Nexstep 3 Physics And Chem

Question 1

How much heat is produced from the complete combustion of 30 grams of methane, if the enthalpy of reaction is -890kj/mol?

Answer 1

1.7•10^6 Joules

Question 2

SEC columns separate in the basis of?

Answer 2

SEC columns separate on the basis of molecular weight. So, two protein with substantially different molecular weights would be most efficiently fractionated.

Question 3

What is the SDS-PAGE protein fractionation technique most appropriate for?

Answer 3

To separate protein on the basis of only molecular weight.

Question 4

What is the Ion-exchange chromatography technique most appropriate for?

Answer 4

Ion-exchange chromatography separates charged particles based on their affinity for charged elements of the ion exchanged columns.

Question 5

A more complete fractionation of proteins using a SEC column could be achieved by using?

Answer 5

A large column. This is because the fractionation depends on its interaction with the matrix inside the column. Increasing the length causes an increase of intearaction with matrix.

Question 6

Steric congestion tends to promote what type of substitutions?

Primary substitutions tend to promote?

Answer 6

Sn1- type of substitutions.

Sn2 types of substitutions.

Question 7

The pH is what compared to the pKa?

Answer 7

Slightly lowered than the Pka

Question 8

Galavanic cells always have cell potentials that are?

Answer 8

Positive.

Question 9

A person having atrial fibrillation will shown an absence of which wave?

What about a myocardial infarction?

Answer 9

Atrial fibrillation or arrhythmia is an irregular time period between heartbeats. The P wave is associated with atrial depolarization. So the P wave will be missing.

The R wave is a strong, sharp electrical signal coming from the ventricles. Absence of a the R wave ventricular fibrillation at best, usually life threatening and associated with a myocardial infraction.

Question 10

How do you calculate current?

Answer 10

By diving the VOLTS by the RESISTANCE the answer is in Amps

Question 11

How is capacitance defined as? And how do you calculate for charge for example?

Answer 11

As the charge stored per voltage: C=q/V

q= V•C answer in C for Columbs

Question 12

In order to emit a photon of energy, an electron must go from?

Answer 12

In order to emit a photon of energy, an electron must go from a higher energy level to a lower energy level. For example from n=5 to n=4

Question 13

What are the names of these acids H3PO5, H3PO4, H3PO3, H3PO2?

Answer 13

Perphosphoric acid is

Phosphoric acid is

Phosphorus acid is

Hypophosphorous acid is

Question 14

A ballon has a volume of 3L at 25 degree Celsius. What is the approximate volume of the ballon at 50 degrees Celsius?

Answer 14

Charle’s law states that there is a direct relationship between the volume of an ideal gas and its temperature, when pressure is constant.

V1/T1=V2/T2

3L/300K • 320K=V2

Question 15

One out of 130 live births show nondisjunction what is the likely hood of a normal birth?

Answer 15

1/130 = approx .008 so 99.2%

Question 16

Kinases vs. phosphatase?

Answer 16

Kinases is an enzyme that phosphorylates. Phosphatase is an enzyme that dephosphorylates.

Question 17

Km is equal to? Why?

Answer 17

The Km is equal to the concentration of the substrate when the the rate is half of the maximum velocity.
This is because the Km values of an enzyme implies that half of its active sites are occupied. A reaction that has reached its maximum velocity means that all of its active sites are occupied. So, The Km is equal to the concentration of the substrate when the the rate is half of the maximum velocity.

Question 18

The only aminoacid that is not chiral is?

Answer 18

The only achiral amino acid is glycine.

Question 19

What is the role of prolactin?

Answer 19

Prolactin is the hormone responsible for stimulating the mammary glands to produce milk.

Question 20

What is the role of calcitonin?

Answer 20

Calcitonin is a thyroid hormone responsible for lowering blood calcium concentrations.

Question 21

What is the role of epinephrin?

Answer 21

Epinephrine, more commonly known as adrenaline, is a hormone secreted by the medulla of the adrenal glands. Strong emotions, such as fear or anger, cause epinephrine to be released into the bloodstream, which causes an increase in heart rate, muscle strength, blood pressure, and sugar metabolism. This reaction, known as the “fight-or-flight response,” prepares the body for strenuous activity.

Question 22

What is the role of luteinizing hormone?

Answer 22

Luteinizing hormone (LH) is a hormone produced by gonadotropic cells in the anterior pituitary gland. In females, an acute rise of LH triggers ovulation and development of the corpus luteum. In males, LH stimulates Leydig cells to produce testosterone.

Question 23

Passive immunity refers to?

Answer 23

Passive immunity is the transfer of active humoral immunity in the form of ready-made antibodies, from one individual to another.

Question 24

Natural immunity refers to?

Answer 24

Natural immunity is immunity that is present in the individual at birth, prior to exposure to a pathogen or antigen, and that includes intact skin, salivary enzymes, neutrophils, natural killer cells, and complement.

Question 25

Cell-mediated immunity refers to?

Answer 25

cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

Question 26

The innate immune system refers to?

Answer 26

The innate (non-specific) immune system includes anatomical barriers, secretory molecules, and cellular components. Among the mechanical anatomical barriers are the skin and internal epithelial layers, the movement of the intestines, and the oscillation of bronchopulmonary cilia.

Question 27

Non-polar or hydrophobic amino acids are?

Answer 27

Alanine - Ala - A 
Isoleucine - Ile - I 
Leucine - Leu - L 
Phenylalanine - Phe - F 
Valine - Val - V 
Proline - Pro - P 
Glycine - Gly - G

Question 28

Charged amino acids often forming salt bridges.

Notice that if an amino acid is not on this list or in the non-polar it is a polar amino acid. Histidine is also polar.

Answer 28

Arginine - Arg - R 
Lysine - Lys - K 
Aspartic acid - Asp - D 
Glutamic acid - Glu - E 
Histidine - His- H

Question 29

Retrovirus have? And the do not have?

Answer 29

Retroviruses have positive-sense RNA genomes, not DNA genomes. They utilize reverse transcriptase.

Question 30

The blood-brain barrier is composed of?

Answer 30

The blood-brain barrier is composed of endothelial cells with tight junctions that prevent the movement of most solutes.

Question 31

What structures are useful when ti comes to cellular mobility?

Answer 31

Flagella and cilia are structures that allow simple eukaryotic and prokaryotic cells to propel themselves or nutrients in their environment.

Rapid actin polymerization near the edge of the cellular membrane is responsible for cellular motility in complex eukaryotic cells

Question 32

Microtubules are reponsible for? And not resposible for?

Answer 32

Microtubule de-polymerization is responsible for separating chromosomes during anaphase of mitosis or meiosis I or II. It does not contribute to overall cell migration.