Definitions 2

Question 1

fat

Answer 1

a solid triglyceride (lipid).
Formed when fatty acids with many double bonds in the hydrocarbon chain (saturated) join to glycerol (animals)

Question 1

oil

Answer 1

a liquid triglyceride (lipid).
Formed when three fatty acids with many double bonds in the hydrocarbon chain (unsaturated) join to glycerol (plants)

Question 2

immiscible

Answer 2

two or more liquids incapable of being mixed to form a homogenous substance. e.g. oil and water

Question 3

Triglyceride

Answer 3

Glycerol and three fatty acids covalently bonded together

Question 4

Ester bond

Answer 4

Name the bond formed between a molecule of glycerol and a molecule of fatty acid

Question 5

Unsaturated

Answer 5

Not all carbon atoms in the hydrocarbon chain of a fatty acid are linked the maximum number of hydrogens. There are one or more double bonds between the carbons

Question 6

Saturated

Answer 6

All carbon atoms in the hydrocarbon chain of a fatty acid are linked to the maximum number of hydrogens. There are no double bonds between the carbons

Question 7

Phospholipid

Answer 7

Composed of glycerol, two fatty acids and a phosphate group

Question 8

Hydrophilic

Answer 8

‘water loving’ A substance which dissolves in or bonds with water (polar substance)

Question 9

Hydrophobic

Answer 9

‘water hating’ A substance which does not dissolve in or bond with water (non-polar substance)

Question 10

Amino acid

Answer 10

Basic monomer of polypeptides

Question 11

Carboxylic acid group

Answer 11

• COOH

Question 12

Amino group

Answer 12

• NH2

Question 13

R group

Answer 13

Variable group of an amino acid

Question 13

Peptide bond

Answer 13

Name of bond linking amino acids together

Question 14

Primary structure

Answer 14

sequence of amino acids in a polypeptide chain

Question 15

Secondary structure

Answer 15

Alpha helix and beta pleated sheets. Held together by hydrogen bonds

Question 16

Tertiary structure

Answer 16

Further folding of the polypeptide chain to form a 3D structure. Held together by disulphide bridges, ionic bonds, hydrophobic bonds and hydrogen bonds

Question 17

Quaternary structure

Answer 17

Two or more polypeptide chains bonded together

Question 18

Alpha helix

Answer 18

Secondary structure of protein. Polypeptide chain spirals to form a helical structure

Question 19

Ionic bond

Answer 19

Bond between groups with a full positive and negative charge

Question 20

Disulphide bond

Answer 20

Covalent bond between two sulphur atoms (found in tertiary structure of protein)

Question 21

Hydrophobic bond

Answer 21

Found in tertiary structure of protein. Bonds formed as the hydrophobic groups of the amino acids associate together

Question 22

Globular protein

Answer 22

3D, spherically shaped protein. Generally water-soluble. Concerned with the metabolism of the body e.g. haemoglobin, enzymes

Question 23

Fibrous protein

Answer 23

3D, long, thin, shaped protein. Structural role in the body e.g. collagen and keratin