Unit 2 part 4 Flashcards
Cell structure
Cell structures that are not considered organelles
- Cell wall -> an extracellular structure
- Cytoplasm -> gel like fluid spread throughout the cell, does not have compartmentalized structure
- cytoskeleton -> Found throughout cell, does not have a compartmentalized structure
Plasma membrane
A phospholipid bilayer that surrounds and encloses cell
- Controls what enters and exits the cell
- Conisdered an organelle (by IB) tho is not a subcellular structure
Cell fractionation
A process that separates cell organelles while preserving functions
- Preparing cells for ultracentrifugation
Steps for cell fractioning
- Homogenization
- Tissue that cells are broken up in a blender. Cells are blended in cold, buffered, solution that is isotone to cytoplasm of cells - Blended solution then filtered to remove large cell debris
Ultracentrifugation
Uses fast centrifuge to separate cell organelles according to density
Steps for ultracentrifugation
- Filtered solution that has the cell organelles is spun at low speed by an ultracentrifuge
- The densest organelle, the nucleus, forms a pellet at bottom of centrifuge tube
- Pellet is removed, process is then repeated at faster speed resulting in a series of pellets containing one type of organelles each time
What is stored in the nucleus?
Eukaryote’s chromosomes are stored in nucleus. Their genetic info is stored in form of DNA for growth and develeopment
How are chromosomes transcribed
Chromosome genes are transcriped into mRNA w/in nucleus
- mRNA leaves nucleus to be translated into polypeptides by ribosomes
How is DNA protected?
DNA is protected in the nucleus from potentially harmful reactions in cytoplasm
Transcription of DNA
Process of transcription of DNA to mRNA occurs in the nucleus and DNA is modified before entering cytoplasm
Translation and transcription in prokaryotes
Prokaryotes don’t have a nucleus meaning there is no separation of the process of transcription and translation
outer membrane (mitochondria)
channels for pyruvate to enter Mitochondrion, b/c it contains protein channels and is not permeable to protons, allowing concentration of protons to build up in intermembrane
Lysosomes
Membrane bound organelle which contain digestive enzymes
Inner membrane
Contains proteins of electron transport chain and ATP syntheses
- Has proton channels and ATP synthase, the protons give energy for ATP synthesis to go from ADP -> P -> ATP
What is the main function of lysosomes?
Digestion of macromolecules w/in cell
What are digestive enzymes w/in a lysosome capable of doing?
Digesting other cell components and are kept separate from cytoplasm and other cell structures by membrane surrounding lysosomes
What happens when a cell is damaged?
Enzymes are released from lysosomes resulting in digestion of cell
How is a phagosome formed?
Lysosomes fuse w/ the phagocytic vacuole and the lysosome’s enzymes digest the bacterium
Mitochondria
Organelles that produce ATP through aerobic respiration and are recognizable on electron micrographs by its folded inner membrane forming cirstae
What is phagocytosis?
Process by which solid materials like bacteria are taken into a cell by endocytosis
Adaptations of mitochondria
- outer membrane
- inner membrane
- inter membrane
- cristae
- chromosomes
Inter membrane (mitochondria)
Small space allowing rapid accumulation of protons
Cristae (mitochondria)
Many folds in inner membrane and increases surface area
Chromsomes (mitochondria)
Singular circular chromosome that contains genetic info to make all proteins
- Synthesizes proteins required for aerobic respiration
