AP Chemistry of Life Bellwork Review

Chemistry of Life Bellwork Review

Multiple Choice

The intracellular pH of human cells is approximately 7.4. Yet, the pH within the lumen (inside) of the human stomach averages 1.5. Which of the following accurately describes the difference between the acidity of the cellular and gastric pH?

• gastric juices contain approximately 6 times more H ions than intracellular cytoplasm of cells and are more acidic

• gastric juices contain approximately 1,000,000- fold more H ions than the intracellular cytoplasm of cells and are more acidic

• the intracellular cytoplasm contain approximately 6 times more H ions than gastric juices and is more acidic

• the intracellular cytoplasm of cells contains approximately 1,000,000- fold more H ions than gastric juices and is more acidic

Multiple Choice

Catabolism refers to breaking down complex molecules into smaller molecules. Many biological processes use hydrolysis for catabolism. Hydrolysis of proteins could directly result in...

• free water

• adenine

• cholesterol

• dipeptides

Multiple Choice

Water is critical component of life due to its unique structural and chemical properties. Which of the following describes a way that the exceptional characteristics of ware are used in nature to sustain life?

• the low polarity of water prevents dissolution of cells and compounds

• the low surface tension and cohesiveness of water facilitates capillary action in plants

• the high heat capacity of water prevents lakes and streams from rapidly changing temperature and freezing completely solid in the winter

• the low intermolecular forces of water results in a boiling point which exceeds the tolerance of most life on the planet

Multiple Choice

Amino acids are the basic molecule units which compose proteins. All life on the planet forms proteins by forming chains of amino acids. Which part of the protein will vary from amino acid to amino acid?

• R group

• hydrogen

• carboxyl group

• ammonia group

Multiple Choice

Which of the following contain both hydrophilic and hydrophilic properties and are often found in cell plasma membranes?

• nucleotides

• phospholipids

• water

• amino acids

Multiple Choice

Maltotriose is a trisaccharide composed of three glucose molecules linked through x-1,4 glycosidic linkages formed via dehydration synthesis. What would the formula be for maltotriose?

• C18H36O18

• C18H10O15

• C18H32O16

• C3H6O3

Multiple Choice

Which of the following contradicts the hypothesis of the experiment that life may have arisen from the formation of complex molecules in the conditions of the primitive Earth?

• complex carbon-based compounds were generated after only one day of exposure to simulated primitive Earth conditions

• nucleic acid compounds such as DNA and RNA were not detected in the mixture during the experiment

• over half of known amino acids involved in life were detected in the mixture during the experiment

• basic sugar molecules were generated and detected in the mixture during the experiment

Multiple Choice

Some amino acids, such as cysteine and methionine, could not be formed in this experiment. Which of the following best explains why these molecules could not be detected?

• the chemical reactions necessary to create amino acids such as cysteine and methionine require more energy than the simulated lightening provided in the experiment

• the chemical reactions necessary to create amino acids such as cysteine and methionine require enzymes for catalysis to occur, which were not included in the experiment

• sulfur-based compounds were not included in the experiment

• nitrogen-based compounds were not included in the experiment

Multiple Choice

A scientists believes that the Miller-Urey experiment failed to yield the remaining amino acids and the nucleic acids because of the absence of critical chemical substrates that would have existed on the following basic compounds, which are associated with volcanism, would need to be added in a follow-up Miller-Urey experiment?

• HCL (acid)

• H2S (gas)

• SiO2 (silica)

• O2 (oxygen)

Multiple Choice

A radioactive isotope of hydrogen called tritium. Tritium differs from the more common form of hydrogen because...

• it contains two neutrons and on proton in its nucleus

• it contains one neutron and two protons in its nucleus

• it differs by its atomic number

• it is radioactive and therefore gives off one electron