Cell Biology: Understanding Prokaryotic and Eukaryotic Cells, Study notes of Cell Biology

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Cell Structure and Function

Two Basic Cell Types:

Prokaryotic vs. Eukaryotic Cells

Two Basic Types

• Remember….cells are the basic unit of life for ALL living things.
• There are two basic types of cells:
  1. Prokaryotic cells – found in bacteria
  2. Eukaryotic cells – found in protists, fungi, plants and animals

As we discuss the differences between Eukaryotic and Prokaryotes fill in you concept map. Eukaryotes Prokaryotes same Nut-Nucleus No Nut-No Nucleus

Characteristics Shared

ONLY WRITE THE BOLDED WORDS IN VENN DIAGRAM

• same basic functions
• Plasma membrane to control what enters and leaves the cell
• “Filled” with cytoplasm
• Contain ribosomes to make protein
• Contain DNA

What Makes Eukaryotic Cells

Different?

ONLY WRITE THE BOLDED WORDS IN VENN DIAGRAM

• Much larger
• Much more complex
• Contain a nucleus to house the genetic material (DNA)
• Linear DNA packaged into chromatin found inside the nucleus
• Contains organelles - specialized structures in the cytoplasm
• Not all have a cell wall

What Makes Prokaryotic Cells

Different?

ONLY WRITE THE BOLDED WORDS IN VENN DIAGRAM

• Much smaller
• Less complex
• No nucleus
• Circular DNA that is found in the cytoplasm
• No organelles found in the cytoplasm
• Surrounded by a cell wall

Eukaryotic Cells

What does size have to do with it?

• Prokaryotic cells are much smaller than eukaryotic cells. Why? - Smaller surface area to volume allows nutrients to easily and quickly reach inner parts of the cell. - Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to: - carry out metabolism - provides energy - transport chemicals throughout the cell

Why do we call them cells?

• In 1665, Robert Hooke was the first to view cells from cork (dead plant material).
• He called them “cells” because they looked like tiny rooms.

Cell Theory

1. All living things are made of CELLS
2. CELLS are the basic units of structure and function in living things 3. New CELLS are produced from existing CELLS

About Cell Membranes 1.All cells have a cell membrane 2.Functions : a.Controls what enters and exits the cell to maintain an internal balance called homeostasis b.Provides protection and support for the cell TEM picture of a real cell membrane.

3.Structure of cell membrane

Lipid Bilayer - 2 layers of

phospholipids

a.Phosphate head is polar (water loving) b.Fatty acid tails non-polar (water fearing) c.Proteins embedded in membrane Phospholipid Lipid Bilayer

• 4. Cell membranes have pores (holes) in it a.Selectively permeable: Allows some molecules in and keeps other molecules out b.The structure helps it be selective! Pores

Proteins Membrane movement animation Polar heads love water & dissolve. Non-polar tails hide from water. Carbohydrate cell markers Fluid Mosaic Model of the cell membrane

Outside of cell Inside of cell (cytoplasm ) Lipid Bilayer Proteins Transport Protein Phospholipids Carbohydrate chains Label the cell membrane in your notes Go to Section: Animations of membrane structure

Types of Cellular Transport

• Passive Transport cell doesn’t use energy

1. Diffusion
2. Facilitated Diffusion
3. Osmosis

• Active Transport cell does use energy

1. Protein Pumps
2. Endocytosis
3. Exocytosis high low This is gonna be hard work!! high low Weeee!! !

• Animations of Active Transport & Passive Transport

Passive Transport

• cell uses no energy
• molecules move randomly
• Molecules spread out from an area of high concentration to an area of low concentration.

• (HighLow)

• Three types:

3 Types of Passive Transport

1. Diffusion
2. Facilitative Diffusion – diffusion with the help of transport proteins 3. Osmosis – diffusion of water

Passive Transport:

1. Diffusion

1. Diffusion : random movement of particles from an area of high concentration to an area of low concentration.

( High to Low )

• Diffusion continues until all molecules are evenly spaced ( equilibrium is reached)- Note: molecules will still move around but stay spread out. http://bio.winona.edu/berg/Free.htm Simple Diffusion Animation

2. Facilitated diffusion : diffusion of specific particles through transport proteins found in the membrane a. Transport Proteins are specific – they “select” only certain molecules to cross the membrane b.Transports larger or charged molecules Facilitated diffusion (Channel Protein) Diffusion (Lipid Bilayer)

Passive Transport :

2. Facilitated Diffusion

Carrier Protein

A B

• 3. Osmosis : diffusion of water through a selectively permeable membrane
• Water moves from high to low concentrations - Water moves freely through pores. - Solute (green) to large to move across. Osmosis animation

Passive Transport:

3. Osmosis

Hypotonic Solution

Hypotonic : The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell): Cell Swells and bursts open ( cytolysis )!

• Osmosis Animations for isotonic, hypertonic, and hypotonic solutions