Biology Unit 2
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
Identify the chloroplast.
A green thing
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
B
Identify a thylakoid.
D
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars. Submit
What stage of cellular respiration is also part of fermentation?
glycolysis
In glycolysis there is a net gain of _____ ATP.
2
Identify the stroma.
E
Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Which of these statements is the correct explanation for this observation?
In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration. Submit
Pyruvate, a three-carbon molecule, is processed into acetyl CoA, a two-carbon molecule. What happened to the missing carbon?
It is lost as carbon dioxide (CO2)
What purpose does fermentation serve?
It regenerates NAD+ from NADH to keep glycolysis going in the absence of oxygen. Submit
During electron transport, energy from _____ is used to pump hydrogen ions into the _____.
NADH and FADH2 ... intermembrane space
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
TRUE
What molecule is split in the oxygen-releasing light reactions of photosynthesis?
Water
Molecules that are amphipathic must contain _____.
both hydrophilic and hydrophobic regions
What process occurs within Box B?
citric acid cycle
When ATP is hydrolyzed into ADP and inorganic phosphate, _____.
free energy is released
An enzyme _____.
is an organic catalyst
The proximate (immediate) source of energy for oxidative phosphorylation is _____.
kinetic energy that is released as hydrogen ions diffuse down their concentration gradient
Movement of vesicles within the cell depends on what cellular structures?
microtubules and motor proteins
Where is a bacterial cell's DNA found?
nucleoid region
In cellular respiration, most ATP molecules are produced by _____.
oxidative phosphorylation
In C3 plants the conservation of water promotes _____.
photorespiration
Which process produces oxygen?
photosynthesis
What is a function of a bacterium's capsule?
protection
In general, enzymes are what kinds of molecules?
proteins
Enzymes work by _____.
reducing EA
In a bacterium, where are proteins synthesized?
ribosomes
The enzyme that catalyzes the fixation of carbon dioxide in photosynthesis is _____.
rubisco
What is the correct label for "A"?
energy of activation
In fermentation _____ is reduced and _____ is oxidized.
pyruvate ... NADH
Look at the graph of reaction rate versus substrate concentration for an enzyme. In which region does the reaction rate remain constant?
region C
How are proteins transported to their correct location in the cell?
Proteins contain molecular "zip codes" that allow them to be shipped to the correct cellular compartment.
Which of the following correctly pairs the process with its inputs and outputs?
Pyruvate processing-Inputs: pyruvate, NAD+; Outputs: acetyl CoA, NADH, CO2 Submit
As a result of its involvement in a reaction, an enzyme _____.
is unchanged
During photosynthesis, the light energy from the sun is captured and stored in the bonds of _____.
sugars
True or false? Osmosis is a type of diffusion.
True
In muscle cells, fermentation produces _____.
lactate and NAD+
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
In glycolysis, what starts the process of glucose oxidation?
ATP
At the end of cellular respiration, protons flow through a protein called ATP synthase, which drives the formation of __________________.
ATP from ADP and inorganic phosphate
The rate of cellular respiration is regulated by its major product, ATP, via feedback inhibition. As the diagram shows, high levels of ATP inhibit phosphofructokinase (PFK), an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP production, decreases. Feedback inhibition enables cells to adjust their rate of cellular respiration to match their demand for ATP. Suppose that a cell's demand for ATP suddenly exceeds its supply of ATP from cellular respiration. Which statement correctly describes how this increased demand would lead to an increased rate of ATP production?
ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.
Chlorophyll can be found in _____.
AandC
Energized electrons from ____ are used to reduce NADP+.
C
The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.
C
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
Interpret the model. Drag "True" or "False" to the end of each statement.
The Golgi apparatus is not shown in this cell, but this does not necessarily mean that this organelle does not occur in the cell. True The large structure in the center is a nucleus. False The relative dimensions and placement of the membranes and organelles in this model are exact representations of those structures in a living cell. False This cell is capable of photosynthesis. True The two lines on the outside of the chloroplasts indicate a double membrane. True
Review the video to determine how the covalent bonds in the products differ from the bonds in the reactants. Drag "True" or "False" to the end of each statement.
The bonds in the products are stronger than those in the reactants. True The electrons are shared equally in the reactants and unequally in the products. True The bonds in the products have higher potential energy than those in the reactants. False The bonds are nonpolar in the reactants and polar in the products. True
Which of the following statements correctly describe(s) the driving forces for diffusion of Na+ and K+ ions through their respective channels? Select all that apply.
The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. The electrochemical gradient is larger for Na+ than for K+.
Corinne has drawn a flow chart to track the fate of carbons during cellular respiration. Interpret her model.
The horizontal lines represent covalent bonds between carbons. True The model shows that the number of carbons decreases over time. False Each pyruvate molecule yields one 2-carbon acetyl CoA and one CO2. True The orange circles represent the carbons in CO2. True Both the red circles and the orange circles represent carbons. True The missing label for the bottom pair of arrows should be "Electron transport chain." False
A trout moves from a warm environment into a cold environment. Predict how the saturation status of hydrocarbon chains might change to ensure proper membrane fluidity in the new cold environment.
The hydrocarbons would become less saturated to increase the fluidity of the membrane.
Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
How are the light-dependent and light-independent reactions of photosynthesis related?
The products of light-dependent reactions are used in light-independent reactions.
What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?
Cell Wall
The structure of a chloroplast is closely tied to its function as the site of photosynthesis. Which statements are true for chloroplasts? Select the three that apply.
They contain the green pigment chlorophyll. They are the sites of reactions that convert solar energy into chemical energy. They have membranous sacs called thylakoids that are surrounded by a fluid called stroma.
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
During the citric acid cycle FADH2 and NADH are produced. What purpose do these molecules serve in the electron transport chain (ETC)?
They serve as electron donors in the ETC. Submit
True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.
True
Drag the terms on the left to complete the sentences on the right.
When molecules move down their concentration gradient, they move from where they are more concentrated to where they are less concentrated. Diffusion across a biological membrane is called passive transport.
A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____.
a nucleus
Which of these enters the citric acid cycle?
acetyl CoA
Which of these is NOT a product of the citric acid cycle?
acetyl CoA
The following question are based on the reaction A + B ↔ C + D shown in the accompanying figure. Which of the following represents the activation energy required for a noncatalyzed reaction in the figure?
c
Which of the following cell structures is only found in algal and plant cells?
chloroplasts
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
cytoplasm
What process occurs in Box A?
glycolysis
Alfred has drawn a flow chart to show a time sequence of four processes of cellular respiration. Which sequence of three labels is the best choice to finish his model?
glycolysis / pyruvate processing / citric acid cycle Submit
Identify Structure A.
glycoprotein
In eukaryotes, the components of citric acid cycling and the electron transport chain are located in the ____.
inner mitochondrial membrane
Which set of reactions uses H2O and produces O2?
light dependent reactions`1
Which organelle plays a role in intracellular digestion?
lysosome
_____ splits water into 1/2 O2, H+, and e- .
A
Structure A is _____.
ATP synthase
Which of the following factors does not affect membrane permeability?
The polarity of membrane phospholipids
Where does the Calvin cycle occur?
E
What is the correct sequence of steps in cellular respiration, starting with glucose?
Glycolysis, pyruvate processing, citric acid cycle, electron transport, oxidative phosphorylation Submit
Plant leaves contain openings called stomata, which allow the diffusion of _______.
H2O, CO2, and O2
Which of the following products of cellular respiration would accumulate if there were no final electron acceptor in the electron transport chain (ETC)?
NADH
Which of the organelles represented by these models is/are considered to have a double membrane?
Three of them
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation Submit
What is the primary function of the Calvin cycle?
synthesizing simple sugars from carbon dioxide
Which of the following factors remains the same over the course of this reaction?
the number and type of atoms
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
Selective Permibility of Mebranes Structure A in the figure is a(n) _____.
transport protein
For each molecule of glucose processed during glycolysis, the net yield is ____.
two molecules of NADH, two of ATP, and two of pyruvate Submit
Choose the correct sequence of numbers to fill in the blanks to balance this equation.
1,2,3 __N2+__H2=__NH3
Yuki has drawn a flow chart to track the major inputs and outputs in cellular respiration. Select the most suitable set of labels for the numbered arrows.
1. produces 2. produces pyruvate used in 3. transfers electrons to
Glycolysis is a series of ___ reactions that occurs in the _____ of cells.
10; cytoplasm
For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle.
2
How many NADH are produced by glycolysis?
2
David has drawn a flow chart to track the ATP inputs and outputs in cellular respiration per molecule of glucose entering glycolysis. According to David's model, how many ATP are gained overall?
29 ATP
For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle.
6
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
Which of the following statements is not true of most cellular redox reactions?
A hydrogen atom is transferred to the atom that loses an electron.
In this model of a reaction, how do you interpret the orange balls being positioned in the middle of a line drawn between two atoms?
A nonpolar bond exists between the two atoms.
Which of these can RAPIDLY pass directly through the phospholipids of the plasma membrane, without the help of a transport protein?
A only (lipid Soluble molecule)
What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
Amphipathic nature
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?
Anion and cation.
Two models of cellular processes are shown, each containing arrows. Select the best verbal translations of what the arrows mean in each model.
Arrow 1 = "then"Arrow 2 = "transport to"
Gaseous hydrogen burns in the presence of oxygen to form water:2H2 + O2 → 2H2 O + energyWhich molecule is oxidized and what kind of bond is formed?
Hydrogen, polar.
Can you identify whether each activity takes place in cellular respiration, in fermentation, or in both?
Cellular respiration only Pyruvate is oxidized. Fermentation only Pyruvate is reduced. Both cellular respiration and fermentation ATPATP is produced. NADHNADH is produced. NAD+NAD+ is produced. Glucose is oxidized.
Review the video to determine which of the statements correctly describe a difference between cellular respiration and fermentation. Drag "True" or "False" to the end of each statement.
Cellular respiration produces more CO2CO2 per mole of glucose than fermentation. True Cellular respiration produces more C O 2 per mole of glucose than fermentation. True Cellular respiration produces more NADHNADH per mole of glucose than fermentation. True Cellular respiration produces more N A D H per mole of glucose than fermentation. True Cellular respiration produces more pyruvate per mole of glucose than fermentation. False Cellular respiration produces more ATPATP per mole of glucose than fermentation. True Cellular respiration produces more A T P per mole of glucose than fermentation. True Cellular respiration produces more lactate per mole of glucose than fermentation. False
The DNA-containing region of this bacterial cell is indicated by the letter _____.
D
Where does the citric acid cycle occur in eukaryotes?
In the matrix of mitochondria
Which of these phosphorylates ADP to make ATP?
E
Which term describes the degree to which an element attracts electrons?
Electronegativity.
Consider a situation in which the enzyme is operating at optimum temperature and pHpH, and has been saturated with substrate. What is your best option for increasing the rate of the reaction?
Increase the enzyme concentration.
Why is chlorophyll green?
It absorbs wavelengths in only the blue and red parts of the visible spectrum. Submit
Which of these is NOT a product of glycolysis?
FADH2
_____ are surface appendages that allow a bacterium to stick to a surface.
Fimbriae
Under anaerobic conditions (a lack of oxygen), glycolysis continues in most cells despite the fact that oxidative phosphorylation stops, and its production of NAD+ (which is needed as an input to glycolysis) also stops. The diagram illustrates the process of fermentation, which is used by many cells in the absence of oxygen. In fermentation, the NADH produced by glycolysis is used to reduce the pyruvate produced by glycolysis to either lactate or ethanol. Fermentation results in a net production of 2 ATP per glucose molecule. During strenuous exercise, anaerobic conditions can result if the cardiovascular system cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a muscle cell's demand for ATP under anaerobic conditions remains the same as it was under aerobic conditions. What would happen to the cell's rate of glucose utilization?
Glucose utilization would increase a lot.
Choose the correct sequence of numbers to fill in the blanks to balance this equation. c2h402+nahco3=nac2h302+h20+2co2
H2O is a product. True There are the same number of hydrogen atoms (H) in the reactants as in the products. True There are the same number of carbon atoms (C) in the reactants as in the products. False The equation is balanced. False The arrow indicates that the atoms of the reactants bond in new ways to form products. True The arrow indicates that the reaction is reversible. False
What molecule is indicated by the letter D?
Oxygen
Which of the following particles could diffuse easily through a cell membrane?
Oxygen (O2)
Which of the following statements is true of the bonds in a water molecule?
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
RuBP
Which of the following sentences is the best translation of the arrow in this chemical reaction? ch4+2o2=co2+2h2o
[These reactants] are transformed into [these products].
The final electron acceptor of cellular respiration is _____.
oxygen
Which of the following can change the shape of an enzyme?
pH temperature phosphorylation all of the above
Identify Structure D.
phospholipid bilayer of membrane
Plant cells and animal cells share many of the same structures, but each type of cell also has unique structures. In this activity, you will indicate which cell structures are found only in plant cells, only in animal cells, or in both plant and animal cells.
plant cell only cellulose cell wall chloroplast central vacuole animal cell only centriole both mitochondrion nucleus endoplasmic reticulum cytoskeleton Golgi apparatus plasma membrane
The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.
plasma membrane
Two fundamental types of cells are known to exist in nature: prokaryotic cells and eukaryotic cells (like the one shown in the Tour of an Animal Cell animation). Both prokaryotic and eukaryotic cells carry out all of the processes necessary for life, but they differ in some important ways. In this activity, you will identify which cell structures are found only in prokaryotic cells, only in eukaryotic cells, or in both types of cells. Drag each cell structure to the appropriate bin.
prokaryotic only nucleoid eukaryotic only lysosome mitochondria nucleolus both ribosomes plasma membrane flagella
Refer again to the graph. In which region is the enzyme saturated with s
region C
What is the function of Structure E?
stabilization of the phospholipids
What name is given to the reactants in an enzymatically catalyzed reaction?
substrate