Cell Transport Mechanisms and Concentration

This video tutorial covers progress checks for unit 2, focusing on cell biology and transport. It begins with an overview of the experiment involving substance L and its entry into mammalian cells. The video explains how to identify the mode of transport, emphasizing active transport due to the concentration gradient. It provides guidance on graphing the data and analyzing the results to determine the external concentration of substance L. The tutorial concludes with a summary and a preview of the next video.

What is the main focus of Unit 2 in the progress checks?

• Human Anatomy

• Ecology and Environment

• Cell Biology and Transport

• Genetics and Evolution

What is the internal concentration of substance L in the mammalian cells?

• 150 millimoles

• 200 millimoles

• 120 millimoles

• 100 millimoles

Which type of transport moves substances against their concentration gradient?

• Osmosis

• Passive Transport

• Facilitated Diffusion

• Active Transport

What is the first step in graphing the data from the experiment?

• Choosing the correct scale

• Drawing the line

• Labeling the axes

• Plotting the points

What is the maximum concentration value used on the graph's scale?

• 50

• 75

• 100

• 150

How do you determine the external concentration of substance L for half the maximal entry rate?

• By measuring the slope of the graph

• By locating the 50% mark on the y-axis

• By finding the peak of the graph

• By calculating the average of all data points

What is the approximate external concentration of substance L for half the maximal entry rate?

• 70 millimoles

• 50 millimoles

• 33 millimoles

• 20 millimoles

What challenge do large proteins face when entering cells?

• They dissolve in the cell membrane

• They easily pass through the membrane

• They require a specific receptor to enter

• They are absorbed by the cell wall

What is required for active transport of large molecules?

• A low pH

• A high temperature

• A transport protein

• A concentration gradient

What happens if substance L is attached to a large protein?

• It breaks down into smaller molecules

• It dissolves in the culture medium

• It cannot enter the cell unless a specific receptor is present

• It enters the cell easily