M1:02 Carbohydrates

Question 1

What percentage of the organic matter of a cell is made up of carbohydrates?

Answer 1

10%

Question 2

Give an example of the functions of carbohydrates

Answer 2

-energy source -energy store eg starch - structure eg cellulose- to form part of larger molecules

Question 3

Give an example of when carbohydrates is used as an energy store

Answer 3

starch

Question 4

Give an example of when carbohydrates is used as a structural molecule

Answer 4

cellulose

Question 5

What are carbohydrates made up of?

Answer 5

carbon hydrogen oxygen

Question 6

Give 2 examples of molecules formed by carbohydrates

Answer 6

nucleic acid and glycolipids

Question 7

What is the essential meaning of carbohydrate and why?

Answer 7

hydrated carnon because the elements are found in proportion (for every carbon present, there is a h2o)

Question 8

What is the simplest form of a carbohydrate called?

Answer 8

monosaccharides

Question 9

What are monosaccharides?

Answer 9

the monomers of carbohydrates that join together to form carbohydrates

Question 10

How many carbon atoms do monosaccharides have?

Answer 10

between 3 and 6

Question 11

What are the main properties of monosaccharides?

Answer 11

-soluble in water- sweet tasting- form crystals

Question 12

How are monosaccharides formed?

Answer 12

the number of carbon atoms in the molecule

Question 13

What are 3-carbon monosaccharides known as?

Answer 13

tricose sugars

Question 14

What are 5-carbon monosaccharides known as?

Answer 14

pentose sugars

Question 15

What are 6-carbon monosaccharides known as?

Answer 15

hexose sugars

Question 16

What are the most common monosaccharides ?

Answer 16

hexoses

Question 17

Give 2 examples of hexose monosaccharides

Answer 17

glucose and fructose

Question 18

How are hexose monosaccharides written?

Answer 18

C6H12O6

Question 19

What structure do pentose and hexose sugars have in nature?

Answer 19

ring structure

Question 20

Give 2 examples of structures of glucose

Answer 20

chains and ring structures

Question 21

How are the H and OH formed in a ring structured in alpha glucose?

Answer 21

the OH at C1 is below the plane of the ring

Question 22

How are the H and OH formed in a ring structured in beta glucose?

Answer 22

the OH at C1 is above the plane of the ring

Question 23

What effect does the structure of the OH at C1 have in the glucose?

Answer 23

some of their properties.

Question 24

Why are the carbons in a glucose molecule labelled 1-6?

Answer 24

to show how the ring structure is made, and to allow us to note where further bonds are found

Question 25

What is an isomer?

Answer 25

different shaped forms of the same molecules

Question 26

How are disaccharide molecules formed?

Answer 26

two monosaccharides joining together via a condensation reaction

Question 27

What kind of a bond is formed during a condensation reaction and what is eliminated?

Answer 27

a glycosidic bond forms and water is eliminated

Question 28

How kind of a reaction breaks a glycosidic bond?

Answer 28

a hydrolysis reaction

Question 29

is a disaccharide a sugar?

Answer 29

yes

Question 30

Give an example of a disaccharide sugar

Answer 30

maltose

Question 31

What is released when glucose molecules break down into simpler molecules of water and carbon dioxide during respiration?

Answer 31

energy

Question 32

What can the energy released during respiration be used for?

Answer 32

to make ATP

Question 33

What is ATP

Answer 33

tiny packets of energy for use in cell processes.

Question 34

What is the word equation for respiration?

Answer 34

glucose + oxygen -> carbon dioxide + water + energy that is used to form ATP

Question 35

What role do enzymes play in the breaking down of glucose?

Answer 35

different specific enzymes drives each step

Question 36

What kind of glucose can animals and plants break down?

Answer 36

alpha glucose

Question 37

What kind of glucose cant plants and animals break down and why?

Answer 37

they cant break down the beta glucose because of the different arrangement of the H and OH at C1

Question 38

Which of the two glucose structures can be respired and which cant?

Answer 38

alpha can be, beta cant be.

Question 39

What is formed when two alpha glucose molecules bond together?

Answer 39

a disaccharide called maltose

Question 40

What is formed when a condensation reaction reoccurs over and over again with maltose?

Answer 40

amylose is produced

Question 41

Where do glycosidic bonds form?

Answer 41

between the carbon number 4 and carbon number 1, so its often called the 1,4-glycosidic bond

Question 42

Why is amylose quite compact?

Answer 42

as the long chains of amylose coil into a spring because of the shape of the glucose molecules and the formation of glycosidic bonds.

Question 43

What can get trapped in the coil of amylose and what affect does this have on the starch test?

Answer 43

iodine gets trapped, causing iodine in the starch tests iodine potassium solution to change colour from yellow/brown to blue/black

Question 44

What is the difference between glucose and coils of amylose?

Answer 44

the coils of amylose are not soluble in water.

Question 45

What does starch consist of?

Answer 45

long, straight chain amylose molecules and branched amylopectin

Question 46

Where is starch stored in a plant?

Answer 46

chloroplasts and elsewhere in the plant in membrane-bound starch grains (in the cells of plant organs eg tubers)

Question 47

Where are there alot of membrane-bound starch grains?

Answer 47

in plant organs, such as potato tubers

Question 48

What is glycogen sometimes referred to as?

Answer 48

animal starch

Question 49

Name 1 similarity and one difference between starch and glycogen

Answer 49

both made up of alpha glucoseglucose chains tend to be shorter and have many more branches

Question 50

Which is more compact, glycogen or starch and why?

Answer 50

glycogen as they have many more branches of amylopectin

Question 51

Where are a lot of glycogen granules found?

Answer 51

in the muscle cells and liver

Question 52

What are starch and glycogen often described as?

Answer 52

energy-storage molecules

Question 53

Name 2 common features of glycogen and starch

Answer 53

-they dont dissolve - they hold glucose molecules in chains so they can be easily broken off the end when needed for respiration

Question 54

Why is it important that starch and glucose do not dissolve in water?

Answer 54

so it doesnt affect the water potential (reduce it)

Question 55

What is needed that isnt part of the equation within a condensation and hydrolysis reaction? and why are they needed?

Answer 55

enzymes , as polysaccharides are stable molecules, they would not simply fall apart in the conditions found within organisms.

Question 56

What happens when alpha and beta glucose molecules condense?

Answer 56

alpha- forms coiled, spring-like chains beta- long, straight chains

Question 57

What are cellulose chains?

Answer 57

straight chain molecules can contain 10,000 beta glucose molecules

Question 58

What are stronger, cellulose chains or amylose chains?

Answer 58

cellulose chains?

Question 59

What is cellulose found in?

Answer 59

plants only

Question 60

What is the most abundant structural polysaccharide in nature?

Answer 60

cellulose

Question 61

How are microfibrils and macrofibrils formed?

Answer 61

by 60-70 cellulose molecules cross-linked by hydrogen bonds, and each set of microfibrils are held together by more hydrogen bonds to form larger bundles called macrofibrils

Question 62

How are the walls of membranes formed?

Answer 62

macrofibrils are embedded in pectins to form the wall

Question 63

What are pectins?

Answer 63

polysaccharide glue of substances

Question 64

What is the function of cell walls?

Answer 64

to give strength to each cell, and the plant as a whole

Question 65

How does the arrangement of macrofibrils help the functioning of a plant?

Answer 65

it allows water to move through and along cell walls and water to pass in and out of cells easily.

Question 66

Why doesnt water cause a plant cell to explode like an animal cell would?

Answer 66

because of the cell wall, instead it just become turgid.

Question 67

What do the arrangement of macrofibrils in cell walls determine? Give an example

Answer 67

how cells can grow/change shape eg when a guard cell walls have macrofibrils that result in the opening and closing of the stomata

Question 68

How is the exoskeleton of insects formed?

Answer 68

polysaccharide chitin

Question 69

What is the basis of the cell walls found around most bacterial cells.

Answer 69

polysaccharide peptidoglycan

Question 70

Give an example of a monosaccharide, its characteristics and its role in organisms.

Answer 70

glucose (6 carbon) ch: small, soluble, sweet and crystallinerole; provides energy via respiration

Question 71

What kind of a carbohydrate is glucose?

Answer 71

monosaccharide

Question 72

What kind of a carbohydrate is deoxyribose?

Answer 72

monosaccharide

Question 73

Give an example of a disaccharide, its characteristics and role in an organism

Answer 73

Maltose ch; small, soluble, sweet and crystallinerole; a sugar obtained when starch is broken down in hydrolysis reactions. It can be split further into glucose

Question 74

What can maltose be broken down into?

Answer 74

glucose

Question 75

Give an example of a polysaccharide found in animals, its characteristics and role in organisms

Answer 75

glycogen ch; large molecules of alpha glucose joined together by condensation reactions, insoluble to water, forms grains/granulesenergy storage carbohydrates in animals and fungi

Question 76

Give an example of a polysaccharide found in plants that consist of alpha glucose molecules, its characteristics and role in organisms

Answer 76

starch ch; large molecules of alpha glucose joined together by condensation reactions, insoluble to water, forms grains/granulesenergy storage carbohydrates in plants

Question 77

Give an example of a polysaccharide found in plants that consist of beta glucose molecules, its characteristics and role in organisms

Answer 77

cellulose ch; large molecules of many beta glucose molecules joined by condensation reactions , insoluble in water, very strong role; structural, found only in plants where it forms cell walls.

Question 78

What is cellulose?

Answer 78

a carbohydrate polymer made by bonding beta glucose molecules together in long chains

Question 79

What is the difference between starch and cellulose?

Answer 79

starch is alpha ( OH below plane) cellulose is beta (OH above the plane)