Organelles of Eukaryotics Flashcards
What does the plasma membrane do?
Surrounds the cell and defines structure
What do ions and glucose require to cross the plasma membrane?
Protein channels or transporters
Why is selective transport important?
Keeps biochemical conditions inside the cell favourable
What does selective transport allow for?
A concentration gradient
What is a concentration gradient across a plasma membrane important for?
Firing of nerve cells and contraction of muscle cells
What is plasma membrane made of?
Phospholipids, proteins, cholesterol and glycolipids
Why do phospholipids create a lipid bilayer?
They are ampiphatic
What does a lipid bilayer in plasma membrane allow for?
Rotation and lateral movement of phospholipids and proteins
Why is fluidity important in plasma membrane?
To allow for cell migration and membrane repair
What type of protein are found in plasma membrane?
Receptors and ion channels
What are the shapes of protein receptors specific to?
The shape of ligands such as hormones, drugs or toxins
Why are protein important in plasma membrane?
Allow for cell to interact with external environment and for transport
Where does transcription take place?
In the nucleus
What is mRNA used for?
Assembling a protein in translation
What is the bulk of nucleus filled with?
Chromatins
What is the nucleus membrane made of?
2 lipid bilayers
What is the outer membrane of the nucleus membrane continuous with?
Endoplasmic Reticulum
What is the function of ER?
The translation of proteins destine for membrane or secretion
What happens to proteins that are secreted from ER to Rough ER?
They undergo post-translational modifications such as addition of a sugar group
What is budding?
When small vesicles break off from the ER and fuse with the Golgi
How goes the Golgi communicate?
Through budding
How are vesicles formed?
Through the budding process
What are lysosomes responsible for?
General destruction of debris and bacteria
What do lysosomes rely on?
Action of acid hydrolase with the vesicle
What are proteasome responsible for?
Targeted degradation of specific proteins
Where are proteasome found?
In the cytoplasm and nucleus
Why may proteins need degradation removed by proteasome?
Due to incorrect folding or too high concentration of protein
What is added to a target protein as a marker for degradation?
A protein ubiquitin
What do mitochondria produce?
Large amounts of ATP
What is the purpose of cytoskeleton?
To provide protein scaffolding
How is cytoskeleton highly dynamic?
By coordinated assembly and disassembly of fibres
How do vesicles move around the cell?
They are attached to microtubules which lengthen and shorten to pull them around the cell
What is special about the nucleolus?
It is a region of the nucleus with no membrane
What is in the nucleolus?
Condensed chromatin with DNA that codes for RNA
What must large molecules have to pass in and out of the nucleus?
Nuclear localisation key sequence
What do free ribosomes do?
Translate cytoplasmic proteins
What is the process of translating cytoplasmic proteins?
- Protein folds as it emerges from ribosome and gets stuck in the cytosol
- Proteins which need to leave the cell or embed in membrane are translated to attach to ER
- The proteins are then transported in vesicles to the cell surface
