Lecture 2 Flashcards
Why are organelles compartmentalized?
It allows the specificity of function and the concentration of reactants to certain parts of the cell.
Where are mitochondrial proteins encoded?
The nucleus
Where are mitochondrial proteins translated?
The cytoplasm
What does mtDNA encode for?
RNA, mostly tRNA and rRNA
Why does the mitochondria have two membranes?
One is bacterial and the outer is eukaryotic because the ancestral mitochondria was absorbed by a eukaryotic cell.
What are cisternae?
The flattened sacs that make up the endoplasmic reticulum.
What is the difference between the rough and smooth ERs?
The rough ER is covered in ribosomes
What is the function of the rough ER?
The ribosomes attached to it translate proteins destined for within the endomembrane system.
What is the function of the smooth ER?
It is responsible for the synthesis of lipids and steroid hormones.
What is the function of the Golgi Body?
It processes and packages proteins, sythesizes polysaccharides, receives proteins from the ER, and modifies proteins by glycosylation (addition of sugars)
What is the function of lysosomes?
They digest all macromolecules.
How does the lysosome appear in microscopy?
It is a large, circular organelle with dense staining in the interior membrane, but is smaller than the nucleus.
What is the function of ribosomes?
To synthesize proteins.
Where can ribosomes be found?
They are free in the cytoplasm or bound to the ER.
Where does all translation begin?
In the cytoplasm.
What makes up a plasma membrane?
Phospholipids, other lipids, proteins, and carbohydrates.
What does amphipathic mean?
It has both hydrophilic and hydrophobic sections.
During centrifugation, what does a particle’s rate of movement depend on?
Size and density (larger or more dense particles have higher sedimentation rates)
What can centrifugation be used for?
Sibcellular fractionation- separates and purifies organelles.
How are samples prepared for centrifugation?
Cells are homogenized (broken up) to separate contents, then forced through narrow orifice or ultrasonic vibration or osmotic shock or enzymatic treatment or manual grinding
Define homogenate
A solution containing intracellular content that can be separated.
What is differential centrifugation?
Slowly increasing speed/duration of centrifugation while sequentially removing the pellet.