Intro to Biology 101 - Chapter 3

Intro to Biology 101- Freshman year fall

What is Cell Theory?

All organism are made up of cells and cells comes from preexisting cells

What is a Cell

Fundamental unit of life

Whats are the characteristics of a Prokaryotic Cell?

• It’s Bacteria

• It’s Small and Simple

• No nucleus

• No Organelles surrounded by membrane

• Has a cell membrane

What are the characteristics of a Eukaryotic Cell?

• It’s All other organisms

• More complex and larger

• Has and Nucleus and Chromosomes are inside

• Have organelles surrounded by membrane

• Has cell membrane

What’s the differences of Eukaryotic Cells and Prokaryotic Cells?

• Prokaryotic Cells are BACTERIA

• Eukaryotic Cells are all other organisms

What surrounds the Cell?

Cell (Plasma) Membrane

What are the characteristics of the Cell membrane?

• Spontaneously forming bilayers of Phospholipids

• Fluid due to the movements of Phospholipids

• Mosaic of lipids, proteins, and cholesterol found in/ on the membrane 

Why do Membranes contain Cholesterol?

Helps maintains membrane fluidity amidst temperature changes

What kind of Proteins does the Cell Membrane Contain?

Integral and Peripheral Proteins

Where can you find Integral Proteins?

• In the structures in the internal region of the cell membrane (inside)

• Both Hydrophobic and Hydrophilic

Where can you find Peripheral Proteins?

• attracted to structures on the surface of the cell membrane (outside)

• only Hydrophilic

What are the different functions that Proteins do in the Cell membrane?

Transporter, Receptor, Enzyme, and Anchor

What are the Cell Membrane Functions?

• Determines the cell shapes and size

• Is Selectively Permeable

• Maintains Homeostasis

What is Selective Permeable?

Allows for only some things to move into or out of the cell

What is Homeostasis?

A Constant environment

What is Passive Transport?

• Does not require energy

• Materiales move WITH the concentration gradient from High to Low

What is Active Transport?

• Requires energy expenditure 

• Materials move AGAINST the concentration gradient from Low to High

How does Passive transport work in the Membrane?

• Facilitated diffusion via Integral proteins through Channels and Carriers

• Helps in Simple Diffusion and Omosis

What is Simple Diffusion?

Passive Movement Across a Permeable Membrane 

How does Simple Diffusion work?

• Movement of molecules from a high concentration area to a low concentration area

• This helps it achieve equilibrium

• Energy is not required

What is Osmosis?

Movement of water molecules from an area of high concentration to low concentration

What is Osmosis influenced by?

Osmolarity / Tonicity

What is Osmolarity/Tonicity?

The Solute in a solution

When are you doing for when you are looking at Osmolarity/Tonicity?

You are always comparing 2 solutions to one another

Hypertonic solution

↑ [Solute] and ↓ [Water] vs. other solution

Hypotonic Solution

↓ [Solute] and ↑ [Water] vs. other solution

Isotonic Solution

Equal [Solute] and Equal [Water] vs. other solution

Why is Osmosis important to cells?

Affects the shape and size of cells due to the Solute concentration

What Happens to Red blood Cells when they are Isotonic?

They are at their normal shape

What Happens to Red blood Cells when they are Hypotonic?

They are Lysed (has been ruptured —> Low Concentration)

What Happens to Red blood Cells when they are Hypertonic?

They are Shrunken (High Concentration)

What Happens to Plant Cells they are Hypotonic?

They are Turgid

• They want this to happen

What Happens to Plant Cells they are Hypertonic?

They are Flaccid

• They do NOT want this to happen

What is the energy that Active Transport uses called?

ATP (Adenosine triphosphate)

What is Primary Transport?

A type of active transport that Creates an electrochemical gradient that drives the movement of other molecules

What is Electrochemical Gradient?

A difference in charge and concentration of ions across the membrane

What is an Example of Primary Active Transport

• Pumps 3 sodium(NA+) ions OUT of the cell and  2 Potassium(K+) ions IN using ATP

• NA+ and K+ are both moving against their Concentration 

What is Secondary Transport?

A Type of active transport in which the movement of one substance against its concentration gradient is powered by the energy stored in the Electrochemical Gradient created by the Primary active transport.

• Does not directly use ATP

What is an Example of Secondary Transport?

• There’s more Na+ outside the cell, and Na+ wants to move back in

• Na+ connects with a protein on the outside and using the energy of Na+ moving inward and pulls the protein into the cell at the same time. Even though glucose moves against its own gradient

• Think about the protein as “hitches a ride” on the energy from Na+

What is the Endomembrane System?

Consist of the plasma (cell) membrane and internal organelles enclosed by membrane

• Found in both plant and animal cells

What is the Endomembrane System Designed for?

To carry information for processing and products to where they are needed

How is the Endomembrane System Connected?

Via Bridges or indirectly by Vesicles that bud off one organelle and fuse to the next

What Processes that occur when vesicles fuse with the cell membrane?

Exocytosis and Endocytosis

What does the Exocytosis do?

Moves materials out of the Cell

What does the Endocytosis do?

Moves materials into the cell

What are the Organelles of the Endomembrane?

• Nucleus

• Endoplasmic Reticulum

• Golgi apparatus

• Lysosomes

What is the Nucleus?

• Found in both Animal and Plant Cells

• Found in the center of the endomembrane system

• The Nuclear envelope contains pores that allows molecules to move into and out of the nucleus

• Contains the cell’s DNA and produces RNA

What’s next to the Nucleus?

The Endoplasmic Reticulum (ER)

What is the Rough Endoplasmic Reticulum?

• Found in both animal and plant cells

• The outer membrane (next to the Nucleus)

• It’s Rough

• It contains ribosomes for producing proteins

What is the Smooth Endoplasmic Reticulum?

• Found in both animal and plant cells

• Is an extension of the rough ER

• It’s Smoother 

• It lacks ribosomes and is important in lipid and steroid synthesis

What are the Golgi Apparatus Functions?

• synthesizing the cell’s carbohydrates 

• sorting proteins and lipids as they move to their final destinations

• Modifying proteins and lipids produced in the ER 

What is the Golgi Apparatus?

• Found in both animal and plant cells

• A series of flattened sacs called cisternae.

• The edge of the cisternae bud off are vesicles that carry proteins or modified sugars to the cell membrane or organelles in the cell

• Enzymes within here can chemically modify proteins and lipids as they pass through in a sequence of steps

• Are part of the of the endomembrane system

What are Lysosomes?

• Found only in Animal Cells

• Are part of the endomembrane system

• Small emebrane-bound sacs filled with digestive enzymes

• Have a proton pump tjhat keeps its internal pH at a 5 (vs. a Ph of 7 in the rest of the cell)

• Digest proteins, old/damged cell parts, defense the cell from bacteria and viruses

What does the mitochondria and chloroplasts have in common?

Both specialize in harness energy for the cell

What does the mitochondria and chloroplasts not have in common?

They grow and multiply independently and contain their own circular genomes

Theory of endosymbiosis

Suggest that mitochondria and chloroplasts were once independent prokaryotic that were engulfed by another cell

What is the Mitochondria?

Harnes energy from organic molecules such as sugars and coverts them to ATP in all Eukaryotic cells

What is the Chloroplast?

• Captures the energy of sunlight to fix atmospheric carbon

• Synthesize simple sugars in plant cells and photosynthetic organisms