Week 2.2 - Chemical Composition of the Body

Question 1

what are the 3 components of an atom

Answer 1

• proton
• neutron
• electron

Question 2

define isotopes

Answer 2

• when a chemical element exists in multiple forms

- same # of protons but different neutrons

Question 3

define ions

Answer 3

when an atom gains / loses an electron

Question 4

define net positive charge

Answer 4

CATIONS

- atom loses an electron

Question 5

give an example of a cation

Answer 5

Na has 11 electrons so loses one and become Na+

Question 6

define net negative charge

Answer 6

ANIONS

- atom gains an electron

Question 7

give an example of an anion

Answer 7

Cl has 17 electrons so gain one and becomes Cl-

Question 8

define molecule

Answer 8

two or more atoms bonded together e.g. oxygen has 2 H atoms

Question 9

define compound

Answer 9

two or more different elements e.g. water has 2 H and 1 O

Question 10

what is the atomic compound of glucose ?

Answer 10

6CH12O6

Question 11

define covalent bond

Answer 11

one or more electrons in the outer shell are shared between the two atoms

Question 12

when does a double bond form ?

Answer 12

when two atoms share two electrons from each atom

Question 13

define polar covalent bond

Answer 13

electrons aren’t always shared equally between 2 atoms but reside close to one atom of the pair

Question 14

define non-polar covalent bond

Answer 14

bonds between atoms with similar electronegativities

Question 15

define electronegativity

Answer 15

the ability of an atom to attract electrons

Question 16

define nonpolar molecules

Answer 16

molecules that contain high proportions of non-polar covalent bonds

Question 17

define hydrogen bonds

Answer 17

when two polar molecules are in close contact, an electrical attraction may form between them

Question 18

define ionic bonds

Answer 18

string attraction between oppositely charged ions

Question 19

define solutes

Answer 19

substances dissolved in a liquid

Question 20

define solvent

Answer 20

the liquid in which solutes are dissolved

Question 21

define solution

Answer 21

the rest of a solute dissolving in a solvent

Question 22

define hydrophilic

Answer 22

molecules that are able to dissolve in water

Question 23

define hydrophobic

Answer 23

molecules with nonpolar covalent bonds that are not able to dissolve in water

Question 24

define amphipathic molecules

Answer 24

special class of molecules that have a polar region at one end and a nonpolar region at the opposite end

Question 25

define inorganic chemistry

Answer 25

the study of noncarbon-containing molecules

Question 26

define organic chemictry

Answer 26

the study of carbon-containing molecules

Question 27

define macromolecules

Answer 27

extremely large molecules composed of thousands of atoms

Question 28

define polymers

Answer 28

repeating macromolecules

Question 29

what are the 3 carbohydrates ?

Answer 29

- monosaccharides - disaccharide - polysaccharides

Question 30

what are the 4 lipids ?

Answer 30

- fatty acids - triglycerides - phospholipids - steroids

Question 31

what are the 2 proteins ?

Answer 31

- amino acid subunits | - polypeptides

Question 32

what are the 2 nucleic acids ?

Answer 32

- DNA | - RNA

Question 33

define carbohydtrates

Answer 33

- provide cells with energy - energy stored in ATP bonds - composed of C, H, and O atoms

Question 34

define monosaccharides

Answer 34

- simples sugars - open chain form - glucose

Question 35

define disaccharides

Answer 35

- composed of 2 monosaccharides - sucrose (table sugar) - dehydration reaction - hydrolysis

Question 36

define hydroxyl group

Answer 36

group of oxygen and hydrogen that binds to molecules

Question 37

define dehydration reaction

Answer 37

removal of hydroxyl group from one monosaccharide and removal of hydrogen atom in the other

Question 38

define hydrolysis

Answer 38

breaking the linkage between monosaccharides by adding water back

Question 39

define polysaccharides

Answer 39

many monosaccharides are linked together to form polymers | - glycogen

Question 40

define lipids

Answer 40

- mainly H and C atoms - linked by nonpolar covalent bonds - source of energy

Question 41

define fatty acids

Answer 41

chain of C and H atoms + acidic carboxyl group at one end

Question 42

define saturated fatty acids

Answer 42

when the carbons in a fatty acid are linked by a singular covalent bond

Question 43

define unsaturated fatty acids

Answer 43

one or more double bonds between carbon atoms

Question 44

define trans fatty acids

Answer 44

modification of fatty acids so the hydrogens are on the opposite sides of the double bonds

Question 45

define triglycerides

Answer 45

- glycerol bonds to 3 fatty acids - synthesised in the liver - stored in adipose tissue

Question 46

define animal triglycerides

Answer 46

high proportion of saturated fatty acid

Question 47

define plant triglycerides

Answer 47

unsaturated fatty acids

Question 48

define phospholipids

Answer 48

third hydroxyl group of glycerol is linked to phosphate

Question 49

define steroids

Answer 49

four interconnected rings of carbon atoms

Question 50

define amino acids

Answer 50

subunit monomers of protein

Question 51

define polypeptides

Answer 51

a sequence of amino acids linked by peptide bonds

Question 52

define primary structure

Answer 52

similar to a string of beads, each bead representing one amino acid

Question 53

define secondary structure

Answer 53

interactions between side groups = folding into more compact structures

Question 54

define tertiary structure

Answer 54

associations between additional amino acid side chains

Question 55

define quaternary structure

Answer 55

proteins that are composed of more than one polypeptide chain bonded together