Question

1. White blood cells such as leukocytes, neutrophils, and monocytes can engulf large foreign substances like bacteria.

During this process the plasma membrane of the white blood cell invaginates, forming a pocket around the bacteria cell. The pocket pinches off, resulting in the bacteria cell being contained in a newly created intracellular vesicle formed from the plasma membrane.

Which of the following processes could be responsible for white blood cells engulfing bacteria cells?

	Exocytosis
	Endocytosis
	Pinocytosis
	Osmosis

2. Water travels up to 124m from the roots to the top of Giant Sequoias. During this journey water travels against the force of gravity through narrow “circulatory” vessels inside of the tree. Which two water properties are responsible to such a feat?! Name AND briefly describe the properties.

Please use complete sentences to explain your answer.

3. You are helping your 13-year old cousin edit their biology lab report about protein structure and function. Then you encounter a sentence in the report that says “the high temperature broke down the protein into many pieces and this affected its ability to function”. How would you correct this misunderstanding?

Answer 1

1) When a foreign pathogen like bacteria is encountered by white blood cells, they engulf the entire bacterial cell by the process called Endocytosis, which means cell Eating. These engulfing WBC are called phagocytes and the process is also called phagocytosis. The engulfed pathogen is digested by lysosomal enzymes in the WBC and the undigested particles expelled out through exocytosis.

Whereas Pinocytosis is called cell drinking, as the cell engulfs the fluid material. Osmosis is the tranfer of molecules from liw to high concentration through semipermeable membrane.

In the question asked about the engulfing of bacterial cell. So, the answer is Endocytosis or Phagocytosis.

2) The two properties of water that helps the water move from roots to the top are Adhesion and cohesion. Water molecule has Oxygen and two hydrogens. Due to electronegativity of Oxygen, they possess partial charges like positive charge for hydrogens and negative for oxygen. Due to these charges, water molecules closely bonded with each other with hydrogen bonds. The compact nature of water is called cohesion. The adjacent water molecules bonded with surface and this attachment is called Adhesion. The cohesion and adhesion helps in the capillary action of water, which is the flow of water upwards in the column.

When the water gets evaporated from the leaves through transpiration. The water through the Xylem moves upward through the capillary action due to both adhesion and cohesion.

3) The proteins are highly unstable and can be easily denatured using high temperatures. The proteins do not become into smaller pieces, instead due to increase in the temperature the confirmational changes takes place in the proteins results in the inactivation of it.

So, due to increase in the temperature leads to inactivation of proteins. The inactivated proteins cannot function.