BIO 1090 -- Unit 1

6. Composed of 1 or more cells

- A cell is the smallest unit of an organism that can be considered alive

Emergent Property

"whole is greater than the sum of its parts" (bicycle parts vs. bicycle)

Aqueous Solutions

- A solution is a liquid consisting of a uniform mixture of two or more substances - The dissolving agent is the solvent - the substance that is dissolved is the solute - When solvent is water = aqueous solution

Water -- the universal solvent

- A versatile solvent that is fundamental to life processes - Its versatility results from its polarity - Table salt is an example of a solute that will go into solution in water (oil does not) - Na and Cl ions are attracted to each other because of their charges

Cytoskeleton

- A web of protein strands within cells - Provides the cell with structure, facilitates the movement of materials inside the cell, facilitates cell movement

1. Assimilate energy

- All organisms must take in energy and materials to grow, develop and reproduce - The chemical reaction through which organisms builds up or breaks down materials is called metabolism

4. Reproduce

- All organisms produce new organisms - Most plants and animals engage in sexual reproduction = cells from two different parents unite to form the first cell of the new organism - Other organism reproduce using asexual reproduction = a single parent produces offspring that are identical to itself

Electron arrangement

- An atom may have 1-3 electron shells - The number of electrons in the outermost shell determines chemical properties - 1st shell full = 2 electrons - 2nd shell full = 8 electrons - 3rd shell full = 8 electrons

Matter

- Anything made of atoms of different elements - Has mass and occupies space - 3 phases: solid, liquid, gas

Ionic and Covalent Bonding

- Attractions between atoms is called chemical bonds - Valence electrons help form ionic and covalent bonds - Atoms will follow the octet rule in ionic/covalent bonding - Octet rule states that atoms prefer to have 8 electrons in the outer/valence shell (except for hydrogen, which prefers to have 2 electrons in outer shell) - Achieving this stable condition may involve gaining, losing, or sharing electrons

7. Evolved from other living things

- Basic traits organisms develop usually do not change but over many generations, they typically evolve/change

Water moderates temperature

- Because of hydrogen bonding, water had a greater ability to resist temperature change than other liquids - Heat must be absorbed to break hydrogen bonds; heat is released when hydrogen bonds form

Lysosomes (recycling center)

- Break down worn-out cellular structures or foreign materials that come into the cell - Contain digestive enzymes

Atoms

- Building blocks of matter - If you want to create matter you will need atoms of different elements - Made up of 3 subatomic particles: protons, neutrons, electrons

Protein makeup

- Building blocks of proteins are amino acids (monomers) - Chain of amino acids = polypeptide - A lg. folded chain of amino acids = protein - 20 diff. amino acids - Proteins can be made of 100's to 1000's of amino acids linked together

Chemical Reactions

- Can rearrange matter but cannot create or destroy matter - Reactants are transformed into products through chemical reactions

Electrons and Reactivity

- Compounds are held together with bonds using electrons - Electrons able to form bonds are the outer electrons (called valence electrons) - Valence electrons help form ionic and covalent bonds

Carbohydrates - Useful for a fast source of energy - Contains C, H, O and have a ring-like structure

- Contain C, H, O - Main source of cellular energy - Plants, animals -- structural purposes - Building blocks -- monosaccharides (monomers of carbs) --> glucose, fructose, galactose - Bread, pasta

Nucleus

- Control center - Surrounded by an envelope and containing DNA, directs the activities of the cell. - Surrounded by a double membrane -- nuclear envelope - DNA in nucleus contains the instructions for making proteins

Atomic number

- Corresponds to the number of protons (top number)

Atomic mass/ Atomic weight

- Corresponds to the number of protons + neutrons

Minerals

- Definite chemical composition - Inorganic compounds - Examples: gold, silver, etc. - Help in bone and tooth formation, blood coagulation, and muscle contraction - Only some are required by body for nutrition

Simple Carbs

- Disachharides (two units) - Sucrose = glucose + fructose - Maltose = glucose x 2 - Lactose = glucose + galactose

Trace elements

- Elements required in miniscule amounts - Some are required to prevent disease - Example: iodine (an iodine deficiency prevents production of thyroid hormones, resulting in goiter and hypothyroidism)

8. Living things grow and develop

- Every organism has a particular pattern of growth and development - During development, a single fertilized egg divided again and again. As these cells divide, the cells begin to look different from one another and perform different functions = differentiation

Lipids - Long term energy storage - Make up cell membranes - Important for insulation - Contain long FA chains

- Fats - Containing C, H, O - Do not easily dissolve in H2O (insoluble) - Function: energy storage, insulation, hormones, lining of all cells, cushioning - Fats, oils, cholesterol, steroids -- testosterone, estrogen - Make up cell membranes - Butter, oil, and cholesterol

Hydrogen Bonds

- Form due to the attraction between a hydrogen atom on one water molecule and the oxygen atom on another - Weak but important

The Cell Wall

- Gives the plant structural strength - Made of cellulose - Animals do not have a cell wall

Water's Life-Supporting Properties

- H2O composes 71% of Earth's surface and 66% of the weight of the human body - Life first evolved in water - All living organisms require water - The chem. reactions of your body occur in cells consisting of 70-95% water - Water is a polar covalent molecule (the negative pole is near the O atom and the positive pole is between the H atoms)

Protein function: - Structural proteins - Storage proteins - Contractile proteins (movement) - Transport proteins - Enzyme proteins (help chemical reactions)

- Hair and nails (collagen and keratin) - Blood (hemoglobin protein carries oxygen) - Muscles (actin/myosin enable movement) - Cellular messengers (receptor proteins transmit signals) - Antibodies (proteins that help defend body) - Brain and nerves (brain signaling) - Enzymes (help digest food) - Cellular construction workers (copying genes, making new proteins)

Proteins - Have involvement in the immune system (antibodies) - Enzymes (speed up chem. reactions) - Large role in muscle development

- Huge range of functions - Most diverse of the macromolecules - Contain C, H, O, N - Meats, beans

Cohesion

- Hydrogen bonding causes H2O molecules to stick together (called cohesion) - It is much stronger for water than other liquids - Water's ability to stick to itself

5. Possess info base that allows for functioning

- Info base encoded in DNA - All organisms store the complex information they need to live, grow and produce in a genetic code written in a DNA molecule

Ionic Bonds

- Involve the transfer of one or more electrons from one atom to another - When two oppositely charged ions attract and the ions are held together it is called an ionic bond - Combine to form new properties (i.e Na+ and Cl- = table salt)

Eukaryotic cells

- Larger, complex cells - Membrane-bound organelles - Unicellular or multicellular - HAVE nucleus - Humans are eukaryotic Example: archaea (extremophiles), animals, body cells, plants, protists, fungi

Ice

- Less dense than liquid water -- take up less space per vol - Density -- mass per unit volume - In ice, molecules are spread further apart then in liquid form

Cells

- Life's fundamental unit - Two categories: prokaryotic and eukaryotic

Nucleic Acids - Includes genetic material

- Macromolecules that: - store info - provide the directions for building proteins - include DNA and RNA - contains C, H, O, N, P

3. Regulation

- Maintaining a relatively constant internal environment - Although conditions outside an organism may change dramatically, most organisms need to keep conditions inside their bodies as constant as possible (called homeostasis)

Ribosomes

- Manufacture proteins (works w/mRNA to synthesize proteins) - Can be found in cytosol/cytoplasm or outside of the ER or nuclear envelope

Electrons

- Negatively charged - Orbit nucleus at high speeds - Have little mass - Number of electrons determines an atom's ion state and chemical reactivity - ONLY electrons are involved in chemical activity - Electrons occur in energy levels called electron shells - Number of protons = number of electrons

Neutrons

- No charge - Located in nucleus - Number of neutrons determines the isotope

2. Respond to environment

- Organisms detect and respond to stimuli from their environment. A stimulus is a signal to which an organisms responds

Protons

- Positively charged - Located in nucleus - The number of protons determines the chemical element - Number of protons = number of electrons

Mitochondria

- Powerhouse of the cell - Makes ATP

Elements

- Pure substance that consists entirely of one type of atom - Listed in order of atomic number

Protein shape

- Shape determines function - A polypeptide chain contains hundreds or thousands of AA linked by pep bonds - The AA sequences causes the polypeptide to assume a particular shape

Prokaryotic cells

- Small, simple cells - No organelles - Unicellular - NO nucleus - Example: bacteria - Have pili

Specific Heat Capacity

- The amount of heat energy required to raise temp of 1 gram of a material by 1 degree C. - Water can take a lot of heat without changing temperature (has high specific heat) - The lg. amount of water on our planet means that our temperatures are fairly stable (i.e deserts are not like this)

Isotopes

- Variants of an element that differs in their number of neutrons - Less stable and may decay over time, emitting radiation - Example: carbon 12, 13, 14 (all have 6 protons but diff # of neutrons)

Adhesion

- When bonds can form between water molecules and something else with an opposite charge - Water's ability to stick to other substances

Eukaryotes and Prokaryotes BOTH:

- contain genetic material (DNA) - contain cytoplasm - contain ribosomes - have cell membrane/plasma membrane

Vitamins

- organic compounds - release energy from food, develop red blood cells, help in blood clotting, maintaining skin, eye, hair. - Examples: A, B, C - All vitamins are required by human body for healthy nutrition

Endoplasmic Reticulum

-Manufacturing Center (proteins, lipids, carbs are made here) - Rough ER (has ribosomes) - Smooth ER (no ribosomes) --> site of lipid synthesis

HW Question 15

1. A(n) IONIC BOND forms when one atom gives up one or more electrons to another atom. 2. Atoms or molecules with a net electric charge due to the loss or gain of one or more electrons are IONS. 3. A(n) COVALENT bond involves the sharing of electron pairs between atoms, also known as a molecular bond. 4. When one pair of electrons is shared between two atoms, a SINGLE bond is formed. 5. When two pairs of electrons are shared between two atoms, a DOUBLE bond is formed. 6. A POLAR bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms. As a result, one end of the molecule has a slightly negative charge and the other a slightly positive charge. 7. Atoms involved in a NONPOLAR bond equally share electrons; there is no charge separation to the molecule. 8. A weak bond called a HYDROGEN bond results from an attraction between a slightly positive region in a molecule and a slightly negative region in the same or a different molecule.

Misfolded proteins are associated with:

1. Alzheimer's disease 2. Mad cow disease 3. Parkinson's disease 4. Sickle Cell Anemia

Characteristics of Living Things

1. Assimilate energy (eats) 2. Respond to environment 3. Regulation 4. Reproduction 5. Possess info base that allows for functioning 6. Composed of 1 or more cells 7. Evolved from other living things 8. Grow and develop

Order: smallest --> largest

1. Atom 2. Molecule 3. Cell 4. Tissue 5. Organ 6. Organ system 7. Organism 8. Population 9. Community 10. Ecosystem 11. Biosphere

HW Question 1

1. H2SO4, sulfuric acid, contains three different types of atoms: hydrogen (H), sulfur (S), and oxygen (O). Each of these atoms represents a different ELEMENT. Since the three types are combined in a fixed ratio, this means that H2SO4 is a(n) COMPOUND. 2. The scientific study of matter is called CHEMISTRY. 3. If two or more atoms are bonded together, they form a(n) MOLECULE. 4. Within a plant, water (H2O) and carbon dioxide (CO2) can be combined (using the energy of sunlight) to produce glucose (C6H12O6) and oxygen (O2). If you were to write out this chemical reaction, water and carbon dioxide are each an example of a(n) REACTANT while glucose and oxygen are each an example of a(n) PRODUCT. 5. The smallest unit of matter that retain all of the physical properties of that type of matter is a(n) ATOM. 6. MATTER is anything that occupies space and/or has any substance.

Eukaryotic cells -- life processes

1. Manufacturing 2. Regulation of materials into and out of the cell 3. Breakdown of molecules 4. Energy processing 5. Structural support, movement, communication

Homework Question: Can you trace the movement of proteins through the endomembrane system?

1. Manufacturing- Rough ER 2. Transport - Vesicle from ER 3. Processing - Golgi App. 4. Transport - Vesicle from Golgi 5. Secretion - Plasma membrane

Q. What four elements make up the bulk of living cells?

1. Oxygen 2. Carbon 3. Hydrogen 4. Nitrogen

Levels of protein folding patterns:

1. Primary: sequence of a chain of AA (linear) 2. Secondary: sequence of AA are linked by hydrogen bonds (beta pleated, alpha helix, random coil) 3. Tertiary: shapes and loops contribute to 3D shape (R groups determine this) --> folded polypeptide chain 4. Quaternary: two or more polypeptide chains

HW Question 8 Which number represents the atomic weight of oxygen?

16.00 (the number below element name)

HW Question 17 What is the maximum number of single covalent bonds a carbon atom can form with other elements?

4

Nucleic acid makeup

5 carbon sugar, phosphate group, nitrogenous base DNA = codes for proteins RNA = messenger molecule carrying DNA

HW Question 16 While the maximum number of electrons required to fill the outermost shell of an atom varies depending on the size of the atom, almost all the smaller atoms (atomic numbers 2-20) are considered stable (nonreactive) when they contain ____ electrons in the outermost shell

8

HW Question 9 How many neutrons are in a typical oxygen atom?

8 (atomic number subtracted from atomic weight)

HW Question 10 How many protons are in a typical oxygen atom?

8 (same as electron #/# above element symbol)

Unsaturated Fatty Acids

= double C to C bonds (not saturated w/H) -- kinks and cannot pack tightly = oil - liquid at rm temp (oils) - plant sources

Saturated Fatty Acids

= maximum # H (no double bond) - solid at rm temp - animal sources Examples: animal fats

Polyunsaturated Fatty Acids

= more double bonds but less saturated Examples: corn/peanut/soybean oil, nuts, omega 3 FA (fish)

Homework Question: What is the basic structure of typical dietary fats?

A glycerol head and three fatty acid tails

Population

A group of interacting individuals of one species

Organ system

A group of organs that work together for a specific function

Polar molecule

A molecule in which the charges are unevenly distributed (meaning that a particular side can be more positive or more negative)

Carbon Chemistry

A versatile atom - It has four electrons in an outer shell that holds eight electrons - It can share its electrons w/other atoms to form up to four covalent bonds

HW Question 4

ATOMIC NUMBER is the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. The number of protons plus neutrons in an atom, represented as an average of all naturally occurring forms of the element, is known as ATOMIC WEIGHT. TRACE ELEMENTS, also called micronutrients, are any chemical element required by living organisms in miniscule amounts, but cells require them to survive. NITROGEN is one of the four elements that make up 96.3% of living cells. CALCIUM is one of the seven elements that make up a small fraction, approximately 3.7%, of living cells. ZINC is one of the fourteen trace elements and is a component of certain digestive enzymes and other proteins.

HW Question 21 Something with a pH of 5 would be _______

Acidic

HW Question 24 Water readily sticks to many other substances, a property called ______.

Adhesion

Homework Question: What are the monomers of proteins?

Amino Acids

Ions (negative or positive)

An atom/molecule with an electrical charge resulting from gain or loss of electrons (atoms w/ positive or negative charge) - When an electron is lost, a positive charge results; when one is gained, a negative charge results - Two ions with opposite charges attract each other (ionic bond)

HW Question 5 What is a trace element?

An element that is required in miniscule amounts for life

Organism

An individual living being

Anion

An ion with a negative charge

Cation

An ion with a positive charge

Homework Question: Which of the following cells contain a plasma membrane

Animal cells, plant cells, and bacterial cells

Why are blood and most other biological fluids classified as aqueous solutions?

Aqueous solution means that the solvent is water and since our body is made up of mostly water, the biological fluids are the solute in a solvent of water. (because it is a bunch of properties in a water based solvent)

Hydrophilic vs. Hydrophobic Vitamins

B1, B2, C, Folic acid / A, D, E, K - Can have more hydrophilic vitamins than hydrophobic

Homework Question: Identify the prokaryotic organism: Fungus, Bacteria, Plant, or Animal

Bacteria

Spontaneous generation

Belief that life arose from non-living matter Example: maggots from meat

Q. Where are hydrogen bonds formed?

Between water molecules (A hydrogen bond is the electrostatic attraction between polar groups that occurs when a hydrogen (H) atom bound to a highly electronegative atom such as nitrogen (N), oxygen (O) or fluorine (F) experiences attraction to some other nearby highly electronegative atom)

Q. Which of the following have the same number of protons, but have different numbers of neutrons? A. 23Na nad 24Mg B. 46Ca and 46Ti C. 7Li and 6Li D. 16O 19F

C. Because it must be the same element (just diff numbers)

Homework Question Based on the suffix, a molecule of "maltose" is most likely what type of macromolecule?

Carbohydrate

Homework Question What are the four classes of large organic molecules important to life on Earth?

Carbohydrates, proteins, lipids, and nucleic acids

Homework Question Organic compounds are distinguished by molecules that contain ________ bonded to other elements.

Carbon

Homework Question Why are all living organisms based on molecules that contain carbon?

Carbon atoms can form strong covalent bonds with many other carbon atoms, and the atoms of hydrogen, oxygen, and nitrogen.

Homework Question: Triglycerides vary with respect to the number of ...

Carbon atoms in the tails; double bonds in the tails

Organic Compounds

Carbon-based molecules - A cell is mostly water but the remainder of it consists of carbon-based molecules - Carbon forms large, complex, and diverse molecules necessary for life's functions

Homework Question: Components in a plant cell only

Central vacuole Cell wall Chloroplast

Q. What is the role/importance of valence electrons?

Chemical reactions occur in this valence shell

HW Question 25 Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____.

Cohesion and resulting surface tension

Organelle

Component of the cell that performs a specific function

Biosphere

Consists of all life on earth (all environments)

Community

Consists of all the interacting populations in an ecosystem

Organ

Consists of multiple tissues that cooperate to perform a specific task

Ecosystem

Consists of the living and nonliving components

Cytosol and Cytoplasm

Cytosol: Jelly-like fluid outside the nucleus in which organelles are immersed Cytoplasm: Region of the cell inside the plasma membrane but outside the nucleus

How many electrons and electron shells does a sodium atom have (its atomic number is 11)? How many electrons are in its valence shell?

Electrons: 11 Electrons in valence shell: 1

HW Question 3 _____ are substances that CANNOT be broken down into other substances by chemical reactions

Elements

Homework Question: Proteins are diverse molecules that perform a wide variety of functions. Which of the following is not a typical function of proteins?

Energy Storage They: transport, catalyze reactions via enzymes, and provide movement

Monounsaturated Fatty Aids

Examples: olive oil, avocados, canola

Flagellum vs. Cilia

Flagellum: long, few Cilia: many, short

HW Question 28 Water is sometimes called the "universal solvent." Is that accurate?

For the most part. Water readily dissolves most substances, but not hydrophobic ones

HW Question 23 Water is the least dense when it ________.

Freezes

Lysosome

Function: breaks down macromolecules using digestive enzymes - Found in animal cells only!

Cell

Fundamental unit of life

Atom

Fundamental unit of matter

Homework Question: Starch and glycogen are complex carbohydrates made by joining together long chains of __________ monomers.

Glucose

Homework Question: Which of the following represents a simple sugar (also called monosaccharides)?

Glucose

Molecule

Group of atoms bonded together

Tissues

Group of similar cells that work together

Purpose of Eating

Growth, maintenance, repair, energy, nutrients (substances in food that provide structural materials and/or energy)

Plant cell

Have three structures not found in animal cells: 1. cell wall 2. a large central vacuole 3. chloroplasts

Homework Question: In the reaction that builds a fat,________ groups react with ________ groups.

Hydroxyl; carboxyl

Homework Question: All lipids are ________.

Hyrophobic

Louis Pasteur

In 1859, Pasteur settles the issue of spontaneous generation and states that all living things arise from other living things --> if cells arise from nonliving things, they will arise in sterile broth (because sterile flask did not grow anything, Pasteur disproved spontaneous generation)

Covalent Bonds

Involve the sharing of one or more electrons between atoms - Nonpolar covalent bonds: equal sharing of electrons (meaning that electric charge is evenly distributed) - Polar covalent bonds: unequal sharing of electrons (charge not evenly distributed) - Two or more atoms held together by covalent bonds form a molecule - The STRONGEST of the chemical bonds - Double covalent bonds: two shared pairs of electrons

HW Question 12 If the number of protons in an atom does not match the number of electrons, the atom is specifically called an ____?

Ion

HW Question 14 All sodium atoms have 11 protons. The nuclei of some sodium atoms contain 12 neutrons and others contain 11. These different forms of sodium are called ______?

Isotopes

Homework Question: If you were looking at a cell under a powerful microscope, what would tell you that it is a eukaryotic cell?

It has a nucleus

TABLE 3.5 Biological Molecules

KNOW THESE**

Organic compounds in living things

Lipids, Proteins, Carbohydrates, Nucleic acids

Homework Question: Which organelle functions to break down and recycle large molecules?

Lysosome

Homework Question: A food company hydrogenated a barrel of fat. The treatment ...

Made the fat less fluid -- Hydrogenation removes double bonds, so the tails can straighten

Transport Vesicles

Membrane bound packages that move substances around cell

Homework Question: What harvests energy from food molecules to make ATP?

Mitochondria

Endomembrane system

Modify, produce, transport proteins

Monomers vs. Polymers

Monomer: monosaccharide, amino acids, a nucleotide Polymer: many monomer units together (polysaccharide, polypeptide, protein, nucleic acid)

Homework Question Which of the following is not made from long chains of glucose?

Monosaccharides

Homework Question Where are the ribosomes located?

On the rough endoplasmic reticulum and in the cytoplasm

HW Question 6 What is the most common element in your body?

Oxygen

Homework Question: Which cellular structure is unique to prokaryotic organisms?

Plasmids

HW Question 20 Water "beads up" on synthetic fabric like polyester but binds to cotton. What is the most likely explanation for this?

Polyester is nonpolar, whereas cotton is polar.

Homework Question What is another name for the polymers of carbohydrates?

Polysaccharides

Complex Carbs

Polysaccharides = many sugars - More difficult to digest and enter bloodstream slower than simple carbs

Homework Question: Enzymes are a type of ________.

Protein

HW Question 2 During a chemical reaction, atoms are ______

Rearranged

Golgi Apparatus

Receiving, Warehouse, and Shipping Center - Distributes the chem. products of the cell - One side is a docking/receiving station and the other a shipping port (proteins finalized and packaged here) - MODIFIES AND PACKAGES PROTEINS

Central Vacuole

Regulates cytoplasm composition, creates internal pressure, and stores cell compounds

Plasma Membrane (Gate Keeper)

Regulates the movement of materials into and out of the cell Made of lipids (phospholipid head, FA tails) Composed of lipids (called lipid-bilayer)

Explain what holds together the atoms in a crystal of table salt?

Salt crystals are held together with ionic bonds. For example, table salt, NaCl, is composed of two ions. The Na ion is positive and the Cl ion is negative. The charges on these ions hold them together into the molecule NaCl.

Chloroplasts

Solar Energy Plants Build molecules using energy from the sun - the sites of photosynthesis to produce glucose - Makes food by converting light energy into chemical energy

Francesco Redi

Sought to disprove spontaneous generation through conducting an experiment --> meat was in jars, one jar uncovered and one covered (both meat decayed but only one open would produce maggots)

Other Lipids

Steroid lipids: carbon rings in their structure Phospholipids: triglyceride w/ a phosphate group attached to it Wax: fatty acids + long chain alcohol

Central Vacuole

Stores nutrients and degrades waste products Stores water and is responsible for the "turgor" pressure in plant cells -- wilting

Plant cell wall

Strong, protective structure made from cellulose fibrils

Disaccharides

Sucrose - main carb in plant sap - rarely used as a sweetener in U.S High-fructose CS - natural glucose in corn syrup is convert to much sweeter fructose

After a hard workout, you may see beads of sweat on your face. Can you explain what holds the sweat in droplet form?

The cohesion of water molecules and its high surface tension hold water in droplets. The adhesion of water to your skin helps hold the beads in place.

HW Question 19 A needle can be made to "float" on the surface tension of water. What causes this surface tension to form?

The cohesion of water molecules to each other

pH - Measure of acidity of the solution

The concentration of H+ ions in an aqueous solution determines its pH Scale from acidic to basic (0-14) - pH of 1 (lots of hydrogen); pH of 14 (little hydrogen)

HW Question 22 Select the most complete explanation of what the pH scale actually measures.

The concentration of hydrogen ions in a solution

HW Question 11 In an atom, the number of neutrons determines most specifically the ____?

The isotope

Homework Question: The presence of many C-C and C-H bonds causes fats to be ...

The many C-C and C-H bonds make fats nonpolar and insoluble in water. They can also be oxidized, releasing much energy.

Homework Question: The most unsaturated fats have ...

The most double bonds -- every double bond is a place where hydrogen could be added.

HW Question 13 Identify the part of the atom that most determines the chemical properties of the atom

The number of electrons

What enables neighboring water molecules to hydrogen-bond to one another?

The oxygen atom has a partial negative charge, and the hydrogen atoms have partial positive charges, this causes a bonded hydrogen atom to be attracted to a bonded oxygen atom

HW Question 26 Which best describes how charges are distributed on a water molecule?

The oxygen end is negative relative to the end with the two hydrogen atoms

Homework Question: Which structure selectively regulates the transport of substances into and out of a plant cell?

The plasma membrane

Homework Question: To a large extent, a protein's function is dependent upon its shape. What determines a protein's shape?

The sequence of amino acids

What is chemically nonsensical about this structure? H-C=C-H

The structure H-C=C-H is nonsensical because the carbons only have 3 bonds each. Carbon (C) has four valence electrons (electrons in the outer shell) and it needs 4 more to fulfill the octet (8) rule. Therefore carbons will make four bonds.

Biology

The study of life

Electronegativity

The tendency for an atom to pull electrons toward itself

HW Question 7 The majority of the elements essential to life are found in what part of the periodic table?

The top third

Micronutrients

Vitamins: organic substances that the body cannot synthesize Minerals: do not contain carbon so are called inorganic (Ca, Cl, Mg, Na, K, Ph)

Explain how the freezing of water can crack boulders.

Water expands as it freezes because the water molecules become spaced farther apart in forming ice crystals. When there is water in a crevice of a boulder, expansion of the water due to freezing may crack the rock

HW Question 27 Relative to other substances, water tends to resist changes in temperature. Why?

Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules

HW Question 18 What is responsible for the unusual chemical properties of water?

Water molecules can form an extensive network of hydrogen bonds with one another

Explain the popular adage "it's not the heat, it's the humidity."

When you sweat in high humidity, the sweat does not evaporate as effectively because there is already so much water in the air. Therefore, less heat is removed from your skin through the heat of vaporization. Your sweat just sits on your body without evaporating (High humidity hampers cooling by slowing the evaporation of sweat)