Which statement best describes hydrogen bonding?
A. a covalent bond that occurs when an negatively charged oxygen donates an electron to a positively charged hydrogen
B. an ionic bond that occurs when a hydrogen shares its lone electron with an oxygen or nitrogen
C. an attactive force between the partial positive charge on a hydrogen and a partial negative charge on an oxygen or nitrogen
D. an attactive force between the partial negative charge on a hydrogen and a partial positive charge on an oxygen or nitrogen
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Water has unique properties that allow it to support life. Which of the following best describes this?
A. Water is a non-polar molecule because oxygen and hydrogen share electrons equally, which allows for hydrogen bonding.
B. Water is a polar molecule because oxygen and hydrogen form polar covalent bonds, which allows for hydrogen bonding.
C. Water covalently bonds with other water molecules, which is the strongest form of bonds.
D. Water forms ionic bonds with other water molecules, which allows it to break bonds easily.
Which of the following statements best describes trace elements?
A. Trace elements are found in very small quantities in cells but still play a critical role in the functioning of living organisms.
B. Trace elements are only found in some living organisms, but not all of them.
C. Trace elements are present in living organisms in small amounts and have no special role in the fuciton of cells.
D. Trace elements are elements that are found in small quantities in nature and living orgamisms uptake them to improve the condition of the environment.
Living matter is made up of many different elements, but 96% of all living matter is comprised of just a few. Which element below is part of this 96%?
A. iodine
B. phosphorus
C. iron
D. nitrogen
1.4 Based upon the structure of the cell membrane, which description of molecules describes those that would most easily pass through a cell membrane?
A. large and hydrophilic
B. hydrophobic and small
C. covalently bonded
D. ring structures with amine groups
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