Biology test

Why is the plasma membrane called a bilayer?

• It is made of two layers of proteins

• It consists of two layers of phospholipids

• It has two functions: protection and structure

• It contains two types of molecules: lipids and carbohydrates

What does the fluid mosaic model describe?

• The process of molecules diffusing through the membrane

• The movement of water across the membrane

• The rigid structure of the membrane

• The dynamic and flexible nature of the membrane with embeddedÂ

What is the primary function of channel and carrier proteins?

• To make the membrane rigid

• To help transport molecules across the membrane

• To create lipids for the membrane

• To store energy for the cell

Which type of transport does NOT require energy?

• Active transport

• Endocytosis

• Passive transport

• Sodium-potassium pump

What happens to an animal cell placed in a hypertonic solution?

• It shrinks as water moves out

• It actively absorbs water

• It remains unchanged

• It swells and bursts

Which of the following is an example of active transport?

• Diffusion

• Osmosis

• Facilitated diffusion

• Sodium-potassium pump

Fill-in-the-Blank by letters

The ……………… model describes the plasma membrane as a dynamic structure with embedded proteins and lipids.

Fill-in-the blank by letters

In passive transport, molecules move from an area of ……………… concentration to an area of…………… concentration.

What happens if a freshwater plant cell is placed in a saltwater solution?

• The salt will enter the cell and make it expand

• The cell will remain the same size

• Water will move into the cell, making it swell and burst

• Water will move out of the cell, causing it to shrink due to plasmolysis.

What happens if a human red blood cell is placed in pure water?

• The red blood cell will become more rigid

• Water will enter the cell, causing it to swell and potentially burst (lysis).

• Water will move out, making the cell shrink.

• The red blood cell will remain unchanged