Bio Molecules

Question 1

Globular proteins

Answer 1

1) spherical/ball shaped eg Hb, myoglobin
2) curl up = NON POLAR hydrophillic R groups point to center of mol AWAY from aqueous environment
3) POLAR hydrophilic R groups outside = mixing + dissociating in water easier
4) usually soluble
5) precise shape - have roles in metabolic activities, specific in nature

Question 2

Secondary structure

Answer 2

• Primary structure coiled + FOLDING itself in specific way
• Fibrous
• Hydrophobic R groups point OUTWARDS
• Water insoluable
• H+ bonds between NH of 1 AA + CO of another AA
• Alpha helix and Beta pleated sheets

Question 3

Polar molecules/bonds

Answer 3

1) have groups with dipoles
2) unequal sharing of e- between atoms, creating a partial +ve and partial -ve charge
2) attracted to H2O molecules as they also have dipoles = are hydrophilic and form H+ bonds
3) soluble in water
Eg- amino acids, glucose, NaC

Question 4

How molecular structure of GLYCOGEN makes it suitable for storage (4)

Answer 4

• 1,4 and 1,6-α glycosidic bond
• ALPHA glucose = used for aerobic rep + releases energy
• lots of branches for enzyme attachment
  2) can be hydrolyzed easily + quickly
  3) compact + insoluble= no effect on water potential

Question 5

Polysaccharides

Answer 5

A polymer whose subunits = monosaccharides joined via glycosidic bonds
• Eg- starch, glycogen, cellulose
• NOT sugars

• if glucose itself accumulated in cells it would dissolve + contents of the cell too concentrated = effects osmotic properties
• storage polysaccharides- convenient, compact, inert & insoluble

Question 6

Define monomer and polymer

Answer 6

• many small molecules that combine to form a polymer (larger molecules).
• large molecules made from many similar repeating subunits e.g proteins/nucleic acids.

Question 7

Define macromolecule and monosaccharides

Answer 7

• large molecules formed due to polymerization of monomers e.g proteins/polysaccharides.
• molecule consisting of a single sugar unit with general formula of C(H2O)n

Question 8

Define isomer

Answer 8

• molecule w/ same chem formula + different structural arrangement

Question 9

Breaking a glycosidic bond: disaccharide and polysaccharides e.g sucrose test

Answer 9

• hydrolysis - water is added into the ring
• disaccharide + polysaccharides broken down into hydrolysis reaction

-Sucrose heated w HCL used to break disaccharide = 2 monosaccharides when testing for non-reducing sugar (sucrose). = positive Benedict’s test

Question 10

Molecule structure of starch (plant)

Answer 10

• made of 2 POLYMERS; Amylose and Amylopectin
• polymer of ALPHA glucose
• via condensation reactions between α-glucose linked by a 1-4 glycosidic links/bonds.
• MAIN storage polysaccharides PLANTS ONLY - inert,compact + insoluable (tightly coiled)

Question 11

Structure of amylose(plant)

Answer 11

• made via condensation joined by 1,4 linked alpha glucose molecules (glycosidic bonds)
• long unbranching/NOT BRANCHED chain
  -forms helix with 6 glucose molecules per turn and 300 per helix = COMPACT

Question 12

Structure of amylopectin(plant)

Answer 12

• polymer of ALPHA glucose joined by 1,4 glycosidic bonds BUT branches of 1,6 glycosidic link bonds
  -branched every 20 monomers = easier hydrolyzed for faster release of glucose monomers

Question 13

Structure of cellulose

Answer 13

• MAIN structural of plant cell wall
• STRAIGHT UNBRANCHED PARELLEL chains
• subunit of BETA glucose
• insoluble + High mechanical strength (maintains turgidity/support)
• staggered ends
• many H+ within cellulose mol = forms microfibrils
• microfibrils held tgt by H+ = fibres

Question 14

Why must polysaccharides be insoluable

Answer 14

• cannot dissolve in water as it affects water potential
• decreases water potential in OSMOSIS
• hydrolysis occurs
• cells burst if water enters (mammals)

Question 15

Reducing sugars test- monosaccharides (simple sugars)

Answer 15

• add equal vol of Benedict’s reagent +food sample IN LIQUID FORM to test tube
• heat gently in boiling tube in WB AT 80ºC for 5 mins
• If RS present = blue,green, yellow, orange/brick red (HIGHEST)
• ^^^ conc of reducing sugars INCREASING

Question 16

Test for non reducing sugar - sucrose P1

Answer 16

• • 2cm^3 of sample to 2 cm^3 dilute HCL
• place in gently boiling water bath for 5 mins (hydrolyses disaccharide into 2 monosaccharides –> fructose + glucose)
• test with pH paper to check solution is alkaline
• Re-test solution w Benedict’s reagent
• Heat solution w 2cm3 of Benedict’s in gently boiling water bath for 5 mins

Question 17

Starch/amylose test

Answer 17

• 2 cm^3 of sample in test tube,
• • drops of iodine/potassium iodide SOLUTION to sample
• sample shaken/stirred
• if blue-black is QUICKLY produced = starch present
• iodine SOLUTION is yellow-brown

Question 18

Proteins test in known liquid ALT TO BIURET

Answer 18

1. mix equal vol of solution + dilute potassium hydroxide
2. run dilute copper sulfate solution —-> solution
3. LILAC ring @ interface = Protein
   - blue to LILAC

Question 19

Groups and their bonds
- AMINE (NH2)
- AA
- CARBS
- LIPIDS

Answer 19

Amine group = Proteins w polypeptide bonds
Amino acids= Peptide bonds
Carbohydrates= glycosidic bond
Lipids= Ester bond and Carboxyl groups (CH2 bonds + CH3 bonds) COCO

Question 20

Why is it impt for alpha and beta glucose to differ?

Answer 20

• ISOMERS
• leads to greater chemical variety
• a- glucose is respiratory
• b- glucose is structured

Question 21

SATURATED vs UNSATURATED

Answer 21

• saturated means molecules contain MAX num of H+ atoms (single bond)
• Unsaturated contaisn double bonds/ molecules contain fewer H+ atoms
• Unsaturated= lower MP than saturated
• Unsaturated fat —> forms oil/liquid
• Saturated fats= Solids

Question 22

Uses of lipids

Answer 22

• insulation
• waterproofing
• energy store
• protection
• cell membrane structure

Question 23

Lipid emulsion test

Answer 23

• take sample & add EQUAL vol of ethanol and EQUAL water vol
• SHAKE sample
• mix & if positive = white emulsion/suspension forms
• lipid present
• limitations= objective milk alr white/cloudy

Question 24

Amino acids are amphoteric, meaning??

Answer 24

• molecules contain both acidic + basic groups

Question 25

What is meant by tertiary protein structure

Answer 25

- PP chain/coiled —-> into globular ss 1. IONIC BONDS = between IONIZED AMINE + IONIZED CARBXYL and +/- R groups 2. H+ BONDS between NH AA + CO of another AA 3. DISULPHIDE BRIDGES between sulfur in R groups of 2 cysteine AA 4. HYDROPHOBIC interaction between R groups of 2 AA interior + HYDROPHILLIC R groups face exterior - R groups attract/repel

Question 26

Label each with their sugar group - Ribose, glucose, maltose, starch, lactose, cellulose, glycogen

Answer 26

- Ribose= MONOSACCARIDE - Glucose= MONOSACCHARIDE - Maltose= DISACCHARIDE - Starch= POLYSACCHARIDE - Lactose= DISACCHARIDE - Cellulose= POLYSACCHHARIDE -Glycogen= POLYSACCHARIDE

Question 27

STARCH v CELLULOSE

Answer 27

- Starch contains a-glucose VS Cellulose contains b- glucose - Starch linked by a- glycosidic bonds VS Cellulose linked by b- glucose glycosidic bonds - starch may contain branched chains VS cellulose unbranched chains

Question 28

heating w X solution breaks glycosisidc bonds

Answer 28

- dilute HCL

Question 29

GLYCOGEN VS COLLAGEN

Answer 29

G then C - Carb vs protein - A glucose vs AA - Glycosidc ponds vs Peptide bond - CHO vs CHON

Question 30

# MACROMOLS Protein as a MACROMOL

Answer 30

Monomer: Amino acids - Each AA has an amine group (-NH₂), a carboxyl group (-COOH), and a unique side chain (R-group). - Role = enzymes, structural components, signaling, transport, etc. - amphipathic (both hydrophilic and hydrophobic regions) because they contain polar and non-polar AA.

Question 31

# MacroMol Carbs as Macromol

Answer 31

Monomer: Monosaccharides (e.g., glucose, fructose) - Typically composed of CHO in a 1:2:1 ratio (e.g., C₆H₁₂O₆). -Provide energy (e.g., glucose) and ss support (e.g., cellulose in plants - hydrophilic because of many O-H groups, making them polar.

Question 32

# Marcomol Lipids as a Macromol

Answer 32

Monomer: Glycerol and fatty acid - Nonpolar or hydrophobic molecules, often containing long hydrocarbon chains. - Energy storage, membrane structure, and signaling molecules (e.g., hormones). - hydrophobic due to long hydrocarbon chains, though some, like phospholipids, have polar heads.

Question 33

# Macromol Nucleic acids as Macromol

Answer 33

Monomer: Nucleotides (composed of a sugar, phosphate group, and nitrogenous base). - DNA and RNA store and transmit genetic information. - DNA serves as the blueprint for life, and RNA plays roles in protein synthesis and regulation. - Hydrophilic because of the negatively charged phosphate groups.

Question 34

List for each monomer which elements are present: - AA - Nucleotides - Simple sugars - Lipids/fatty acids

Answer 34

- CHON - CHONP - CHO - CHO

Question 35

why do nuclotides need phosohorus + why do AA need nitrogen

Answer 35

- Phosphorus is essential for the phosphodiester bonds that link nucleotides together in DNA and RNA. - Amino Acids need nitrogen for the amine group (-NH₂). -

Question 36

Non polar mol/bonds

Answer 36

- Equal sharing of electrons, leading to no significant charge difference - Hydrophobic: Repelled by water because they can’t form H+ bonds with water molecules.