What is the charge of oxygen in a H2O molecule? - answer-Slightly negative
Draw a diagram of hydrogen bonding on paper - answer-Diagram of hydrogen bonding
Why is ice less dense than liquid water? - answer-The hydrogen bonds between molecules in ice are slightly further apart than the average...
2.1.2 Biology Biological Molecules
What is the charge of oxygen in a H2O molecule? - answer-Slightly negative
Draw a diagram of hydrogen bonding on paper - answer-Diagram of hydrogen bonding
Why is ice less dense than liquid water? - answer-The hydrogen bonds between molecules in ice are
slightly further apart than the average distance between liquid water molecules
What is an advantage to living organisms of ice being less dense than water? - answer-Ice floats and
forms an insulating layer on top of ponds, maintaining a constant temperature for organisms
Why is water a good solvent? - answer-It's polar so other charged molecules are attracted to it
Why is water's high specific heat capacity useful for organisms? - answer-It can be used as a coolant, to
buffer temperature changes during chemical reactions and to provide a constant temperature for
aquatic organisms
Why is water cohesive and adhesive? - answer-Water is cohesive because the hydrogen bonds mean
water molecules are attracted to one another. Water is adhesive because it can be attracted to other
polar molecules.
Why is it useful to organisms that water is cohesive and adhesive? - answer-Water acts as a good
transport medium. These properties also mean that it can move upwards through narrow tubes via
capillary action.
What are 3 examples of hexose monosaccharides? - answer-Glucose, fructose, galactose
What is a hexose monosaccharide? - answer-One with 6 carbon
What is a pentose monosaccharide? - answer-One with 5 carbons
What are 2 examples of pentose monosaccharides? - answer-Ribose and deoxyribose
What is the difference between alpha and beta glucose? - answer-The OH group is below Carbon 1 on
alpha, and above it on beta
Why is glucose soluble in water? - answer-Because it contains OH groups which make it polar
What is the bond between two monosaccharides called? - answer-Glycosidic bond
What is the disaccharide version of alpha glucose? - answer-Maltose
What is a reaction which creates water called? - answer-A condensation reaction
What is the addition of water to a disaccharide in order to split it into 2 monosaccharides called? -
answer-Hydrolysis
, What is the test for reducing sugars called? - answer-Benedict's test
What is Benedict's Reagant? - answer-An alkaline solution of Copper (II) Sulfate
What colour would blue Benedict's Reagant change to if reducing sugars are present? - answer-Red
Are all monosaccharides reducing sugars? - answer-Yes
Are most disaccharides reducing or non-reducing sugars? - answer-Non-reducing
Why does Benedict's Reagant turn red when reducing sugars are present? - answer-Because the blue
Cu2+ ions have an electron is added to form brick red Cu+ ions
What is the method for testing for reducing sugars? - answer-1. Add 2cm cubed of a food sample (liquid
or crushed with water)
2. Add 2cm cubed of Benedict's Reagant
3. Place the test tube in an 80°C water bath
What is the method for testing for a non-reducing sugars? - answer-1. Confirm that the sugar is not a
reducing sugar
2. Add 2cm cubed of food sample in liquid form to a test tube
3. Add 2cm cubed of hydrochloric acid
4. Place in 80°C hot water bath for 5 minutes
5. Remove and slowly add sodium hydrogencarbonate until the solution is neutral
6. Re-test the solution using the Benedict's test
How can you make the Bendict's Test quantitative? - answer-Use a colorimeter to test the transmission
of red light in the solutions. More reducing sugars= more red light
What are 2 examples of biosensors? - answer-Pregnancy test, blood sugar monitor
What is an analyte in a biosensor? - answer-The sample containing the molecule you are testing for
What is the receptor in a biosensor? - answer-The part which interacts with the molecule you are testing
for
What is the transducer in a biosensor? - answer-Detects the change in the receptor and provides a
response
What does the display in a biosensor do? - answer-Gives a visual representation of the change in the
receptor
What colour does iodine change to when starch is present? - answer-Changes to black because iodine
molecules become trapped in the helix of the starch
What is the polysaccharide version of beta glucose called? - answer-Cellulose
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