Chapter 5 HW

In which organism would you likely find a chlorosome?

Green sulfur bacteria Yes! Green sulfur bacteria contain chlorosomes. Chlorosomes, or chlorobium vesicles, house bacteriochlorophylls.

What provides electrons for the light reactions?

H2O Electrons are stripped from water in the light reactions of photosynthesis. This is one of the reasons plants need water.

Which of the following can be used as a final electron acceptor for aerobic respiration?

Molecular oxygen explanation: has to be organic

Glycolysis produces energy in which form?

NADH and ATP

According to the animation, which compounds provide electrons to the system?

NADH and FADH2

Which of the following statements regarding competitive inhibitors is true?

competitive inhibitors decrease the rate of enzyme activity

What enables competitive inhibitors to bind to a specific enzyme?

competitive inhibitors have structures that resemble the enzyme's substrate

How many net ATPs can be made from one molecule of glucose in glycolysis?

2 explanation: produce 4 but you need to give back 2 to reuse cycle

What is the net production of ATP in glycolysis?

2 ATP

How many molecules of ATP can be generated from 1 molecule of NADH? FADH?

3 ATP and 2 ATP

Put the following steps of bacterial replication in the correct order, starting from a parent cell. Cell elongation Septum formation Chromosome replication Separation of daughter cells

3, 1, 2, 4

What connects the two photosystems in the light reactions?

An electron transport chain An electron transport chain connects the two photosystems in the light reactions.

Why are enzymes important to biological systems?

Enzymes decrease the amount of activation energy required for chemical reactions to occur.

What is meant by the statement "Enzymes are biological catalysts"

Enzymes speed up the chemical reactions in living cells

Why does FADH2 yield less ATP than NADH?

FADH2 electrons enter the electron transport chain at a lower energy level.

Which of the following statements about glycolysis is true?

Glycolysis is also called Embden-Meyerhof pathway

A broth medium has been inoculated, and microbial numbers will be counted periodically to generate a bacterial growth curve. At 2 hours after inoculation, the culture has progressed through lag phase and is now in log phase. At this point, the population size is 1 million cells. The generation time is 30 minutes. Assuming the continuation of log growth, how many cells would there be at 2 hours of growth in log phase?

16 million There would be approximately 16 million cells. In the 2-hour interval of log growth, there are four 30-minute generations. This is four doublings of the 1 million organisms present at hour 2. 1 million cells x 24 = 16 million cells

Which step is the step for which glycolysis is named?

4th step because that's when the 6 carbon sugar also known as GP becomes 2 three carbon sugar

Which of the following equations represents photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2

What two molecules are produced by the light reactions and used to power the Calvin cycle?

ATP and NADPH

Why is ATP required for glycolysis?

ATP makes it easier to break apart glucose into 2 3-Carbon molecules

What is the intermediate product formed by pyruvic acid during alcoholic fermentation?

Acetaldehyde

Noncyclic photophosphorylation employs which photosystem(s)?

Both photosystem I and photosystem II

What is the correct general equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP energy

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?

Carbon dioxide (CO2) Carbon dioxide provides the carbon atoms that are incorporated into sugars in photosynthesis. This is why plants need to take in carbon dioxide.

Why might some cells uncouple the electron transport chain?

Cells can use the energy from the proton gradient for functions other than producing ATP, such as heat generation.

A chemostat is continuous culture system that is designed to promote and prolong exponential growth and prevent bacteria from entering stationary phase. How might this work?

Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells.

In which of the following organelles does photosynthesis take place?

Chloroplast

How does cyanide poisoning result in the decrease of ATP production?

Cyanide permanently reduces cytochrome a3, preventing other components to change into the oxidized state. This causes the proton gradient to break down, stopping ATP synthesis.

Which of the following is a bacterium that performs oxygenic photosynthesis?

Cyanobacteria Yes! Like plants and algae, cyanobacteria are oxygenic; meaning that their photosynthetic process generates oxygen.

Why do all enzymatic reactions need activation energy?

Energy is required to disrupt a substrates stable electron configuration

Which of the following statements about fermentation is true?

It is an alternative way to return electron carriers to their oxidized state.

What is the fate of the NAD+ newly regenerated by fermentation?

It returns to glycolysis to pick up more electrons.

What is the role of pyruvic acid in fermentation?

It takes the electrons from NADH, oxidizing it back into NAD+.

Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium?

Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields. Submit

Which of the following is an acid produced by fermentation?

Lactic acid and propionic acid

What transports electrons from the light reactions to the Calvin cycle?

NADPH is an electron carrier that picks up electrons in the light reactions and releases them in the Calvin cycle.

How long does it take for the daughter cells to initiate or start the next round of replication?

No time is required -- they are ready to divide immediately after DNA replication and separation of the daughter cells is complete if conditions are right.

If high amounts of sulfanilamide are in the presence of an enzyme whose substrate is PABA, what outcome is expected?

PABA will not be catalyzed explanation: because sulfanilamide has a similar structure to PABA therefore acting as an inhibitor to PABA

What is the key difference between photoheterotrophs and photoautotrophs?

Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source.

Where would you expect to find electron transport chains in a prokaryote? eukaryotes?

Plasma Membrane and inner membrane of mitochondria

This activity asks you to consider various methods of counting or estimating the size of bacterial populations and to select the method that will provide the most accurate data for plotting a bacterial growth curve. Which of the following methods would be most appropriate for gathering data to plot a bacterial growth curve throughout the four phases?

Plate count

What is meant by substrate-level phosphorylation?

Production of ATP by transferring phosphates directly from metabolic products to ADP

How does the proton gradient help ATP synthase to make ATP?

Protons move from outside the membrane to inside the membrane.

Which of the following types of organisms uses hydrogen sulfide for reducing power?

Purple sulfur bacteria Yes! Purple sulfur bacteria employ anoxygenic photosynthesis with hydrogen gas, sulfur compounds such as hydrogen sulfide, or sulfur as an electron donor (reducing power) in photosynthesis.

What is the fate of electrons in noncyclic photophosphorylation?

Reduce NADP+ to NADPH Submit

where does the energy come from to power the formation of GTP?

Succinyl CoA explanation: The combination of breaking down succinyl and CoA via water creates high energy bond = GTP

Glycolysis

Sugar splitting

When bacteria are inoculated into a new sterile nutrient broth, their numbers don't begin to increase immediately. Instead, there is a lag phase that may last for an hour or even several days. Why don't bacterial numbers increase immediately?

The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes. Explanation: A new medium may not have the same nutrients that were available in the medium from which an inoculum was taken. The bacteria may have to synthesize different amino acids, growth factors, or enzymes to enable them to grow in this new medium. Once those are synthesized, the growth rate is likely to increase, and the cells will move into log (exponential) growth phase.

Why does lack of oxygen result in the halt of ATP synthesis?

The chain shuts down and can no longer pump hydrogen ions across the membrane, and the proton gradient cannot be maintained.

What enables the copied chromosomes to separate during binary fission?

The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes.

According to the animation, what does the electron transport chain do to the concentration of hydrogen ions (protons)?

The concentration of protons is higher outside the membrane than inside.

After a period of rapid growth (log phase), bacterial growth rates will slow and enter the stationary phase. The number of viable cells no longer increases, but instead stays constant. In this activity you will indicate the statements that correctly describe what is happening during stationary phase.

The number of cells that are dying is balanced by the number of new cells that are being formed. The cells are likely running out of nutrients. Harmful waste products may be accumulating. Explanation: During the stationary phase, the number of viable cells does not increase and remains constant, or stationary. This phase begins as the nutrient supply is depleted and/or waste products begin to accumulate at a toxic level.

What would happen if the septum did not form during binary fission?

The parent cell would now have two copies of the chromosome.

Which of the following is a trait unique to photosynthetic eukaryotes?

The presence of chloroplasts

Which step involves the release of carbon dioxide?

The third and fourth steps

What is the fate of the NADPH molecules created during noncyclic photophosphorylation?

They are used in the Calvin-Benson cycle. Submit

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

Starting with three cells, how many cells would result from three rounds of replication?

Twenty-four

What is one difference between ubiquinones and cytochromes?

Ubiquinones are not made of protein; cytochromes are.

Which of the following situations does not result in a breakdown of the proton gradient?

Uncoupling proteins

According to the animation, what does oxygen get reduced to at the end of the electron transport chain?

Water

Drag the following descriptions to the appropriate location on the bacterial growth curve.

You have correctly labeled the bacterial growth curve, including the axes and the four phases: lag, log, stationary, and death phases. Keep in mind that some microorganisms may still be viable at the end of death phase. Surviving bacteria, even just one bacterium, may begin to divide and restore the population if conditions for growth become favorable again.

The reactions involved in producing larger compounds from smaller compounds is called

anabolism

Each of the three graphs shown below includes data collected during exponential growth of a species of bacteria grown in three different growth conditions. Which growth condition resulted in the longest generation time?

c The graph of exponential growth under growth condition C illustrates the slowest rate of growth and, thus, the longest generation time.

According tot he animation, the reactions that occur between glucose and pyruvic acid?

can either be anabolic or catabolic

where does the energy required for anabolic reactions come from?

catabolic reactions

The process of generating ATP using a proton gradient is referred to as

chemiosmosis.

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis Glycolysis, the breakdown of glucose into two molecules of pyruvic acid, takes place in the cytosol, outside the mitochondria.

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

according to the animation, oxidative phosphorylation

is a catabolic process

the pentose phosphate pathway

is an example of anabolism.

the use of amino acids to make proteins

is an example of anabolism.

in metabolism, energy that it not used

is given off as heat

Lipases break down

lipids

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion

which of the following is needed as a reactant for the first step of the citric acid cycle?

oxaloacetic acid

What carbon molecules remain at the end of glycolysis?

pyruvic acid

What is the driving force of energy production in steps 6 & 7?

the oxidation of 3 carbon compounds

Which step(s) of the kreb cycle does not produce any usable energy?

the second and seventh steps

How does a competitive inhibitor slow enzyme catalysis?

they compete with the substrate for the enzymes active site

The light reactions take place in the _________ and the Calvin cycle takes place in the _________.

thylakoids; stroma Within the chloroplast, the light reactions take place in the flattened sacs called thylakoids and the Calvin cycle takes place in the thick fluid called the stroma.