B2.2 Organelles and Compartmentalization Flashcards
Define organelles
Discrete subunits of cells adapted to specific functions
Define the function of microvili (not discussed earlier)
Tiny hair-like structures that absorb nutrients better by giving the cell an increased surface area.
- To absorb the nutrients of the small intestines
Why does the Nucleus “control the cell”
Contains the DNA that operates all the cellular functions (?)
How does lysosome recycle old/damaged organelles?
They engulf it, “ingest it” w. their enzymes
Outline the no-membrane, single membrane and double membrane-bound organelles in both prokaryotic and eukaryotic cells
Do prokaryotes have compartmentalization
No
Describe the compartmentalization of eukaryote cells
Due to the membrance-bound organelles, the organelles create a compartment with controlled conditions inside
- separates the the insides of an organelle from outside
- like a bag
- chloroplasts have double membrane — not as easily disturbed
Are cell membranes organelles?
No
Explain the three parts of cell that are not organelles
Cell wall
- extracellular (not inside the cell)
Cytoplasm
- not specialized to perform specific functions
- it is just where everything is happening
Cytoskeleton
- not a discrete structure
- CANNOT be differentiated from other cells
- why?
- discrete: specific and easily identifiable shape
Explain the differential centrifugation
Purpose: to get the different the different organelles
1.) Cells in a homogenizer (blender)
2.) Puts in a centrifuge (spins around), turns into homogenate
3.) The denser materials will form solid pellets which could be removed easier
4.) Continue process removing denser pellets to get the parts you want
Is cell membrane an organelle?
Yes because it has a specific function
Outline the advantages of the separation of the nucleus and cytoplasm into separate compartments
-
safeguards the DNA
- DNA wouldn’t be compromised/affected by outside (e.g. chemical reactions in the cytoplasm)
- THEREFORE translation cannot begin immediately after transcription thus, mRNA can still be modified (post transcriptional modification)
- minimizes mutation
-
makes functions more efficient
- tailored to the specific functions of the organelle
Define the process of translation
The process of making protein from RNA
Explain transcription
RNA gets the code from DNA and can get in and out of the nucleus so it acts like a “secretary” to act as gene code for ribosomes to create protein (translation)
Transcription (AKA DNA to RNA) -> Translation (RNA to protein)
Distinguish genes vs genomes
Genomes:
- total genetic composition of the cell
Genes:
- part of genes
Advantages of compartmentalization
1.) Increasing chance of collision of enzymes and substrates
- creates a surface for them to touch the organelles (??)
2.) Protects cells from degradation
3.) Conditions, such as pH, can be maintained
- (no. 2 and no. 3 connect because of lysosomes)
4,) Large areas of membrane can become dense with proteins for a specific process
- see B2.1
- many proteins with diff. functions
define hydrolyze
make simpler
Explain why lysosomes need a membrane
They contain a high concentration of enzymes capable of hydrolyzing (breaking down) polymers (basically they have a lot of digestive enzymes that can break down stuff)
All of their enzymes are acid hydrolases which are active at an acidic pH.
If acidic hydrolases are released, everything outside would not work due to their acidity.
- that is why the lysosomes need a membane/proctection
Describe the example of phagocytic vacuole and the following terms: phagocyte, phagocytosis and phagocytic vacuole
Definition:
Phagocyte - a cell that performs phagocytosis
- phagocytosis - a type of endocytosis that lets pathogens in to kill them
-phagocytic vacuole - phagosome, contains the pathogen/large molecule that entered the cell membrane.
Phagocytosis
Cell uses the plasma membrane to engulf a large particle, giving rise to an internal compartment called a phagocytic vacuole (AKA the phagosome)
Describe the inner membrane
contains the electron transport chains and ATP synthase (aka materials for ?? for creating ATP)
-> electron celectricity energy atp (to help me remember)
Describe the intermembrane space of mitochondria
Where a high concentration of protons is generated by the electron transport chains
Describe the matrix [2]
What?: The fluid filling the compartment inside the inner mitochondrial membrane.
Purpose: To contain enzymes and substrates for Krebs cycle and link reaction. Due to this, aerobic respiration can be performed more rapidly.
Describe the nucleoplasm
semi-fluid matrix found inside the nucleus is called nucleoplasm.
Give the term of DNA found within the nucleus
Chromatin
Describe the nuclear envelope
- Two concentric membranes, called the inner nuclear and the outer nuclear membrane
- Allows only small non-polar (no charge) molecules due to their phospholipid bilayers.
- Continuous with ER
Describe the nucleus during cell division (PROPHASE)
1.) Prophase
- chromosomes condense and the nucleolus disappears
- nuclear membranes fragmented into vesicles (so like a catabolic ver. of the first creation of the cell membrane).
- the nuclear pore complexes dissociate.
- because the membranes “fragment” to form tiny vesicles
Outline the different parts in the mitochondria
Additional:
Krebs Cycle and Link Reaction takes place in the matrix bc:
- its like the cytoplasm of the membrane (mitochondria)??
- the link reaction is supposed to make the glucose usable for KC (so thats why its in the matrix)
ETC is in the inner membrane
- bc the ATP synthase (to create ATP — main purpose of ETC) is in there
Outline the different parts in the nucleus
Describe the nucleus during cell division (TELOPHASE)
-> Comes after prophase (so the nuclear membrane fragmented into the smaller vesicles)
During Telophase:
1.) The nuclear membrane vesicles bind to the chromosomes (the long line ones)
2.) The vesicles fused with one another and then absorbed the chromosomes.
3.) Then the fuse vesicles that absorbed the chromosomes will fuse again to make a complete single nucleus wherein the chromosomes decondense (aka unravel to like string) and the nuclear pore complexes reassemble
