*Which of the following statements is true?

a. peptidoglycan is comprised of cross-linked fatty acids

b. the cell walls of most bacteria are composed of peptidoglycan

c. Gram-negative bacteria have a relatively thick layer of peptidoglycan

d. peptidoglycan is found mainly in the cell walls of fungi, algae and plants

e. answers (a) and (b) are both correct

* The cell membrane of bacteria

a. is semi-permeable.

b. is usually a lipid bilayer

c. prevents cell lysis due to high intracellular osmotic pressure

d. answers (a) and (b) are correct e. answers (a) and (c) are correct

* A bacterial species has a generation time of 15 minutes and is growing exponentially. If there are 2 cells initially how many cells are there after 90 minutes?

a. 256 b. 128 c. 64 d. 32 e. none of the above

*Most bacterial cells reproduce by

a. the budding of daughter cells from a mother cell

b. forming spores that later germinate

c. binary fission

d. production of gametes and sexual reproduction

I am going to a lab next week on Acids, Bases, PH and Buffers, but i need some help, especially on Buffers.

Q.5 Which solution(s) showed the greatest and which solutions(s) showed little or no change change in pH? Why? regarding which ones, i do understand that i need to do the lab first.

I understand bufferss resist a change in PH when a small amount of strong acid OR strong base is added to it. This means that the PH of the buffers does not change significantly (by more than 1 PH unit) when a small amount of strong acid or base its added Can you please give me an example? i dont understand when say (by more than 1 unit)

In contrast, unbuffered solutions will show significant PH changes ( greater than 1 PH unit) when a small amounts of strong acid or base are added. Can you give an example? i dont understand where it say (greater than 1 PH unit) i will appreciate your help.

Python Chemicals can be described as either acids or bases. The pH scale measures the concentration of hydrogen ions in a chemical to determine just how acidic or basic it is. For this task you are going to determine whether a chemical is acidic or basic based on its pH value, and how strongly it has that property. Remember, don't call input() or print() anywhere, just use the parameters provided and return statements.

You must have at least one conditional in each function. You cannot import any module. A couple of the tasks have individual restrictions; note them, as we will remove points for any task that does not follow the requirements.

def chemical_strength(pH): Accepts one floating point parameter for the pH value, and then:

• Determines if the pH value is valid (pH must be between 0 and 14 inclusive).

• You’ll return the string "bad measurement" if pH value doesn't make sense.

• Determines a description of the chemical based on its pH value.

  o A pH of less than 7 is an acidic chemical, however, we will be more specific:

• ▪ a pH value less than or equal to 1 is a "very strong acid"
  ▪ a pH value between 1 and 4 (exclusive) is a "strong acid"
  ▪ a pH value of exactly 4 is a "plain acid"

  ▪ a pH between 4 and 6 (exclusive) is a "weak acid"

  ▪ a pH value greater than or equal to 6 is a "very weak acid"
  o A pH of more than 7 is a basic chemical, however, we will be more specific:

  ▪ a pH value less than or equal to 8 is a "very weak base"
  ▪ a pH value between 8 and 10 (exclusive) is a "weak base"
  ▪ a pH value of exactly 10 is a "plain base"
  ▪ a pH value between 10 and 13 (exclusive) is a "strong base"▪ a pH value greater than or equal to 13 is a "very strong base"

  o If the pH is exactly 7, the chemical is simply "neutral"

• Returns the strength description as a string, e.g. "weak acid", "very strong base" etc.• Examples:

  o #pH is in between 4 and 6
  chem_strength(4.7) → 'weak acid'

  o # pH is outside of the valid pH range chem_strength(15.43) → 'bad measurement'

1. Can you make yogurt with lactose - free milk? Why?
2. Which milks are best suited to making yogurt? Which are not well - suited to making yogurt? Explain your recommendations.
3. Rennin is widely used in the food industry to make cheese. Can you explain why you can’t use the enzyme (such as rennin) to make cheese from hard boiled milk?
4. Can you still coagulate cheese protein when the pH is far lower than 4.6?  Explain your suggestions.

947.Ethanol metabolism in the liver results in the increase of the NADH/NAD⁺ ratio in the liver cytosol.

946.In gluconeogenesis, the regulatory enzyme fructose 1,6-bisphosphatase is inhibited by AMP.

945.Glucose-6-P dehydrogenase deficiency can lead to drug-induced hemolytic anemia because not enough NADH is generated.

944.Glucagon and epinephrine are similar in that both promote glycogenolysis.

943.Phosphofructokinase activity can be decreased by AMP.

942.Protein phosphatase can reverse the action of the kinase on enzymes.

Enzymes. When k2 is very small compared to k–1 the KM becomes a Kd (or in some textbooks this is called a KS ) for the ES complex. A Kd is really an equilibrium constant (Keq ) for a dissociation reaction in which the products are the dissociated form of the reactants. Write the reaction for which this Kd equals the Keq for your reaction. Make a generalization about the relationship between KM and enzyme-substrate binding affinity.

When k2 is very small compared to k1 and k–1, what process is rate determining?

What is characteristic of an enzyme-coupled receptor? How is it different from GPCRs?

Discuss the activation of a receptor tyrosine kinase and it's subsequent assembly of an intracellular signaling complex.

Describe the GTPase Ras in detail and what role does it play in regards to RTK.

Discuss the role of Ras in cancer. Is this a proto-oncogene or tumor suppressor gene and why?

What is MAP kinase? What time does it play in RTK?

Discuss the activity of the P1 3-kinase Akt with regards to apoptosis and cell survival.

(THREE PARTS) Ethyl alcohol is formed by enzyme action on sugars and starches during fermentation. The UNBALANCED equation is as follows: C6H12O6 ----> CO2 + C2H6O

A) Write the balanced chemical equation.

B) If the density of ethyl alcohol is 0.789 g/mL, how many gallons of ethanol alcohol can be produced by fermentation of 100.0 lb of sugar? C) How many gallons of ethyl alcohol was produced from the fermentation of 100.0 lbs of sugar if your homemade still only operates at a yield rate of 89.6%?

1. Which error prone enzyme leads to increased mutation rates in RNA viruses?
   1. DNA dependent DNA polymerase
   2. RNA dependent RNA polymerase
   3. DNA dependent RNA polymerase
   4. RNA dependent DNA polymerase
2. Antigenic drift permits viruses to evade which host defense?
   1. Innate
   2. Adaptive
   3. Interferon
   4. All of the above
   5. None of the above
3. Antigenic drift can lead to vaccine resistance?
   1. Correct
   2. Incorrect
4. Is antigenic drift a normal evolutionary process for viruses?
   1. Yes
   2. No

In the guide RNA, is there greater stringency for homology at the 5’ or 3’ end of the RNA?

Where, precisely, does the CRISPR/Cas9 system digest the target DNA?

What class of enzyme is Cas9

Name two other gene editing systems that are distinct from CRISPR/Cas. Give one reason why the CRISPR/Cas9 system is preferred by 9 out of 10 scientists that recommend editing genomes?

How many different types of CRISPR/Cas systems are there in bacteria and archaea?