Biological Molecules Flashcards
Name the Chemical Elements that makes up the Biological Molecules for Carbohydrates
Carbon,Hydrogen, and Oxygen
Name the Chemical Elements that makes up the Biological Molecules for Lipids
Carbon,Hydrogen, and Oxygen
Name the Chemical Elements that makes up the Biological Molecules for Proteins
Carbon,Hydrogen,Oxygen, Nitrogen and Sulphur
Name the Chemical Elements that makes up the Biological Molecules for Nucleic acids
Carbon,Hydrogen,Oxygen, Nitrogen and Phosphorus
How would you represent Hydrogen Bonding in a diagram
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
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
Allows gases to dissolve e.g. oxygen for fish
Water as a solvent can allow * gases to dissolve e.g. oxygen for fish*
Name another for aquatic organisms
Polar / ionic , substances can dissolve e.g. so aquatic plants can take up ions
Water has a high latent heat of vaporisation
Which can be used for _______ e.g. sweating / panting / transpiration
Cooling
Why is Water Cohesive
Water molecules are attracted to each other because of hydrogen bonds
Water has a high specific heat of capacity
This means in animals it is
1.Slow to change temperature
2.Internal body temperature changes minimised
Water as a solvent can allow polar / ionic , substances can dissolve e.g. so aquatic plants can take up ions
Name another for Plants
Can form long unbroken columns of water in xylem vessels due to cohesion between molecules
Reactant in photosynthesis
Water has properties of cohesion
How does this effect aquatic organisms
What is the role of water for aquatic organisims (specifically cohesion)
Organisms can use surface of water (as habitat); e.g.; water boatman due to surface tension due to cohesion between water molecules
FILL THE BLANK
1.Water is a ____ at normal temperature
2.________ Bonding between water molecules
3.________ are more difficult to seperate
1.WATER
2.HYDROGEN
3.MOLECULES
Water has High heat capacity
Which means…
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
Define Hydrolysis
Breaking a bond with the addition of water
Define Condensation
In terms of breaking/making bonds
Formation of a bond with the release of water
This question is about Protein Structure
Draw an Amino Acid
H
(H2)- N - C - (COOH)
R
This question is about Protein Structure
Define Primary Structure
The sequence / order of amino acids in a polypeptide
This question is about Protein Structure
Define Secondary Structure
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)
This question is about Protein Structure
Define Tertiary Structure
Secondary Structure undergoes futher coiling and folding to form a 3D Structure held by bonds and hydrophobic / hydrophilic interactions
This question is about Protein Structure
Name the 3 Types of bonds
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 *
Define Hydrophilic Interactions
Hydrophilic R groups* on outside* and Hydrophobic R groups on inside of soluble globular proteins
Define Hydrophobic Interactions
Hydrophobic R groups* on outside* and Hydrophillic R groups on inside of soluble globular proteins
This Question is about the Structure Of Haemoglobin
What is the quaternary structure of haemoglobin
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)
What is the general formula of Carbohydrates
Cx(H2O)y
What is the types of carbohydrates
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.
Glucose is a Hexose , Meaning…
6 Membered Ring
CH2OH Side Chain in Glucose
OH above Carbon 3
Ribose is a Pentose , Meaning…
5-membered ring
CH2OH Side chain as in glucose
OH below carbon 3
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
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)
This question is about Chemical Tests
What is the test for Proteins
- Add Biuret solution: positive turns blue to lilac
This question is about Chemical Tests
What is the test for Reducing sugar
- Add / use , Benedict’s (reagent) and heat to >70C ; NOT use water bath alone
- Turns from blue to green / yellow / orange / brown / red (precipitate)
This question is about Chemical Tests
What is the test for Non reducing sugar
- Hydrolysis by boiling , with acid / HCl
- Add Benedict’s reagent
This question is about Chemical Tests
What is the test for Starch
Iodine solution turns yellow to blue/black
What is the test for Lipids
- mix with alcohol/ethanol
- add water
- positive : forms emulsion / milky colour / cloudy
Describe the structure and properties Cellulose
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.
Describe the structure and properties Amylose
- Made of alpha glucose joined by 1,4 glycosidic bonds
- Linear: linear non-branching “straight” chains
- Compact : chain coils to form a helix
This question is about Lipids
What is the structure of a Triglyceride
- 3 fatty acids ;
- 1 glycerol ;
- ester linkages formed by condensation reaction
This question is about Lipids
What is the structure of a Phospholipids
- 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
What is the structure of Haemoglobin
-Globular
-Hydrophillic R group on the outside
-Hydrophobic R group in the inside
-Similar proportion of glycine to other amino acids
-4 chains
What is the structure of Collagen
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
Describe the effects of Denaturation and PH
- 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
What are features of globular proteins
- 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
What is a Conjugated Protein
A protein containing a prosthetic group
What are features of fibrous proteins
- Regular repeating sequences of amino acids
- Insoluble in water
- Form fibres
- Structural function e.g.
Collagen and elastin in connective tissue
Keratin in hair
Keratin has alot of _B_L_A_N_K__
Keratin acts as a B_L_A_N K and is waterproof
- Cystine Residues, making it strong
- Barrier
Elastin has BLANK and Blank to make in strong and extentable to strech and recoil
Crosslinks and Coils
