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…
Where are the vesicles originally built?
E.R
So again, what’s one job of the E.R?
To make membrane
Where do E.R vesicles go?
A primary route of traffic is to the Golgi. From the E.R to the Golgi
The Golgi apparatus has MULTIPLE ________ ____
flattened sacs
Each of these sacs contains _______.
Enzymes…which recall, run the biochemistry of the cell
And each sac…a ______ set of enzymes
different
And what the Golgi does is ______ vesicles…for example, from the E.R…it then _______ vesicles…from sac to sac. They’re called ________. From ________ to ________. and eventually ___ ___ vesicles to other destinations.
receive vesicles transmit vesicles cisternae From cisternae to cisternae bud off vesicles
So _______, ______ and ___ vesicles.
Receive, transmit, and bud vesicles
The Golgi ______ E.R products.
processes
By process, we mean chemically _______.
chemically modify…covalently modifies E.R products. For example…oligosaccharides are added.
The Golgi is like an _______ _____ within the cell.
assembly line
Export is called ________.
secretion
Where do Golgi vesicles go? I think that’s the next question. What are the two possibilities?
One possibility is to the *cell membrane. *
Another possibility is to lysosomes.
Lysosomes are bodies capable of ____.
“lysis.” It means cutting or breaking
What is export called?
Secretion
One destination is to the ____ ______, which results in _______ of those proteins.
cell membrane, secretion
A lysosome is a body containing lysis, or __________ enzymes
hydrolytic enzymes
A lysosome is a membrane bound ____, fluid filled and contains _______.
sac, enzymes
What do lysosomes do? What lysosomes do is to _____ to vesicles from the ____ ________.
fuse to vesicles from the plasma membrane.
What’s the point to fuse with such a vesicle?
To digest whatever is in this vesicle
Sometimes we’ll call these vesicles _____ _______.
food vacuoles, because what they brought in…is effectively food for the cell
How many membrane does Golgi have?
One membrane
How many membrane does a lysosome have?
One membrane
If this cell were an amoeba, you better believe that cell has _______. Remember that amoeba get their nutrients through this sort of import. Though* ___________.*They swallow other cells. Once they do, lysosomes go to town, digesting what’s in that food vacuole.
lysosomes, endocytosis
Macrophage is literally a ___ _____.
“big eater”
_________ have also been shown to shallow and destroy cancer cells.
Macrophages
Another function of lysosomes is to…
break down a cell’s own organelles
Why would you break down your own organelles?
It’s a recycling mechanism. It’s old…past it’s time…lets break it down and recycle its component parts
Okay, again, a figure from another textbook showing this mechanism of lysosome function in a little bit more detail. So here is the lysosome, again…we said it _______ vesicles from the Golgi…right…here is the lysosome…now the lysosome has encountered a what? A ____ _______…from here…a _____ ______…and encountering it, the lysosome actually _____ with the food vacuole, exposing this food to the lysosomal enzymes.
RECEIVES, food vacuole, food vacuole, fuse
What is the purpose in sending protein to the lysosome? How does a lysosome get it’s hydrolytic enzymes in the first place? What are hydrolytic enzymes, what kind of biomolecule is that?
Enzymes…PROTEIN…
How does a lysosome get protein? Where do these things come from?
THEY COME FROM THE GOLGI APPARATUS, YEAH!
Proteins leaving the Golgi, going to the lysosome are _______ protein to the lysosome.
DELIVERING
Lysosomes mediate __________ digestion.
INTRAcellular
Do not confuse digestion in the cell which occurs by ________, with digestion OUTSIDE of cells, which is what happens in your __ _____.
lysosomes, GI tract
This process of recycling the cell’s components using lysosomes is called ________.
Autophagy. It means just eating yourself
If a cell is specialized for secretion…specialized for export…it will be rich in ___ and it will be rich in ______.
E.R and Golgi, for the purpose of secretion
So macrophage will have a lot of ________, amoeba will have a lot of ________
lysosomes
Let’s tie up this section by once again recognizing there’s two sets of ribosomes found in the cytosol
- *One set is found drifting in the cytosol…not anchored to any surface…we call those ____ _______.**
- *The other set of ribosomes, in the cytosol, are bound to the surface of the E.R, we call them _______ ________.**
free ribosomes
bound ribosomes
What are bound ribosomes for?
They’re for making proteins for the E.M.S.
They’re making E.R proteins…for example, chaperons. They’re Golgi proteins…for example, the various Golgi enzymes…we said are found within those cisternae…where do they come from? THE ROUGH E.R, MADE BY BOUND RIBOSOMES.
Lysosomal ribosomes are made by _____ _______.
bound ribosomes
What about proteins that are found in the cell membrane? How do those get there?
They’re made by a bound ribosome
Bound ribosomes also make proteins for ________.
secretion. Those proteins that are destined to leave the cell and function somewhere in the body…somewhere in the body outside of cells…such as digestive enzymes…such as antibodies…such as hormones, some of which are proteins.
What about free ribosomes? What do we need free ribosomes for? Make proteins for what?
For the CYTOSOL! THEY’REIN THE CYTOSOL AFER ALL.
What else do free ribosomes make protein for?
Mitochondria and chloroplast
Mitochondria and chloroplast get most of their proteins from the _______…import them from the _______.
cytosol
Recap of the E.M.S…
They manufacture biomolecules - think _____ __ and _______ __
rough E.R, smooth E.R
They sort biomolecules - think _____ ______
Golgi apparatus
They ship biomolecules - again, _____ ______
Golgi apparatus
They export biomolecules - think _______ _______
transport vesicle
They import biomolecules - think _____ ______
food vacuole
They even recycle biomolecules - think _______ engaged in _______
lysosome engaged in autophagy
Mitochondria and chloroplast _____ energy
convert
True/false: The mitochondria and chloroplast are NOT parts of the endomembrane system
TRUE, they are NOT
Since mitochondria and chloroplast are NOT parts of the endomembrane system, they cannot…
they cannot bud or receive transport vesicles
They have their own ____ and _______.
DNA and ribosomes
What do you conclude about these organelles? They can contain DNA…they contain ribosomes…therefore they can make…_______. They can make _______. And this is the…third place…that you find ribosomes.
PROTEINS
So what are the three different ribosomes and where are they found?
Free ribosomes - found in the cytosol
Bound ribosomes - found on the surface of the rough E.R
Mitochondria and chloroplast ribosomes - found in the mitochondria and the chloroplast
Mitochondria and chloroplast don’t make all of their protein, but they make some of their protein. Most of their protein, in fact, is imported. Imported from the ______.
cytosol.
How many membrane does the mitochondria have?
TWO membrane
The mitochondria has two membrane…
An outer membrane, which has _______ structure.
An inner membrane, which is highly _______.
smooth, folded
Where is the ATP made?
Surface of the INNER membrane
Remember…_____…rich in mitochondria…____, does so much for our body…rich in mitochondria.
muscle, liver
What does the chloroplast do?
Makes sugar…makes sugar FOR the mitochondria
How many membrane surround the chloroplast?
TWO…hard to see
There’s actually a third membrane floating around within the chloroplast, what is it called?
Thylakoid membrane.
Chloroplast is _____ than the mitochondria.
bigger
___________ theory is the origin of mitochondria and chloroplast.
Endosymbiont
So how do you get multiple membrane?
If you swallow a membrane bound structure…then you have additional membrane…that could explain how you have additional membrane in mitochondria and chloroplast
How do they grow?
They themselves divide, like a fission process
What does “semi-antonymous” mean?
It’s a reference to the possession of DNA, and to the ability to divide
What is it that gives cells such broad shape?
Cytoskeleton
What is the cytoskeleton made of?
PROTEIN
How do vesicles travel about the cell? From the E.R to the Golgi, from the Golgi to the cell membrane…it’s not just diffusion…they’re moving along __________ ______ like a…train on tracks…like a train on tracks…it’s like a cable…moving along…
cytoskeletal fibers
Also provides _______. The cell itself can move. You’ve seen the flagellum, that is an extension of the cell skeleton.
motility
Last but not least…the cell skeleton can reorganize itself…It can reconstruct itself into specialized structures for a particular purpose…so it’s _______.
dynamic
There are _____ components of the cell skeleton.
three
What are the three components of the cell skeleton?
Microfilaments, intermediate filaments, microtubules
What is the diameter of a microfilament?
7 nm
What is the diameter of an intermediate microfilament?
8-12 nm
What is the diameter of a microtubule?
25 nm
Microfilaments are made of _____
actin
Intermediate filaments are made of ______
keratin
Microtubules are made of ______
tubulin
__________ have a role in CELL DIVISION.
MICROTUBULES
__________ grab the chromosome and pull them apart.
Microtubules
It’s the microtubules that make up the structure known as the “_______ _______.”
mitotic spindle. Pulls apart the chromosomes.
The proteins of _________ are made by ribosomes floating free in the cytosol.
mitochondria
Mitochondria are able to make some of heir own proteins because they posses ____
DNA
Which ribosomes make lysosomal enzymes?
Ribosomes on the E.R
Pancreatic enzymes are secreted into the small intestine where they help to break down carbohydrates, proteins, and lipids for absorption. Pancreatic cells must be particularly rich (abundant) in ___.
E.R
Digestion in the GI tract does NOT involve ________.
lysosomes
What type of interaction holds the phospholipid bilayer together?
Hydrophobic interactios
It was also understood that the membrane contains ______.
Protein. RICH in protein.
What did the fluid mosaic model say about the location of protein?
it said that the protein is often embedded…embedded in the lipid bilayer. It may be embedded partially…it may be embedded completely, so that it completely spans the membrane, from one side to the other. It completely spans, it’s TRANSMEMBRANE in its position.
How a protein is arranged, with respect to the membrane, will depend upon its ______ _____ makeup
amino acid
Membrane also has _______
SUGARS
Where are sugars attached?
Sugars are attached to protein on the outer layers of the membrane
So if you were to bump into a cell, the first thing you may encounter is a ______
sugar
What’s the importance of the sugars on the surface of the cell?
The sugar gives the cell its IDENTITY
Sugars lead to identification of…
self
Phospholipids are moving ________.
laterally
Why can’t phospholipids flip flop?
Flip flopping means taking the hydrophilic head through the hydrophobic core. “Highly unfavorable.”
Can proteins move laterally?
Yes
Fluidity is essential…why?
The fluidity will allow tiny ____ to form…where maybe small molecules can move across.
gaps
What influences fluidity?
Temperature
As temperature increases, fluidity _______***
INCREASES. More thermal energy, more diffusion.
As temperature decreases, fluidity ________***
DECREASES
Another fact that increases fluidity is the precise chemistry of ______ ______
fatty acids
If the temperature is too hot, what can you do?
Make more SATURATED fatty acids
Making more saturated fatty acids will make the membrane more _______.
viscous, helping to balance out that higher temperature
If the temperature were to go down, what would you do?
Make more UNSATURATED fatty acids
________ also helps to control fluidity.
Cholesterol
Cholesterol, recall has that ____ ring steroid structure.
four
What is that little head on the cholesterol?
HYDROXYL GROUP
In that position, the phospholipids are prevented from packing too tightly, so the membrane does not become too _______. At the same time, the phospholipids are restricted in their ability to dance around.
viscous
So cholesterol helps to keep it in the middle. Prevent the membrane from being too ______ or too ___.*** Just right.
vicious, fluid
Every membrane has its own set of ______…specific for that organelle
proteins
The proteins can be embedded into the hydrophobic core…or they can be restricted to a surface…if they’re embedded, we call them **______ membrane proteins…if they’re restricted to a surface, we call them *________ membrane proteins.
integral, peripheral
Integral…yeah…this is integral, this is integral. These are not only embedded, they’re spanning the membrane, they’re __________…recall that.
transmembrane
Again, these oligosaccharides, which are joined to proteins…GIVE THE CELL ITS _______. Allowing your body to distinguish the self from the microorganism
IDENTITY
Do animals have a cell wall?
NO
Do animals have a cell wall? NO. But we do have a carbohydrate rich structure beyond the cell membrane…that’s called the _____ _________ ______.
extra cellular matrix
The ________ _______…the _________ ________…meaning the amino acid makeup of the protein will determine its precise disposition within the membrane
primary structure
The membrane proteins have precise _________.
orientation
Which proteins join one cell to another? (Exam)
Cell junction proteins
So what is the answer then forming things across the membrane?
The proteins are going to be an indispensable part of transporting substances across the membrane
The membrane is ________ permeable
selectively
A pure bilayer will allow _____ and ______ molecules to cross easily.
Like who?
Small and non polar.
Ex: Oxygen, CO2
If you are _____ and _____, you will be partially blocked.
Like who?
small and polar.
Ex: water (H2O)
If you are _____ and _____, forget it…you are totally blocked.
Like who?
Large and polar
ex: glucose
If you are _____, YOU ARE TOTALLY BLOCKED.
charged
Oxygen comes right in…we need that in abundance…okay, no problem…glucose, we also need that in abundance…it can’t get in, right? Sodium, potassium, electrolytes…we need to move them across, we cannot move across.
So…the second consideration is…there are _______ ______.
transport proteins
What is diffusion?
Random movement from an area of high concentration to an area of low concentration
What if it’s at low concentration but you need it now? In those situations, there is a way to push it across the membrane…effectively concentrating it within the cell, and that is known as _______ ______
Active transport
In passive transport, there is no _____ of energy.
input
In active transport, there is _____ of energy to movement from ___ to ____.
input, low to high
Notice that, even though you’re going high to low, you can even go the other way…yeah, this guy here is going the other way because it’s _______.
RANDOM, random movement
This is NOT chemical equilibrium, this is called _______ equilibrium
difffusion
Passive transport DOES involve ______, but there is NO INPUT of energy.
Energy, thermal and potential
What are the two types of diffusion?
Simple diffusion - movement directly across the lipid bilayer. Must be small and non-polar
Facilitated diffusion - if you are polar and/or charged, you can diffuse, but you need a transport protein.
