Chapter 2 - Chemicals in the Human Body

Question 1

Define atoms

Answer 1

Smallest unit of chemical elements

Question 2

Covalent vs. Ionic bonds

Answer 2

Covalent bonds share valence electrons
Ionic bonds give away valence electrons (ion want it)

Question 3

Non-polar Covalent Bonds

Answer 3

Electrons are shared equally

Lipid molecules have fatty acid tails
- not water soluble

Question 4

Polar covalent bonds

Answer 4

Electrons are not shared equally; they have positive and negative ends
ex. Water

Question 5

Cation + anions

Answer 5

In an ionic bond, one atom gives elections to another so that both have filled electrons

The electron donor is positively charged, now is called the cation

The electron receiver is positively charged, now is called the anion

Question 6

Hydrophilic vs hydrophobic

Answer 6

Hydrophilic: molecules that can dissolve in water
Hydrophobic: molecule’s that repel water

Ionic bonds are much weaker than covalent, they easily dissociate when dissolved in H2O

Question 7

pH

Answer 7

Water molecules break to form free hydrogen ions and hydroxide ions

(below 7 = acidic, above 7 = basic)

Question 8

Buffers

Answer 8

Buffers stabilize H+ concentration in a solution.
In blood, 2 molecules stabilize pH:
1) bicarbonate (HCO3-) und carbonic acid (H2CO3)

Question 9

Acidosis vs alkalosis

Answer 9

• if blood falls below 7.35 pH, it is called acidosis
• if blood rises above 7.45 pH, it is called alkalosis

Question 10

Carbohydrates

Answer 10

Organic molecules containing carbon, hydrogen, and oxygen, ring shaped

CnH2nOn

Question 11

Monosaccharide vs disaccharide vs polysaccharide

Answer 11

Monosaccharide: simple sugar, single ring
Disaccharide: 2 monosaccharides covalently bonded together
Polysaccharide: numerous monosaccharides
jointed together

Question 12

Lipids

Answer 12

Consist of non-polar hydrocarbon chains and rings

Hydrophobic = lipophilic

Categories: Triglycerides, phospholipids, steroids

Question 13

Triglycerides

Answer 13

Include fat and oil (diet), stored in adipose tissue

1 glycerol molecule joined with three fatty acids

Fatty acids: C and H chains

Question 14

saturated vs unsaturated fats

Answer 14

saturated fats = single bond (solid at room temp)
unsaturated fats = double bond (liquid at room temp)

Question 15

phospholipids

Answer 15

major component of cell membrane
polar head made up of phosphate
nonpolar tails made up of fatty acid

Question 16

micelles

Answer 16

groups of phospholipids
(polar head faces water)

Question 17

steroids

Answer 17

*only lipid with a ring structure
*cholesterol, sex etc.
*nonpolar and insoluble in water
*able to pass through cell membranes
*easy access to our DNA

Question 18

anabolic steroids

Answer 18

*mimic testosterone
*increase protein synthesis and cellular tissue (muscle)
*increase cholesterol, blood pressure
*more blood flow to tissues, higher BP
*cancer too

Question 19

what determines the function of the protein

Answer 19

the structure determines the function of the protein

Question 20

how many different amino acids are there?

Answer 20

20 different amino acids

Question 21

what is the functional group of protein

Answer 21

*Amino Acid
*an amine group (carboxyl group and a functional group)

Question 22

what kind of bonds hold together the tertiary structure of a protein

Answer 22

weak bonds hold the tertiary structure together. It is easily denatured (unfolded) due to changes in pH or temperature

Question 23

What are amino acids linked with

Answer 23

Peptide bonds

Question 24

What is a glycoprotein composed of?

Answer 24

Protein + carbohydrate

Question 25

What is a lipoprotein composed of?

Answer 25

Protein + lipid

Question 26

What are the 3 macromolecules that make up the cell?

Answer 26

Lipids, Carbohydrates, and Proteins

Question 27

define enzymes

Answer 27

enzymes are biological catalysts:
1. increase rate of rxn
2. are not changed by the rxn (so it can be used again)
3. do not change the nature of the reaction (the rxn can ouccur without the enzyme, just slower rxn rate)

Question 28

activation energy

Answer 28

the energy required for the reactancts to engage in a reaction

Question 29

adding heat to a rxn

Answer 29

adding heat increases the likelihood of a rxn occuring = increases rxn rate

Question 30

catalysts

Answer 30

help the rxn occur at lower temperatures by lowering the required activation energy

Question 31

describe how enzymes work with conformation and active sites

Answer 31

• each enzyme has a specifc conformation, with pockets that serve as active sites in the enzyme
• the reactants are called substates, and they fit into the active site

Question 32

describe the 2 models of enzyme activity

Answer 32

lock and key model
Induced fit model: enzyme structural change (wraps around substrate)

Question 33

enzyme-substrate complex

Answer 33

temporary bonds form creating the enyzme-substrate complex

Question 34

enzyme activity

Answer 34

measured by the rate at which substrate is converted to product

Question 35

conditions that influence enzyme activity

Answer 35

• temperature
• pH
• concentration of cofactors and coenzymes
• concentration of enzyme and substrate

Question 36

effects of temperature on enzymes

Answer 36

an increase in temp will increase rate of rxn until the temp reaches above body temp. At this point the enzyme is denatured.

Sustained high fever = denatured proteins

Question 37

effects of pH on enzymes

Answer 37

enzymes exhibit peak activity within a narrow pH range = pH optimum
optimium pH reflects the pH of the fluid the enzyme is found in (stomach vs saliva)

Question 38

coenzymes

Answer 38

• an additional small molecule to aid in the rxn
• they transport hydrogen atoms and other small molecules between enzymes

Question 39

cofactors

Answer 39

• metal ions (Ca²⁺, Mg²⁺, Mn²⁺, Zn²⁺)
• help form the active site through a conformational change of enzyme or help in enzyme-substrate binding.

Question 40

substrate concentrations

Answer 40

as substrate concentration increases, rate of rxn increases until the enzymes become saturated.

Question 41

metabolic pathway

Answer 41

• formed by many enzymes
• most rxns are linked together in a chain or web

Question 42

allosteric inhibition

Answer 42

• negative feedback
• what is turned on must be turned off
• main goal of allosteric inhibition: keep a specific final product from accumulating

Question 43

branch point

Answer 43

• are often inhibited by a form of negative feedback in which one of the final products inhibits the branch point enzyme
• a divergent pathway becomes favored (chocolate chip cookies to PB cookies)