Biological molecules Flashcards
Define: “Anabolism”
Synthesis of small particles into larger molecules
Define: “Catabolism”
Breakdown of larger molecules to smaller particles
Give 4 examples of micromolecules
Amino acids, Fatty acids, Monosaccharides, Nucleotides
Give 4 examples of macromolecules
Proteins, Lipids, Carbohydrates, DNA/RNA
Give 3 examples of monosaccharides
Glucose, Fructose, Galactose
Give 3 examples of disaccharides
Sucrose, Lactose, Maltose
Give 4 examples of polysaccharides
Glycogen, Starch, Cellulose, Inulin
State the general formula of carbohydrates
Cn(H2O)n
State the general formula of monosaccharides
(CH2O)n
State the difference between alpha-gluclose & beta-glucose
Alpha-glucose has its hydroxide group below the first carbon atom, while beta-glucose has its hydroxide group above the first carbon atom.
State 2 roles of monosaccharides in living organisms
Source of energy in respiration (glucose) & building blocks for larger molecules.
Explain how monosaccharides (glucose) are good sources of energy.
Due to its large number of CH bonds, when broken up, it releases energy (ATP)
Explain the difference between a condensation reaction and hydrolysis in monosaccharides
Condensation: How 2 monosaccharides join together to form disaccharides
Hydrolysis; Addition of water, reverse of condensation—breaks up a disaccharide to form 2 monosaccharides
Which polysaccharide(s) make up starch?
Alpha-glucose amylose and amylopectin
State the difference between amylopectin and amylose
Amylose: A polysaccharide joined by many 1,4-linked alpha glucose molecules. (Spring-like structure)
Amylopectin: A polysaccharide joined by many 1,4-linked alpha glucose molecules & 1,6- linked alpha gluclose molecules (Branched-structure due to 1,6 linkages)
Which polysaccharide(s) make up glycogen?
Alpha-glucose amylopectin
Which polysaccharide(s) make up cellulose?
Beta-glucose, 1-4 beta linkages
List the properties of cellulose (4)
Very high tensile strength, provides support, responsible for cell expansion, freely premeable
OR
> Higher tensile strength
> freely permeable
> mechanical strength
> inelastic
List 3 lipids
Triglyceride, phospholipids, and cholesterol
Describe the structure of Triglycerol
3 fatty acids that link to a glycerol molecule, forming an ester bond.
State the properties of lipids (6)
Hydrophobic, non-polar, energy reserves, insulation against loss of heat, buoyance, metabolic source of water
Explain why lipids are good for storage (3)
doesnt dissolve in water/bodily fluids, doesnt affect osmotic balance, has higher calorific values than carbohydrates
Describe the structure of phospholipids
2 fatty acids and one phosphate group attaches to the glycerol, phosphoester bond between phosphate and glycerol and ester bond between the amino acids and glycerol.
Explain why unsaturated lipids (plants) are healthy.
Dissolves easily / lower melting point
state the role of proteins (Forms: __) (5)
Haemoglobin, antibodies, makes up all enzymes, keratin (makes hair, surface layer of skin, nails), Collagen (makes up our bones and wall of arteries)
State the name of the bond between amino acids that form proteins.
Peptide bond
Describe the structure of an amino acid
Amine group - R group - carboxylic acid
(NH2 - R - COOH)
(In proteins) Explain what a ‘primary structure’ is
A simple strand structure joined by peptide bonds.
( a.a - a.a - a.a - a.a )
(In proteins) Explain what a ‘secondary structure’ is
Composed of two structures:
Alpha-Helix : Polypeptide chain coiled due to the attraction of molecues, forming a helix shape.
Beta-Pleated sheet : polypeptide; a much looser, straighter shape.
(Proteins) Give examples of where alpha-helix is found and where beta-pleated sheet is found.
Alpha-Helix : hemoglobin and myoglobin
Beta-pleated sheet: silk protein
(In proteins) Explain what a ‘tertiary structure’ and the 3 bonds that can be found in it and where
The secondary structure coils and folds to form 3-dimensional shapes that contains hydrophobic interactions between R groups.
Four bonds included:
-Disulphide bonds (Between cysteine molecules)
-Hydrogen bonds (R)
-Ionic bonds (R)
(In proteins) Explain what a ‘quaternary structure’ is with one example
A 4 unit structure, each unit containing a different combination of amino acids.
E.g. Haemoglobin
Explain the difference between globular proteins and fibrous proteins, as well as 2 examples for each.
Globular: Protein whose molecules are spherical/ball-shaped (tertiary structure) (Curls up so non-polar, hydrophobic R groups point into the center of the molecule, while the polar, hydrophylic R groups remain on the outside)
E.g., hemoglobin, myoglobin
Fibrous: Proteins with long strands, insoluble
Fibrous: Protein with long strands, insoluble and have structural roles (quaternary structure)
E.g., keratin, collagen
Describe the structure of water
Unshared negative electrons on oxygen give it a slight negative charge
State 5 properties of water
1) High specific heat capacity
2) High latent heat of evaporation
3) Cohesive
4) Good solvent
5) Less dense when solid
What is the monomer of protein
Amino acids
What is the monomer of lipids
Fatty acids (and glycerol)
What is the monomer of carbohydrates
Monosaccharides
What is the monomer of DNA/RNA/Nucleic acids
Nucleotides
Why is it important to have 2 types of glucose (alpha & beta)? (List 2-3)
Greater chemical variety, alpha glucose is respiratory, beta glucose is structural
Why are phospholipids arranged the way they are in cell membranes?
Polar heads mix with water; non-polar tails do not. Thus, heads face water on both sides with tails to middle
In an amino acid, what does the R-group represent?
Rest of the molecule/side chain
Give an example of an R-group (2)
Hydrogen, Methyl group (CH3)
What is the molecular formula for amylose?
C6H10O5
