4.1 & 4.2 water and carbohydrates

Question 1

how can metabolic reactions occur?

Answer 1

metabolic reactions can only occur if the chemicals which are reacting are dissolved in water

Question 2

why does plasma contain lots of water?

Answer 2

so substances like glucose can dissolve in it; these dissolved substances are transported around the body

Question 3

how does water help digestion take place?

Answer 3

water dissolves enzymes and nutrients in the alimentary canal in order for digestion to occur

Question 4

how does urine form?

Answer 4

urea, waste products from kidneys, dissolved in water

Question 5

what is another word for ‘simple sugar’?

Answer 5

monosaccharides

Question 6

what atoms do carbohydrate molecules contain?

Answer 6

6 carbon; 12 hydrogen; 6 oxygen

Question 7

what is the molecular formula for a glucose?

Answer 7

C₆H₁₂O₆

Question 8

what is the name of a complex sugar and how is it formed?

Answer 8

disaccharide; the junction of two simple sugar molecules

Question 9

what are examples of a complex sugar?

Answer 9

sucrose and maltose

Question 10

what is the name of a very large molecule made by the multiple junctions of simple sugars?

Answer 10

polysaccharide

Question 11

how many joined sugar molecules does a polysaccharide contain?

Answer 11

thousands of joined sugar molecules in a long chain

Question 12

what is the polysaccharide found in animal cells?

Answer 12

glycogen

Question 13

are polysaccharides soluble?

Answer 13

no

Question 14

what are carbohydrates needed for?

Answer 14

energy

Question 15

how much energy does one gram of carbohydrate release?

Answer 15

17kJ (kilojoules)

Question 16

how is the energy released?

Answer 16

the energy is released by respiration

Question 17

what carbohydrate is normally used in respiration?

Answer 17

glucose

Question 18

what carbohydrate is transported in plants?

Answer 18

sucrose

Question 19

what do plants convert their carbohydrates to when necessary?

Answer 19

glucose

Question 20

what do plants store carbohydrates as?

Answer 20

starch

Question 21

what do animals store carbohydrates as?

Answer 21

polysaccharides glucose

Question 22

how much glucose can animals store and where is it mostly stored?

Answer 22

only small quantities can be stored; in the cells in the liver and the muscles

Question 23

what is the criss-crossing fibres from which the plant’s cell wall is constructed?

Answer 23

polysaccharide cellulose

Question 24

how to test for carbohydrates?

Answer 24

by adding Benedict’s solution to the food and heating it

Question 25

what colour will the be produced if the food contained reducing sugar?

Answer 25

brick-red (blue>green>yellow>orange>brick-red)

Question 26

how to test for starch?

Answer 26

add iodine solution to a sample of the food

Question 27

what colour is obtained if the food contains starch?

Answer 27

blue-black (remains orange-brown if none)

Question 28

define metabolic reactions

Answer 28

the chemical reactions that take place inside a living organism

Question 29

what connects glucose molecules together in polysaccharides?

Answer 29

covalent bonds

Question 30

glucose is a _________

Answer 30

monosaccharide