The Structure and Func.on of Macromolecules: GRU1L4 Carbohydrates

Transcription

1 The Structure and Func.on of Macromolecules: GRU1L4 Carbohydrates

2 Do Now: WHAT IS TABLE SUGAR MADE UP OF? Sucrose (table sugar) Composed of a glucose molecule and a fructose molecule Please draw the structure of sucrose in your notes

3 OBJECTIVES SWBAT describe the structure and func:on of carbohydrates 3

4 Carbohydrates

5 MACROMOLECULES

6 KP1: Carbohydrates, lipids, proteins, and nucleic acids are the 4 macromolecules that make up life All living things are made up of four classes of large biological molecules: Carbohydrates Lipids Protein Nucleic Acids Macromolecules are large molecules composed of thousands of covalently bonded atoms Molecular structure and function are closely related. 6

7 Carbohydrates Carbohydrates are composed of C, H, O Function: CH 2 O (C. 1: H. 2: O.1) (CH 2 O) x energy energy storage raw materials structural materials Monomer: sugars ex: sugars, starches, cellulose sugar sugar sugar sugar sugar sugar sugar sugar

8 Iden:fying a carbohydrate molecule: All carbohydrates have: C, H, O and nothing else!!

9 Carbohydrates Monomer = monosaccharides Repeated subunits that make up carbohydrates C:H:O = 1:2:1 Polymer = polysaccharides Long chain of monosaccharides

10 Carbohydrates Most common and important carbohydrate: GLUCOSE!! (C 6 H 12 O 6 ) Major energy source Necessary for cellular processes and respira:on

11 Linear diagram Glucose

12 Draw!! GLUCOSE

13 Ring diagram Glucose

14 Sugars Most names for sugars end in -ose Classified by number of carbons 6C = hexose (glucose) 5C = pentose (ribose) 3C = triose (glyceraldehyde) H C O CH 2 OH CH 2 OH H C OH H HO H OH O H H OH HO H O Glyceraldehyde H OH OH H Glucose Ribose HO H H H C H OH

15 Sugar structure 5C & 6C sugars form rings in solution Where do you find solutions in biology? In cells!

16 Carbons are numbered 5' C C 6' O 4' C C 1' C 3' C 2' energy stored in C-C bonds

17 Simple & complex sugars CH 2 OH Monosaccharides simple 1 monomer sugars glucose, fructose Disaccharides 2 monomers sucrose, maltose Polysaccharides large polymers starch, cellulose, glycogen H HO H OH H Glucose O H OH H OH

18 EXAMPLES OF SUGARS Figure 2.9 Monosaccharides

19 Building Sugars: glycosidic linkages Monosaccharides are covalently bonded by condensation reactions forming glycosidic linkages, forming disaccharides. place text art pg 27 here

20 Building sugars Dehydration synthesis monosaccharides disaccharide glucose H 2 O glucose maltose glycosidic linkage

21 LACTOSE Glucose + Galactose -----> Lactose + H 2 O 21

22 EXTENSION What is lactose intolerance? Lactose is the primary sugar found in dairy products. Lactase is an enzyme your body produces to help you digest that sugar. If you don t have enough lactase, you might experience gas, bloa:ng, cramps, or diarrhea a]er you eat dairy products. This is called being lactose-intolerant. 22

23 Oligosaccharides Oligosaccharides contain several monosaccharides. Many have additional functional groups. They are often bonded to proteins and lipids on cell surfaces, where they serve as recognition signals. The human blood groups (ABO) get their specificity from oligosaccharide chains.

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26 KP2: Carbohydrates are used for shortterm energy and structure Monomer: Monosaccharide (single sugar), multiple of CH 2 O Use: Short-term energy EX: Glucose (C 6 H 12 O 6 ) Polymer: Polysaccharides (many sugars linked together) Use: Energy storage and structure EX: Starch, Cellulose, Glycogen 26

27 Figure 3.10 Polysaccharides Starch granules in a potato tuber cell Starch (amylose) Glycogen granules in muscle and liver tissue Glucose monomer Glycogen Cellulose microfibrils in a plant cell wall Cellulose molecules Cellulose Hydrogen bonds between OH groups (not shown) attached to carbons 3 and 6

28 Such Elegance! 28

29 STARCH AND GLYCOGEN

30 Cellulose: the main component of plant cell walls. It is the most abundant carbon-containing (organic) biological compound on Earth. Very stable; good structural material

31 CELLULOSE: STRUCTURAL SUPPORT

32 The Hydrogen bonds in Cellulose 32

33 Cellulose: Structural Polysaccharide The polysaccharide cellulose is a major component of the tough wall of plant cells Like starch, cellulose is a polymer of glucose, but the glycosidic linkages differ The difference is based on two ring forms for glucose: alpha (α) and beta (β) 33

34 Isomers E.g., alpha (a)-glucose vs. beta (B)-glucose H and OH groups flipped (structural isomer)

35 What is Beta Glucose Beta glucose is an isomer of D-glucose whose OH group of the first carbon atom is located on the same side from the CH 2 OH group. Beta glucose is the building block of cellulose. 35

36 Cellulose Most abundant organic compound on Earth herbivores have evolved a mechanism to digest cellulose most carnivores have not that s why they eat meat to get their energy & nutrients cellulose = undigestible roughage But it tastes like hay! Who can live on this stuff?!

37 Helpful bacteria How can herbivores digest cellulose so well? BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Ruminants

38 Cow can digest cellulose well; no need to eat other sugars Gorilla Can t digest cellulose well; must add another sugar source, like fruit to diet

39 Types of Polysaccharides: Energy Storage Starch, a storage polysaccharide of plants, consists entirely of glucose monomers Plants store surplus starch as granules within chloroplasts and other plastids The simplest form of starch is amylose 39

40 What is Alpha Glucose Alpha Glucose is an isomer of D-glucose whose OH group of the first carbon atom is located on the opposite side as the CH 2 OH group. Alpha glucose is the building block of starch. α- 40

41 Starch v. Cellulose Enzymes that break down starch (hydrolyze alpha linkages). Alpha glucose is compact, yet its molecules can be easily taken apart. On the other hand, the molecules of beta glucose are very stable; hence they cannot be easily taken apart.

42 Starch v. Cellulose In starch, all the glucose repeat units are oriented in the same direc:on. But in cellulose, each successive glucose unit is rotated 180 degrees around the axis of the polymer backbone chain, rela:ve to the last repeat unit. 42

43 Starch and Cellulose Structures 43

44 Digesting starch vs. cellulose starch easy to digest enzyme cellulose hard to digest enzyme

45 Cellulose: A termite s best friend! To digest cellulose, organisms must produce the enzyme cellulase. Humans and termites are unable to produce cellulase themselves. Cellulose in human food passes through the diges:ve tract as insoluble fiber Termites have symbio:c organisms (protozoa and bacteria) living in their gut which can produce the enzyme cellulase, helping them to digest cellulose. 45

46 Polysaccharides: Random Acts of Biology Some microbes use enzymes to digest cellulose Many herbivores, from cows to termites, have symbiotic relationships with these microbes Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods (crunch!) Chitin also provides structural support for the cell walls of many fungi 46

47 Who knew? 47

48 Types of Polysaccharides: Energy Storage Glycogen is a storage polysaccharide in animals Humans and other vertebrates store glycogen mainly in liver and muscle cells Glycogen can be converted to glucose to provide energy. 48

49 Schema.c two-dimensional cross-sec.onal view of glycogen: Highly branched. A core protein of glycogenin is surrounded by branches of glucose units. The en:re globular granule may contain around 30,000 glucose units 49

50 Quiz: Guided Prac:ce What three atoms are present in all carbohydrates and in what ra.o? Carbohydrates are composed of C, H, O CH 2 O (C. 1: H. 2: O.1)

51 Quiz: Guided Prac:ce When two monomers come together to form a chain, what molecule is released? 51

52 Quiz: Guided Prac:ce What is the monomer of a carbohydrate called? monosaccharide 52

53 Quiz: Guided Prac:ce What is the function of cellulose? Structural support in plants Source of glucose (energy supply) in herbivores like cattle, and termites (that harbor bacteria and protozoa that can digest cellulose). 53

54 Quiz: Guided Prac:ce What is a Glycosidic linkage? Monosaccharides are covalently bonded by condensation reactions that form glycosidic linkages, forming disaccharides. 54

55 Quiz: Guided Prac:ce What are sucrose and lactose made up of? 55

56 INDEPENDENT PRACTICE Compare the structures of cellulose, starch and glycogen with respect to compactness. 56

57 Structure of cellulose, starch and glycogen 57

58 EXIT TICKET: THINK PAIR SHARE How does the structure of cellulose contribute to structural strength in plants. 58

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