Biology 212 Homework Questions

It can be seen from the figures provided (see PDF version question 12 if this is difficult to see on the screen here) that adding potassium to the extra cellular fluid around one type of taste bud cells ____ membrane potential. This makes sense because adding potassium outside the cell makes the equilibrium potential of K+ ____, as equilibrium potential is a measure of ____. In panel m we see that "tastants" cause membrane potential to change through the movement of ____ the cell, and the change in membrane potential leads to ATP export.

depolarizes (make less negative) less negative the concentration gradient of an ion sodium into

Which of the following best describes how phloem sap is driven from source to sink regions of the plant. Note that all of these answers match some aspect of the process, but only one describes the bulk flow of material through the plant.

difference in pressure potential within the phloem

During phototropism auxin ____ are relocated within cells of the ____. When auxin enters a cell in the shoot elongation zone it K+ the proton pump. This ____ the cell. This voltage change causes ____ ions to ____ the cell though channels. It also ____ the cotransporter thought which the driving force acting on ____ drives the import of ____. All this solute movement ____ cell osmotic potential. This causes water to ____ the cell, which ____ pressure potential in the cell. The ____ in pH in the wall space activates _____, which cuts quick links between ____.

efflux carriers tip activates hyperpolarizes K+ enter activates H+ sugar decreases enter increase(s) decrease(s) expansions microfibrils

The statement that Kb codes for a transcription factor that increases Katrinase expression ____ because ____

false if true Kb Vmax activity and concentration would be lower than Wt

The statement that "Kb codes for a competitive inhibitor of Katrinase" is ____ because ____

false if true Kb-Km would be lower than Wt

The rate limiting reaction of aerobic respiration involves the phosphorylation of ____ by the enzyme ____. The rate at which this enzyme makes product is ____ when ATP levels rise because the molecule ____ binds to an ____ site on the enzyme and acts as a(n) ____ ____. When ATP levels fall ____ binds to ____ of ____ This interaction leads to an increase of cellular ____, so that this is an example of a _____ feedback loop

fructose phosphate phosphofructokinase decreased ATP allosteric indirect inhibitor AMP an allosteric site phosphofructokinase [ATP] negative

Glucose-phosphate production by an enzyme extracted from cells taken from the much-feared Lilyputin in media with four different glucose levels is provided above. The fasting blood sugar levels of this animal fall between 0.04 and 0.06 sugar units. The enzyme catalyzing this reaction must be ____ and the cells from which the enzyme was extracted could have been ____. The substrate of this enzyme is ____. If you added insulin to the media you would expect the enzyme rate to ____.

glucokinase pancreatic beta cells glucose stay the same

potassium

has/have a negative equilibrium potential

sodium

has/have positive equilibrium potential

Human systemic iron homeostasis regulated by the hormone ____. This hormone is ____ . An increase in the activity of this hormone in the blood leads directly to a reduction in the activity of ____ . This leads to a decrease in the number of Fe ____ bound to ____ that is circulating in the blood

hepcidin a protein ferroportin +++ transferrin

Glucose-phosphate production by an enzyme extracted from cells taken from the much-feared Lilyputin in media with four different glucose levels is provided above. The fasting blood sugar levels of this animal fall between 0.40 and 0.60 sugar units. The enzyme catalyzing this reaction must be ____ and the cells from which the enzyme was extracted could have been _____. The Km of this enzyme to three decimal places is ____

hexokinase muscle cells 0.075

Panel A tells us that the hormone CORT changes the membrane potential of pancreatic beta cells in a medium containing high levels (8mM) of glucose. Panel C provides the activity of the KATP channels in beta cells in low and high sugar media and in high sugar plus CORT. Stars indicate that the only significantly difference is between the 0 mM glucose activity data and the high sugar treatments (the two short bars are not different). In panel A CORT delivery timing is indicated by the line above the graph. The data shows us that CORT ____ beta cells after a short delay and that it does this ____ altering Katp function. Panels C-E in this next figure show us CORT activity in both control and GIRK2 loss of function beta cells. This data supports the hypothesis that ____ ____ ____ which in turn _____ insulin secretion. Given all the data provided on this page, what ion is moving through the beta cell membrane as a resu

hyperpolarizes without CORT activates GIRK inhibits potassium

When it sense cold, the ____ sends a signal in the form of a ____ to ____ cells which leads to activation of ____ proteins. This process includes release of ____ G protein subunit that can interact with ____. We now know that lipid signals ____ sufficient to drive UCP gene expression in this pathway. Activation of this signal pathway would lead to an increase in the rate of activity of ____. We can assume that the activity of the TRPM2 channel in the mouse hypothalamus ____ lead to an increase in the process discussed above.

hypothalamus neurotransmitter brown fat uncoupler a stimulatory adenylate cyclase are glycolsis, the kreb cycle, and the electron transport chain would not

ATP

is the fuel used by the pump

Cells of an individual with an active immune response to infection will take up ____ iron from ____. Injected iron will ____ malaria symptoms.

less the gut exacerbate (make worse)

The cells of the ____ are the primary target of the hormone glucagon, which is made in the ____. These cells respond by increasing their rate of ____, and decreasing their rate of ____.

liver pancreas gluconegenesis glycogen synthesis

Conversely, [loss of function] mutations in the TMPRSS6 gene lead to overexpression of hepcidin. In this case, patients suffer from the condition IRIDA.14Links to an external site. These individuals suffer from a form of IRIDA that typically does not improve with oral iron treatment ... novel thiazolidinone derivatives appear to act on hepcidin expression by decreasing Tmprss6 activity. Based on this report: IRIDA seems to be a condition that includes ____ blood iron. TMPRSS6 seems to be an ____ Patients with IRIDA don't improve with oral iron treatment because ____.

low an inhibitory transcription factor this condition deactivates ferroportin

What is the mechanism that allows Glomus cells to detect and signal low oxygen conditions? Individuals lacking a functional version of the gene for this version of the enzyme have glomus cells that replace it with the enzyme version present in most other cell types. This leads to ____ Glomus cells have versions of the enzyme ____ with a ____ than this enzyme has in other cells. This causes signal generation leading to ____ ____ resulting in ____. an inhibitor of complex III activity in these cells would presumably ____ this cell type. Adding K+ to the interstitial fluid surrounding these cells would presumably lead to ____ breathing.

lower blood sugar cytochrome c oxidase higher Km potassium channel closure or deactivation plasma membrane depolarization depolarize faster

Outside a cell, auxin is in its ____ form but in the cytoplasm it is in ____ form. Because of this, auxin can enter cells via ____, but must exit via ____, and so the location of these dictates the direction of auxin flow.

neutral anion the lipid bi-layer channels/carriers

Ammonium is the principle ____ containing nutrient of the ____ bacteria.

nitrogen nitrifying

The GOE led to ____ of massive quantities of ____, and ever since organisms have completed for this material, adopting strategies that have driven significant evolutionary change.

oxidation iron

The great oxidation event (GOE) was the result of ____ carried out by ____.

photosynthesis cyanobacteria

Alan Hodgkin and Andrew Huxley used ____ neurons to update the existing paradigm of how membrane potential changes from resting potential in a cell from simply closing ____ channels to a more complex process of opening and closing ____ channels when they discovered that membrane potential didn't just do to zero during a nerve impulse, it actually becomes ____

squid potassium sodium and potassium positive

The primary site of gas exchange in leaves is ____. Plant regulate gas exchange levels though the action of ____. The cost of carrying out gas exchange is ____.

the spongy mesophyl guard cells water loss

Fluid exits the blood until Blood pressure decreases to 1.61Kpa. The Ψo of the interstitial fluid is -1.68Kpa in this region. So, the osmotic potential of the blood must be _________Kpa. You answer should given to the nearest hundredth of a Kpa.

-3.29

If this animal became temperature acclimated with a Lower critical temperature of 105°x with no change in BMR it would have a heating cost of _______ MRU/degree, please just type in a number for your answer, not the units. Use decimal version if answer contains a fraction and round to three decimal places.

0.261

Match the Genotype and construct to the # of root epidermal cells that are blue 1. wer- with Glabra::GUS 2. cpc- & Glabra- with Glabra::GUS 3. wer- & cpc- with 35s::Glabra 4. Wild type with 35s::CPC and Glabra::GUS

1. 0% root epidermal cells that are blue 2. 100% root epidermal cells 3. 50% root epidermal cells 4. 0% root epidermal cells

Match the Genotype and construct to the # of root epidermal cells that form hairs 1. wer- with Glabra::GUS 2. cpc- & Glabra- with Glabra::GUS 3. wer- & cpc- with 35s::Glabra 4. Wild type with 35s::CPC and Glabra::GUS

1. 100% 2. 100% 3. 0% 4. 100%

For each of the following questions, identify the relative values of Ψω, Ψο or Ψp by completing the statements using > or <. 1. Xylem Ψp 15 feet up from the roots of a tree is __ Xylem Ψp 5 feet up from the roots of a tree. 2. Ψw of air at 100% humidity is __ Ψw of air at 60% humidity 3. Expected transpiration rate at 100% humidity is __ at 60% humidity 4. Ψw outside air on dry day is __ Ψw air in leaf space 5. Ψo of guard cell of open stomata is __ Ψo of guard cell of closed stomata 6. pore diameter of ABA influenced stomata is __ pore diameter with no ABA

1. < 2. > 3. < 4. < 5. < 6. <

1. During which time period(s) is K+ exiting the pacemaker cell through voltage gated channels? 2. During which time period(s) is Na+ entering the pacemaker cell through voltage gated channels? 3. Which Voltage Line represent a membrane potential of 0mV 4. Which Voltage Line represents "threshold potential" 5. At the moment pointed to by the arrow

1. C and D 2. A and D 3. B 4. C 5. Calcium is entering the cell though voltage gated channels

Match the substances on the left, with the proper descriptions of their involvement in phloem loading 1. chloride 2. water 3. sugar

1. not involved 2. driven though the membrane by water potential 3. bought though the membrane against concentration, charge is irrelevant

If ABA treatment of guard cells makes them flaccid and completely closes the stomata and the osmotic potential has changed by 3.1 Kpa to -2.4Kpa, we can assume that the pressure potential in these cells before ABA arrived was _______ Kpa

3.1

The results and biological model in these figures come from a set of experiments intended to support the hypothesis that ____required for the delivery of ____ from a particular set of taste bud cells to neurons that deliver taste information the brain, and that this protein is activated by ____. The activities of the other components of the model illustrated by panel m are not directly supported by the results shown in panel h.

CALHM1 channels are ATP depolarization

How does the level of carbon dioxide in the atmosphere influence the number of stomata on leaves?

Developing leaves make more stomata when older leaves detect low carbon dioxide levels

The statement that "kb codes for a competitive activator of Katrinase" is ____ because ____

False if true kb- Vmax activity would be lower than Wt on the graph

It is evident that the allosteric regulator that the GCK-HH mutation fails to bind is ____. Patients with this allele would have symptoms of ____.

an inhibitor low blood sugar

Blood pressure is greatest in the ____. Blood flow rate ____ as blood moves from the heart through vessels and back to the heart. The vessels whose sum cross sectional area is greatest are the ____. ____ are vessels with remarkable valves that maintain blood flow directionality. Blood pressure in the arteries is __ pressure in the veins Blood velocity in the arteries is __ velocity in the capillaries

arteries stays the same capillaries veins > >

In the nodules of legumes, the order of affinity for oxygen of the following 3 proteins is ____ > ____ > ____.

bacterial cytochrome c oxidase leghemoglobin nitrogenase

____ and ____ both lead to stomatal opening using overlapping pathways. The membrane potential of the ____ cells become ____ during opening. The water potential of the cell ____ during opening. The driving force on potassium during the opening is ____. The well wall adjacent to the stomatal pore expand vertically ____ than the walls distal from the pore.

blue light low carbon dioxide guard more negative decreses negative more

In pancreatic beta cells the membrane spanning sugar importing ____ has ____ Km for glucose than those found in muscle cells. Increases in the rate at which this step occurs lead to ____ Activity of a channel that allows ____ to ____ the cell. Changes in this channel activity alter the likelihood that ____ will ____ the cell though another channel. The coincidence detector in beta cells that allows coordination of response to multiple forms of carbohydrate is a(n) ____ that dictates whether _____ will ____ the cell. Ultimately it is ____ flow through the cell membrane that dictates whether or not insulin will exit the cell via ____.

carrier/channel higher decreased potassium exit calcium enter channel sodium enter calcium exocytosis

Flaccid guard cells are components of ____. Menisci involved in transpiration are found ____. Evaporation occurs ____ during transpiration. ____ is not under tension. During transpiration, ____ concentration is highest ____.

closed stomata in the wall space spongy parenchyma in the wall space of spongy parenchyma cells water vapor in air spaces in the air spaces between spongy parenchyma

What is driving iron though ferroportin?

concentration

Na/K pump

create(s) equilibrium potential

leak channel

create(s) resting potential

flow = ____ x ____ flow = total pressure / ____ resistance is proportional to 1/____ to the ____ power

cross sectional area velocity pressure drop resistance vessel radius 4th

The shade acclimation response occurs in response to ____. The shade avoidance response occurs in response to ____. Of the two, only ____ involves an increase in stem length.

a low R:FR light ratio a low R:FR light ratio shade avoidance

needs graph What is the insulin secretion level of the double mutant at fasting blood sugar? what is the insulin secretion level of the double mutant at elevated blood sugars? How much insulin secretion would you expect in wild type b-cells in the presence of elevated blood sugar but no fructose present

above 10% but below 40% 60% maximal 60% maximal