4.1 & 4.2 water and carbohydrates Flashcards
how can metabolic reactions occur?
metabolic reactions can only occur if the chemicals which are reacting are dissolved in water
why does plasma contain lots of water?
so substances like glucose can dissolve in it; these dissolved substances are transported around the body
how does water help digestion take place?
water dissolves enzymes and nutrients in the alimentary canal in order for digestion to occur
how does urine form?
urea, waste products from kidneys, dissolved in water
what is another word for ‘simple sugar’?
monosaccharides
what atoms do carbohydrate molecules contain?
6 carbon; 12 hydrogen; 6 oxygen
what is the molecular formula for a glucose?
C₆H₁₂O₆
what is the name of a complex sugar and how is it formed?
disaccharide; the junction of two simple sugar molecules
what are examples of a complex sugar?
sucrose and maltose
what is the name of a very large molecule made by the multiple junctions of simple sugars?
polysaccharide
how many joined sugar molecules does a polysaccharide contain?
thousands of joined sugar molecules in a long chain
what is the polysaccharide found in animal cells?
glycogen
are polysaccharides soluble?
no
what are carbohydrates needed for?
energy
how much energy does one gram of carbohydrate release?
17kJ (kilojoules)
how is the energy released?
the energy is released by respiration
what carbohydrate is normally used in respiration?
glucose
what carbohydrate is transported in plants?
sucrose
what do plants convert their carbohydrates to when necessary?
glucose
what do plants store carbohydrates as?
starch
what do animals store carbohydrates as?
polysaccharides glucose
how much glucose can animals store and where is it mostly stored?
only small quantities can be stored; in the cells in the liver and the muscles
what is the criss-crossing fibres from which the plant’s cell wall is constructed?
polysaccharide cellulose
how to test for carbohydrates?
by adding Benedict’s solution to the food and heating it
what colour will the be produced if the food contained reducing sugar?
brick-red (blue>green>yellow>orange>brick-red)
how to test for starch?
add iodine solution to a sample of the food
what colour is obtained if the food contains starch?
blue-black (remains orange-brown if none)
define metabolic reactions
the chemical reactions that take place inside a living organism
what connects glucose molecules together in polysaccharides?
covalent bonds
glucose is a _________
monosaccharide
