The following statement describes what level of structure in a protein? Several separate proteins link together to form an active enzyme.
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) none of the above
Question 2
In one type of fuel cell the following oxidation-reduction reactions are taking place:
2 H2 + O2 2 H2O
What is the fuel ?
A) H2
B) O2
C) H2O
D) all of the above
E) none of the above
Question 3
Why do soils that contain a high percentage of clay retain plant nutrients so well?
A) The ions of clay tend to be positively charged while nutrients tend to be negatively charged.
B) Water cannot penetrate through clay very well, which means that nutrients are not readily washed away.
C) Clay contains many magnetic particles, which have the effect of holding onto the nutrients.
D) Because of a lack of water, the nutrients are not dissolved, which means they adhere as a solid to the clay particles.
Structure of plasmodesmata
Models of the α helix, showing different aspects of its structure
DNA detail structure
The b sheet, another common secondary structure in proteins
Proteins
Typical bacterial size and structure