Can the exact same sequence of amino acids fold into different tertiary structures?

what kind of concentration effects can be seen in the self assembly of amino acids?

Suppose you used a paper chromatography method to separate all the amino acids, but aspartate (aspartic acid) and glutamine were not resolved. Which of the following would be your best next step to separate these 2 amino acids? There may be more than one possibility. Pick one choice and justify it.
Choices: (paper electrophoresis at pH 2) (paper electrophoresis at pH 12) (paper chromatography)
(trypsin treatment) (paper electrophoresis at either pH).

3. Describe the two major routes by which the amino groups are removed from amino acids: transamination, oxidative deamination. Describe the role played by pyridoxal phosphate, glutamate, α–ketoglutarate, and glutamate dehydrogenase in these processes.

5

The carbon assimilation (Calvin cycle) stage of photosynthesis requires:

Group of answer choices

ATP, NADPH and CO2

ATP, NAD, and hydrogen

ATP, NADPH, and oxygen

ATP, hydrogen, and oxygen

6

Which of the following would you expect to find predominating in the plasma membrane of a unicellular eukaryotic organism thriving in glacier ice?

Group of answer choices

20 carbon long fatty acids with 1 double bond

16 carbon long fatty acids with 3 double bonds

20 carbon long saturated fatty acids

18 carbon long fatty acids with 1 double bond

5

Which statement is correct about facilitated diffusion?

Group of answer choices

facilitated diffusion requires energy in the form of ATP

facilitated diffusion can transport a molecule against a concentration gradient

facilitated diffusion can occur only in specific cell types

the rate of facilitated diffusion is limited by the number of transport proteins in the membrane

6

Which of the following statements about glycolysis is true:

Group of answer choices

glycolysis does not operate in the absence of O2

glycolysis produces a net gain of ATP

the end products of glycolysis are CO2 and H2O

glycolysis has steps involving oxidation, but not reduction reactions

the enzymes for glycolysis are located in the golgi

7

The oxidized form of this electron carrier is:

Group of answer choices

FADH2

FAD

8

The photosystem that captures light at 680 nm

Group of answer choices

PSII

PSI

9

Location of the light independent reaction

Group of answer choices

Stroma

Thylakoid

10

Which of the following does not occur as the result of the noncyclic flow of electrons in photosynthesis?

Group of answer choices

NADP+ picks up hydrogen ions and electrons, forming NADPH

ADP is phosphorylated to produce ATP

water is split, releasing O2

FADH2 is oxidized into FAD

11

Which of the following is not a major function of the plasma membrane?

Group of answer choices

production of DNA used to make proteins for the cell membrane

regulation of ions and molecules passing into and out of the cell

contact, recognition, and communication between cell types

separation of fluid and contents between the inside and outside of the cell

What are the possible fates of glucose that is produced by photosynthesis?

Your research team identifies a bird species that has defective amylase. What would be the result of this defect?

Which of the following statements regarding feedback inhibition is true?

You clone a genetically-modified plant that has increased expression of amylase in the roots of a raspberry plant. What would you expect to occur?

A plant is grown in soil depleted in magnesium and potassium, but rich in phosphorous and available ground water. Which if the following would occur?   

Plants and fungi have a symbiotic (mutually beneficial) relationship in that fungi provide __________ to plants, and plants provide ___________ to fungi.

You are growing Brassica rapa plants in the lab. A mutation is introduced into a subset of plants that impairs mitochondrial function in cells. Which of the following pathways of cellular respiration would be affected?

Which of the following statements regarding noncyclic electron flow (the Z-scheme model) and cyclic electron flow are correct?

2. Protein purification
a) Determine the subunit composition of a protein from the following information:

Molecular Mass by Gel Filtration: 200 kD

Molecular Mass by SDS-PAGE: 100kD
Mass by SDS-PAGE with 2-mercaptoethanol

   40kD and 60 kD

b) In what order would E, H, and V be eluted from a DEAE column at pH 8?

c) You have a mixture of 3 proteins, one is 100 amino acids long, another 350 amino acids long, and the third is 600 amino acids long. Sketch the chromatogram ( a plot of elution time/volume as a function of A280) for a gel filtration chromatography experiment to separate these three proteins. Assume each protein is equally abundant and has a statistically normal number of tryptophans.

d) what would you do to validate the chromatographic observations in c) above?

*Please answer b thru d*

17. Which histone is required to compact the “beads on a string” chromatin into higher-order chromatin structures such as the 30 nm fiber?

18. Certain lysine amino acids (K’s) in the core histone tail can be acetylated. How would this chemical modification of the nucleosome affect the transcription of a gene?

19. Certain protein/protein complexes do not bind DNA, but regulate processes such as transcription and replication. These proteins can associate with the chromatin by recognizing chemical modifications in the core histone tails of the nucleosome. This process represents the “histone code”. Separately, a protein that folds into its three-dimensional functional structures can have different domains with different functions. Assume that a certain protein that increases transcription does not recognize a specific DNA sequence, but rather associates with acetylated lysine amino acids in the histone tails. What domain in this protein would allow it to associate with these acetylated lysine amino acids?

SNARE helical motifs share a universal length (~60 amino acids). The N’ to C’ terminal zippering to form a highly stable four-helical bundle is thought to provide the energy to fuse membranes. First principles suggest that a longer SNARE four helical bundle would provide greater fusion energy per SNARE bundle, necessitating fewer SNAREs for each membrane fusion. However, families of longer SNAREs (e.g., 120 or 180 amino acids) are unknown. Suggest a possible rationale for why longer SNAREs don’t co-exist with our common ~60 amino acid SNARE motifs.

Enolase is an enzyme that catalyzes one reaction in glycolysis in all organisms that carry out this process. The amino acid sequence of enolase is similar but not identical in the organisms. Researchers purified enolase from  Saccharomyces cerevisiae, a single-celled eukaryotic yeast that grows best at  37°C, and from  Chloroflexus aurantiacus, a bacterium that grows best at the much higher temperature of  55°C. The researchers compared the activity of purified enolase from the two organisms by measuring the rate of the reaction in the presence of varying concentrations of substrate and a constant amount of each enzyme at both  37°C and  55°C.

(a) Depending on the organism, the optimal  pH for enolase to catalyze its reaction is between  6.5 and  8.0.  Describe how a  pH below or above this range is likely to affect enolase and its catalytic ability.

Question 2

(b)  Identify the appropriate negative control the researchers most likely used when measuring the reaction rate in the presence of each organism’s enolase.

Question 3

(c) The researchers predict that for any particular concentration of substrate, the  C. aurantiacus enolase-catalyzed reaction is more rapid at  55°C than at  37°C. Provide reasoning to  justify the researchers’ prediction.