Biological Molecules

Question 1

Name the Chemical Elements that makes up the Biological Molecules for Carbohydrates

Answer 1

Carbon,Hydrogen, and Oxygen

Question 2

Name the Chemical Elements that makes up the Biological Molecules for Lipids

Answer 2

Carbon,Hydrogen, and Oxygen

Question 3

Name the Chemical Elements that makes up the Biological Molecules for Proteins

Answer 3

Carbon,Hydrogen,Oxygen, Nitrogen and Sulphur

Question 4

Name the Chemical Elements that makes up the Biological Molecules for Nucleic acids

Answer 4

Carbon,Hydrogen,Oxygen, Nitrogen and Phosphorus

Question 5

How would you represent Hydrogen Bonding in a diagram

Answer 5

Dashed line between (O) on one molecule and (H) on the adjacent molecule

Hydrogen / H, bond label (on any drawn bond between 2 molecules)

(delta positive) + on each drawn H and (delta negative) - on each drawn O

Question 6

Water as a solvent can allow polar / ionic , substances can dissolve e.g. so aquatic plants can take up ions

Name another for aquatic organisms

Answer 6

Allows gases to dissolve e.g. oxygen for fish

Question 7

Water as a solvent can allow * gases to dissolve e.g. oxygen for fish*

Name another for aquatic organisms

Answer 7

Polar / ionic , substances can dissolve e.g. so aquatic plants can take up ions

Question 8

Water has a high latent heat of vaporisation

Which can be used for _______ e.g. sweating / panting / transpiration

Answer 8

Cooling

Question 9

Why is Water Cohesive

Answer 9

Water molecules are attracted to each other because of hydrogen bonds

Question 10

Water has a high specific heat of capacity

This means in animals it is

Answer 10

1.Slow to change temperature

2.Internal body temperature changes minimised

Question 11

Water as a solvent can allow polar / ionic , substances can dissolve e.g. so aquatic plants can take up ions

Name another for Plants

Answer 11

Can form long unbroken columns of water in xylem vessels due to cohesion between molecules

Reactant in photosynthesis

Question 12

Water has properties of cohesion

How does this effect aquatic organisms

What is the role of water for aquatic organisims (specifically cohesion)

Answer 12

Organisms can use surface of water (as habitat); e.g.; water boatman due to surface tension due to cohesion between water molecules

Question 13

FILL THE BLANK

1.Water is a ____ at normal temperature
2.________ Bonding between water molecules
3.________ are more difficult to seperate

Answer 13

1.WATER
2.HYDROGEN
3.MOLECULES

Question 14

Water has High heat capacity
Which means…

Answer 14

water slow to change temperature
lakes / oceans / large volumes , provide thermally stable environment;
large amount of energy must be removed for water to freeze;
ice floats on water / water freezes from top down;
insulates water beneath;
large bodies of water don’t freeze completely / animals can still swim etc.;
(change in density with temperature) causes currents to circulate nutrients

Question 15

Define Hydrolysis

Answer 15

Breaking a bond with the addition of water

Question 16

Define Condensation

In terms of breaking/making bonds

Answer 16

Formation of a bond with the release of water

Question 17

This question is about Protein Structure

Draw an Amino Acid

Answer 17

H

(H2)- N - C - (COOH)

R

Question 18

This question is about Protein Structure

Define Primary Structure

Answer 18

The sequence / order of amino acids in a polypeptide

Question 19

This question is about Protein Structure

Define Secondary Structure

Answer 19

Coling/ Folding of the chain of amino acids peptide chain , in the primary structure to form

- Alpha Helix
- Beta Pleated Sheet

Held by hydrogen bonds between amino acids in same chain ;(between -NH and -CO)

Question 20

This question is about Protein Structure

Define Tertiary Structure

Answer 20

Secondary Structure undergoes futher coiling and folding to form a 3D Structure held by bonds and hydrophobic / hydrophilic interactions

Question 21

This question is about Protein Structure

Name the 3 Types of bonds

Answer 21

Disulfide Bonds (covalent) between sulphur atoms in cysteine residues
Ionic Bonds between oppositely charged R groups
Hydrogen Bonds *between delta positive and delta negative R groups *

Question 22

Define Hydrophilic Interactions

Answer 22

Hydrophilic R groups* on outside* and Hydrophobic R groups on inside of soluble globular proteins

Question 23

Define Hydrophobic Interactions

Answer 23

Hydrophobic R groups* on outside* and Hydrophillic R groups on inside of soluble globular proteins

Question 24

This Question is about the Structure Of Haemoglobin

What is the quaternary structure of haemoglobin

Answer 24

4 polypeptides / subunits ;
2 α, chains and 2 β, chains ;
prosthetic group is haem which contains Fe2+
1 haem group per polypeptide / 4 haems (per molecule)

Question 25

What is the general formula of Carbohydrates

Answer 25

Cx(H2O)y

Question 26

What is the types of carbohydrates

Answer 26

**Monosaccharides**- these are simple sugars, with the general formula (CH2O)n, where n can be 3–7 **Disaccharides**-these are formed from two monosaccharides **Polysaccharides**-these are large molecules formed from many monosaccharides.

Question 27

Glucose is a Hexose , Meaning...

Answer 27

6 Membered Ring CH2OH Side Chain in Glucose OH above Carbon 3

Question 28

Ribose is a Pentose , Meaning...

Answer 28

5-membered ring CH2OH Side chain as in glucose OH below carbon 3

Question 29

*Glucose exists in different forms called structural isomers. Two common isomers are alpha glucose and beta glucose.* What is the **difference** between **Alpha and Beta Glucose**

Answer 29

In **alpha- glucose** the **hydroxyl (OH)** group on **carbon 1 is below the plane** of the ring structure In **beta-glucose** the **hydroxyl (OH)** group on **carbon 1 is above the plane** of the ring structure *Think ABBA (alpha below, beta above)*

Question 30

# This question is about Chemical Tests What is the test for Proteins

Answer 30

* Add Biuret solution: positive turns blue to lilac

Question 31

# This question is about Chemical Tests What is the test for Reducing sugar

Answer 31

* Add / use , Benedict’s (reagent) and heat to >70C ; NOT use water bath alone * Turns from blue to green / yellow / orange / brown / red (precipitate)

Question 32

# This question is about Chemical Tests What is the test for Non reducing sugar

Answer 32

* Hydrolysis by boiling , with acid / HCl * Add Benedict’s reagent

Question 33

# This question is about Chemical Tests What is the test for Starch

Answer 33

Iodine solution turns yellow to blue/black

Question 34

What is the test for Lipids

Answer 34

* mix with alcohol/ethanol * add water * positive : forms emulsion / milky colour / cloudy

Question 35

Describe the structure and properties Cellulose

Answer 35

Polymer (polysaccharide) * Made of beta glucose linked by glycosidic bonds * Each molecule is flipped 180; Straight chains * held together by hydrogen bonds Forms fibrils * cross linkage between chains * strong; * insoluble ; Role: Cellulose is found in plant cell walls: * It doesn’t coil and forms straight bundles known as microfibrils which are strong. * Although very strong the cell wall is fully permeable. * The hydrogen cross-links make cellulose very resistant to hydrolysis also making it an excellent structural carbohydrate.

Question 36

Describe the structure and properties Amylose

Answer 36

* Made of alpha glucose joined by 1,4 glycosidic bonds * Linear: linear non-branching “straight” chains * Compact : chain coils to form a helix

Question 37

# This question is about **Lipids** What is the structure of a **Triglyceride**

Answer 37

* 3 fatty acids ; * 1 glycerol ; * ester linkages formed by condensation reaction

Question 38

# This question is about **Lipids** What is the structure of a **Phospholipids**

Answer 38

* 1 less fatty acid (residue) / 2 fatty acid (residues) not 3 ; * 1 less ester bond / 2 ester bonds not 3 ; * phosphate ; ; * hydrophilic / polar , end / head

Question 39

What is the structure of **Haemoglobin**

Answer 39

-Globular -Hydrophillic R group on the outside -Hydrophobic R group in the inside -Similar proportion of glycine to other amino acids -4 chains

Question 40

What is the structure of **Collagen**

Answer 40

*Peptide bonds , between amino acids in a polypeptide (Primary Structure) Every 3rd amino acid is , same/glucine* *Coil/Sprial/Helix* **Left handed Helix** **Glycine / Small R Group, allows closeness ** **Three Polypeptide Chains** **Hydrogen bonds between peptide chains** *Hydrophobic R groups on the outside* *adjacent molecules joined by crosslinks crosslinks/end of molecules*

Question 41

Describe the effects of **Denaturation and PH**

Answer 41

* loss of tertiary structure / loss of 3D structure * change in pH/[H+] alters charge distribution on protein molecule; * hydrogen / ionic , bonds break * changes shape of protein

Question 42

What are features of **globular proteins**

Answer 42

* Almost spherical-often with specific shapes which are complementary to other shapes e.g. * active sites in enzymes * Signalling molecules such as hormones including peptide hormones e.g. insulin

Question 43

What is a **Conjugated Protein**

Answer 43

A protein containing a prosthetic group

Question 44

What are features of **fibrous proteins**

Answer 44

* Regular repeating sequences of amino acids * **Insoluble in water** * **Form fibres** * Structural function e.g. Collagen and elastin in connective tissue Keratin in hair

Question 45

Keratin has alot of _B_L_A_N_K__ Keratin acts as a _B_L_A_N K_ and is waterproof

Answer 45

1. Cystine Residues, making it strong 2. Barrier

Question 46

Elastin has BLANK and Blank to make in strong and extentable to strech and recoil

Answer 46

Crosslinks and Coils