biochem practice

Which letter above shows the energy of activation for the enzyme-catalyzed reaction?

C

Which of the following best describes the reaction shown below?

an exergonic reaction

Which letter shows the potential energy of the product?

D

Which level of protein structure is most related to specificity?

tertiary.

Which of the following is an example of a hydrogen bond?

the attraction between the oxygen of one water molecule and the hydrogen of an adjacent molecule.

Which module correctly depicts a neutral atom of hydrogen?

B. 1 Positve, 1 Negative

Which of the following statements about a particular molecule is correct? And gives you a reason for your answer.

H2O is a polar molecule because part of the molecule is positively charged while the remaining is negatively charged

Here is a sketch of two amino acids--the building block of polypeptide. When they combine into dipeptide, certain atoms are removed. Which atoms are removed?

HOH

The pH of blood

Is normally close to 7.4

Which of the following is correct about isotopes of carbon?

They are chemically identical because they have the same number of electrons.

Which of the following is stored in the human liver for energy?

glycogen

Clothes washing detergent must be able to remove grease and oil stains from clothes while also dissolving and washing away in the rinse water. Which of the following is the correct structure of the detergent molecules? And the correct reason for it.

one end of a detergent molecule is nonpolar in order to dissolve oil stains, while the other end is polar to dissolve in the rinse water

Chaperonins are involved with

proper folding of proteins

What statement is correct about pH?

pure water has a neutral pH of 7 because the concentration of hydrogen ions equals the concentration of hydroxyl ions

Which of the following can be used to determine the rate of an enzyme-catalyzed reaction?

the rate of substrate used up

All of the following statements are correct about enzymes EXCEPT

they raise the energy of activation of all reactions

One drop each of water (HOH) and ethyl alcohol (C2H5OH) Are placed onto a glass slide.

water molecules exhibit greater cohesion tension than do those of ethyl alcohol

Which of the following pairs of base sequences could form a short stretch of DNA?

5'-TTAA-3' with 3'-AATT-5'

Proteins are formed in a ribosome as amino acids are strung together in a particular sequence determined by instructions by DNA. Here is a diagram of an experiment to investigate protein production and function.

HSP is critical to normal ribosome function

In 1957 after rigorous testing, a pharmaceutical company in West Germany introduced a new drug to the market as a sedative and sleeping drug for pregnant women. It was called thalidomide and was very effective. Doctors in 46 countries prescribed it to millions of women. Tragically, the drug was responsible for thousands of babies being born with missing or abnormal arms, hands, legs, or feet to mothers who had taken the drug while pregnant. The product was subsequently removed from the market even though the pharmaceutical company proved that the drug contained pure thalidomide with no contaminants. Which of the following statements best explains the most likely problem with the drug?

the drug contained molecules that were isomers and mirror images of each other. One version worked as expected, while the other caused birth defects.

All of the following are characteristics of water EXCEPT

water molecules have little attraction to each other