Chapter 5.3.1 (Exam 1) Organelles Flashcards
Eukaryotic Cells Contain Organelles
What are the two fundamental types of cells?
Prokaryotic
Eukaryotic
Name two key differences between eukaryotic and prokaryotic cells.
Eukaryotic cells are about 10 times larger than those of prokaryotes
Eukaryotic cells have membrane-enclosed organelles that carry out specific functions
What are ribosomes? Are they organelles?
Sites of protein synthesis
They are not organelles, but structures
What are the two subunits of ribosomes?
Ribosomal RNA (rRNA) and 50 different protein molecules
Where do you see ribosomes in eukaryotic cells? Prokaryotic cells?
Eukaryotic cells: Rough ER, free-floating in cytoplasm
Prokaryotic cells: free-floating in cytoplasm
What is the nucleus and what is it made of?
The largest organelle that contains the DNA of the cell
Double membrane nuclear envelope that contains pores and is continuous with the ER
What are the responsibilities of the nucleus?
Site of DNA replication and transcription
Contains most of the DNA
Assembly of ribosomes in region called the nucleolus
What are chromosomes made up of?
Long thin strands of DNA combined with protein called chromatin
What happens to chromatin before cell division?
Before cell division, chromatin condenses, and individual chromosomes are visible in the light microscope
What is the endomembrane system?
Interconnected system of membrane-enclosed compartments
Includes the cell membrane, nuclear envelope, ER, Golgi Apparatus, and Lysosomes
The endomembrane system is not entirely connected. How are substances carried between different elements of the endomembrane system?
Tiny, membrane-surrounded vesicles shuttle substances between the various compartments
What is the endoplasmic reticulum (ER)?
Network of membranes in the cytoplasm with a large surface area
Consists of Rough ER and Smooth ER
What is the lumen?
Space within a membrane-bound organelle or structure
What is the Rough ER (RER)?
Ribosomes are attached to this extended membrane, making it seem rough
What are the roles of the RER?
New proteins enter the RER’s lumen and are modified, folded, and transported to other regions via vesicles
What is the Smooth ER (SER)?
It has no ribosomes and is continuous with the RER
What are the roles of the SER?
Chemically modifies small molecules like drugs and pesticides so they can be easily removed
Site of glycogen degradation to release glucose
Synthesizes lipids and steroids
Stores calcium ions
