Biology Chapter 4

When were microscopes first created?

1590

Who first observed cells using the microscope.

Robert Hooke

What is a Light Microscope (LM)?

visible light is passed through the specimen and then through glass lenses. 

What are Electron Microscopes (EM):

focuses a beam of electrons through the specimen or onto its surface

What is a scanning electron microscope (SEM)?

used for detailed study of the topography of a specimen. Result is an image of the specimens surface that appears 3D

What is a Transmission Electron Microscope (TEM)?

used to study the internal structures of cells

What is Resolution?

 measure of clarity of the image

What is Magnification?

 the ratio of the size of an image to the size of the original object

What is Contrast?

 difference in brightness between the light and dark areas of an image

What are the Advantages of a Light Microscope?

• Cheaper

• Easy to operate

• Smaller

• Shows natural color

• Simple prep

What are the Disadvantages of a Light Microscope?

• Low resolution

• Lower magnification

• Requires a lot of adjusting to get the result you wan

What are the Advantages of an Electron Microscope?

• Ultra High resolution

• Large magnification

• Detailed images

What are the Disadvantages of an Electron Microscope?

• Super Expensive

• No color

• No Live Specimens

• Complex prep

• Hard to Operate

When would you use a light Microscope?

When viewing live organisms and need it to be in color. Also, when you don’t need it to be super in depth

When would you use an Electron microscope?

When it is too small to be seen with a light microscope and you need to magnify something extremely

When would you use an Scanning Electron microscope?

When you need high resolution and 3D images of a cell or object's surface.

When would you use an Transmission Electron Microscope?

When you need to see the internal structures of organisms in a detailed way.

What Is Cell Fractionation?

A technique used to study cell structure and function where broken-up cells are centrifuged until a pellet is formed from cell components.

How is Cell Fractionation useful?

 It allows people to see each part of a cell broken up and individually instead of seeing it all as one. 

What are the similarities between Prokaryotic and Eukaryotic Cells?

• Both contain DNA

• Both have a Plasma Membrane

• Both have Cytoplasm

• Both have Ribosomes

What are the differences in Prokaryotic Cells?

• Smaller

• No Nucleus

• No Membrane - Bound Organelles

What are the differences in Eukaryotic Cells?

• Larger

• Has a nucleus

• Has Membrane-Bound Organelles

What is a Prokaryotic cell?

A cell lacking a membrane-bound nucleus and containing its DNA in an unbound region called a nucleoid. 

What is a Eukaryotic Cell?

A cell characterized by containing a nucleus bounded by a double membrane as well as membrane-enclosed organelles. 

What is an organelle?

Membrane-enclosed structures within eukaryotic cells.

What is the nucleus?

Enclosed most of the DNA in eukaryotic cells and most of the genes in Eukaryotic Cells. 

What are ribosomes?

Cellular complexes made of rRNA and protein that carry out protein synthesis.

What are the functions of the Endomembrane System?

synthesize, modify, package, and transport proteins and lipids

What is the Smooth Endoplasmic Reticulim?

The portion of the endoplasmic reticulum lacking ribosomes, involved in lipid synthesis, drug detoxification, and storage of Ca2+ ions.

What is the Rough Endoplasmic Reticulim?

The portion of the endoplasmic reticulum studded with ribosomes on its outer surface, responsible for producing secretory proteins and membrane components.

What is the Nuclear Envelope?

A double membrane perforated by pore structures that encloses the nucleus, separating its contents from the cytoplasm.

What is the Golgi Apparatus?

An organelle composed of flattened sacs (cisternae) that modifies, stores, sorts, and ships products received from the endoplasmic reticulum.

What are lysosomes?

membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules

What are Vesicles?

Stores, transports, or digests cellular products and waste 

What are Vacuoles?

large vesicles derived from the ER and the golgi apparatus. Selective in transporting solutes There are food vacuoles, contradictile vacuoles, and the central vacuole. 

What is the Cell Membrane?

Made of a double layer of phospholipids and other lipids The primary function of the cell membrane (plasma membrane) is to separate the cell's interior from its external environment while acting as a selective barrier that regulates the movement of substances in and out of the cell

What is the Nuclear Lamina?

netlike array of protein filaments, that maintains the shape of the nucleus by mechanically supporting the nuclear envelope

What is Chromatin?

complex of DNA and proteins making up chromosomes. 

What are ribosomes?

complexes made of rRNA and protein; cellular components that carry-out protein synthesis. 

What are free Ribosomes?

 suspended in the cytosol

What are bound ribosomes?

attached to outside of endoplasmic reticulum or nuclear envelope

What is the Mitochondria?

 site of cellular respiration; powerhouse of the cell

How do the smooth and rough ER differ?

The smooth ER synthesizes lipids, produces steroid hormones, detoxifies chemicals, and stores calcium ions. The Rough ER Synthesizes and folds proteins 

What makes up the Golgi Apparatus?

 It is a series of flattened, membrane-bound sacs called cisternae. There is the Cis face and the Trans Face. 

What is the Cis face responsible for?

The side that receives products from the ER.

What is the trans face responsible for?  

 The side that ships products to other destinations

Glycoproteins do what?

They help the cell identify their components from foreign invaders.