Carbohydrates

Question 1

what are types of biological molecules? (5)

Answer 1

carbohydrates, proteins, lipids, nucleic acid - DNA and RNA, ATP

Question 2

what do all biological molecules contain?

Answer 2

carbon, hydrogen, oxygen

Question 3

what are the three groups carbohydrates can be split in to?

Answer 3

monosaccharides, disaccharides, polysaccharides

Question 4

what are the characteristics and types of hexose-sugars? And where are they found?

Answer 4

energy source, sweet, soluble
glucose, fructose and galactose all have the same chemical formula C₆H₁₂O₆ - but constructed differently. glucose is found in plants and animals, fructose is found in plants ONLY and galactose is found in animals ONLY.
there are two types of glucose: alpha glucose found in plants and animals and beta glucose found in plants ONLY

Question 5

what are some fun facts about pento-sugars?

Answer 5

C5H10O5 -ribose sugar and C6H10O4 - dioxyribose used for structural purposes - for RNA, DNA and ATP

Question 6

what are some fun facts about triose-sugars?

Answer 6

C3H6O3 these sugars are part of respiration

Question 7

what are the three main disaccharides and what monosaccharides make them?

Answer 7

• sucrose = alpha glucose and fructose
• lactose = alpha glucose and galactose
• maltose = alpha glucose and alpha glucose

Question 8

what are the characteristics of the disaccharides?

Answer 8

sweet, soluble and, used for respiration

Question 9

what are condensation reactions and therefore the chemical formula for the disaccharides?

Answer 9

the reaction it takes to make a disaccharide is a condensation reaction. H2O is formed and the oxygen that is left creates a 1-4 glycosidic bond with carbon 4. By adding one molecule of water we can break the 1-4 glycosidic bonds - this is called hydrolysis. disaccharides + water = monosaccharides. hydrolysis is the use of water to separate bonds. the chemical formula of disaccharides = C12H22O11

Question 10

what are the three main types of polysaccharides and their functions?

Answer 10

starch - found in plants, storage of alpha glucose
glycogen - found in animals, storage of alpha glucose
cellulose - makes the cell wall, structural, polymer of beta glucose

Question 11

what is starch made up of and what is its function?

Answer 11

it’s a polymer of alpha glucose, plant storage polysaccharide. Made up of:
- amylose: coiled springs are formed, alpha helix structured, long alpha glucose polymer chain
- amylopectin: helps hydrolyse more alpha glucose to get sugars, makes branches, it has a 1-6 glycosidic bond

Question 12

what are polysaccharides not?

Answer 12

THEY ARE NOT SUGARS

Question 13

why does starch have a helix structure?

Answer 13

it’s compact - stores lots of glucose in a small space which is used for respiration to generate/transfer energy (ATP)
it’s insoluble - stores lots of starch (amylose) without is affecting water potential

Question 14

what’s the point of the branching and 1-6 glycosidic bond?

Answer 14

• branching increases surface area, more terminal ends so the rate of hydrolysis is great and therefore releases more alpha glucose per second
• 1-6 glycosidic bonds are so that the plant can hydrolyse more alpha glucose

Question 15

what is glycogen?

Answer 15

is the storage polysaccharides in animals, more amylopectin branching because humans need more energy (ATP) than plants

Question 16

what are the functions of cellulose?

Answer 16

present in plants, has a slow decomposition, it’s the most abundant molecule on the planet, it’s mechanically very strong ad it’s polymer of beta glucose

Question 17

What are hydrogen bonds?

Answer 17

they are electrostatic forces of attraction between molecules

Question 18

Are hydrogen bonds weak or strong?

Answer 18

hydrogen bonds are individually weak BUT on mass provide strength and stability

Question 19

why does one beta glucose turn 180 degrees for the hydroxyl groups to react?

Answer 19

if carbon 1 and 4 want to react one beta glucose has to turn 180 degrees in order that the hydroxyl groups will be next to each other and therefore be able to react and form a 1-4 glycosidic bond

Question 20

what is the structure of cellulose?

Answer 20

long straight unbranched chain

Question 21

what do hydrogen bonds have to do with cellulose?

Answer 21

cellulose chains run parallel to each other, hydrogen bond cross-bridges between the cellulose chains

Question 22

how do you get from cellulose to the cell wall?

Answer 22

hundreds of cellulose chains come together to make microfibrils, hundreds of microfibrils come together to make a macrofibril, macrofibrils come together to form the cell wall