which has more H+ ions: pH 8 or pH 9? |
| increases the hydrogen concentration in a solution (pH 6 and lower) | acid |
| can completely ionize in water | strong acid |
| 1M HS | Which is a stronger acid: 1M HS or 0.1 M HF? |
| can partially ionize in water | weak acid |
| pH = 7; equal concentration of H+ and OH- ions | neutral solution |
| increase the concentration of OH- ions (pH 8 and higher) | bases (alkaline |
| NaOH splitting into Na+ and OH-; ammonia reacting with hydrogen to increase OH- concentration | What are two examples of bases increasing the OH- concentration |
| help keep a constant pH; carbonic acid in blood breaks down into bicarbonate and H+ ions if blood is too acidic, but CO2 and H2O if conditions are normal | buffers |
| reversible reactions | many buffers are capable of... |
Created by:
MBarfield