16
Chapter 5: Homeostasis and Cell Transport

Chapter 5: Homeostasis and Cell Transport. The steady – state physiological condition of the body of a cell. Cell membranes help organisms maintain

Embed Size (px)

Citation preview

Page 1: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

Chapter 5: Homeostasis and Cell Transport

Page 2: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

The steady – state physiological condition of the body of a cell.

Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave cells.

Page 3: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain
Page 4: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

Lipid Bilayer with embedded proteins. Phospholipid bilayer with some proteins extending from one side of the membrane to another and some proteins are embedded only half-way

Proteins are utilized for both PASSIVE AND ACTIVE TRANSPORT

Carbohydrate chains are located on the outer surface of the membrane. If they are attached to phospholipids they are known as GLYCOLIPIDS. If they are attached to proteins they are called GLYCOPROTEINS.

Carbohydrate chains help with cell to cell recognition

Page 5: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

What determines the permeability of a substance across the cell membrane?

o Size

o Polarity

oHydrophobic vs. hydrophilic

oCharge

Page 6: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain
Page 7: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

The cell membrane is described as selectively permeable because it allows some substances to pass in or out but not others.

The size, charge, and polarity of a substance determines its permeability.

The cell membrane is permeable to gases such as carbon dioxide and oxygen since gases are small.

The cell membrane is permeable to water and other small, polar molecules.

Page 8: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

CELL MEMBRANES help organisms maintain HOMEOSTASIS by controlling what substances may enter or leave the cell.

Page 9: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

Some substances can cross the cell membrane without any input of energy by the cell in a process called PASSIVE TRANSPORT.

The simplest type of PASSIVE TRANSPORT is DIFFUSION.

Page 10: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration

Page 11: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain
Page 12: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

The difference in the concentration of molecules across a distance or across a membrane is known as a Concentration Gradient.

Page 13: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain
Page 14: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

In the absence of other influences, diffusion will eventually cause the molecules to be in equilibrium.

Equilibrium – the concentration of molecules will be the same throughout the space the molecules occupy.

Page 15: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain
Page 16: Chapter 5: Homeostasis and Cell Transport.  The steady – state physiological condition of the body of a cell.  Cell membranes help organisms maintain

How does the cell membrane help the cell to maintain homeostasis?

Why is the cell described as selectively permeable? What characteristics of a substance can determine its permeability?

Draw and label a cross section of the cell membrane. Make sure to include the phospholipids, embedded carrier proteins, ion channel proteins, carbohydrate chains as recognition antennas.