Answer:
Option D, Gastric Juices
Explanation:
The second line of defense is a non specific defense mechanism in which no specific individual is targeted but all invaders are killed in general way. Some common mode of second line of defense are - Phagocytic cells (white blood cells), inflammatory responses, macrophage system etc. The second line of defense comes into action when the invader has surpassed the first line of defense which include either physical barrier like skin, mucous membrane, hair, cilia etc. or chemical barriers like gastric juices, saliva, Hyaluronic acid etc.
Hence, gastric juice does not belong to second line of defense.
Thus, option D is correct.
It would cause the cell membrane to "pop" like a balloon. b the cell would not be able to get enough of the gases and nutrients it needed. c the cell could not be part of a small organism, such as a mouse. d there would not be enough resources in the cell's environment to feed it.
Answer: DNA is a molecule made up of two strands, twisted around each other in a double helix shape. The two strands are complementary which have a 5 prime end and a 3 prime end. To understand this question you must first understand the steps that follow.
DNA Replication:
<u>Step one: </u>
DNA Helicase (unzips) separates the strands.
<u>Step two:</u>
DNA Primase starts the process and makes a small piece of RNA called a primer. This marks the starting point for the DNA.
<u>Step three:</u>
DNA Polymerase binds to the primer and will make the new strand of DNA. DNA Polymerase can only add DNA bases in one direction, from the 5 prime end to the 3 prime end.
- The leading strand is made continuously.
- The lagging strand does not run continuously because it runs in the opposite direction. Each fragment is started with an RNA primer. DNA Polymerase then adds a short row of DNA bases from the 5 prime to 3 prime direction. This results in okazaki fragments because it can only replicate in small chunks. The process is repeated.
<u>Step four:</u>
Once the new DNA is complete the enzyme exonuclease removes all the RNA primers from both strands of DNA.
<u>Step five:</u>
Another DNA Polymerase fills in the gaps that are left behind with DNA.
<u>Step six:</u>
DNA Ligase seals up the fragments in DNA, in both strands to make a continuous double strand.
<u>Final answer:</u>
DNA Replication cannot replicate at the same time due to the leading and lagging strand.
Good luck!
