9.1 Photosynthesis

The diagram shows the molecular structure of adenosine triphosphate (ATP)

Which of these events occurs during the normal function of ATP in the cell?

• A chemical bond forms between the adenine unit and the third phosphate group.

• The chemical bond breaks between the adenine and ribose units.

• The chemical bond breaks between the ribose unit and the first phosphate group.

• The chemical bond breaks between the second and third phosphate groups.

Which statement BEST describes the relationship between adenosine diphosphate (ADP) and adenosine triphosphate (ATP)?

• With an input of energy, ADP rearranges to become ATP.

• Without any energy change, ADP rearranges to become ATP.

• With an input of energy, ADP combines with a phosphate group to become ATP.

• With a release of energy, ADP combines with a phosphate group to become ATP.

Chloe is developing a model of photosynthesis. The first part of the model is shown below.

Which would be the MOST useful next step for Chloe to develop the photosynthesis model further?

• Extend the lines for sunlight so that they pass through the autotroph.

• Represent a chemical reaction in the autotroph that produces high-energy carbohydrates.

• Represent a chemical reaction in the autotroph that produces high-energy proteins.

• Draw a circle to represent a heterotroph, and draw a line to connect it to the autotroph.

A mushroom gains its energy by decomposing the tissues of dead organisms. Should mushrooms be classified as autotrophs, heterotrophs, in both groups, or in neither group, and for what reason?

• They are autotrophs because they do not eat their food, as animals do.

• They are autotrophs because decomposition is very similar to photosynthesis.

• They are heterotrophs because their food is made by other organisms.

• They are both autotrophs and heterotrophs, because they may grow in sunlight or darkness.

Neurons are cells of the nervous system. As part of its normal function, a neuron pumps sodium ions (Na+) out of the cell and potassium ions (K+) into the cell. Which statement describes the role of energy in this process?

• The process releases energy that is used to make ATP.

• The process releases energy in the form of heat.

• The process requires energy that is provided by the sodium and potassium ions.

• The process requires energy that is provided by ATP.

Cells use a molecule called ______________________ is used to store and release energy like a battery. The energy is stored in chemical bonds between _____________________ groups of the molecule, and the energy is released when the chemical bonds are broken.

• RNA, nucleotide

• DNA, Ribose

• ATP, Phosphate

• CMP, oxygen

Plants, algae, and some bacteria use the energy of sunlight in the process of _______________________ . The process converts the energy from sunlight into chemical energy stored in the bonds of_________________________.

• herbivory, proteins

• photoperiodism, carbon dioxide

• photosynthesis, carbohydrates

• respiration, water molecules