Question

biology 1 eoc assessment sample questions

1. as food travels through the digestive system, it is exposed to a variety of ph levels. the stomach has a ph of 2 due to the presence of hydrochloric acid (hcl), and the small intestine has a ph ranging from 7 to 9. hcl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. which of the following most likely happens to pepsin as it enters the small intestine?

a it becomes inactive.
b it begins to replicate.
c its shape changes to engulf large proteins.
d its activity increases to digest more proteins.

1. genes for medically important proteins can be cloned and inserted into bacteria, as shown in the diagram below.

plasmid vector + dna fragment with human gene → recombinant plasmid
recombinant plasmid + bacterial dna → transformed bacterial cell
transformed bacterial cell → bacterial cell produces human protein
why can bacteria recognize a human gene and then produce a human protein?
a dna replication in bacteria and humans is the same.
b bacterial cells contain the same organelles as human cells.
c the basic components of dna are the same in humans and bacteria.
d bacterial cells and human cells contain the same kind of chromosomes.

Explanation:

For question 11, pepsin is active in the acidic environment of the stomach. The small intestine has a basic pH. Enzymes like pepsin are pH - sensitive and become inactive in an environment with a pH different from their optimal one.
For question 12, the basic components of DNA (nucleotides) are the same in all living organisms. This allows bacteria to recognize human genes and produce human proteins when the genes are inserted into them.

Answer:

1. A. It becomes inactive.
2. C. The basic components of DNA are the same in humans and bacteria.