Chapter 2: Molecular Interactions

Question 1

All physiological processes are based on…?

Answer 1

-Chemical interactions

Question 2

What are the 6 elements the body is composed of?

Answer 2

99% of the human body is made of 6 elements. -Carbon, C -Hydrogen, H -Oxygen, O -Nitrogen, N -Phosphorus, P -Sulfur, S

Question 3

What are atoms and what do they contain?

Answer 3

-Atoms are the smallest unit of an element, they contain protons (+ charged, in nucleus), neutrons (uncharged, in nucleus), and electrons (- charged, orbiting nucleus).

Question 4

What are chemical bonds?

Answer 4

-Strong force of attraction holding atoms together in a molecule or crystal as a result of sharing or transfering electrons.

Question 5

What are covalent bonds?

Answer 5

• A chemical bond formed by the sharing of valence electrons between atoms.
• Can be nonpolar: electrons are shared equally
• Can be polar: electrons are not shared equally

Question 6

What are ionic bonds?

Answer 6

-A chemical bond in which an atom donates an electron to another atom to achieve filled outer shells for both atoms. -Electron donor becomes + charged (cation) -Electron receiver becomes - charged (anion)

Question 7

How much of the human body is composed of water?

Answer 7

-65% of the human body is made up of water and other fluids

Question 8

What are some valuable properties of water?

Answer 8

• Good solvent (most substances dissolve in it)
• Polar molecule

Question 9

What are molecules that dissolved readily in water called? How about molecules that do not dissolve readily in water?

Answer 9

• Molecules that dissolve readily in the water are Hydrophilic, tend to be ionic compounds
• Molecules that do not dissolve readily in water are Hydrophobic.

Question 10

What are ions? What happens when an ionic compound is placed water?

Answer 10

• Ions are atoms that are electrically charged as a resulting of “gaining” or “losing” an electron.
• When ionic compounds are placed in water, they tend to dissociate and revert back to their constuient ions.
• Negative side of water is attracted to (+) cation (atom that lost electrion)
• Postive side of water is attracted to (-) anion (atom that gained electron)

Question 11

What is a Hydrogen Bond?

Answer 11

• (Intermolecular interaction) It is a weak bond formed between two polar molecules based on opposite charged attracting.
• Happens between water molecules, amino acids in a protein –> shape, and it holds the two strands of the DNA molecule together.

Question 12

What is an acid? What makes a solution acidic?

Answer 12

-An acid is a chemical species that donates protons or hydrogen ions and/or accepts electrons. A solution is acidic when more H⁺ ions than OH^- ions are present. pH is <7.

Question 13

What are Bases? When is a solution Basic?

Answer 13

-An aqueous substance that can accept hydronium ions. A solution is basic when there ar more OH^- ions than H⁺ ions. The pH would be >7.

Question 14

When is a solution neutral?

Answer 14

-When H⁺ ions are equal to OH^- ions. The pH = 7

Question 15

What are Buffers? What do they do? How does it apply to blood?

Answer 15

• Solutions used to stabilize an optimum pH of a liquid.
• Buffers neutralize H+ concentration in solutions.

-In blood, pH is stablized by bicarbonate (HCO₃^-) and carbonic acid (H₂CO₃) system:

HCO₃^- + H⁺ <–> H₂CO₃ <–> H₂O + CO₂

• If blood falls below pH 7.35, condition is called Acidosis (too little base)
• If blood falls below pH 7.45, condition is called Alkalosis (too little acid)

Question 16

What are Organic Molecules? What is a crucial element for Organic Molecules? Why is it crucial?

Answer 16

• Organic molecules are molecules that contain Carbon (C) and Hydrogen (H)
• Carbon, an important element, has four outer electrons and forms 4 bonds.
• Carbon forms the backbone of all organisms on earth in terms of…
• Proteins
• Carbohydrates
• Lipids
• Nucleic acids
• Chains and rings of carbons bonded to other atoms.

Question 17

What are functional groups? How does Carbon play into this?

Answer 17

• A group of atoms reacting as one: a group of atoms that reacts as a single unit and determines the properties and structure of a class of compounds.
• Carbon forms the backbone for these reactive groups.
• These classes of molecules are named after their functional group.

Question 18

What are Carbohydrates? What function do they serve in our body? Give examples of these carbohydrates.

Answer 18

• Carbohydrates are organic molecules such as sugars and starch that contain carbon, hydrogen, and oxygen.
• Serve as the primary source of energy in our bodies.
• A simpler form of a carbohydrate is a monosaccharide (meaning “mono” = single, “sacchar” meaning sugar). Some monosaccharide sugars include: glucose, fructose, galactose.
• A disaccharide is two monosacchardies joined by a covalent bond: sucrose, maltose, lactose
• A polysaccharide is many monosacchardies joined together: starch.

Question 19

What is Glycogen? What is Cellulose?

Answer 19

• Glycogen is a polysaccharide made in liver cells and muscle cells of animals to store sugar in a cell.
• Cellulose is a polysaccharide made by plants that is not digestible by humans.

Question 20

How are bonds that hold monosaccharides together are formed?

Answer 20

• Monosaccharide covalent bonds are formed by dehydration synthesis.
• Dehydration synthesis is when hydrogen is removed from one molecule and hydroxyl is removed from another to form water. This inturn causes the monomers to join together.

Question 21

How are bonds broken between molecules such as monosaccharides?

Answer 21

• Hydrolysis is a chemical reaction or process in which a chemical compound reacts with water to break a bond between its molecules.
• Water is split and used to complete individual molecules such as monosaccharides.

Question 22

What does Dehydration Synthesis and Hydrolysis do to help with Physiological Functioning?

Answer 22

-Dehydration synthesis and hydrolysis help by building/breaking fats, proteins, and nucleic acids.

Question 23

What are lipids? Are they soluble in water? What are common types of lipids?

Answer 23

• They are nonpolar hydrocarbon chains and rings.
• They tend to be insoluble in water or polar substances.
• Fats, oils, fatty acids, phospholipids, steroids, waxes. Triglycerides are made up of glycerol and three molecules of fatty acids.

Question 24

What are phospholipids? Where can they be located? How are they positioned? How do they help transport lipids throughout the body?

Answer 24

• They are lipids (nonpolar hydrocarbon chains and rings) combined with a polar phosphate group.
• They are located on the cell membrane, forming a bilayer which has hydrophilic phosphates poing outward on each side and hydrophobic fatty acids and glycerol pointing inward.
• The phospholipids form micelles (which are like tiny balls of molecules) to help suspend and transport lipids in aqueous environment of body.

Question 25

How are proteins formed? What is their function?

Answer 25

- Proteins are formed from chains of at least 20 aminoacids that are joined by a peptide bond formed by dehydration synthesis. - With dehydration synthesis, H is removed from amino functional group end and OH is removed from carboxyl function group end of other amino acid. From there, the two amino acids form a peptide bond inbetween. - The function of these proteins are cell structure, enzymes, antibodies, receptors, and carriers.

Question 26

What groups do amino acids have?

Answer 26

-They have an amino group, carboxyl group, and functional groups.

Question 27

What are steroids? What are examples of steroids in our bodies?

Answer 27

- Steroids are a class of lipids that have a cholesterol core of four carbon rings. - Examples of steroids in our bodies include hormones such as testosterone, estrogen, and cortisol. - Examples of other molecules that are steroids are vitamin D and bile salts.

Question 28

Specifically, what are chains of amino acids called? What are primary structures? What are secondary structures? What are tertiary structures? What are quanternary structures?

Answer 28

- Chains of amino acids are called polypeptides. (varies from 3 to 4,500 amino acids) - Primary structures are the sequence of amino acids. - Secondary structures are the hydrogen bonds between neighboring amino acids forming alpha helices and beta folds. - Tertiary structures are attraction of amino acids to further away that folds the protein into a specific 3D shape. - Quaternary structures are when some proteins composed of multiple polypeptide chains covalently bond together into this structure.

Question 29

What are conjugated proteins? What are some examples?

Answer 29

-A conjugated protein is combination of a protein and other molecule. - Some examples include glycoprotein = Protein + Carbohydrate (ABO blood type groups) - Lipoprotein = Protein + Lipid (Transports lipids in blood)

Question 30

Define Nucleic Acids. What are the different types of Nucleic acids? What are the building blocks of all these nucleic acids?

Answer 30

- Nucleic acids are the building blocks of the human being and other organisms. - Different types of nucleic acids include DNA, RNA, mRNA, and tRNA. - The building blocks of nucleic acids are nucleotides which are composed of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Question 31

What is DNA? How is it formed?

Answer 31

- DNA is Deoxyribonucleic Acid, it carries the main genetic information a cell needs. - DNA's backbone is formed by deoxyribose bonds with a phosphate group. Nitrogen then bases hydrogen bonds to each other to form a double-stranded DNA helix. - Cytosine goes with Guanin, Thymine with Adenine.

Question 32

What is RNA? What does it do? What is its structure?

Answer 32

- RNA is ribonucleic acid. - RNA serves to copy and carry information from DNA and help process it throughout the cell. It is also responsible for the synthesis of proteins. It helps serve as a catalyst for the synthesis a peptide bond. - Similar to DNA structure but... * Contains ribose sugar instead of deoxyribose * Single stranded instead of double stranded * Has uracil instead of thymine

Question 33

What are the three types of RNA and what do they do?

Answer 33

- The three types of RNA are Messenger RNA, Transfer RNA, Ribosomal RNA. They all play a role in protein synthesis. - Other RNA-related molecules serve important functions in the body: ATP, cAMP, NADH, FAD.