Exam #2 - Lecture Notes 10-12 Flashcards
The SA to volume ratio becomes ______ as the cell gets bigger.
smaller
And when the SA to volume ratio is too small, you really lose the ability to ______ the cell’s large volume.
nourish
Where is the central vacuole found?
Plant cells
What is the central vacuole going to do?
It’s going to INCREASE the SA to volume ratio
True/false: Prokaryotes are single celled, whereas eukaryotes are multicellular.
FALSE, because there are single celled eukaryotes.
Prokaryotes are invariably…
single cellular
Achea tend to live in…
extreme environments…like a deep sea vent…like a hot spring…near boiling temperatures. A microorganism will THRIVE.
Besides the nucleus, where else is there DNA in a eukaryotic cell? And name one.
It’s within organelles in the cytoplasm.
So DNA found in organelles.
Ex: mitochondria
What are the three main differences that distinguish prokaryotes and eukaryotes?
1) Eukaryotes have a nucleus
2) Eukaryotes have membrane-bound sub cellular structure
3) The size of eukaryotes tend to be larger.
Prok: 1-10 micrometers
Euk: 10-100 micrometers
Do bacteria have DNA?
Yes, BACTERIA HAVE DNA! They have chromosomes!
Is the DNA in a bacteria enclosed in a membrane?
No
Where is the DNA in a bacteria located?
In a region of the cell wall called the “nucleoid”
What’s the one feature you need to know about a bacterial cell?
They do not have membrane bound organelles
Which one has a cell wall?
BOTH
Bacteria have a cell wall, but so do many eukaryotes, although not all, not ________.
animals
Most DNA in eukaryotes is in the nucleus, so where is the rest of it?
The rest of it is found in organelles, such as the mitochondria
Common features of all cells…
ALL CELLS HAVE A ____ _________.
CELL MEMBRANE
What is the composition of that cell membrane?
Phospholipid bilayer
The cytoplasm is everything between the _______ ______ and the ____ ________.
between the nuclear membrane and the cell membrane
Everybody has PROTEIN, so everybody needs _________.
ribosomes
Again, what does the large central vacuole, found in plato cells, help to do?
Helps to increase the SA to volume ratio
What is the mitochondria for?
ENERGY. Sites of ATP synthesis
Eukaryotes are __x larger than prokaryotes.
10x larger
The ___ ______ maintains the internal chemistry of the cell.
cell membrane/plasma membrane
One function of the cell membrane is that it maintains the internal chemistry of the cell.
What are two other main functions?
1) Receptors - receive signals in multicellular organisms…could be a hormone. Even in single celled life, can receive a signal from the environment. Receptors are part of that membrane.
2) Transport - What good is a barrier against atoms…? Against atoms…if we cannot bring in nutrients, if we cannot bring in sugar, if we cannot bring in amino acids. It’s useless. We have to have transport capability within that barrier, and we do and we have other functions as well.
We just said the membrane is more than a barrier! It has receptor capability! It has transport capability! Just to transport what you want, and not poisons and toxins. How do you have that functionality if you don’t have the best of all molecules…______.
PROTEINS.
Again, what is the composition of the cell membrane? (3)
Phospholipids, other lipids, diverse proteins
Why do we, eukaryotes, require membrane bound organelles?
The ability to compartmentalize certain functions so they don’t get mixed up
Can bacteria make ATP
Of course, energy source
True/False: There was ATP being made by bacteria well before there was ever a eukaryotic cell.
True
Is the mitochondria essential to making ATP?
No, bacteria make it, but they do it in a small space…they’re 10x smaller than euk’s.
Why do we have organelles?
We have a huge volume compared to little bacteria
Organelles _________ nutrients.
concentrate nutrients, so that they can readily find the enzyme that will then convert that to something else
When we import glucose, we begin to catabolize, we begin to break it down…but VERY QUICKLY we begin to move it to the __________. Concentrate the sugar in _______ where it’s rich, where enzymes can readily act upon it.
Mitochondria
So what is the purpose of the organelles?
Compartmentalization
We have organelles that are full of enzymes that will break through anything…expect the membrane that contains them. They can digest anything…that’s a dangerous organelle…we keep those enzymes locked up in _________.
lysosomes
What is the purpose of isolating biochemistry?
So it doesn’t interfere with other parts of the cell
Membrane is always going to provide _______. So just as the cell membrane has additional functionality, so do the ________ membranes have functionality.
So they’re not just barriers…they have function as well.
function, interior
All of the membrane bound organelles possess either ___ or ___ membrane. Either ___ or ___ lipid bilayer.
one or two
How many membrane does the nuclear envelope have?
Two membrane
How many membrane does the E.R have?
One membrane
How many membrane does the Golgi have?
One membrane
How many membrane does the mitochondria have?
Two membrane
All the organelles contain _______ solutions.
aqueous
Muscle cells are particularly _______ in mitochondria.
RICH, ABUNDANT…all true. They’re LOADED with mitochondria because they need so much ATP. They depend upon ATP
Another cell, ____ metabolically active may not have so much mitochondria in it
less
In order for the nuclear pores to work, two membranes must…
come together, so the two membrane FUSE at the nuclear pores
What are the nuclear pores used for? Is there anything SPECIFIC that MUST pass through the nuclear pore?
RNA! RNA is made in the nucleus, but decoded in the cytosol. RNA must be exported though nuclear pores
EVERY ORGANELLE CONTAINS ________!
PROTEIN
DNA is wrapped around _____ proteins.
histone
Protein is made by the _______.
ribosome
A ribosome has ____ parts.
two
Two ______ make up the ribosome. One _____, one ______.
subunits, one large, one small
What are the two groups of ribosomes?
Free ribosomes - One group making protein in the cytosol
Bound ribosomes - Another group making protein on the surface of the E.R
At any instant in time
The endomembrane system is a system of membrane INSIDE the cell…that is _______ joined.
Indirectly
What does that mean, “indirectly” joined?
Indirectly joined in that, you can break off a piece here and send it over here
So in a sense, indirectly joined means breaking off a piece and sending it to another part of the membrane. And what is broken off and sent is called a _______ _______.
transport vesicle
What are the five parts of the E.M.S?
E.R, Golgi, lysosomes, food vacuoles, cell membrane
Why is the cell membrane part of the E.M.S? It’s not really “endo” or “inside.”
It’s part of the E.M.S because it can bud off a vesicle
What is the E.R connected to?
Nuclear envelope, namely, the outer membrane of the nuclear envelope
How many membrane does the E.R have?
One membrane
What’s the function of the E.R?!
TO MAKE PROTEIN! It’s got ribosomes. Functioning ribosomes. They’re in the process of making protein.
What happens to the protein? (According to that specific diagram?) It is threaded across the E.R membrane, into the internal space called the _______.
lumen
What is the interior of the E.R called?
The lumen
Where do the protein go?
Inside. So the protein was made here, it’s threaded inside and there it is, inside the E.R lumen
The rough E.R also contains which type of proteins?
Chaperon proteins
Chaperons help proteins _____.
fold. Preventing undesired interactions from other proteins in that process
What happens to the protein once it folds and in the E.R lumen? WHAT HAPPENS NEXT?
What are the two possibilities?
1) The protein stays in the E.R. A ______ protein might stay in the E.R…CHAPERON PROTEIN. How does it get there? It’s made by a ribosome.
2) The protein can leave the E.R.
How does the protein leave the E.R?
It can bud off in a transport vesicle. That is the only way to get out of the E.R.
In order to travel to another part of the endomembrane system, the only place this vesicle can go is to…
more E.M.S. For example, Golgi
What is a primary destination of vesicles leaving the E.R?
Golgi
What is the ‘cisternae’?
The individual folds of E.R
What is the function of the smooth E.R?
To make lipids!
ALL of the lipids we have discussed…phospholipids, cholesterol, fats…all of that…biochemistry happens at the ________ ___…makes lipid.
Smooth E.R
What’s another function of the smooth E.R?
Detoxifies toxic substances. Detoxifies drugs.
What’s the exception to this?
It’s a cell specific function.
True/false: All smooth E.R detoxify toxic substances.
FALSE. It’s a cell specific function, NOT all smooth E.R detoxifies. Only some smooth E.R detoxifies.
For example…the smooth E.R found where?
In the human liver. The smooth E.R in the liver cells detoxifies.
Yet another function, and this is also a liver specific function…the smooth E.R…
stores glycogen, which is the storage polysaccharide. Smooth E.R stores it.
Where on the smooth E.R of the liver cells does the smooth E.R store the glycogen?
On the surface
Name all the functions of the smooth E.R
1) makes lipids
2) detoxifies toxic substances (cell specific function, typically in the liver cells)
3) stores glycogen, a storage polysaccharide (cell specific function, typically in the liver cells)
Name the functions of the E.R
Makes protein and lipid
What cell structure is made of lipid and protein that might well be manufactured by the E.R?
THE CELL MEMBRANE
The rough E.R is capable of dehydration to make what?
To make protein
The other one we’ve talked about is the _______. _______…FULL of ribosomes indicating that much protein is made within the _______.
cytosol
But also on the surface of the…
rough E.R
Remember, proteins that are actually made in the E.R actually end up within the E.R in an internal fluid filled space called the ______.
lumen
How does a protein leave the E.R lumen?
In a transport vesicle
Remember, the ______ _______ is what defines various membrane sin the ell as being part of the E.M.S. E.R, Golgi, lysosomes, food vacuoles, cell membrane….ALL components of the endomembrane system…which means they can ‘bud off’ membrane…and receive membrane between each of those structures…
transport vesicle
Cell membrane contains ______ and _______.
lipid and protein
The lumen is loaded with protein…what are the two options for the protein?
It can REMAIN there…again, could be chaperon protein.
OR, it can LEAVE the E.R in a transport vesicle
So we said that one job of the E.R is to make ________, right? Rough E.R makes protein, smooth E.R makes lipid…so those are the two constituents of the ____ _________.
membrane, cell membrane
So how does a cell get big? How does it GROW?
By vesicles…as it obtains vesicles…