Chapter 5-7 hw and iclicker questions

Pinocytosis

"Cell drinking", when the cell engulfs extracellular fluid. creates a small vesicle, unlike phagocytosis which makes a vacuole

A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes? 1. mitochondrial matrix 2. cytoplasm 3. mitochondrial inner membrane 4. plasma membrane

1

C4 plants differ from C3 and CAM plants in that C4 plants _____. - transfer fixed carbon dioxide to cells in which the Calvin cycle occurs -use PEP carboxylase to fix carbon dioxide - open their stomata only at night - are better adapted to wet conditions -use malic acid to transfer carbon dioxide to the Calvin cycle

1

In eukaryotes, most of the high-energy electrons released from glucose by cellular respiration __________. 1. reduce NAD+ to NADH, which then delivers them to the electron transport chain 2. are bound to FAD to be sent through the process of oxidative phosphorylation 3. are used for synthesizing lactic acid 4. are used to form ATP by the citric acid cycle

1

Lactase is essential for digesting lactose in milk. This enzyme is specific for this sugar. Why? 1. There is a precise compatibility between the active site and the lactose molecule. 2. Reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules. 3. Molecules and active sites vary in size; only properly sized molecules can fit. 4. Specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed.

1

Osmosis is often viewed incorrectly as a process driven directly by differences in solute concentration across a selectively permeable membrane. What really drives osmosis? 1. he difference in water concentration across a selectively permeable membrane 2. the first law of thermodynamics 3. the difference in the height of water columns on either side of a selectively permeable membrane 4. the difference in sugar or ion concentration across a selectively permeable membrane

1

Paper chromatography is used to _____. - separate components in a material of interest - detect radioactivity - force photosynthesis to occur - produce glucose

1

Part complete Current evidence indicates that the process of photosynthesis arose more than three billion years ago. Its origin had a huge impact on existing organisms and on the physical characteristics of the biosphere. Which major physical change could be attributed to photosynthesis? - Photosynthesis drastically increased the oxygen content of the atmosphere. - Photosynthesis allowed much higher levels of ultraviolet light to reach Earth's surface. -Photosynthesis drastically increased the carbon dioxide content of the atmosphere . -Photosynthesis drastically raised Earth's surface temperature.

1

Part complete The Calvin cycle describes the conversion of ___. - carbon dioxide to carbohydrates - carbohydrates to proteins - water to carbon dioxide - carbon dioxide to amino acids

1

Part complete What two molecules are produced by the light reactions and used to power the Calvin cycle? ATP and NADPH C6H12O6 and RuBP G3P and H2O C6H12O6 and O2 CO2 and O2

1

Part complete Which of the following best describes the electron transport chain? Electrons pass from one carrier to another, releasing a little energy at each step. Hydrogens are added to CO2 to make an energy-rich compound. Acetyl CoA is fully oxidized to CO2. Electrons are pumped across a membrane by active transport.

1

Some human cells, such as nerve cells, are restricted to aerobic respiration to recycle NADH and FADH2. If these cells are deprived of oxygen, then __________. oxidative phosphorylation would come to a halt because there wouldn't be any oxygen to "pull" the electrons down the transport chain proton gradient formation would continue, but ATP synthase function would stop glycolysis could still continue indefinitely ATP production would continue because the cell would perform fermentation

1

Which of the following is a difference between active transport and facilitated diffusion? 1. Active transport requires the expenditure of cellular energy, and facilitated diffusion does not. 2. Facilitated diffusion involves transport proteins, and active transport does not. 3. Active transport involves transport proteins, and facilitated diffusion does not. 4. Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot.

1

Which of the following molecules is broken down in cellular respiration, providing fuel for the cell? 1. glucose 2. ATP 3. water 4. oxygen

1

Which of these enters the citric acid cycle (also called the Krebs cycle)? 1. acetyl CoA 2. pyruvate 3. G3P 4. glucose 5. NADH + H+

1

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells? 1. the similarity of the drug molecule to other molecules that are transported into the target cells 2. the phospholipid composition of the target cells' plasma membrane 3. the nonpolar, hydrophobic nature of the drug molecule 4. the concentration of the drug molecule that is transported in the blood

1

Which statements about the fluid mosaic structure of a membrane are correct? Select the three correct statements. 1. The diverse proteins found in and attached to membranes perform many important functions. 2. The kinky tails of some proteins help keep the membrane fluid by preventing the component molecules from packing solidly together. 3. Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane. 4. Membranes include a mosaic, or mix, of carbohydrates embedded in a phospholipid bilayer. 5. The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center

1, 3, 5

For each glucose that enters glycolysis, _____ NADH enter the electron transport chain. 4 6 2 0 10

10

A molecule moves down its concentration gradient using a transport protein in the plasma membrane. This is an example of 1. endocytosis. 2. facilitated diffusion. 3. diffusion. 4. active transport. 5. exocytosis.

2

Although the reactions of the Calvin cycle are not directly dependent on light, they usually do not occur at night. Why? - It is often too cold at night for these reactions to take place. - The Calvin cycle depends on products of the light reactions. - Carbon dioxide concentrations decrease at night. - Plants usually open their stomata at night.

2

How many NADH are produced by glycolysis?

2

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? 1. potentiation 2. cellular respiration 3. anabolism 4. redox 5. digestion

2

Part complete A single glucose molecule produces about 38 molecules of ATP through the process of cellular respiration. However, this only represents approximately 34% of the chemical energy present in this molecule. The rest of the energy from glucose is __________. 1. used directly for energy 2. converted to heat 3. used to make water from hydrogen ions and oxygen 4. stored as fat

2

Part complete Each turn of the citric acid cycle generates one ATP and ___ additional energy-rich molecules: __________. 1. four; 2 NADH and 2 FADH2 2. four; 3 NADH and 1 FADH2 3. two; 1 NADH and 1 FADH2 4. three; 2 NADH and 1 FADH2

2

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? G3P Carbon dioxide (CO2) RuBP Glucose (C6H12O6) Sucrose (C12H22O11)

2

Which energy-rich molecule produced by cellular respiration directly powers cell work? 1. glucose 2. ATP 3. water 4. oxygen

2

A red chemical dye known as phenol red changes to yellow when CO2 is present. A small green plant seedling is placed in phenol red and then placed in the dark. Which of the following is most likely to occur? 1. The solution is yellow to begin with, and it will turn red because respiration is occurring. 2. The solution is red to begin with, and it will turn yellow because photosynthesis is occurring. 3. The solution is red to begin with, and it will turn yellow because respiration is occurring. 4. The solution is yellow to begin with, and it will turn red because photosynthesis is occurring.

3

In C3 plants the conservation of water promotes _____. 1. a shift to C4 photosynthesis 2. photosynthesis 3. photorespiration 4. the opening of stomata 5. the light reactions

3

Most NADH molecules generated during cellular respiration are produced during __________. 1. the electron transport chain 2. glycolysis 3. the citric acid cycle 4. the reduction of oxygen

3

Part complete A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via __________. 1. active transport 2. osmosis 3. endocytosis 4. passive transport

3

Part complete In nutrient-rich environments (like your mouth), bacteria can use the provided amino acids to synthesize their proteins. However, should the environmental conditions change and become nutrient-poor, bacteria would need to synthesize their amino acids. They can do this using __________. 1. glucose 2. ATP 3. citric acid cycle intermediates 4. glyceraldehyde 3-phosphate

3

Part complete Utah's Great Salt Lake has an average salinity seven times higher than that of the oceans. Very few multicellular organisms live in this harsh environment. An example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. These brine shrimp must _____. 1. actively pump water back out of their cells to counter its inflow due to osmosis 2. synthesize membranes that are impermeable to substances that upset osmotic balance 3. actively pump water back into their cells to counter its loss due to osmosis 4. actively pump salt back out of their cells to counter its inflow due to osmosis

3

The final electron acceptor of cellular respiration is _____. 1. NADH 2. CO2 3. oxygen 4. FADH2 5. water

3

The impact of a sufficiently large asteroid or comet is one of the theories that have been put forward to explain why dinosaurs, as well as many other plant and animal species, became extinct 65 million years ago. Why would this extinction-level event have had such a major impact on Life on Earth? The toxic fumes produced meant that the dinosaurs could no longer breathe. It created enormous tidal waves and huge forest fires. It produced dust and other particulates that would block out the sun. It increased the temperature of the planet.

3

The sodium-potassium pump uses energy from ATP to move sodium ions out of the cell, and potassium ions into the cell. This is an example of 1. facilitated diffusion. 2. diffusion. 3. active transport. 4. exocytosis. 5. passive transport.

3

Through respiration, humans breathe in O2 and breathe out CO2. However, what would happen if we did not breathe in O2? We would not be able to perform lactic acid fermentation. We would not have enough enzymes to catalyze reactions. We would not make enough ATP to meet our energy requirements We would not be able to synthesize organic molecules from inorganic molecules.

3

Water crosses the plasma membrane 1. using a process that requires energy from the cell. 2. through cotransport. 3. through facilitated diffusion or diffusion. 4. against its concentration gradient. 5. through active transport.

3

Which of the following equations represents photosynthesis? C6H12O6 + 6O2 → 6CO2 + 6H2O 6CO2 + 6O2 → C6H12O6 + 6H2O 6CO2 + 6H2O → C6H12O6 + 6O2 C6H12O6 + 6CO2 → 6O2 + 6H2O 6H2O + 6O2 → C6H12O6 + 6CO2

3

Which of the following statements regarding glycolysis is FALSE? 1. Glycolysis plays a role in both fermentation and respiration. 2. Glycolysis is the most widespread metabolic pathway found in Earth's life. 3. Glycolysis evolved in an oxygen-rich environment. 4. Glycolysis does not require compartmentalization by internal

3

Which of these are by-products of cellular respiration? 1. glucose and water 2. ATP 3. heat and water water 4. ATP and water

3

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to treat people with bacterial infections. However, he can't do this because _____. 1. glycolysis produces so little ATP that the drug will have little effect 2. bacteria are facultative anaerobes; they usually don't need to perform glycolysis 3. bacteria do not perform glycolysis 4. human cells also perform glycolysis; the drug might also poison them

4

Aquaporins are proteins that facilitate the transport of __________ across the membrane. 1. salt 2. proteins 3. urine 4. water

4

Azidothymidine (AZT) is an antiretroviral drug used in the treatment of HIV. It shares a structural similarity to a nucleotide. What might be the mode of action for this drug? 1. noncompetitive inhibition 2. mixed inhibition 3. feedback inhibition 4. competitive inhibition

4

Endocytosis moves materials _____ a cell via _____. 1. out of ... diffusion 2. into ... facilitated diffusion 3. into ... a transport protein 4. into ... membranous vesicles 5. out of ... membranous vesicles

4

Given the relatively modest number of calories burned by anything but the most vigorous activities, why can people consume over 2,000 kilocalories a day, yet maintain a healthy body weight? 1. Not all calories are created equal, so a person who consumes 2,000 kilocalories of sugar- and fat-laden processed food will gain weight, whereas a person who consumes 2,000 calories of nonprocessed, low-carbohydrate food will not. 2. They can't, and this has led to a problem of obesity in the United States. 3. People really should exercise vigorously for one to two hours per day. 4. Most of the energy consumed in food is spent maintaining the body's functions, so only a fraction of food energy needs to be burned in exercise.

4

In cellular respiration, most ATP molecules are produced by _____. 1. substrate-level phosphorylation 2. cellular respiration 3. photophosphorylation 4. oxidative phosphorylation 5. photosynthesis

4

Part complete Both mitochondria and chloroplasts _____. - obtain electrons from water - reduce NAD+, forming NADP - release oxygen as a by-product - use an H+ gradient to produce ATP

4

Part complete Cells A and B are the same size and shape, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____. 1. A ... its membrane transport proteins will not be saturated 2. A ... the diffusion gradient there is shallower 3. B ... the oxygen molecules inside cell B have a higher kinetic energy 4. B ... the diffusion gradient there is steeper

4

Part complete The primary function of light absorption by photosystems I and II is to produce __________. fluorescence heat oxygen free, energized electrons

4

We inhale O2 and we exhale CO2. Carbon dioxide is produced __________. 1. when oxygen acquires electrons and protons at the end of the electron transport chain 2. during the formation of pyruvate 3. during the electron transfer steps of oxidative phosphorylation 4. in the reaction that creates acetyl CoA (coenzyme A) from pyruvate

4

What is the main cause of the current amplification of global climate change? 1. depletion of the ozone layer 2. melting polar ice 3. lowered sea levels 4. Human activity is increasing the concentration of greenhouse gases, which delays the escape of heat from the planet.

4

Photosynthesis is an __________ process in which carbon is __________, whereas cellular respiration is an __________ process in which carbon is __________. endergonic : oxidized : exergonic : reduced endergonic : oxidized : endergonic : reduced exergonic : reduced : endergonic : oxidized endergonic : reduced : exergonic : oxidized

4.endergonic : reduced : exergonic : oxidized

In glycolysis, what starts the process of glucose breakdown? 1. NADPH 2. ADP 3. Pyruvate 4. FADH2 5. ATP

5

What name is given to the process by which water crosses a selectively permeable membrane? 1. diffusion 2. passive transport 3. phagocytosis 4. pinocytosis 5. osmosis

5

ATP synthase phosphorylates what?

ADP

1. In ___ plants, the first product of carbon fixation is the three-carbon compound 3-PGA formed in the Calvin cycle.

C3

In ______ plants, CO2 is first fixed into a four-carbon compound, which moves into bundle-sheath cells and releases CO2 to the Calvin cycle.

C4

In ________ plants, stomata are open at night, and CO2 is first fixed into a four-carbon compound, which releases CO2 to the Calvin cycle during the day.

CAM

Which of these is NOT a product of glycolysis? water NADH + H+ ATP pyruvate FADH2

FADH2

ATP is not produced during photosynthesis; it is only produced during cellular respiration. T/F

False

T/F There is only one way of doing photosynthesis

False (C3, C4, and CAM)

What provides electrons for the light reactions? The Calvin cycle CO2 O2 H2O Light

H2O

During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

NADH and FADH2; inter-membrane space

Oxygen is the final electron acceptor for cellular respiration. What is the final electron acceptor in the light reactions of photosynthesis?

NADP+

What transports electrons from the light reactions to the Calvin cycle? NADH Chlorophyll NADPH FADH2 An electron transport chain

NADPH

Part complete The light reactions of photosynthesis generate high-energy electrons, which end up in __________. The light reactions also produce __________ and __________.

NADPH; ATP; oxygen

. When such plants close their stomata on hot, dry days to conserve water, _______ builds up in the leaf and is added to RuBP in place of CO2. A two-carbon product of this reaction is broken down to CO2, consuming ATP and generating no sugar.

O2

True or false. Guard cells open during the day to allow gases to flow through the stomata.

True

Why doesn't the antibiotic penicillin harm humans? 1. Human cells do not have cell walls. 2. Penicillin attacks the nervous system. 3. Penicillin attacks plasma membranes. 4. The dosage given to kill bacteria is too low to harm humans.

a

Which of these is NOT a product of the citric acid cycle (also called the Krebs cycle)? CO2 NADH + H+ FADH2 ATP acetyl CoA

acetyl CoA

what type of experiment was used in calvin's experiment?

algae

What connects the two photosystems in the light reactions? An electron transport chain A thylakoid A chain of glucose molecules The Calvin cycle Chlorophyll

an electron transport chain

In an experiment, a plant was given __________ containing a heavy isotype of oxygen (18O), and the heavy oxygen atoms were used to make sugar.

carbon dioxide

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive carbon. The mice were closely monitored, and in a few minutes, radioactive carbon atoms showed up in __________.

carbon dioxide

Part complete The radioactive isotope used in the Calvin experiments was ____. carbon-12 carbon-14 nitrogen-15 boron-8

carbon-14

In which of the following organelles does photosynthesis take place? Nucleus Mitochondrion Ribosome Chloroplast Central vacuole

chloroplast

The photosystems contain _________________

chlorphyll

In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells. cytoplasm grana stroma stoma thylakoids

cytoplasm

The energy released as electrons are passed along the _______________________ is used to pump protons into the thylakoid compartment.

electron transport chain

The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell. This describes the process of 1. exocytosis. 2. endocytosis. 3. diffusion. 4. active transport. 5. passive transport.

endocytosis

during cellular respiration __________ is oxidized and __________ is reduced.

glucose; oxygen

hypertonic

greater concentration of solute outside of the cell (shrink)

Part complete Solar radiation warms the surface of the planet and then is radiated back in the form of __________. heat CO2 ozone UV radiation

heat

The proximate (immediate) source of energy for oxidative phosphorylation is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient

In muscle cells, fermentation produces _____.

lactate and NAD+

Sports physiologists at an Olympic training center want to monitor athletes to determine at what point their muscles begin to function anaerobically. They could do this by checking for a buildup of _____. ADP lactic acid carbon dioxide ATP

lactic acid

Which of the following leaf types would be the most efficient at absorbing sunlight? Needlelike leaves All of these leaf types are equally efficient at absorbing sunlight. Small, narrow leaves Large, broad leaves

large, broad leaves

In most green plants, chloroplasts are concentrated in the

mesophyll

Diffusion across a biological membrane is called

passive transport

facilitated diffusion is a type of

passive transport

Autotrophs that utilize light as their energy source are

photoautotrophs

The apparently wasteful process described in sentence 2 is called __________________ .

photorespiration

Energized electrons from ______________ are used to reduce NADP+.

photosystem I

____________ splits water into 1/2 O2, H+ and e-

photosystem II

Bacteria have no membrane-enclosed organelles. However, some still generate ATP through cellular respiration. Where might the electron transport chain be found in these organisms? plasma membrane mitochondria cytoplasm nucleoid region

plasma membrane

What does not occur during the Calvin cycle?

release of Oxygen

In all three types of plants, the enzyme _________ brings CO2 into the Calvin cycle.

rubisco

When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.

splitting water

Part complete Which of the following structures allows for gas exchange between the tissues of a leaf and the atmosphere? Stomata Vascular bundle Cuticle Epidermis

stromata

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

why is it difficult for C3 plants to carry out photosynthesis in hot and dry climates?

the closing of the stromata keeps CO2 from entering and O2 from leaving the plant

Where does the calvin cycle occur?

the stroma

Where is chlorophyll found in a plant cell?

thylakoid membranes

Chlorophyll is located in _______ which are found in ________, which are concentrated in the __________.

thylakoids; chloroplasts; mesophyll

Part complete The light reactions take place in the _________ and the Calvin cycle takes place in the _________. chloroplasts; mitochondria thylakoids; stroma inner membrane; outer membrane mitochondria; chloroplasts stroma; thylakoids

thylakoids; stroma

A gram of fat oxidized by cellular respiration produces approximately __________ as much ATP as a gram of carbohydrate. View Available Hint(s) half twice 4 times 10 times

twice

In photosynthesis _____ is oxidized and ______ is reduced .

water; carbon dioxide

During light reactions electron are derived from _____ and energy from _______.

water; sunlight