MCDB 1B: Final quizzes
T/F: Movement of mineral ions in the soil into a root's vascular tissue (xylem) tales place by apoplastic transport past the Casparian strip of the endodermis
F
T/F: The NADPH generated in the thylakoid stroma is used to oxidize RuBP to 3PG
F
T/F: Cells of the collecting duct can adjust their water permeabilities by altering the density of aquaporins in their membranes. This is regulated by ADH
T
When analyzing how C3, C4 and CAM plants differ in terms of Carbon FIxation a) C4 plants fix CO2 by converting PEP to OAA b) CAM plants utilize spatial separation of the cells responsible for Carbon Fixation and the cells that are responsible for sugars through the Calvin-Benson cycle c) C3 plants have RuBisCo that is highly specific to CO2 and therefore does not require isolation from O2 generated by water splitting and/or closing of the leaf stomata d) only C4 plants utilize PEP as the initial 3 carbon compound that CO2 is fixed into e) none of the above are true
a) C4 plants fix CO2 by converting PEP to OAA
Which of the following statements about the movement of potassium ions through open stomata is true? a) K+ enters guard cells, water follows, and the cells become turgid b) K+ leaves guard cells through plasmodesmata and they become less turgid c) K+ enters guard cells and they become less turgid d) K+ leaves guard cells and they become turgid e) K+ reaches equilibrium in guard cells and their surroundings
a) K+ enters guard cells, water follows, and the cells become turgid
Match the following components of the renal tubule with the correct function/property. 1. Proximal Convoluted Tube 2. Descending Limb of the Loop of Henle 3. Thin ascending Limb of the Loop of Henle 4. Thick Ascending Limb of the Loop of Henle 5. Collecting Duct a) cells that require ATP to *pump* ions/Na+ into the medulla b) impermeable/decreased permeability to ions c) absorption of amino acids, sugars, water, and ions d) passive, facilitated diffusion of ions/Na+ into the medulla e) ADH-regulated aquaporins that allow for the reabsorption of water into the medulla
1. c 2. b 3. d 4. a 5. e
The photosystems allow plant chloroplasts to harvest light energy. When thinking about the two photosystems that comprise typical 'green' plants a) photosystem II splits water within the thylakoid lumen, increasing the H+ gradient in this membrane enclosed structure b) photosystem I is located 'upstream' to photosystem II, in that PS I will donate electrons to PS II c) PS I is responsible for cyclic photophosphorylation to generate ample NADPH for the Calvin Benson Cycle d) ATP and NADPH production occurs in the lumen of the thylakoid e) Photosystem I, II, and the ETC are all responsible for building the H+ gradient within the thylakoid lumen
a) Photosystem II splits water within the thylakoid lumen, increasing the H+ gradient in this membrane enclosed structure
Kidney function involves 3 main processes: 1) filtering the blood, 2) absorption of nutrients and ions, 3) secretion of waste products and buffers. What below are part of the 1) filtration of blood at the renal corpuscle? a) only the small solutes that can diffuse between the podocytes' finger-like processes can enter the Bowman's Capsule b) the basal lamina is a gel-like matrix of collagen and other glycoproteins. This is like a sieve that only small molecules can pass through c) proximal convoluted tubule screens out cells and molecules, like platelets or large plasma proteins like albumin, by active transport d) the endothelium of the capillaries that comprise the glomerulus have fenestrations on their surface that enable small molecules to transit the capillary wall e) all of above
a,b,d
Plants and plant cells are unique as there are defined age gradients at each level that can be observed! In terms of the plant cell wall, what below is FALSE? a) the primary cell wall is older and located outside of the plant secondary wall b) is the site of a major plant compartment of the plant body, the symplast c) largely consists of a meshwork of hydrophilic cellulose, hemicellulose and pectin in a well-hydrated (water-rich) environment d) have a lower pH than the cytoplasm e) none of the above are false
b) is the site of a major plant compartment of the plant body, the symplast
In the light reactions of photosynthesis a) light energy is used to generate a H+ gradient across the outer chloroplast membrane that drives chemiosmotic ATP synthesis b) isolate thylakoids should produce ATP if pre-incubated in an acidic buffer, then transferred to a neutral solution containing ADP + Pi, even if maintained in total darkness c) an excited chlorophyll molecule in the reaction center of Photosystem I acts as an oxidizing agent of water, but a reducing agent to the ETC d) regeneration of the P680 in photosystem II occurs by cyclic photophosphorylation e) light energy is converted to metabolic energy in the form of ATP and NADH
b) isolated thylakoids should produce ATP if pre-incubated in an acidic buffer, then transferred to a neutral solution containing ADP + Pi, even if maintained in total darkness
In regards to how the kidney regulates the pressure of your blood... a) the renin-angiotensin-aldosterone system stimulates water reabsorption by increasing the number of aquaporins in the distal convoluted tubule b) the ADH system is activated by increase in the blood osmolarity (blood is more salty) to stimulate the release of ADH into the blood stream. This is perceived by the epithelial cells of the collecting duct to place aquaporins in the plasma membrane c) the ANP system is activated in response to atrial stretch. ANP increases the retention of Na+ and H2O whil inhibiting the synthesis of aldosterone, renin and ADH d) B and C e) A, B, and C
b) the ADH system is activated by increases in the blood osmolarity to stimulate the release of ADH into the blood stream. This is perceived by the epithelial cells of the collecting duct to place aquaporins in the plasma membrane
Considering the epithelial cells that compromise the renal tubule lining, what below is FALSE? a) the cells that comprise the descending limb of the loop of Henle are 'thin' to allow for more efficient movement of molecules, like water, through osmosis via facilitated diffusion b) the cells of the thin ascending limb of the loop of Henle are thick and have many mitochondria that produce ATP to power the active transport required to move salt/ions into the medulla c) the epithelial cells that compromise the collecting duct/tube of the nephron possess vesicles that possess many aquaporins d) the epithelial cells of the distal convoluted tubule can alter the osmolarity of the waste fluid by actively transporting salt/ions out of the tubule into the interstitial space of the cortex e) multiple options above are false
b) the cells of the thin ascending limb of the loop of Henle are thick and have many mitochondria that produce ATP to power the active transport required to move salt/ions into the medulla
Which of the following processes contributes the most to generating the negative water potential in a leaf? a) the pressure placed on the leaf by the cuticle (the waxy film that protects the epidermal tissues of a leaf) b) the evaporation of water from mesophyll cells c) the movement of water into the leaf by root pressure d) the increased K+ pumped out of guard cells e) the movement of water from the veins into the leaf
b) the evaporation of water from mesophyll cells
In addition to regulating salt and water balance, kidneys also play a role in regulating the pH of blood. Which of the following statements about pH balance in the blood is TRUE? a) the kidneys control the level of CO2 in the blood b) the net effect of H+ secretion into kidney tubules is an increase in blood pH c) HCO3- (bicarbonate) is the major buffer present in the blood d) B and C e) none of the above
d) B and C
Which of the following factors has a direct impact on the orientation and expansion of plant cells? a) initial cellulose microfibril orientation b) lignin deposition c) turgor pressure d) all of the options influence cell growth
d) all of the options influence cell growth
A plant cell placed in distilled water will a) expand until the solute potential reaches that of the distilled water b) become more turgid until the solute potential reaches that of the distilled water c) become less turgid until the solute potential reaches that of distilled water d) become more turgid until the pressure potential of the cell reaches its solute potential e) become less turgid until the pressure potential of the cell reaches the outside water potential
d) become more turgid until the pressure potential of the cell reaches its solute potential
In CAM metabolism a) fixed carbon is shuttled from mesophyll to bundle sheath cells b) the problems of photorespiration are reduced by isolating the enzyme PEP carboxylase from high levels of dissolved O2 c) carbon fixation by the Calvin cycle occurs at night to avoid photorespiration d) carbon is fixed via C4 metabolism at night and by the Calvin cycle in the day e) fixed carbon is stored in the vacuole in the form of G3P, a 4 carbon compound
d) carbons is fixed via C4 metabolism at night and by the Calvin cycle in the day
When sucrose is added to phloem cells at a source via the apoplastic pathway of loading a) water follows by osmosis and the hydrostatic pressure pushes the sucrose toward a sink b) water follows primarily by mass/bulk flow through abundant plasmodesmatal connections to adjacent mesophyll cells c) most of the sugar is loaded directly into the sieve type elements, bypassing the companion cell d) active transport of sucrose molecules from a leaf's apoplast to its phloem requires cotransport with protons e) A and D
e) A and D
When you think about the two pathways by which the phloem can be loaded with sugars generated by the mesophyll cells of the leaf... What is FALSE below? a) sugars move towards the phloem through mesophyll cells by the symplastic pathway. This is due to diffusion of the sugar down its concentration gradient b) entry into the phloem (through the companion cell) can be either through a symplastic or apoplastic pathway c) in the apoplastic loading pathway, movement of sugars into the companion cells require ATP and a H+ gradient to pull the sugar into the companion cells (against the sugar gradient) through a protein symporter d) the increased concentration of sugars at the source increases the pressure potential of the phloem, resulting in the movement of phloem sap (tree blood) to sink areas (which have less pressure) e) all of the above are true
e) all of the above are true
Which of the following physiological responses would NOT correct for a drop in glomerular blood pressure? a) stimulation of aldosterone release by the adrenal cortex b) elevation of the body's central blood pressure by angiotensin c) stimulation of thirst in the brain by angiotensin d) constriction of the efferent renal arterioles e) constriction of the afferent renal arterioles
e) constriction of the afferent renal arterioles
When considering phloem loading, unloading, and transport, what below is INCORRECT? a) phloem loading (of some plants) requires channel proteins to export sugars into the apoplastic space between parenchymal cells and companion cells b) phloem loading and unloading requires a proton gradient established by an ATPase that pumps protons into the plant cell wall c) phloem transport of sugars works on the principle of increased psi P in the areas of loading and decreased psi P in the areas of unloading. This allows for bulk flow of the phloem d) like vessel elements in xylem, phloem sieve tube elements are like stacked cans that allow for the movement. However, unlike vessel elements sieve tube elements are alive and allow for bidirectional movement of the phloem e) increases solute concentration in the phloem reduces overall water potential in the phloem (vs the xylem). This allows for the osmotic movement of water from the xylem into the phloem located at both the source and sink areas
e) increased solute concentration in the phloem reduces the overall water potential in the phloem (vs the xylem). This allows for the osmotic movement of water from the xylem into the phloem located at both the source and sink areas
The ATP needed in the Calvin Cycle a) is produced by both cyclic and noncyclic (aka the Z-scheme) photophosphorylation b) is used during the "sugar shuffle" that regenerates RuBP c) is used during the carboxylation of RuBP d) all of the above e) only A and B
e) only A and B
Which of the following statements regarding the human kidneys is FALSE? a) sodium chloride diffuses out of the thin ascending limb of the loop of Henle b) sodium chloride is actively transported out of the thick ascending limb of the loop of Henle c) although the descending limb of the loop of Henle is permeable to water, the ascending limb is not d) as urine passes through collecting ducts, water leaves due to the concentration gradient established in the medulla e) the urine passing through the collecting ducts is more concentrated than the surrounding interstitial fluid in the medulla, so water moves out of collecting ducts
e) the urine passing through the collecting ducts us more concentrated than the surrounding interstitial fluid in the medulla, so water moves out of collecting ducts
Positive pressure (psi P) potential within a cell is most likely to result in... a) a decrease in the diffusion of ions into that cell b) an increase in the diffusion of ions out of that cell c) a decrease in the uptake of water by that cell d) an increase in the uptake of water by that cell e) an increase in uptake of both water and ions by that cell
c) a decrease in the uptake of water by that cell
In C4 plants, the function of the four-carbon compound that is synthesized in the mesophyll cells is to a) reduce NADP+ b) combine with CO2 to produce glucose c) carry CO2 to the bundle sheath cells d) drive the synthesis of ATP e) close the stomata
c) carry CO2 to the bundle sheath cells
At a source, sucrose moves into the phloem in the apoplastic pathway by a) tension within sieve tubes produced by sucrose unloading at sink cells b) osmosis c) secondary active transport into companion cells (using the proton gradient and symport of the sugar) d) strictly symplastic movement from adjacent mesophyll cells e) A and D
c) secondary active transport into companion cells (using the proton gradient and symport of the sugar)
An epithelial root hair plant cell has a turgor/pressure potential of 0.5MPa and an solute/osmotic potential of -0.75. Therefore... a) the cell has a water potential of -1.25MPa b) the cell has a water potential of 1.25MPa c) the cell has a water potential of -0.25 d) will take up water from the surrounding soil if the soil water potential is -1.0MPa e) C and D
c) the cell has a water potential of -0.25
Which of the following descriptions of mammalian nephron components is INCORRECT? a) cells of the proximal convoluted tubules have many microvilli and mitochondria b) the osmolarity of the urine is controlled, in part, y changing the rate of NaCl transport in the distal convoluted tubule c) the site of greatest water reabsorption is the thick ascending limb of the loop of Henle d) the cells of the descending limb of the loop of Henle are permeable to water, whereas those of the ascending limb transport NaCl but not water e) urine is less concentrated when it leaves the loop of Henle than when it entered it
c) the site of greatest water reabsorption is the thick ascending limb of the loop of Henle
Nutrients such as sugars and amino acids are replaced in the bloodstream following filtration through the kidney because a) they are not forced from the glomerulus into the Bowman's capsule b) they are actively transported out of the ascending limb of the loop of Henle c) they are actively transported out of the proximal convoluted tubule d) they move by diffusion down their concentration gradients from the lumen of the collecting duct into the surrounding medulla tissue e) B and C
c) they are actively transported out of the proximal convoluted tubule
The Calvin Benson cycle use the energy trapped in ATP and NADPH generated by the light reactions to build sugars from CO2. What below is FALSE regarding this sugar-building cycle? a) initially RuBP is carboxylated by RuBisCo where atmospheric CO2 is captured and put into the cycle b) ATP and NADPH generated by the light reactions are used to reduce 3PG to a more energetic/reduced G3P c) more ATP (from the light rxns) are required to regenerate the remaining G3P to RuBP for the initial CO2 fixation d) in the absence of light, the Calvin Benson cycle will continues to reduce 3PG to G3P indefinitely, but will be unable to regenerate RuBP e) photorespiration occurs when RuBisCo inadvertantly captures O2 instead of CO2. In this situation, instead of generating two molecules of 3PG, photorespiration results in 1 molecule of 3PG and 1 molecule of a 2 carbon compound called 2PG
d) in the absence of light, the Calvin Benson cycle will continue to reduce 3PG to G3P indefinitely, but will be unable to regenerate RuBP
Which statement regarding the primary cell walls of plants is false? a) they contain pectins b) they contain hemicellulose c) the primary cell walls of two adjacent cells are separated by the middle lamella d) the contain high concentrations of hydrophobic lignins
d) they contain high concentrations of hydrophobic lignins
