What are the 4 common features of all life forms?
Plasma membrane
Cytosol
Chromosome (DNA)
Ribosome
Some characteristics of prokaryotes are…..?
No nucleus
DNA not bound by a membrane
Single circular piece of chromosome
Additional external structures that promote attachment
What are some examples of prokaryotes?
Bacteria and Archaea
Some characteristics of eukaryotes are….?
Have a nucleus
DNA located inside nucleus
Additional DNA are located in other areas of the cell
Membrane bound organelles
Things are more segregated or compartmentalized
What are some examples of eukaryotes?
Animals, plants, fungi, and protists
Does size correlate with function?
Yes
What are some important cell features?
Plasma membrane forms the boundary of every cell
Surface area : volume ratio of the cell is important
The smaller the cell, will the surface area : volume ratio be smaller?
No
Does an increase in cell size correspond to an increase in membrane surface area?
No
What contains the ‘bulk’ of the DNA inside the cell?
Nucleus
What is responsible for supporting the nucleus?
Nuclear Lamina
What is the nuclear lamina?
Protein framework that’s attached to the inside face of the nuclear membrane
Nucleus shape is supported
What are chromosomes?
Long segments of DNA complied together with protein
What’s chromatin?
DNA + Protein
When are chromosomes tightly condensed and easily visible as individual units?
During cell division
When there is no cell division, are DNA more loose and active?
Yes, when DNA is more active, it’s considered to be loose
What happens to the nucleus during cell division?
It dissappears
Can a cell have more than 1 nucleolus?
Yes
Where is rRNA made?
In the nucleolus
What are ribosome made of?
rRNA and protein
Where do ribosomes exist in the cell?
Free in the cytoplasm
Bound to endoplasmic reticulum
Where are the proteins made by free cytoplasmic ribosomes destined to be?
Proteins are destined to stay in the cell
Do attached ribosomes synthesize proteins to stay inside the cell? If no, then where do they go?
No.
The proteins typically get inserted into membranes, packaged into organelles, and secreted from the cell
What does the endomembrane system include?
Nuclear membrane
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane
What are the 2 types of endoplasmic reticulum?
Rough ER + smooth ER
What are the functions of the smooth ER?
Lipid production
Detoxification of drugs
Store calcium ions
What are the functions of rough ER?
Produce more membrane phospholipids
Bound ribosomes produce proteins that’ll be secreted by the cell, packaged to other organelles, and inserted to the membrane
What is the process of synthesis, packing and modification of secretary protein by the endoplasmic reticulum?
- Polypeptide gets synthesized by ribosome, then inserted to the rough ER cavitiy via protein pore.
- Sugar chains gets linked to Polypeptide producing glycoprotein.
- Once ready for export, molecule is packaged into a transport vesicle.
- Transport vesicle travels to golgi apparatus where it gets further processed.
Products of the golgi maybe…
Secreted from the cell
Added to the plasma membrane or to organelles membranes
What is the cis and trans face of the golgi?
Cis: receiving end that receive transport vesicles for ER
Trans: shipping end that gives rise to vesicles which travel to other sites
What are the flattened sacs of the golgi called?
Are they interconnected?
Cisternae
No
What does the no. of golgi stacks correlate with?
The quantity of proteins secreted
What is the function of the golgi?
Serves to modify and store proteins that arrived from endoplasmic reticulum
Do different cisternae have different enzyme packages?
Yes
When the golgi makes sugars to be secreted from the cell, how does it export?
Gets secreted from the Trans face of the golgi, then gets fused with the cell membrane to get exported. (Exocytosis)
