Micro Module 6

Select all of the products of glycolysis to test your understanding of this process.

- 2 ATP (net) - 2 pyruvic acids - 2 NADH - H20

Label the image to test your understanding of the most common pathways of glucose metabolism.

- After glycolysis, there are three main catabolic pathways that can be used to produce energy or needed precursor molecules. - These include aerobic respiration, anaerobic respiration, and fermentation. - Each pathway uses different electron acceptors and yields different amounts of ATP.

Label the image to test your understanding of photosynthetic reactions.

- Autotrophs convert the energy in sunlight to generate chemical energy through the process of photosynthesis. - There are two phases, the light-dependent and light-independent reactions. - Overall, the process converts carbon dioxide and water to glucose and oxygen.

Select all of the phrases below that represent the structure and function of enzymes.

- Enzymes are the critical molecules which enable and control cellular metabolism. Enzymes are composed of protein. - As such, their activity is affected by temperature and pH. - Enzymes increase the rate of chemical reactions within the cell and their activity can be adjusted by a variety of regulatory mechanisms. - Enzymes are much larger than the substrates with which they interact. - Generally the substrate must fit into the active site of the enzyme. - Enzymes work by lowering the activation energy of a reaction. - They are recycled and are not used up in a reaction, so they can operate at very low concentrations. - They are not incorporated into the reaction products

Match the term to the phrase that most accurately describes it to test your understanding of enzyme terminology.

- Exoenzymes are produced within a cell and then exported to the outside of a cell, where they function. - Endoenzymes stay within a cell and function there. - The production of regulated enzymes can be turned on (induced) or off (repressed) as needed. - Constitutive enzymes are present in relatively constant amounts within a cell all the time.

Drag the images or descriptions to their corresponding class to review characteristics of enzyme function and regulation.

- The production of enzymes can be controlled. - Constitutive enzymes are always produced whereas the production of other enzymes is either induced or repressed in response to substrate concentrations. - The activity of existing enzymes can also be controlled through competitive or noncompetitive inhibition

Label the image to review how catabolic and anabolic reactions intersect in the metabolism of carbohydrate and non-carbohydrate compounds.

- This question reviews amphibolism, the integration of catabolic and anabolic reactions, in the metabolism of carbohydrate and non-carbohydrate compounds. - This integration is very important for cell efficiency. - A given molecule can serve a variety of purposes, and the organism gets the maximum benefit out of all available nutrients.

Label the figure to review the various patterns of metabolism exhibited by biological cells.

- This question reviews the various patterns of metabolism exhibited by biological cells. - Metabolic pathways can be linear, where the product of one reaction becomes the substrate for the next. - Cyclic pathways regenerate the starting molecule through a series of reactions. - Branched pathways can provide alternative methods for processing of nutrients.

Select all of the statements below that are true of enzymes to test your understanding of their structure and function.

-Enzymes are the critical cellular molecules which make possible and control cellular metabolism. -Enzymes are composed of protein. -As such, their activity is affected by temperature and pH. -Enzymes increase the rate of chemical reactions within the cell and their activity can be adjusted by a variety of regulatory mechanisms. -Enzymes are much larger than the substrates with which they interact. -Generally the substrate must fit into the active site of the enzyme. -Enzymes work by lowering the activation energy of a reaction. -They are recycled and are not used up in a reaction, so they can operate at very low concentrations. -They are not incorporated into the reaction products.

Select each of the statements that describe the Krebs cycle.

-The Krebs cycle is a cyclic pathway of 8 reactions, 2 of which are redox reactions. -During these redox reactions, electrons are picked up by NAD (in 3 of the steps) and by FAD (in 1 of the steps). -The end product of glycolysis, pyruvic acid, must be converted to acetyl CoA prior to entering the cycle. -The molecule oxaloacetic acid picks up the acetyl group from acetylCoA, and in the last step of the cycle, oxaloacetic acid is regenerated. -Carbon dioxide is released at 2 different steps in the cycle. -Each turn of the cycle generates 1 ATP molecule.

How many net ATP molecules are produced for each glucose molecule that enters glycolysis?

2 -4 molecules of ATP are produced in glycolysis, but 2 must be used up in the reactions - therefore, 2 net ATP molecules are produced for each glucose molecule that enters glycolysis.

For each glucose molecule that enters glycolysis, how many times does the Krebs cycle turn?

2 -for each glucose molecule that enters glycolysis, 2 pyruvic acid molecules are produced -each enters the Krebs cycle, and therefore, 2 circuits must be completed.

The NET production of ATP upon the completion of the series of glycolytic reactions is ______ molecule(s) of ATP.

2 -in the "bottom half" of glycolysis, 4 ATPS are made. In the "top half", 2 ATPS are broken down, so the net production of ATP is 2.

A single NADH gives rise to ___ATP molecules in the electron transport system

3 -NADH feeds into the first complex of the electron transport chain with a total of 3 complexes pumping H+ ions

For one turn of the Krebs cycle, how many NADH are produced?

3 -for 1 turn of the Krebs cycle, 3 NADH are produced.

The two 3-carbon molecules which glucose is split into are converted through a series of steps into the final 3-carbon molecule. During these later steps, _____ molecule(s) of ATP are made.

4 - in the "bottom half" of glycolysis, 4 ATPS are made. In the "top half", 2 ATPS are broken down, so the net production of ATP is 2.

In glycolysis, 2 ATP produce____ATP_____oxygen.

4, without

During the electron transport chain, ATP will be made from ______.

ADP + Pi -during the oxidative phosphorylation reactions in the electron transport chain, ATP will be made from ADP + Pi.

Glycolysis makes products that feed into _____. - Krebs cycle - fermentation - electron transport

All of the choices are correct. - pyruvate made during glycolysis can be used either in the Krebs cycle or fermentation, and the NADH+ is used in the electron transport chain.

Which of the following statements regarding metabolism is FALSE?

Anabolic reactions are degradative. -catabolic reactions degrade, anabolic reactions synthesize. -remember this by thinking of body builders using anabolic steroids to build muscle

FAD, NADP, NAD, and coenzyme A are all carriers of

Both hydrogens and electrons are correct

Which of the following correctly represents the mechanism of enzyme function, where S is "substrate" and E is "enzyme" and P is "product"?

E + S --> E-S --> E-P --> E + P

Move the terms into the correct empty boxes to complete the concept map.

Enzymes, comprised of protein or RNA, can convert substrates into products. They act as catalysts to enhance the rate of a reaction by reducing the required activation energy. Enzymatic activity can be altered, however, by temperature and pH.

An enzyme can only bind one reactant at a time.

FALSE

An enzyme speeds up a chemical reaction in the cell, but can only be used once.

FALSE

Anabolic reaction produce ATP to create new molecules

FALSE -anabolic reactions use ATP to make new molecules

In bacteria and eukaryotes, the Krebs cycle takes place in the mitochondria.

FALSE -bacteria do NOT have mitochondria.

The Krebs cycle is part of fermentation, as well as cellular respiration.

FALSE -in fermentation, the pyruvic acid from glycolysis proceeds down another metabolic pathway, and the Krebs cycle does NOT occur.

As the electron transport carriers shuttle electrons, they actively pump _____ into the outer membrane compartment, setting up a concentration gradient called the proton motive force.

H+ ions (the respiratory chain)

If an organism utilizes aerobic respiration, how does it utilize pyruvic acid?

It is converted to acetyl CoA

Select the statement that accurately reflects fermentation

It results in the incomplete oxidation of glucose -fermentation is the incomplete oxidation of glucose in the absence of oxygen

Metabolism

Metabolism is a collective term for both anabolic and catabolic reactions. - Anabolism refers to synthesis reactions only. - Catabolism refers to energy-releasing reactions that break down molecules.

The two 3-carbon molecules glucose is split into are converted through a series of steps into pyruvate. During these steps

NAD+ is converted to NADH - during the conversion stages of 3-carbon molecules that result in forming pyruvic acid (pyruvate), NAD+ is reduced to NADH.

Select the electron carriers used by cells.

NAD, FAD, NADP -the electron carriers used by cells include NAD (nicotinamide adenine dinucleotide), FAD (flavin adenine dinucleotide), and NADP (nicotinamide adenine dinucleotide phosphate).

Hydrogens are transported from other reactions to the electron transport chain by ______.

NADH and FADH

Choose the statement that reflects the most surprising aspect of the discovery of photosynthetic organisms at great depths on the ocean floor.

Photosynthetic organisms have not been known previously to perform photosynthesis using light other than sunlight or "artificial" light from electric lights -the most surprising aspect of the discovery of photosynthetic organisms at great depths on the ocean floor is their survival in the absence of sunlight which doesn't penetrate to these depths. -this is the first discovery of organisms that can perform photosynthesis using light other than sunlight or "artificial" electric lights.

Which of the following represents a correct sequence during photosynthesis?

Photosystem II - ATP production - Photosystem I - NADPH production

Choose the statement that most describes the role of the Calvin cycle in photosynthesis to test your understanding of this process.

The Calvin cycle is the "synthesis" part of photosynthesis, the set of reactions that actually convert CO2 to organic carbon compounds

Choose the statement that most accurately states the significance of the electron transport system.

The electron transport system transforms the energy of electrons into the potential energy of an electrochemical gradient (proton gradient) across the cell membrane (bacteria) or inner mitochondrial membrane (eukaryotes). This proton gradient provides the energy used by ATP synthase to phosphorylate ADP, producing ATP

Choose the term that best describes the relationship between the light dependent and light independent reactions of photosynthesis to test your understanding of these processes.

The light dependent reactions provide the ATP and NADPH that are necessary for the light independent reactions -the light dependent reactions harvest light energy, converting it to ATP and split water, providing electrons which are transferred to NADP, forming NADPH. -the ATP and NADPH are then used by the light independent reactions to reduce CO2 to organic carbon compounds

The electron carrier proteins in the electron transport chain shuttle electrons to

a terminal acceptor -the electron carrier proteins in the electron transport chain shuttle electrons to a terminal acceptor -in the case of aerobic respiration, this terminal acceptor is oxygen

The energy released during the reactions of glycolysis is used to form ______.

adenosine triphosphate - energy released during the oxidation reactions of glycolysis is used to form adenosine triphosphate (ATP), the energy-carrying molecule for the cell.

The electron transport chain is part of ______.

aerobic respiration

Although both aerobic respiration and anaerobic respiration utilize glycolysis, the Krebs cycle, and an electron transport system, ____ respiration uses O2 as the final electron acceptor at the end of the electron transport system, whereas_____ respiration uses an inorganic molecule other than O2 is the final electron acceptor.

aerobic, anaerobic -in aerobic respiration, oxygen gas (O2) is the final electron acceptor at the end of the electron transport system. -in anaerobic respiration, an inorganic molecule other than O2 is the final electron acceptor. An example of a common electron acceptor used in anaerobic respiration is NO3

_______ refers only to energy-requiring processes that result in synthesis of cell molecules and structure.

anabolism

The protein in a conjugated enzyme is referred to as the ____ whereas the combination of the protein and the nonprotein cofactor is known as the _____.

apoenzyme, holoenzyme

Early in glycolysis, two phosphates are added to the glucose molecule. These phosphates come from

breaking down ATP - early in glycolysis, ATP is converted into ADP and the phosphates are added to the ends of the glucose molecule.

The NADH involved in the electron transport chain is made

by redox reactions in glycolysis and the Krebs cycle -NADH is made by redox reactions in both glycolysis and the Krebs cycle. -carbohydrates are oxidized and NAD+ is reduced.

Select the statement that more accurately reflects the Calvin Cycle:

carbon-fixation is an important step in this cycle -the Calvin Cycle is a set of light-independent reactions that use ATP to make glucose

Which of the following contain a metal ion which can accept and donate electrons?

cytochromes -cytochromes such as cytochrome c contain a metal ion which can accept and donate electrons

In eukaryotes, glycolysis takes place in the ____.

cytoplasm

Where does the Krebs cycle take place in bacteria?

cytoplasm -the Krebs cycle takes place in the cytoplasm in bacteria -bacteria do NOT possess a nucleus or mitochondria.

Where do NADH and FADH2 go after being produced in the Krebs cycle?

electron transport chain -NADH and FADH2 go to the electron transport chain -located in the cell membrane of prokaryotes or the inner mitochondrial membrane of eukaryotes.

Enzymes that function inside the cell are

endoenzymes

The high-energy electrons of photosystem I are directly passed on to ______.

ferrodoxin

The final acceptor for electrons and hydrogens in aerobic respiration is ______.

free oxygen

Glycolysis is the breakdown of ______.

glucose - glycolysis in both aerobic + anaerobic organisms

The Krebs cycle occurs after _______.

glycolysis -the pyruvic acid molecules formed in glycolysis are first oxidized and then enter the cyclical pathway known as the Krebs cycle.

The electron transport chain in bacteria is located

in the cell membrane

In bacteria, the electron transport chain is located

in the plasma membrane

Where does carbon dioxide go when it is released during reactions of the Krebs cycle?

it diffuses out of the cell -carbon dioxide is a by-product of the Krebs cycle reactions and when produced, it is released from the cell by diffusion.

Which statement accurately reflects the Krebs Cycle?

it produces 8 reduced coenzymes per glucose molecule -the Krebs Cycle takes place in the cytoplasm of prokaryotes and within the mitochondrial matrix of eukaryotes, and generates reduced coenzymes for use in the ETS

After glycolysis, pyruvate can be converted into ______ under anaerobic conditions.

lactic acid -after glycolysis, pyruvate can be converted into lactic acid under anaerobic conditions

Select the correct statement regarding photosynthesis:

light-dependent reactions are catabolic -light-dependent reactions are catabolic and produce ATP that is used by light-independent reactions that are anabolic and require (not produce) ATP

Glycolysis is an example of which metabolic pattern:

linear

The term used to describe all of the chemical reactions within a cell is

metabolism

All of the chemical reactions that occur within a cell are collectively referred to as:

metabolism -metabolism is the sum total of the all of the chemical reactions that occur within a cell

Hydrogen consists of ______.

one proton and one electron

Exoenzymes are typically involved in chemical reactions

outside of the cell

The energy released during the reactions of glycolysis is released by ______ reactions.

oxidation

During aerobic respiration, the last carrier protein transfers a pair of electrons to ______.

oxygen

Which of the following is NOT necessary for respiration?

oxygen

Which of the following is NOT a catabolic process?

photosynthesis -photosynthesis is an anabolic process -all of the others do involve the breakdown of complex molecules and the release of energy, and therefore, they are considered catabolic.

The electrons excited by sunlight are replaced by electrons from _______ in photosystem I, and by electrons from ________ in photosystem II.

photosystem II; water

The main purpose of cellular respiration is to _____.

produce energy -main purpose of cellular respiration is to catabolize glucose, providing energy for the production of ATP.

Enzymes are ______.

proteins

Enzymes are

proteins that function as catalysts

In this reaction, ATP synthase uses energy from ______ to make ATP.

protons re-entering the cell -in this reaction, ATP synthase uses energy from protons re-entering the cell to make ATP

The two 3-carbon molecules that glucose is split into during glycolysis are converted through a series of steps ending in what 3-carbon molecule?

pyruvate - the two 3-carbon molecules glucose is split into during glycolysis are converted through a series of steps into pyruvate, a key metabolite.

The process of decarboxylation involves _______.

removing carbon

During the electron transport chain in bacteria, protons are

shuttled to the outside of the cell membrane -during the electron transport chain in bacteria, protons are shuttled to the outside of the cell membrane -bacteria do not possess mitochondria like eukaryotes

Which of the following binds to the active site of an enzyme?

substrate

Which metabolic pathway produces the most NADH?

the Krebs Cycle

Fatty acids are oxidized in

the Krebs cycle -catabolism of non-carbohydrate compounds

Cells prefer to use carbohydrates as energy sources because

they are such good donors of hydrogen and electrons - cells prefer to use carbohydrates such as glucose as energy sources because they are such good donors of hydrogen and electrons.

Coenzyme Q

transfers protons from inside the membrane to outside the membrane -Coenzyme Q transfers protons from inside the membrane to outside the membrane

The last carrier protein in the electron transport chain transfers

two electrons to oxygen

The function of the enzyme ATP synthase is to

utilize the energy of the proton motive force to convert ADP to ATP