A 65.0 mL solution of 0.113 M potassium alaninate (H2NC2H5CO2K) is titrated with 0.113 M HCl. The pKa values for the amino acid alanine are 2.344 (pKa1) and 9.868 (pKa2), which correspond to the carboxylic acid and amino groups, respectively. a) Calculate the pH at the first equivalence point b) Calculate the pH at the second equivalence point

Which of the following types of substances are weak electrolytes in aqueous solution at 298 K? CHOOSE ALL CORRECT ANSWERS, there may be more than one correct answer.

weak acids

strong bases

aminium salts

ionic salts

metals

strong acids

weak bases

non-metals

metalloids

Multiple choice: All of the following describe the properties of water except:

A) it is cohesive and therefore, pours easily.

B) it has a high specific heat and so it takes a lot of energy to raise the temperature of water.

C) when water is heated, the heat spreads easily throughout the body of water.

D) it vaporizes at a low temperature, meaning that it only requires a minimal amount of energy to cause a lot of water to evaporate.

Choose the FALSE statement:

A) Carbon, oxygen and nitrogen are common elements in the molecules making up your body because of their ability to form multiple covalent bonds.

B) On the pH scale of 0-14, a pH less than 7 is considered basic and a pH greater than 7 is acidic.

C) If a phospholipid bilayer were placed in a non-polar environment the orientation of the molecules making up this membrane would be the reverse of the water-borne arrangement.

Choose the FALSE statement:

A) Protein molecules are always composed of a single strand or chain of amino acids folded into a random shape.

B) When ATP is hydrolyzed to ADP, the energy released is used to perform work; the products of this hydrolysis will be recycled back to ATP through the digestion of foodstuffs.

C) In the absence of enzymes, the reactions of the cell occur too slowly to support the needs of the cell.

1-

Which of the following is true regarding the make-up of the ribosome?

Group of answer choices

The RNA make up more of the ribosome mass than the protein components.

It contains more RNA subunits than protein subunits.

The proteins play a larger role in the catalytic activity of the ribosome.

The nomenclature of the subunits (ie 50S) refers to the number of protein and RNA subunits

2-

Which one of the following experimental results does not support the hypothesis that the ribosome is a ribozyme?

Group of answer choices

Peptidyl transferase activity is not inactivated by treating the ribosome with detergent.

Peptidyl transferase activity can be inactivated by base changes in the rRNA.

Ribosomes from thermophilic organisms are more stable than from E. coli.

All of the answers support the hypothesis.

There are no proteins observed within 18 angstroms of the peptidyl transferase active site in the crystal structure.

3-

Which of the following best describes the tRNA binding sites of the ribosome?

Group of answer choices

All tRNAs leave the ribosome through the A site.

Each tRNA that associates with the ribosome must first bind in the P site and then moved to the A site.

Only one of the three sites can be occupied by a tRNA molecule at any given time.

The P site contains the tRNA molecule covalently bound to the growing chain of amino acids.

9) The site of the bacterial cell where ATP is produced is the:

a)   plasma membrane

b)   cell wall

c)   flagella

d)   nuclear region

e)   cytoplasm

44) Which of the following is regulated by an operator:

a) DNA sythesis

b) protein synthesis

c) RNA synthesis

d) b and c

e) all of the above

44) Which of the following is regulated by an operator:

a) DNA sythesis

b) protein synthesis

c) RNA synthesis

d) b and c

e) all of the above

56) Single amino acids are found on:

a) DNA

b) mRNA

c) tRNA

d) rRNA

e) Proteins

77) If a solution of 1x107 bacteria/milliliter were diluted one million times and then one tenth of a milliliter of that dilution was added to a Petri dish, how many bacterial colonies would you find after incubation for one or two days:

a) 1

b) 10

c) 100

d) 1,000

e) 10,000

78) If a solution of 1x105 bacteria/milliliter were diluted ten thousand times and then one tenth of a milliliter of that dilution was added to a Petri dish, how many bacterial colonies would you find after incubation for one or two days:

a) 1

b) 10

c) 100

d) 1,000

e) 10,000

True or false?

True False  In cell membranes, cholesterol decreases membrane fluidity below the transition temperature, but increases membrane fluidity above the transition temperature.
True False  Escherichia coli cells grown at 40°C would be expected to have a lower percentage of unsaturated fatty acids in their membranes than cells grown at 20°C.
True False  If a sphingolipid contains sialic acid (a.k.a. neuraminic acid) in its oligosaccharide headgroup, the headgroup will have a new negative charge of minus one.
True False  Groups lining the pores of transport proteins form weak non-covalent interactions with solute molecules that replace the water molecules that normally hydrate the solute.
True False  In active transport, the transported species moves across the membrane against a concentration gradient.
True False  Myristoyl, palmitoyl, and farnesyl groups anchor otherwise soluble proteins to the extracytoplasmic face of the plasma membrane.
True False  Triacylglycerols have three ester-linked phosphoryl groups that can in turn be ester-linked to serine, choline, ethanolamine, or inositol.
True False  In an amphipathic alpha helix, non-polar amino acid side chains face one side of the helix, and polar uncharged side chains face the other side.

Please answer all 4 questions thank you!

1) During lipid digestion, emulsification occurs in the __________________, whereas formation of chylomicrons occurs in the _____________________.

2) Mass movements of fecal matter through the colon are triggered by ___________________.

3) Individual amino acids and glucose enter the cells that line the lumen of the digestive tract via ___________________.

4) Digestion can be divided up into mechanical and chemical processes. The primary function of mechanical processes is to

1. Hemoglobin is the protein found in red blood cells that transports oxygen from your lungs to your cells. Below is a segment of the DNA sequence that codes for a normal hemoglobin protein (the entire gene is much longer). Using the DNA sequence provided, transcribe the sequence into mRNA. Use the bottom strand as the coding strand.

5’ A C T G C C C A T G G T G C A C C T G A C T C C T G A G G A G 3’

3’ T G A C G G G T A C C A C G T G G A C T G A G G A C T C C T C 5’

5`-CUC CUC AGG AGU CAG GUG CAC CAU GGG CAG U-3`

2. For hemoglobin, translate the mRNA strand from step 5 to the correct amino acid sequence. Make sure to start translation only after reaching the start codon.

Leu-Leu-Arg-Ser-Gln-Val-His-His-Gly-Gln

3. Sickle cell disease is a symptom of a genetic mutation that alters the structure of the hemoglobin protein. This mutation decreases the function of hemoglobin so it does not transport oxygen efficiently. Below is a segment of the DNA sequence that codes for a sickle cell hemoglobin protein (the entire gene is much longer). Using the DNA sequence provided, transcribe the sequence into mRNA. Use the bottom strand as the coding strand.

5’ A C T G C C C A T G G T G C A C C T G A C T C C T G T G G A G 3’

3’ T G A C G G G T A C C A C G T G G A C T G A G G A C A C C T C 5’

3'- GAG GTG TCC TCA GTC CAC GTG GTA CCC GTC A-5'

5'-CUC CAC AGG AGU CAG GUG CAC CAU GGG CAG U-3'

4. For sickle cell hemoglobin, translate the mRNA strand from step 7 to the correct amino acid sequence. Make sure to start translation only after reaching the start codon.

This is the translation from mRna his- arg- ser- gln- Val- his- his- gly- gln

5. Compare the two DNA template strands from step 5 and step 7. Compare the sequences and identify the sickle-cell mutation. How many and what nucleotides changed due to the mutation?

6. Compare the two mRNA strands from step 5 and step 7. Compare the sequences and identify the sickle-cell mutation. How many and what codons changed due to the mutation?

7. Compare the two amino acid strands from step 6 and step 8. Compare the sequences and identify the sickle-cell mutation. How many and what amino acids changed due to the mutation?

1. A complete deficiency of urea cycle enzyme usually causes death soon after birth, but a partial deficiency may be tolerated.

1. Explain why hyperammonemia (high levels of ammonia in the blood) accompanies a urea cycle enzyme deficiency.
2. What dietary adjustments might minimize ammonia toxicity?