Question

7|Unit7- Cell Membrane & Passive Transport

barrier
This lesson was about the cell membrane
portant functions; to provide a
Summary
protect the cell, and to control
very important in helping the cell maintain_
double layer of
bilayer
lipids
. The cell membrane has three
between the cell and its surroundings, to
what enters and leaves the cell, which is
homeostasis. The cell membrane is a
which is why it is sometimes referred to as the lipid
Embedded in the lipids are different kinds of protiens. Protein
help in a process called facilitated diffusion. Protein
_use ATP to move molecules across the cell membrane.
proteins are used for sending and receiving chemical messages. Carbohydrates
so cells can identify each other. The structure of
mosaic because it is composed of many
in the cell membrane act as
the cell membrane is referred to as a
parts that move freely throughout the lipid bilayer. The cell membrane is said to be
because it allows some, but not all, substances through.
There are three factors that affect whether or not a substance can move through the cell
membrane-its
and

Answer 1

The cell membrane is a selectively permeable phospholipid bilayer containing embedded proteins and carbohydrates that regulate substance movement and cell communication. Passive transport allows materials to move without energy, while active transport requires energy. This system maintains cellular homeostasis.

Step-by-step explanation:

Understanding the Cell Membrane and Passive Transport

The cell membrane is fundamental to cellular function, providing a barrier between the internal workings of a cell and its surrounding environment. It's structured as a phospholipid bilayer with hydrophilic heads and hydrophobic tails, creating a selectively permeable membrane that allows only certain substances to pass through based on size, polarity, and presence of specific transport mechanisms. Proteins and carbohydrates are embedded within this bilayer, serving various roles such as transport, signalling, and cell recognition.

In the realm of passive transport, substances move across the cell membrane without the expenditure of cellular energy. This process includes simple diffusion, facilitated diffusion via transport proteins, and osmosis. In contrast, active transport requires energy, often in the form of ATP, to move substances against their concentration gradient using specialized protein pumps or vesicle-mediated mechanisms.

The cell membrane's structure and function are described by the fluid mosaic model, highlighting its flexible nature and the diverse array of molecules that make up its composition. The membrane's selective permeability is crucial for maintaining homeostasis within the cell, ensuring that essential nutrients are absorbed, metabolic wastes are expelled, and harmful substances are kept out.