Chapter 2: The Chemical Level - PART 2

Question 1

what % of our body does water take up?

Answer 1

55-60% of a lean adults body mass Other inorganic compounds add 1-2%

Question 2

what are organic compounds? type of bond? what % of the human body do they make up?

Answer 2

always contain carbon, usually contain hydrogen, and always have covalent bonds. Most are large mol-ecules and many are made up of long chains of carbon atoms. Organic compounds make up the remaining 38–43% of the hu- man body.

Question 3

In a solution, a substance called the ______dis- solves another substance called the _______

Answer 3

solvent, solute

Question 4

Solutes that are charged or contain polar covalent bonds are ___________. which means

Answer 4

hydrophillic they dissolve in water

Question 5

. Molecules that contain mainly nonpolar covalent bonds, by contrast, are

Answer 5

hydrophobic - are not very water soluble ex. vegetable oil

Question 6

explain the process that occurs when salt dissolves in water

Answer 6

The electronegative oxygen atom in water molecules attracts the sodium ions (Na􏰈), and the electropositive hydrogen atoms in water molecules attract the chloride ions (Cl􏰊). Soon, water molecules surround and separate Na􏰈 and Cl􏰊 ions from each other at the surface of the crystal, breaking the ionic bonds that held NaCl together.

Question 7

What is a hydrolysis reaction?

Answer 7

decomposition reactions break down large nutrient molecules into smaller molecules by the addition of water molecules = enable dietary nutrients to be absorbed into the body

Question 8

What is a dehydration synthesis reaction

Answer 8

when two smaller molecules join to form a larger molecule - a water molecule is one of the products formed

Question 9

Why is water said to have a high heat capacity? (meaning water can absorb or release a relatively large amount of heat with only a modest change in its own temperature.)

Answer 9

the large number of hydrogen bonds in water. As water absorbs heat energy, some of the energy is used to break hydrogen bonds. Less energy is then left over to increase the motion of water molecules, which would increase the water’s temperature.

Question 10

why is it important that water’s heat of vaporization is high

Answer 10

because when water evaporates from the surface of the skin it takes lots of heat = cooling mechanism

Question 11

______ is a major component of mucus and other lubricating fluids.

Answer 11

water

Question 12

Where is lubrication especially necessary in the body

Answer 12

the chest (pleural and pericardial cavities) ,abdomen (peritoneal cavity), where internal organs touch and slide over one another and joints

Question 13

define mixture (give example)

Answer 13

a combination of elements or compounds that are physically blended together but not bound by chemical bonds. For example, the air you are breathing is a mixture of gases

Question 14

what are the 3 common types of liquid mixtures?

Answer 14

solutions, colloids, and suspensions

Question 15

define solution

Answer 15

solutes in a solution remain evenly dispersed among the solvent molecules. Because the solute particles in a solution are very small, a solution looks clear and transparent

Question 16

define a colloid

Answer 16

The solute particles in a colloid are large enough to scatter light, > appear translucent or opaque (ex. milk)

Question 17

define a suspension (give ex)

Answer 17

the suspended material may mix with the liquid or suspending medium for some time, but eventually it will settle out ex. blood

Question 18

What kind of mixture is milk

Answer 18

both a colloid and a solution

Question 19

what is a mole?

Answer 19

the amount of any substance that has a mass in grams equal to the sum of the atomic masses of all its atoms

Question 20

what happens when n inorganic acids, bases, or salts dissolve in water

Answer 20

they dissociate that is, they separate into ions and be- come surrounded by water molecules

Question 21

define an acid (what else is it referred to)

Answer 21

a substance that dissociates into one or more hydrogen ions (H+) and one or more anions. Because H􏰈+is a single proton with one positive charge, an acid is also referred to as a proton donor.

Question 22

Define a base

Answer 22

removes H+ from a solution and is therefore a proton acceptor. Many bases dissociate into one or more hydroxide ions (OH-) and one or more cations.

Question 23

How does salt dissociate in water?

Answer 23

dissociates into cations and anions, neither of which is H+ or OH-

Question 24

The more hydrogen ions (H+) dissolved in a solution, the more _____ the solution; the more hydroxide ions (OH-), the more ___–(alkaline) the solution.

Answer 24

acidic, basic

Question 25

To ensure homeostasis, intracellular and extracellular fluids must contain almost balanced quantities of what?

Answer 25

acids and bases

Question 26

Explain how the pH scale works what pH does an acidic vs. basic solution have?

Answer 26

concentration of H+ in moles per liter. midpoint =pH 7, where the concentrations of H+ and OH- are equal (neutral, ex. water) solution that has more H+ than OH- is an acidic solution and has a pH below 7. A solution that has more OH- than H+ is a basic (alkaline) solution and has a pH above 7.

Question 27

What do buffers do?

Answer 27

chemical compounds that can convert strong acids or bases into weak ones to maintain homeostasis

Question 28

how does the carbonic acid-bicarbonate buffer system work?

Answer 28

.Carbonic acid (H2CO3) can act as a weak acid, and the bicarbonate ion (HCO3-) can act as a weak base. Hence, this buffer system can compensate for either an excess or a shortage of H+

Question 29

The chain of carbon atoms in an organic molecule is called the _________

Answer 29

carbon skeleton

Question 30

what are functional groups?

Answer 30

other atoms or molecules bound to the hydrocarbon skeleton. Each type of functional group has a specific arrangement of atoms that confers characteristic chemical properties on the organic molecule attached to it

Question 31

Define macromolecules and polymers

Answer 31

1)Small organic molecules can combine into very large molecules that are called macromolecules (are usually polymers) 2). A polymer is a large molecule formed by the covalent bonding of many identical or similar small building-block molecules called monomers

Question 32

what are isomers?

Answer 32

Molecules that have the same molecular formula but different structures

Question 33

What are carbohydrates? what are their 2 functions?

Answer 33

sugars, glycogen, starches, and cellu- lose (2-3% of your body) 1) function mainly as a source of chemical energy for generating ATP needed to drive metabolic reactions 2) few are used for building structural units. One example is deoxyribose

Question 34

what are the 2 types of simple sugars?

Answer 34

Monosaccharides and disaccharides

Question 35

what are Monosaccharides

Answer 35

made of three to seven carbon atoms. They are designated by names ending in “-ose” with a prefix that indicates the number of carbon atoms.

Question 36

what are disaccharides?

Answer 36

a molecule formed from the combination of two monosaccharides by dehydration syn- thesis

Question 37

What are polysaccharides?

Answer 37

each polysaccharide molecule contains tens or hundreds of monosaccharides joined through dehydration synthesis - they are insoluble in water and do not taste sweet

Question 38

what is the main polysaccharide in the human ?

Answer 38

glycogen: made entirely of glucose monomers linked to one another in branching chains. A limited amount of carbohydrates is stored as glycogen in the liver and skeletal muscles.

Question 39

What are lipids?

Answer 39

18–25% of body mass, contain carbon, hydrogen, and oxygen few covalent bonds = hydrophobic

Question 40

What are lipoproteins?

Answer 40

To become more soluble in blood plasma, other lipid molecules join with hydrophilic protein mole- cules. The resulting lipid/protein complexes are termed lipopro- teins. Lipoproteins are soluble because the proteins are on the outside and the lipids are on the inside

Question 41

what are the two types of fatty acids?

Answer 41

saturated contains only single covalent bonds between carbon on hydrocarbon chain (each carbon atom of the hydrocarbon chain is saturated with hydrogen) An unsaturated fatty acid contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain

Question 42

The most plentiful lipids in your body and in your diet are the ___________ - what are they?

Answer 42

triglycerides - consists of two types of building blocks, a single glycerol molecule (backbone) and three fatty acid molecules (attached by dehydration synthesis)

Question 43

The chemical bond formed where each water molecule is removed is an ________

Answer 43

ester linkage

Question 44

. A ___ is a triglyceride that is a solid at room temperature, An ___ is a triglyceride that is a liquid at room temperature

Answer 44

fat (saturated fatty acids) , oil (Monounsaturated or polyunsaturated fatty acids)

Question 45

Excess dietary carbohydrates, proteins, fats, and oils are all deposited in _______ tissue as

Answer 45

adipose, triglycerides

Question 46

what is the structure of phospholipids?

Answer 46

glycerol backbone and two fatty acid chains attached to the first two carbons. In the third position (the head), however, a phosphate group (PO43-) links a small charged group that usually contains nitrogen (N) to the backbone

Question 47

molecules s that have both polar and nonpolar parts are said to be ________

Answer 47

amphipathic ex. phospholipids

Question 48

what is the structure of a steroid? how are they synthesized

Answer 48

four rings of carbon atoms.

• Body cells synthesize other steroids from cholesterol which has a large nonpolar region consisting of the four rings and a hydrocarbon tail.

Question 49

what are Eicosanoids? what are the 2 principle sub classes?

Answer 49

lipids derived from a 20-carbon fatty acid called arachidonic acid

1) prostaglandins : variety of functions
2) Leukotrienes: participate in allergic and inflammatory responses

Question 50

What is cholesterol?

Answer 50

( synthesized in the liver) it is the starting material for synthesis of other steroids in the body.

Question 51

what are proteins (structure, %, )

Answer 51

large molecules that contain carbon, hydrogen, oxygen, and nitrogen (some contin sulfur) 12–18%

Question 52

list proteins 6 functions

Answer 52

1) Structural Form structural framework of various parts of body.
2) Regulatory - Function as hormones that regulate various physiological processes; control growth and development; as neurotransmitters, mediate responses of nervous system.
3) Contractile Allow shortening of muscle cells, which produces movement

4) Immunological Aid responses that protect body against foreign substances and invading pathogen
5) Transport Carry vital substances throughout body.
6) Catalytic - Act as enzymes that regulate biochemical reactions.

Question 53

What is an amino acid?

Answer 53

monomers of proteins

Question 54

The covalent bond joining each pair of amino acids is a ______

Answer 54

peptide (forms b/w carbon of carboxyl group or one of the amino acids and the nitrogen of the amino group of another)

Question 55

When two amino acids combine, a _____ results. Adding another amino acid to a dipeptide produces a ______. Further additions of amino acids result in the formation of a chainlike peptide (4–9 amino acids) or ________ (10–2000 or more amino acids

Answer 55

dipeptide, tripeptide, polypeptide

Question 56

What are the 4 levels of structural organization in proteins? and the types of bonds that hold them together

Answer 56

1) primary structure is the unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain
2) The secondary structure of a protein is the repeated twisting or folding of neighboring amino acids in the polypeptide chain ( alpha helixes (clockwise spirals) and beta pleated sheets)) - stabalized by hydrogen bonds
3) The tertiary structure refers to the three- dimensional shape of a polypeptide chain. disulfide bridges —hydrogen bonds, ionic bonds, and hydrophobic interactions—also help determine the folding patter
4) quaternary structure: the arrangement of the individual polypep- tide chains relative to one another

Question 57

define denaturation

Answer 57

. If a protein encounters an altered environment, it may unravel and lose its characteristic shape (secondary, tertiary, and quaternary structure)

Question 58

What two parts do some enzymes consist of?

Answer 58

—a protein portion, called the apoenzyme and a nonprotein portion, called a cofactor.

Question 59

what are the 3 important properties of enzymes?

Answer 59

1) Enzymes are highly specific. Each particular enzyme binds only to specific substrates 2) Enzymes are very efficient. catalyze reactions 100 million to 10 billion times more rapid than rxns without enzymes 3) Enzymes are subject to a variety of cellular controls. Their rate of synthesis and their concentration at any given time are under the control of a cell’s genes.

Question 60

what is the active site?

Answer 60

, the part of the enzyme that catalyzes the reaction

Question 61

what is induced fit?

Answer 61

the active site changes its shape to fit snugly around the substrate once the substrate enters the active site

Question 62

What are nucleic acids?

Answer 62

first found in the nuclei of cells - they are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.

Question 63

What are the two varieties of nucleic acid?

Answer 63

1) deoxyribonucleic acid (DNA) forms the inherited genetic material inside each human, each geneis a segment of a DNA molecule. 2) Ribonucleic acid (RNA), relays instructions from the genes to guide each cell’s synthesis of proteins from amino acids.

Question 64

A nucleic acid is a chain of repeating monomers called _________

Answer 64

nucleotides

Question 65

What are the 3 parts of each nucleotide of DNA?

Answer 65

1) Nitrogenous base. four nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Adenine and guanine are larger, double-ring bases called purines, thymine and cytosine are smaller, single-ring bases called pyrimidines
2. Pentose sugar. A five-carbon sugar called deoxyribose attaches to each base in DNA.
3. Phosphate group. alternate with pentose sugars to form the “backbone” of a DNA strand

Question 66

What is the double helix model?

Answer 66

DNA = spiral ladder Two strands of alternating phosphate groups and deoxyribose sugars form the uprights of the ladder. Paired bases, held together by hydrogen bonds, form the rungs.

Question 67

the RNA nucleotide is the pentose ______

Answer 67

ribose

Question 68

what is Adenosine triphosphate (ATP) what is it’s structure?

Answer 68

the “energy currency” of living > trans- fers the energy liberated in exergonic catabolic reactions to power cellular activities that require energy (endergonic reactions) >f three phosphate groups attached to adenosine, a unit composed of adenine and the five-carbon sugar ribose.

Question 69

addition of water causes the Removal of the third phosphate group which produces a molecule called _________ This reaction creates _______

Answer 69

adenosine diphosphate (ADP) ENERGY

Question 70

What is required to turn ADP back into ATP? what are the 2 phases?

Answer 70

catabolism of glucose in a process called cellular respiration.

1. Anaerobic phase. do not require oxygen, glucose is partially broken down by catabolic reactions into pyruvic acid. Each glucose molecule that is converted into a pyruvic acid molecule yields two molecules of ATP.
2. Aerobic phase. In the presence of oxygen, glucose is completely broken down into carbon dioxide and water.