Cell Structures, Cell Transport, and Immune System

Standards SC.912.L.14.52 Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics. SC.912.L.14.1 Describe the scientific theory of cells (cell theory), and relate the history of its discovery to the process of science. SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport). SC.912.L.18.10 Connect the role of adenosine triphosphate (ATP) to energy transfers within a cell.

Cell Theory Three central tenets: All living things are made of cells. NOTE: Cells were discovered in 1665. “Cell Theory” was not complete until 1838. What invention allowed people to study cells for the first time? Three central tenets: All living things are made of cells. Cells are the basic unit of life. Cells come from pre-existing cells.

Challenge The cell theory was first proposed in 1838. Evidence obtained through additional scientific investigations resulted in the current cell theory. Which statement describes a component of the original cell theory that was removed because of the new scientific knowledge? A. All living things are made of cells. B. All cells come from other preexisting cells. C. Cells form through spontaneous generation. D. Cells are the basic structural and functional units of life.

Cell Structure: The Cell Membrane The membrane is made of TWO OPPOSITE-FACING LAYERS of “phospholipids.” The phosphate head is hydrophilic. The lipid tail is hydrophobic. These guys form together naturally, linked next to one another, forming a gel-like membrane.

Cell Structure: The Cell Membrane PARTS: Phospholipid bilayer Protein channels Cholesterol Peripheral proteins (“glycoproteins”) Carbohydrates

Cell Structure: The Cell Membrane https://www.youtube.com/watch?v=Qqsf_UJcfBc Fluid mosaic model

Cell Transport Two kinds: Active Transport Passive Transport If there’s a membrane surrounding the cell, how does it get the nutrients it needs to survive?

Cell Transport - Passive NO ENERGY REQUIRED! YES! Facilitated diffusion Osmosis – diffusion with water What is a “concentration gradient?”

Cell Transport - Active Protein channels (small things!) Vesicle Movement (big things!) IMPORTANT: THIS TAKES ATP, THE CELL’S SOURCE OF ENERGY!

Immune System Cells and proteins fight infections. CELL SQUAD Phagocyte – they eat pathogens! T cells – they destroy infected body cells! B cells – they produce antibodies, proteins that make pathogens ineffective! Infected cells – they produce “interferons” which help healthy cells become immune!

Challenge The immune system has both specific and nonspecific defenses against viral infections. Which statement describes a nonspecific response of the immune system in fighting viral infections? A. T cells are produced to search out and destroy the viruses. B. Memory B cells are activated to rapidly respond to the viral infection. C. Plasma cells quickly replicate and release antibodies that bind to the viruses. D. Virus-infected cells produce interferons that lead to the inhibition of viral replication.