Chapter 2: Cell Biology (Cell Compounds)

Question 1

why is water a polar molecule

Answer 1

the hydrogen and oxygen atoms don’t equally share the electrons that bond them together causing negative and positive poles

Question 2

what is hydrogen bonding (2)

Answer 2

• hydrogen atoms in water molecules become attracted to the oxygen atoms in other water molecules causing them to bond
• this holds DNA strands together

Question 3

how is water a solvent

Answer 3

its polarity makes ions separate and bond to the water molecules

Question 4

how does water regulate temperature (2)

Answer 4

hydrogen bonds between water molecules help absorb heat without drastic changes in temperature
-this helps with homeostasis within the human body

Question 5

how is water a lubricant

Answer 5

it contributes to the fluids around joints, preventing them from grinding when you use your limbs

Question 6

acids (2)

Answer 6

• substances that release H+ ions when in H2O and contain a higher concentration of H+ than OH-
• anything with a pH <7 is acidic

Question 7

bases (2)

Answer 7

• substances that release OH- ions when in H2O and contain a higher concentration of OH- than H+
• anything with a pH >7 is basic

Question 8

buffers (2)

Answer 8

• substances that regulate pH and help them resist pH changes
• they operate by taking up excess hydrogen/hydroxide ions

Question 9

why is the pH scale importance (4)

Answer 9

• it is important that the pH in our bodily fluids are within their normal healthy range
• if our blood pH drops too low, acidosis results
• if our blood pH rises too high, alkalosis results, both conditions are life threatening
• our stomach is acidic and our small intestine is basic in order for the reactions within them to be most effective and for the enzymes to function properly