1. Carbohydrates, Lipids and Proteins (Biological Building blocks)
IB Biology – Assessment Statements to 3.2.7

2. Chemistry of Life Organic chemistry is the study of carbon compounds
Carbon atoms are versatile building blocks
bonding properties
4 stable covalent bonds
Carbon chemistry = organic chemistry
Why is it a foundational atom?
What makes it so important?
Can’t be a good building block if you only form 1 or 2 bonds.

3. Organic and Inorganic Compounds
Organic compounds contain carbon (C) and occur naturally only in the bodies of living organisms.
They almost always contain hydrogen (H), usually contain oxygen (O) and nitrogen (N),
Sometimes contain phosphate (P), sulfur (S), iron (Fe), copper (Cu), sodium (Na), chlorine (Cl) or potassium (K) in small amounts.
Assessment Statement 3.2.1

4. Organic and Inorganic Compounds
Inorganic compounds do not usually contain carbon. This term is used when referring to any compound that is not organic.
Assessment Statement 3.2.1

5. Organic and Inorganic Compounds
Carbon molecules can form long chains or rings. Allowing for multiple branches for bonding.
The size and arrangement of organic compounds are unlimited.
Organic compounds are divided into 4 groups:
Carbohydrates
Lipids
Proteins
Nucleic acids.
Assessment Statement 3.2.1

6. Complex molecules can be assembled like building blocks.

7. Hydrocarbons can grow…

8. Isomers
Molecules with same molecular formula but different structures (shapes)
different chemical properties
different biological functions
6 carbons
6 carbons
6 carbons

9. Identify amino acids

10. Form affects function
Structural differences create important functional significance
amino acid alanine
L-alanine used in proteins
but not D-alanine
medicines
L-version active
but not D-version
sometimes with tragic results…
stereoisomers

11. Form affects function Thalidomide
prescribed to pregnant women in 50s & 60s
reduced morning sickness, but…
stereoisomer caused severe birth defects

12. Viva la difference!
Basic structure of male & female hormones is identical
identical carbon skeleton
attachment of different functional groups
interact with different targets in the body
different effects

13. Macromolecules
Smaller organic molecules join together to form larger molecules
4 major classes of macromolecules:
carbohydrates
lipids
proteins
nucleic acids

14. Our Organic Friends!
Assessment Statement 3.2.2

15. Carbohydrates
Assessment Statement 3.2.3
Made of C, H and O, where the ratio of C to H to O is 1:2:1.
There are monosaccharides, disaccharides and polysaccharides.
Monosaccharides are
the simple sugars. Their
molecular formula is
C6H12O6.
They are single unit sugars.
Glucose, fructose and galactose.

17. Identify Glucose
Assessment Statement 3.2.2

18. Identify Ribose
Assessment Statement 3.2.2

19. Carbohydrates Most important source of energy – total
energy gain is 4 Calories/gram
Carbohydrates are built from sugar molecules (ending in “ose”).
Some famous sugars include:
Glucose (found in human blood -#1 brain food),
Fructose (plant sugar),
deoxyribose (the sugar portion of DNA),
Cellulose (a polysaccharide that makes up plant walls- commonly known as ruffage or fiber).
Assessment Statement 3.2.6
Assessment Statement 3.2.3

20. Carbohydrates
Disaccharides are double sugars and are made by combining 2 simple sugars together into a two unit sugar.
Examples are sucrose, maltose and lactose.
Polysaccharides are long chains of repeating sugar units.
Multiunit sugar – more than two sugars combined.
Examples are starch, glycogen and cellulose.
Glycogen is stored in animal cells and is
often refered to as animal starch.
Glycogen is made up of 16 to 24 glucose
molecules. The liver converts glycogen
into glucose units for energy.
Assessment Statement 3.2.3

21. List one function each for:
Glucose, lactose, glycogen in animals:
Glucose = monosaccharide, major energy source for fuelling cellular respiration.
Lactose = disaccharide, energy source found in mammalian milk
Glycogen = polysaccharide; energy storage in liver.
Assessment Statement 3.2.4

22. List one function each for:
Fructose, sucrose and cellulose in plants:
Fructose = monosaccharide: energy component in flower nectar
Sucrose = disaccharide: energy molecule transported via phloem
Cellulose = polysaccharide: major structural component of plant cell walls.
Assessment Statement 3.2.4

23. LIPIDS Commonly known as “fat” – total energy gain 9 Calories/gram.
Foods – fish, olive oil, red meat, nuts.
Are a key component in cells, especially in the cell membrane.
They are made of C, H and O.
Yield twice as much energy as carbohydrates.
Lipids are made up of fatty acids and glycerol.
2 types of lipids: saturated and unsaturated.
Assessment Statement 3.2.6
Assessment Statement 3.2.6

24. LIPIDS
Structure: Lipids are made up of two portions a glycerol head and fatty acid tails.
glycerol fatty acids

25. LIPIDS
Lipids can also go through condensation and hydrolsis, just like carbohydrates and proteins.

26. LIPIDS 3 functions of lipids:
Energy Storage: lipids provide concentrated long-term energy storage which can release fuel for cellular respiration as needed.
Cell membrane: the main component of cell membraes are phospholipids
Thermal insulators: reduce the loss of heat from an organism (e.g. an under the skin layer of lipids).
Assessment Statement 3.2.6

27. LIPIDS
When an unsaturated fat has only one unsaturated bond, it is known as monounsaturated. When a fat has more than one unsaturated bond it is known as polyunsaturated.
Assessment Statement 3.2.6

28. LIPIDS
Phospholipids and triglycerides and waxes are three important groups of lipids.
Phospholipids are the building blocks of the fluid mosaic model of the cell membrane. They have a phosphate/glycerol head that is polar and hydrophillic and two fatty acid tails that are hydrophobic.
Triglycerides – are another type of lipid found in the body. These special lipid molecules are built from one glycerol and three fatty acids with the help of an enzyme.

29. Saturated Fats
Lipids that are solid or semi-solid at room temperature are said to be saturated (loaded up with covalent bonds to H atoms).
E.g. Butter, shortening and marbling in meat.
Saturated fats are very stable at room temperature.

30. Unsaturated Fats
Lipids that are liquid at room temperature are said to be unsaturated (containing double bonds, or less H atoms).
E.g. Oil is an example of an unsaturated fat.
Unsaturated fats are easier to break down in the body than saturated fats. Hense the push for people to use vegetable or canola oil rather than butter while cooking.

31. Lipid Groups
Waxes – are the third group of lipids. They are formed from long chains of fatty acids joining long-chain alcohol or carbon rings. Waxes are insoluble in water, and are used for water proofing plant leaves or animal feathers and fur.
Fats & Diet – stable fats in the body (saturated fats) tend to stay put once ingested leading to plaque in the arteries and ultimately to health complications (e.g. stroke, cancer, high blood pressure, type two diabetes).
Cholesterol – not all fat is bad. Cholesterol is required by the cell membrane and is also important for the production of hormones (specifically sex hormones – estrogen and testosterone). There are two different types of cholesterol in the blood HDL and LDL. HDL is the “good” cholesterol and LDL is the “bad” cholesterol.

32. PROTEINS
Proteins are made of C, H, O and N. They are the most abundant organic compound found in living cells.
The most important macromolecule in the body.
Their importance can not be underestimated!
They form:
The structural parts nails, hair, cell membrane and cartilage
Pigments (skin, eyes and chlorophyll),
Hormones
Contractile material of muscle tissues
Antibodies
Enzymes.

33. PROTEINS The building blocks of proteins are amino acids.
The amino acids are bonded together by peptide bonds to form proteins.
The smallest protein consists of 50 amino acids bonded together and the largest consists of over 100, 000.

34. PROTEINS Proteins Rule Everything in the Body!
Total energy gain is 4 Calories/gram. (however, energy gain is not their main function).
Your body requries 22 essential amino acids, but can only produce 8!
We must rely on digestion to gain the other amino acids we need.
22 different amino acid groups give rise to an infinite amount of proteins.

35. PROTEINS Proteins are large molecules constructed of many amino acids.
Again, condensation and hydrolysis apply to this macronutrient.
The bond that is formed from an acid group (COOH) and the amino group (NH2) is called a peptide bond. Because of this special bond, proteins are frequently called polypeptides (many peptide bonds).
Assessment Statement 3.2.5

36. PROTEINS
Assessment Statement 3.2.2

37. PROTEINS
Shapes – primary (linear), secondary (coiled), tertiary (bent-coiled) and quarternary (compact with a specific structure).
You can unfold a protein (de-nature) by exposing the protein to heat, radiation or a change in pH. (i.e. frying an egg, baking a cake, UV exposure, x-rays).

38. PROTEINS
Assessment Statement 7.5.1

39. Protein Structure Primary protein structure:
Sequence and number of amino acids
Each position occupied by one of 20 amino acids
Linked by peptide bonds
Assessment Statement 7.5.1

40. Protein Structure Secondary protein structure:
Assessment Statement 7.5.1
Protein Structure
Secondary protein structure:
Weak hydrogen bonds between amino and carboxyl groups.
Form at regular intervals, creating a regular structure (not from the interactions between variable R groups)
Alpha helix = coiling into a helix
Beta pleating = a folded sheet as polypeptide folds back onto itself.
Not all of a polypeptide forms secondary structure in most proteins.

41. Protein Structure Tertiary protein structure:
Assessment Statement 7.5.1
Protein Structure
Tertiary protein structure:
Interactions between variable R-groups forming
Hydrophobic interactions between non-polar amino acids
Hydrogen bonds between polar amino acids
Ionic bonds between ionic amino acids
Covalent bonds between sulfur containing amino acids
Producing the three dimensional folded structure of most proteins.

42. Protein Structure Quarternary protein structure:
Assessment Statement 7.5.1
Protein Structure
Quarternary protein structure:
Aggregations of polypeptides form interactions between more than 1 polypeptide
Polypeptides + non-proteinaceous molecules, such as:
Metals, e.g. iron in hemoglobin
Vitamins as enzyme co-factors
Nucleic acids as in ribosomes
Carbohydrates in glycoproteins
Lipids in lipoproteins.

43. Outline the difference between fibrous and globular proteins, with reference to two examples of each type of protein.
Fibrous:
Long fibers or sheets formed by parallel polypeptide chains
Dominated mostly by secondary structure
Mostly water insoluble
Great strength and/or strechiness from affects of regular H-bonds
Collagen in connective tissue
Actin and myosin in muscle tissue
Assessment Statement 7.5.2

44. Outline the difference between fibrous and globular proteins, with reference to two examples of each type of protein.
Globular:
Folded into complex 3D irregular spherical shape
Dominated mostly by tertiary structure
Mostly water soluble
Functions determined by 3D shape
Enzymes such as amylase
Hormones such as insulin
Transport such as hemoglobin
Protective, such as immunoglobulins
Assessment Statement 7.5.2

45. Explain the significance of polar and non-polar amino acids
Amino acids fit into three groups:
Polar
Ionic
Non-polar
Assessment Statement 7.5.3

46. Ionic and Polar amino acids
Have hydrophillic R groups
Attracting the protein to water
Forming H bonds and ionic bonds between different amino acid R groups
Contributing to tertiary structure
Assessment Statement 7.5.3

47. Non-polar amino acids Have hydrophobic R groups
Repelling the protein from water
Forming hydrophobic bonds between different amino acid R groups
Contributing to tertiary structure
Contributing to protein attraction to fatty acids in the phospholipid bilayer
Assessment Statement 7.5.3

48. Polar and Non-polar Amino Acids:
The distribution of polar and non-polar amino acids in a protein determine where in a membrane or cell a protein will be located and the function it will perform.
Assessment Statement 7.5.3

49. State four functions of proteins, giving a named example of each.
Haemoglobin
A protein containing iron that transports O2 from the lungs to all parts of the body in vertebrates.
Actin and Myosin
Proteins that interact to bring about muscle movement (contractions) in animals
Insulin
A hormone secreted by the pancreas that aids in maintaining blood glucose level in vertebrates
Immunoglobulins
Group of proteins that act as antibodies to fight bacteria and viruses.
Amylase
Digestive enzymes that catalyses the hydrolysis of starch.
Assessment Statement 7.5.4

50. Metabolism
All the chemical reactions that occur in your body. Approximately 200, 000 chemical reactions occur daily within one single cell.
Catabolic and anabolic reactions are two types of reactions that occur inside the cells.
Catabollic reactions occur when large chemicals are broken down into smaller components.
Anabollic reactions, complex chemicals are built from smaller components.

51. CONDENSATION & HYDROLYSIS
The chemical compounds of life are made by dehydration synthesis and broken down by hydrolysis. Condensation occurs when molecules bond together by removing a water (H2O) molecule. Enzymes are involved in this type of synthesis. Disaccharides, polysaccharides, lipids and proteins can be made this way. Hydrolysis is the breaking apart of molecules by replacing it with a water molecule at the place where it was removed in dehydration synthesis.
Assessment Statement 3.2.5

52. Condensation
Polymers are long molecules built by linking repeating building blocks in a chain by removing water.
monomers
building blocks
repeated small units
covalent bonds
H2O HO H
Condensation!
Assessment Statement 3.2.5

53. How to build a polymer Condensation reaction
Condensation allows for synthesis!
joins monomers by “taking” H2O out
1 monomer provides OH–
other monomer provides H+
together these form H2O
requires energy & enzymes
H2O HO H
enzyme
Condensation reaction
Assessment Statement 3.2.5

54. CONDENSATION RECAP
Condensation builds larger molecules by releasing water
It is an ANABOLIC REACTION
Used to build carbohydrates, lipids, and proteins!
Requires an ezyme to act as a catalyst and speed the reaction along.
Condensation of amino acids to form proteins.
Assessment Statement 3.2.5

55. Assessment Statement 3.2.5

56. Assessment Statement 3.2.5

57. How to break down a polymer
Hydrolysis – aka. digestion
use H2O to breakdown polymers
reverse of condensation
Cleaves off one monomer at a time
H2O is split into H+ and OH–
H+ & OH– attach to ends
requires enzymes
H2O HO H
enzyme
Hydrolysis
Assessment Statement 3.2.5

58. HYDROLYSIS RECAP
Breaks bonds in larger molecules to produce smaller pieces.
It is a CATABOLIC REACTION
Used to break apart carbohydrates, lipids and proteins.
Requires the use of an enzyme to act as a catalyst and spead the reaction along.
Assessment Statement 3.2.5

59. HYDROLYSIS RECAP Assessment Statement 3.2.5

60. CONDENSATION & HYDROLYSIS
Assessment Statement 3.2.5

61. Assessment Statement 3.2.5

62. Assessment Statement 3.2.5

63. Assessment Statement 3.2.5

64. LIPIDS – saturated vs. unsaturated

65. Let’s See How you are doing with a mini-quiz!
Get out a piece of paper and try the next few questions! We will return to these questions to discuss your answers at the end. Ready? Set? Here we go! 

66. Quiz time!

67. Question 2:

68. Question 3 and 4

69. Question 5