6. The Membrane

Endocytosis and Exocytosis

A Level Biology Revision "Endocytosis and Exocytosis OCR / Edexcel"

Endocytosis and Exocytosis Example 1

Which means of particle transport is shown in the figure below?<img class="fr-dib" src="https://static.studychannel-prd.pearsonprd.tech/courses/biology/thumbnails/images/068d2010" style="width: 648px;">

Cell Membrane Transport - Transport Across A Membrane - How Do Things Move Across A Cell Membrane

Endocytosis, exocytosis, phagocytosis, and pinocytosis explained!

Endocytosis Allows Entry to the Cell

 No. Osmosis is a special case of passive transport involving the movement of water across a membrane. 

 No. Passive transport involves small molecules that require no special assistance in crossing the membrane. 

 No. Cells use exocytosis to move products out of the cell. 

 No. Active transport is used to move small molecules against the concentration gradient. In this case, large antibody molecules are concentrated in the digestive tract, so movement into the cells would be down the gradient. 

Consider a process that moves large molecules into the cell.

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process?

Exocytosis Allows Exiting from the Cell

Endocytosis & Exocytosis

Amoeba eats  paramecia ( Amoeba's lunch ) [ Amoeba Endocytosis / Phagocytosis  Part 1 ] 👌

BioFlix: Exocytosis and Endocytosis

 Phagocytosis: secretion of large particles from the cell by fusion of vesicles with the plasma membrane 

 No. Phagocytosis is a type of endocytosis, so it involves bringing material into the cell, not secretion from the cell. 

 Exocytosis: the movement of water and solutes out of the cell by passage through the plasma membrane 

 No. Exocytosis does move water and solutes out of the cell, but it does so by the fusion of vesicles with the plasma membrane. 

 Osmosis: passive diffusion of water and small solutes across a membrane 

 No. Osmosis is the diffusion of water across a membrane, but it does not include the diffusion of other solutes. 

 None of the listed responses is correct. 

 No. One of the other choices is correct. 

 Pinocytosis: the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane 

Carefully consider the results of each process. .

Which of the following pairs correctly matches a membrane transport process to its primary function?

 No. Although the Golgi is involved in the shipment of phospholipids to the plasma membrane, endocytosis is a process that removes phospholipids from the plasma membrane by budding off of small vesicles. 

 No. Active transport is important in most cellular processes, but it does not add new phospholipids to the plasma membrane. Although the rough ER is responsible for the synthesis of proteins destined for the plasma membrane, the rough ER is not involved in lipid biosynthesis. 

 Receptor-mediated endocytosis and smooth ER and Golgi 

 No. Receptor-mediated endocytosis results in the loss of phospholipids from the plasma membrane. Although the smooth ER is involved in lipid synthesis, nothing in this answer here accounts for the replacement of membrane proteins. 

 Flip-flop of phospholipids from one side of the plasma membrane to the other and the Golgi 

 No. Flip-flop of phospholipids between sides of a membrane normally does not occur, and it could not increase the area of the membrane if it did occur. 

Consider the origin of new phospholipids that are added to the plasma membrane.

Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?

Endocytosis, phagocytosis, and pinocytosis | Biology | Khan Academy

Pinocytosis brings only water molecules into the cell, receptor-mediated endocytosis brings in other molecules also

Pinocytosis increases the surface area of the plasma membrane, receptor-mediated endocytosis decreases it

Pinocytosis is nonselective, receptor-mediated endocytosis offers more selectivity

Pinocytosis can concentrate substances from the extracellular fluid, receptor-mediated endocytosis cannot

The difference between pinocytosis and receptor-mediated endocytosis is that ________.

It forms intracellular vesicles from inward folding of the plasma membrane. 

It requires fusion of vesicles with the plasma membrane. 

It secretes large molecules out of the cell. 

It is responsible for removing large waste particles that cannot be recycled by the cell.

Which of the following is NOT&nbsp;a true statement regarding exocytosis?

 No. Passive transport allows molecules to move through the lipid bilayer and only down their concentration gradient. 

 No. Facilitated diffusion provides low-resistance pathways for molecules to cross the membrane, but it allows molecules to move only down their concentration gradient. 

 No. Osmosis is a special case of simple or facilitated diffusion involving water. 

 No. Channels are one type of protein that permits facilitated diffusion. This method does not allow for concentrating molecules in the cell. 

Consider which of these processes moves a substance into a cell against its concentration gradient.

Which of the following enables a cell to pick up and concentrate a specific kind of molecule?

Animation: Exocytosis and Endocytosis

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