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Do lipid bilayers actually bond to eachother? Do they take energy to come together?
No they do not bond they simply come together because it is much more favourable than being surrounded by water, therefore it is spontaneous and takes no energy
Describe a phospholipid in terms of polarity
How many membranes does a eukaryote have in the entire cell? prokaryote? how does the prokaryotic system differ for functions such as energy production and protein production?
- many many
- essentially only 1
- all of the energy and protein production will be done on the plasma membrane in a prokaryote
Are all ribosomes attached to the RER? where are they primarily in prokaryote?
- No there are some free floating
- plasma membrane inside
in a eukaryote does the plasma membrane compose lots of the membrane total?
is the lipid bilayer symmetric at all? is it the same on the outside as the inside?
NO not at all none of those are true
Where does the permeability of the membrane come from?
does the polarity on a protein spanning the entire membrane change or is it constant?
are phospholipids stuck in one spot on the membrane?
NO the fluid mosaic model basically says they can all move around all they want their may be some tougher spot but an individual phospholipid doesn't stay in the same place for long
Can proteins move around the membrane?
Yes but not to the same extent that phospholipids can, they may be anchored by microtubules or even lipid rafts
What forms a lipid raft
Cholesterol to keep particularly important proteins in place
While many membrane bound organelles are created by___ (multiple words or sentence), _____ 's derivation is best described by the ___________ theory lending to its unique traits
- simply endocytosis of an area of the membrane with the specialized equipment (recall proks had it on the plasma membrane)
WHat are some unique traits of the mitochondria which lends evidence to the endosymbiotic theory
- has its own DNA
- self replicating
- respiration occurs on the inside membrane
- have their own prokaryotic ribosome
What were some benefits of endocytosis and compartmentalized organelles?
Greater specialization as well as control over special compartments, it also could make better use of the volume inside the cell instead of only having functional systems on the plasma membrane
During endocytosis or exocytosis is the outside every exposed to the inside?
Essentially base on the theory that all organelles are just endocytoticly formed the inside of all of them would be originally?
What is meant by tri-laminar plasma membrane
3 layers of plasma membrane visible from electron micrograph 2 head layers and one tail layer.
is the majority of the plasma membrane made up of phospholipids??
Probably although a large amount is also proteins so it is not always
What are 5 membrane functions?
- Protein synthesis
- Transmembrane transport
- Pinocytosis, phagocytosis and exocytosis and endocytosis
Endocytosis is broken up into
In reference to what a cell does, cell drinking is_____ cell eating is _____ and cell defecating is ______
So the two main headings of a cells transportation across the membrane is endocytosis and exocytosis what do you call the coordinated combination of the two too transverse the cells distance
What are the two ways endocytosis can occur? Explain each of them
- Endocytosis by smooth vesicles- simply cell indiscriminantly absorbing from outside environment, seen more in capilleries and can be paired with transcytosis
- Endocytosis by coated vesicles - Special area covered in receptors to catch the specific something it is looking for (receptor mediated endocytosis)
What have viruses and bacteria done with endocytosis and exocytosis?
They have hijacked this entire system to use it for their own purpose of infecting and enter the cell
What are 4 components of the nucleus that we learned of? Describe each slightly.
- Nuclear envelope - Membrane surrounding nucleus
- Chromatin -all tangled and indistinguishable DNA lengths within nucleus
- Nucleolus - Area of nucleus where ribosomes are made specifically, in heavy protein making cells it can be distinguished
- Nuclear matrix - Nuclear skeleton
What are two things attached to the nuclear envelope?
Do all cells have 1 nucleus? Explain?
- NO some can have more than 1 = macrophages, skeletal muscles etc
- Some can have less than one nucleus = Red blood cells
To eat solid particles a cell partakes in ?
Where do we see the dark dense chromatin in the cell? What is this? What is it in contrast too?
- Around the edges of the nucleus
What is the glue that is used to attach heterochromatin to the inside fo the nucleus
Lamins or fibrous lamina
Which chromatin is more active and less tightly packed, heterochromatin or euchromatin?
Why can we see the membrane of a nucleus under a light microscope? Is it because it is thick enough?
NO it is because the heterochromatin attaches on and makes it appear thicker and more visible
What do pores appear as under a microscope?
A break in the heterochromatin
Is a pore like an uncontrolled hole?
No it has basically a plug in it to control the flow and regulate what goes inside
Describe how DNA is wound in chromatin starting with the DNA helix and ending with coiled nucleoprotein fiber
DNA helix is wrapped around the ball called histones and then packed into a 4 pack called an octomer of histones Which is stuck end to end with other octomers to form a nuclear protein filament Which is wound again to form a nuclear protein fiber
is the nucleolus all one piece of chromatin?
No it is all the chunks of chromatin from every individual chromosome that have to do with making ribosomes all congregated into one area
When you see a nucleolus you know a cell is engaged in?
Is a nucleolus homogenous or does it have its own sections?
Has its own sections
What are the 4 sections of the nucleoulus we learned?
- Nuclear organizer region
- fibrillar region
- Granular region
- nucleolar associated chromatin
During mitosis what happens to the nucleus?
- Dissovles and the chromtins are pulled apart via spindles on the end
How many membranes on a mitochondria? Which is permeable?
Why are the folds of the inside of the mitochondria so important? What can you tell by them?
- Cause increase SA
- Can tell if engaging in ATP or lipid production (longitudinal = ATP production, tubular fingerlike prjections = lipid production)
Inner part of mitochondria called?
How does the mitochondria decide if the cell lives or dies?
Because mitochondria gives all apoptotic signals
How are mitochondria replicated?
Like a bacteria, formed from a predescessor (budding)
in terms of the inner membrane of the mitochondria describe cristae and tubuli
tubuli is the name for the finger or tube like foldings of the inner mitochondria when in lipid biosynthesis mode and cristae are the shelf patterns seen when the mitochondria are in ATP producing mode