Biological Molecules

Question 1

What causes hydrogen bonding between water molecules?

Answer 1

Hydrogen bonds form between slightly positive hydrogen atoms and slightly negative oxygen atoms in water molecules

Question 2

What are four roles of water in organisms?

Answer 2

(A) Solvent. (B) Transport medium. (C) Coolant. (D) Habitat

Question 3

Define monomers and polymers.

Answer 3

Monomers are single subunits. Polymers are long chains of monomers bonded together

Question 4

What are condensation and hydrolysis reactions?

Answer 4

Condensation joins molecules and releases water. Hydrolysis breaks molecules using water.

Question 5

Which elements are found in carbohydrates?

Answer 5

Carbon, hydrogen and oxygen.

Question 6

Which elements are found in lipids?

Answer 6

Carbon, hydrogen and oxygen.

Question 7

Which elements are found in proteins?

Answer 7

Carbon, hydrogen, oxygen, nitrogen and sulfur

Question 8

Which elements are found in nucleic acids?

Answer 8

Carbon, hydrogen, oxygen, nitrogen and phosphorus.

Question 9

What is the structure of α-glucose?

Answer 9

Six-carbon ring with OH below carbon 1.

Question 10

What is the structure of β-glucose?

Answer 10

Six-carbon ring with OH above carbon 1.

Question 11

What is the structure of ribose?

Answer 11

Five-carbon ring with one oxygen atom.

Question 12

What is the difference between a hexose and a pentose sugar?

Answer 12

Hexose has 6 carbons. Pentose has 5.

Question 13

What two monosaccharides form sucrose?

Answer 13

Glucose + fructose

Question 14

What two monosaccharides form lactose?

Answer 14

Glucose + galactose.

Question 15

What two monosaccharides form maltose?

Answer 15

Glucose + glucose.

Question 16

How are polysaccharides formed?

Answer 16

Formed in condensation reactions between monosaccharides.

Question 17

How are glycosidic bonds broken?

Answer 17

Broken in hydrolysis reactions.

Question 18

What are the two components of starch?

Answer 18

Amylose (unbranched, 1,4 bonds) and amylopectin (branched, 1,4 and 1,6 bonds)

Question 19

What is the structure of glycogen?

Answer 19

Highly branched, compact polymer of α-glucose

Question 20

What is the structure of cellulose?

Answer 20

Linear chains of β-glucose with hydrogen bonds forming microfibrils.

Question 21

How is the structure of starch related to its function?

Answer 21

Amylose is compact. Amylopectin is branched for rapid glucose release

Question 22

How is the structure of glycogen related to its function?

Answer 22

Highly branched for rapid glucose release in animals.

Question 23

How is the structure of cellulose related to its function?

Answer 23

Strong fibres for cell wall support.

Question 24

What is the structure of a triglyceride?

Answer 24

Glycerol + 3 fatty acids.

Question 25

What is the structure of a phospholipid?

Answer 25

Glycerol + 2 fatty acids + phosphate group

Question 26

What is the difference between saturated and unsaturated fatty acids?

Answer 26

Saturated: no double bonds. Unsaturated: one or more double bonds.

Question 27

What bond is formed in triglyceride synthesis?

Answer 27

Ester bond between glycerol and fatty acid.

Question 28

How are triglycerides broken down?

Answer 28

Broken by hydrolysis of ester bonds.

Question 29

What are the functions of triglycerides?

Answer 29

Energy store. Insulation. Buoyancy

Question 30

What are the functions of phospholipids?

Answer 30

Form bilayers. Structural role in membranes

Question 31

What is the role of cholesterol?

Answer 31

Stabilises membranes. Regulates fluidity.

Question 32

What is the general structure of an amino acid?

Answer 32

Central carbon with H, carboxyl, amine and R group

Question 33

What bond is formed in peptide synthesis?

Answer 33

Peptide bond

Question 34

What are the four levels of protein structure?

Answer 34

Primary, secondary, tertiary, quaternary

Question 35

What interactions are involved in tertiary protein structure?

Answer 35

Hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic and hydrophilic interactions.

Question 36

What is a conjugated protein?

Answer 36

Protein with a prosthetic group.

Question 37

Name a conjugated protein.

Answer 37

Haemoglobin

Question 38

Give two examples of globular proteins.

Answer 38

Enzymes and insulin.

Question 39

Give three examples of fibrous proteins

Answer 39

Collagen, keratin, elastin

Question 40

What is the role of calcium ions?

Answer 40

Nerve transmission. Muscle contraction. Enzyme cofactor

Question 41

What is the role of sodium ions?

Answer 41

Nerve impulses. Osmotic balance.

Question 42

What is the role of potassium ions?

Answer 42

Nerve impulses. Stomatal opening.

Question 43

What is the role of hydrogen ions?

Answer 43

pH regulation.

Question 44

What is the role of ammonium ions?

Answer 44

Source of nitrogen.

Question 45

What is the role of nitrate ions?

Answer 45

Source of nitrogen for amino acids and nucleotides.

Question 46

What is the role of hydrogencarbonate ions?

Answer 46

Buffers blood pH.

Question 47

What is the role of chloride ions?

Answer 47

Chloride shift in gas transport.

Question 48

What is the role of nitrogen ions?

Answer 48

Component of ATP, DNA, membranes

Question 49

What is the role of hydroxide ions?

Answer 49

pH balance.

Question 50

What is the biuret test used for?

Answer 50

Proteins

Question 51

What is the Benedict’s test used for?

Answer 51

Reducing sugars

Question 52

How do you test for non-reducing sugars?

Answer 52

Hydrolyse with acid, then Benedict’s test.

Question 53

What is the iodine test used for?

Answer 53

Starch

Question 54

What is the emulsion test used for?

Answer 54

Lipids

Question 55

What is colorimetry used for?

Answer 55

Measures concentration of solutions via light absorbance

Question 56

What is chromatography used for?

Answer 56

Separation based on solubility in solvent.

Question 57

What is the formula for calculating Rf value?

Answer 57

Rf = distance moved by solute / distance moved by solvent