Carbohydrates

Question 1

What are carbohydrates

Answer 1

They are the most abunndant organic molecule in nature and are the primary storage molecules in most living things.

Question 2

Carbohydrates contain what bonds

Answer 2

C-C and C-O

Question 3

What happens when a carbohydrate is used as fuel

Answer 3

Its carbon becomes carbon dioxide(C=O bonds) and its hydrogen becomes water(O=H bonds). The energy released when these bonds are formed are greater than the energy needed to initially split the bonds. This energy is used by the body for walking, running talking etc

Question 4

What are Monosaccharides

Answer 4

Monosaccharides are simple sugars that easily dissolve in water and are sweet to taste

Question 5

What functional groups can monosaccharides be

Answer 5

Ketone group (Ketose sugar) and Aldehyde functional group (Aldose sugar)

Question 6

Describe the structures of glucose

Answer 6

Glucose can either be a chain or ring structure. The ring structure is highly favored because it is more stable. The chain structure is easily soluble and broken down so to gain stability it falls in on itself to for the ring.

Question 7

How does glucose turn from its alpha form to its beta form

Answer 7

Glucose exists in both alpha and beta forms where the hydrogen and hydroxil groups can rotate along the plane at Carbon num 1

Question 8

What is a Chiral Carbon and which carbon has this title

Answer 8

A chiral carbon is a carbon that is bonded to 4 different groups. Carbon num 1 is bonded to H, OH, C2 and O so it is a chiral carbon

Question 9

What is an Isomer

Answer 9

It is a chemical structure that has the same formula but is structurally different

Question 10

Name the two types of disaccharides and what the first one does

Answer 10

Reducing and Non Reducing Disaccharides. The Reducing disaccharide has the ability to reduce Copper 2t ions to Copper ions

Question 11

Name the 3 types of Disaccharides and describe their glycosidic bonds

Answer 11

Maltose: 2 alpha glucose (alpha 1-4 glycosidic bonds)
Sucrose: 1 alpha glucose 1 alpha fructose (alpha 1-2 glycosidic bonds)
Lactose: 2 beta galactoses (beta 1-4 glycosidic bonds)

Question 12

Describe Maltose Sucrose and Lactose

Answer 12

Maltose exists naturally in all food it is sweet to taste and it is a reducing agent
Sucrose is made by higher-order plants it is also sweet to taste but is not a reducing agent. It is broken down by the enzyme invertase
Lactose is the main component of milk, it is a reducing agent and it is not easily digested without the enzyme Lactase.

Question 13

What is starch

Answer 13

Starch is a homopolymer of alpha glucopyronose units with the chemical formula C6 H10 05. It is an energy storage system in plants. Its structure is compact and it is polymeric and branching. Starch has low solubility in water and possesses low ability to absorb water and oil but it has good iodine binding and a relatively high viscosity and gelatanization ability

Question 14

What is amylose and amylopectin

Answer 14

Amylose in starch is lower than amylopectin having 20% to 30% it is a linear structure of glucose isomers that bind together in alpha 1-4 glycosidic linkages
Amylopectin in starch is higher than amylose having 70-80% it is a branching structure of glucose isomers that bind linearly in alpha 1-4 and branching in alpha 1-6 glycosidic linkages. The concentration of amylose and amylopectin determines the physical and functional properties of starch

Question 15

What does the ratio of amylose to amylopectin affect in starch

Answer 15

It affects the structure of the starch in terms of crystallinity, size of granules, chemical nature and the arrangement of polymers in the granule

Question 16

What is glycogen

Answer 16

It is a multibranched polysaccharide of glucose that serves as an energy storage in animals fungi and bacteria. Glycogen is one of two forms of energy reserves in the body. It is the short term while the long term is triglyceride stored in andipose tissue. Glycogen is a branched biopolymer consisting of linear chains of glucose residues with an avg chain length of approximately 8-12 glucose units and 2000-60000 residues per one molecule

Question 17

Describe the branching in glycogen

Answer 17

Glucose units are linked together linearly in alpha 1-4 linkages and branches are linked alpha 1-6 between the first glucose of the new branch and a glucose from the stem chain.

Question 18

How does branching affect glycogen

Answer 18

It makes the glycogen very insoluble and unnreactive in animal cells. It also allows many enzymes to work simultaneously releasing high energy when needed.

Question 19

How does glycogen become glucose in the body

Answer 19

When it is broken down by the enzyme glycogen phophorylase

Question 20

What is cellulose

Answer 20

Cellulose is a molecule consisting of hundreds and sometimes thousands of carbon hydrogen and oxygen atoms.It is the main substance in the walls of plant cells helping plants to remain stiff and upright. Humans can not digest cellulose but it is important in the diet as fiber. Herbivores such as cows and goats have the enzyme cellulase which allows them to break it down;

Question 21

What is the structure of cellulose

Answer 21

It is a polysaccharide made of thousands of glucose units bonded by beta 1-4 linkages. In the bond every other glucose unit is flipped upside down. They are bonded together by hydrogen bonds. Multiple cellulose strands are called fibrils and large bundles are called fibers. Cellulose is strong with high tensile strength and is able to expand without breaking when the plant is turgid.