The building blocks of life.

Transcription

1 The building blocks of life.

2 All the functions of the cell are based on chemical reactions.

3

4

5

6 the building blocks of organisms BIOMOLECULE MONOMER POLYMER carbohydrate monosaccharide polysaccharide lipid protein fatty acid & glycerol amino acid triglyceride polypeptide (protein) nucleic acid nucleotide DNA or RNA polymers are formed when smaller building monomers bond covalently.

7 water is removed a covalent bond forms a dehydration synthesis

8 polymers are disassembled by Hydrolysis water added covalent bond broken

9

10 Their importance is all in the name: Greek for first place These are very large, 3 dimensional macromolecules. Responsible for almost all functions in a living organism all proteins have C, H, O and N

11 In you: function as a body builder and repairer when recovering from injury Sources: fish, meat, poultry, dairy products, nuts, eggs, beans, etc. are used as energy only as a last resort

12 All proteins consist of polymers that are folded into specific shapes Their shape, controls their function

13 They are very important as structural molecules in the cell, as energy sources, and most importantly as enzymes Spider web silk is a structural protein.

14 Amino acid Proteins are often called polypeptides because they are made of long chains of building blocks called amino acids. central C also bonded with a N and an R group R groups unique side chains

15 - R groups can be any of 20 different forms giving 20 naturally occurring amino acids (in living things) Important later when we look at DNA

16 AA s cannot be stored, they must be continually eaten 8 (of 20) are essential Need N from foods to manufacture other AA s Sources: animal proteins (complete) plant proteins (incomplete)

17 Several amino acids must be ingested your body cannot manufacture them and you can only get them from certain foods

18 amino acid peptide bonds polypeptide carboxyl amino

19 Carboxyl group amino group -C-N- link is relatively inflexible

20 structure of proteins: Primary Secondary Tertiary Quaternary

21 "The sequence of amino acids in the polypeptide chain." Amino acids are bound together with a "peptide" bond.

22 folding There are two types of secondary structure in proteins, the α-helix and the β-pleated sheet.

23 The attraction of the R groups within the same chain can cause the chain to twist into a coil (αhelix) held together by hydrogen bonds between the hydrogen and oxygen atoms of the amino acid backbone.

24 Keratin is a structural protein found in hair and nails, skin, and tortoise shells. The ahelix nature of wool is what makes it shrink.

25 Caused by hydrogen bonding between the hydrogen atoms (amino group) and the oxygen atoms (carboxyl group) of amino acids on two chains (or more) lying side-by-side.

26 The β-pleated sheet is often found in many structural proteins, such as "Fibroin", the protein in silk and spider webs.

27 When proline, (an aa) occurs in the polypeptide chain a "kink" in the ahelix develops. (Kinks can also be caused by repulsive forces between adjacent charged R groups.) These kinks create a 3 dimensional chain arrangement held together by weak hydrogen bonds but also by much stronger disulfide bridges - covalent bonds between two amino acids of cystine. Other strong linkages such as Ionic bonds can also form between regions of the same polypeptide creating the tertiary structure.

28 The strong covalent bonds hold the protein in its specific 3D shape. The 3D shape creates "pockets" or "holes' in the surface of the protein which are very important in enzyme function (as we shall see).

29 This last level of organization is simply taking 2 or more tertiary proteins and sticking them together to form a larger protein. Many enzymes and transport proteins are made of two or more parts.

30 Hemoglobin: an oxygen carrying protein in red blood cells which is made of 4 parts.

31

32 temperature increases ph

33 Proteins when heated can unfold or denature. This loss of three dimensional shape will usually be accompanied by a loss of the protein s function. If the denatured protein is allowed to cool it will usually refold back into it s original conformation.

34 Protein is not useful in and of itself. It must be broken down into its amino acids to be used by the body. Heated proteins have their amino acids fused together into enzyme-resistant bonds the body cannot fully break down. It instead partially breaks them down into polypeptides, which the body must then expel as useless.

35 When a biological reaction occurs, Energy is involved.

36 generally, chemical reactions proceed only after an initial input of energy

37 the amount of Energy needed to start a reaction Activation Energy

38 In non-living systems can use HEAT to increase the Kinetic energy and overcome this energy barrier (activation energy) But. that would kill most living cells

39 So If we could lower the energy barrier The reaction could proceed with less energy input.

40 The amount of energy needed is important, but so is the time it takes for the reaction to occur. Many reactions that occurs in cells takes too long to be useful therefore cells have to speed them up.

41 In living organisms are biological catalysts Substances that increases the rate of reactions without being permanently altered by that reaction.

42 for example The catalyst increases the rate of the reaction but is not permanently altered in the process

43

44 All enzymes are proteins But not all proteins are enzymes They interact with other molecules non-covalently by shape and chemistry Catalysts do not cause a reaction that would not happen eventually on its own.

45 The chemical that an enzyme works on is called a substrate Active site ENZYME The enzyme binds to the substrate at the active site

46 Enzymes are highly specific each chemical reaction in an organism requires its own specific enzyme an enzyme and substrate that are compatible link up at the ACTIVE SITE.

47 enzymes are named for the substrate they act on OR by the pathways they participate in ase ending example: Hydrolyzes amylose

48 When an enzyme and substrate link up, it forms the ENZYME-SUBSTRATE COMPLEX where the enzyme goes to work (can put together or take apart a substrate.) substrate Active site enzyme

49 enzymes are never changed by their reactions!

50 When the enzyme and products separate: the enzyme is ready to work on another substrate.

51 Enzymes catalyze biological reactions by assisting effectively lowering - the activation energy needed for the reaction to proceed, resulting in increasing the rate of reaction.

52 enzymes act by: orienting substrates

53 inducing strain temporarily altering the chemistry of the substrate

54 concentration of the substrate temperature concentration of the enzyme ph

55