Lecture 9 Part 1
Where is most genetic Material located?
What two events occur here?
1. Nucleus
2. DNA replication & DNA transcription
What are the functions of mitochondria & chloroplasts?
Mitochondria: Cellular Respiration
Chloroplasts: photosynthesis
What organelle contains chromosomes? What do chromosomes equal?(What are in chromosomes)?
Nucleus.
Chromosomes= DNA + Protein.
What two features are in Plant cells, but not animal cells?L9SL48
1. Chloroplasts-enable plant cells to photosynthesize
2. Vacuoles: water-filled organelles that contributes structural rigidity of plants.
What causes rigid cell walls in plants? SL41
Cellulose
What role do signal recognition particles play in directing protein synthesis to the endoplasmic recticulum?
They recognize the N-terminal hydrophobic sequence and halt translation temporarily.
What are nucleoids? What are Plasmids?
Nucleiod: area where chromosome(DNA) is located(includes a single circular chromosome)
Plasmids: small circular DNA.(Specific to prokaryotes).
What is the endosymbiotic theory of origin?
The energy processing organelles(mitochondria & chloroplasts) arose from a symbiotic relationship between a prokaryote and a eukaryote.
What is the enodmembrane system for?
For Manufacturing and shipping proteins.
Why are motor proteins(i.e. myosin, kinesin,etc.) needed to move things around the cell?
They carry cargo(organelles, vesicles, chromosomes,etc.) across cell's complex cytoplasm using ATP power.
Why do mitochondria and chloroplasts have double outer membranes?
Endosymbiotic theory, endosymbiosis, where ancestral, free-living prokaryotic cells were engulfed by a host cell. The inner membrane originated from the prokaryote's plasma membrane, while the outer membrane was derived from the host cell's vesicle.
What is the functional significance of the double membrane structure found in mitochondria and chloroplast?
It allows these organelles to regulate their own internal environment and energy production.
Control entry and exit of molecules from the nucleus to the cytoplasm.
What is the role of Rough ER and what is attatched to it?
Rough ER is the site of protein synthesis for proteins that will be exported from the cell, or used in organelles in the endomembrane system. Ribosomes are attatched to the RER to be exported/secreted.
What is the role(s) of Smooth ER? What does Smooth ER lack?
Smooth ER is the site of phospholipid & steroid synthesis.
Lacks attatched ribosomes
What must proteins that enter the endomembrane system have?
A hydrophobic N-terminal signal sequence
What would be the consequence of deleting the N-terminal signal sequence from a protein that is destined for secretion.
It will be synthesized into the cytoplasm.
What does the Golgi Apparatus do?
modifies proteins & lipids synthesized from the Rough ER & sorts proteins and lipids and targets them to their final destination.
(Smooth ER usually adds unique sugar "tag" that directs them to proper destination)
What is the Extracellular Matrix composed of?S43
Glycoproteins- proteins with some attached carbohydrate groups
Proteoglycans-long polysaccharide chains linked to a specific core proteins
Polysaccharides-long chain polysaccharides
Where do proteins that are fully translated on the RER function?
1. In organelles/structures that are part of the endomembrane system.
2. As integral membrane proteins in the plasma membrane.
3. They get secreted from the cell in which they were made
What directs proteins translated on free floating ribosomes in the cytoplasm to their final destination where they function?
1. Internal amino acid signal sequence signals proteins that will function in the nucleus.
2. A short N-terminal signal sequence will signal proteins that will work in the mitochondria or chloroplast
3. No signal sequence for proteins that will function in the cytosol
What is endocytosis?
Energy dependent process by which cells absorb molecules via vesicles pinching off from the plasma membrane
How do plasmids contribute to bacterial survival and adaptation in their environment?
They often contain antibiotic resistance genes that provide selective advantage.
What is a Lysosome, what does it do, and how does it do it? L9S27
Lysosomes are small digestive organelles that use hydrolytic enzymes to breakdown macromolecules. Lysosomes are used for digestion & waste processing.
Involved in autophagy & phagocytosis.
List the roles of the three parts that makeup the cytoskeleton: Actin filaments, Microtubules, & Intermediate filaments L9SL36
Actin filaments: muscle contraction, cytoplasmic streaming, cell division, etc.
Microtubles: chromosome distribution, vesicle transport, cell motility(cilia & flagella), etc.
Intermediate filaments: provide structural support)
1. What is responsible for cytoplasmic streaming in plants?
2. What is the Extrachromosomal small DNA molecule in Bacteria called?
3. What transports proteins from the ER to the golgi?
4. What is composed of sugars and proteins, and located outside of plasma membrane of animal cells?
5. What powers the flagella or cilia of an organism?
1. Microfilaments
2. Plasmid
3. Secretory Vesicle
4. Extracellular Matrix
5.Mircotubules
What is Phagocytosis?
breakdown of extracellular particles.
What is Autophagy?
Degradation of unnecessary or damaged cellular components(or normal during cell starvation)
What distinguishses the cis and trans face of the Golgi Apparatus?
Cis face receives proteins from the ER while trans face ships them to their destination.