1
Q
Cell Theory
A
- all living things are made of one or more cells
- cells are the smallest units of life
- cells give rise to more cells (cell division)
2
Q
Prokaryotes
A
- have bacteria and archaea
-have been around longer
-first cell type
-smaller than Eukaryotes
no membrane bound organelles - unicellular, no nucleus
3
Q
Typical Bacterial Cell
A
- inside the plasma membrane:
- cytoplasm
- Nucleoid region- no nucleus, but we do have areas where the DNA goes and becomes dense.
- ribosomes (make proteins)- site of protein synthesis- you take a bunch of amino acids and link them up to make a polypeptide chain
- Outside the plasma membrane:
- cell wall- made up of lipids, polysaccharides
- glycocalyx- sticky outside area and secretions
- appendages- hair like
- Plasma membrane is made outside of a macromolecule, that is a phospholipid bilayer
4
Q
Eukaryotic Cells
A
- membrane-bound nucleus
- compartmentalized functions
- organelles
- variety in shape, size and organization (based on DNA)
- between species
- between cell types (also in prokaryotes)
- DNA is stored within a nucleus
- levels of complexity is very extreme
- also have flagella
- our DNA is stored in the nucleus and it is stored there
5
Q
Centrosome
A
site where microtubules grow and centrioles are found
6
Q
Nuclear Pore
A
passageway for molecules into and out of the nucleus
7
Q
Nucleus
A
are where most of the genetic material is organized and expressed
8
Q
Nucleolus
A
site for ribosome subunit assembly
9
Q
Lysosome
A
site where macromolecules are degraded
10
Q
Ribosome
A
site of polypeptide synthesis
11
Q
Chromatin
A
a complex of protein and DNA
12
Q
Plasma Membrane
A
membrane that controls movement of substances into and out of the cell; site of cell signaling
13
Q
Cytosol
A
site of many metabolic pathways
14
Q
Golgi Apparatus
A
site of modification, sorting and secretion of lipids and protiens
15
Q
Peroxisome
A
site where hydrogen peroxide and other harmful molecules are broken down
16
Q
Peroxisome
A
site where hydrogen peroxide and other harmful molecules are broken down
17
Q
Cytoskeleton
A
protein filaments that provide shape and aid in movement
18
Q
Mitochondrion
A
Site of ATP synthesis
19
Q
Smooth ER
A
site of detoxification and lipid synthesis
20
Q
Rough ER
A
site of protein sorting and secretion
21
Q
Surface area to volume
A
- increasing surface area comes at expense of greatly increasing volume (if you don’t change shape)
- SA is the area exposed to the surface and outside world
- Volume- the space inside
- Example: if you increase the size without changing the shape, SA and volume don’t change at the same rate, so what happens is when something gets bigger, the ratio goes down
- Example: Picture; one has 27 cells other has one huge cell. They both take up the same amount of volume but the SA of them is not the same
22
Q
Cytosol
A
- inside the plasma membrane, but outside organelles
- cytoplasm- everything inside plasma membrane
- liquidy
- includes organelles and cell walls
- main component is the liquid matrix in which everything exist in the cell
- Cytosol is the main region for eukaryotic metabolism(either breaking things down or building them up)
23
Q
Molecular Synthesis & Breakdown
A
-sum of all chemical reactions by cells
-cytosol- main coordinating region for eukaryotic metabolism
- anabolism is going from small to large, dehydration or condensation reaction
catabolism- going from a large molecule to a small molecule
24
Q
Cytoskeleton
A
- network of protein filaments
- 3 parts; microtubules, actin filaments(muscle contractions) and intermediate filaments
- they form networks to maintain cell shape
- within the cytosol we have a network of fibers
- cell motility is the ability of a cell to be able to move
- flagella is composed largely of these filaments
25
Cytoskeleton: Microtubules
- 25nm
- hallow tubule composed of the protein tubulin
- function: cell shape, organization of cell orangelles; chromosome sorting in cell division; intracellular movement of cargo; cell motility (cilia and flagella)
26
Cytoskeleton: Intermediate Filament
- 10nm
- twisted filament
- can be composed of different proteins including keratin, lamin and others that form twisted filaments
- function: cell shape; provides cells with mechanical strength, anchorage of cell and nuclear membanes
27
Cytoskeleton: Actin Filament
- 7nm
- spiral filament
- two intertwined strands composed of the protein actin
- Function: cell shape; cell shape muscle contraction; intracellular movement of cargo; cell movement, cytokines in animal cells
28
Flagella and Cilia
- 9 + 2 array
- help our cells move around
- plenty of eukaryotic cells have this
- structure for eukaryotic cells is more complex than for prokaryotic cells
- a single flagellum helps propel the cell forward, if a single celled swimming animal, this is helpful
- cilia may have a large flagella with many very small cilia and they help with the motility
- if u take a single flagella and look inside you see a particular arrangement of microtubules, every time u see a circle they are little microtubules that are called the 9+2
- there are 9 pairs of microtubules on the outside and 2 on the inside
29
Nucleus and Endomembrane System
- includes plasma membrane too
- directly connected or pass materials via vesicles
- this is what's going on inside the eukaryotic cell
- nucleus has its own membrane around and then we have all of these membrane bound organelles and that is a pathway from the nucleus to the plasma membrane
- a lot of fluidity between all these organelles, they are nit isolated, always moving material and sort of separating from one another
- example: make protein then export out of cell, make the protein in nucleus and has to leave cell and protein synthesis has to happen somewhere. Nucleus to the ER and its transported by vesicles to these various other systems and out
- the way material moves from one organelle to another is by fusing. A little vacuole will fuse and will become part of the organelle and pinch itself and come off later
30
Nuclear Envelope
- double membrane enclosing the nucleus
- outer membrane continuous with ER
- they are attached or fused together
- outer membrane and ER are both continuous
- Nuclear pores- openings, this is where material enter or exit the cell
31
Nucleus
- contains
- chromosomes - where DNA is stored
- we package DNA into chromosomes and proteins are in there
- chromosomes are highly packaged DNA that are wrapped around with a bunch of proteins
- DNA + Protein = Chromatin
- Nuclear matrix- similar to cytosol, outside the nucleus has these skeletons going through it into the cytoskeleton within the nucleus
- filamentous network
- organizes chromosomes
- Nucleolus- area is super highly condensed where the genetic material is
- ribosome assembly
- we have 23 chromosomes and each of the 46 pairs need to be in the right spot and in the right order to be used properly
- each chromosome has its own little home and it is organized by the filamentous network
32
Nucleolus
area that is highly condensed and where genetic material is also hyper condensed
- ribosome assembly
- protein are made here
33
Endoplasmic Reticulum
- network of membranes
- cisternae= flattened, fluid-filled tubules
- Rough ER- protein synthesis and sorting, has ribosomes so it is more bumpy shape
- protein synthesis- ribosomes are the site of protein synthesis. So making protein and sorting. You have a gene that has directions to make a protein and in protein you have to make sure it knows where its going in order to function, either inside or outside the cell
- Smooth ER- detoxifying, carbohydrate metabolism, calcium balance, lipid synthesis and modification
- bunch of flattened structures surrounded by membranes, each is called a cisternae
- inside filled with liquid
34
Golgi Apparatus/Body/Complex
- stack or flattened compartments
- vesicles transport materials between stacks
- secretion, processing and protein sorting
- detached from the rest
- farther away from the nucleus
once you've made some proteins and they've synthesized in the ER whatever material that needs to be managed go to the Golgi
-it decides what is being secreted out of the cell (exported), processing (stable) and protein sorting(this is going here and that goes there)
-the Golgi has 2 sides
35
Structure of the Golgi
- Golgi has 2 sides
- the cis side and the trans side
- cis is on the same side
- trans is on the opposite side
- cis is relative to the nucleus and ER
- Trans faces to the plasma membrane and to the ER then to the nucleus
- when they go from the ER to the Golgi, they hit the cis phase and get processed in the flattened area and then if its exported out of the cell it gets pinched off all the vesicles and to the trans side
36
Lysosomes
- contain acid hydrolases
- hydrolysis
- many types to break down different macromolecules
- Autophagy
- Recycling worn-out organelles
- some organelles like mitochondria is now old and worn out, what you can do is take the old mitochondria and break it down to its building blocks, and use those building blocks to make something new within the cell
- breaking a lot of things up
- a lot of things go under catabolism or catabolic reactions, large molecules being broken to a bunch of small molecules
- Autophagy is an enzyme
37
Vacuoles
- varied functions
- depending on cell type and environmental condtions
- central vacuole in plants
- support and storage
- in plants it takes up a bulk of space in cells and stores nutrients in the space and puts pressure in the cell wall and allows it to stand up right
- contractile vacuole in protists (use them to move by contracting them and use them to squirt)
- expelling water
- phagocytic vacuole in protists and WBC'S
- degradation
- part of their job is too recognize antigens or pathogens and destroy them
- digest bacterial phage
- move between different parts of the endomembrane system
- they are bigger and used for storage within the cell
- what they do depends on cell type
- example: these are big in plant cells because they hold a bunch of water
38
Central Vacuoles in Plants
- used to squirt water in them
- use them as motility function
- in WBC and part of their job is too recognize antigens or pathogens and destroy them
- Phagocytosis is when a cell engulfs something and spits it out
- takes up a lot of space
- if you don't water plants they die, this process the structural support of water for plants
39
Peroxisomes
- catalyze breakdown of moelcules
- by removing an H or adding an O
- H2O2= byproduct
- catalase breaks down H2O2 into water and oxygen
- similar to lysosomes necause they alos break things up
- they use hydrogen peroxide as a byproduct
- catalyze takes the hydrogen peroxide that is produced and basically breaks it down to water and oxygen
- another organelle that breaks down molecules that does it in a very specific way that in such a way you end with hydrogen peroxide as a byproduct
40
Synthesis of Peroxisomes
1. vesicles bud from the ER and fuse with each other to form a premature peroxisome
2. the import of additional proteins and lipids results in a mature peroxisome
3. mature peroxisomes may divide to produce more peroxisomes
- they bud off of the smooth ER
- the little vesicles are filled with all types of chemicals
- once it is a mature peroxisome, they can break down and detoxify things
- derived from the smooth ER
41
Plasma Membrane
- Boundary between cell and environment
- functions:
1. membrane transport
- gate keeper, decides what gets in the cell and what gets out
2. cell signaling (receptors)
- they have to be coordinated with one another, in the PM you have a phospholipid bilayer and all different proteins embedded, some proteins have carbohydrate chains that stick out to outside environment and these chains act as a chemical receptors, come in and bing the chain and start a whole chain reaction in the cell just from that signal to the cell
3. cell adhesion
- cells sticking together, multicellular organisms is how their cells stay together
42
Function of the Plasma Membrane: Cell adhesion
proteins in the plasma membrane of adjacent cells hold the cells together
-2 proteins sticking together
43
Function of the Plasma Membrane: Membrane transport
proteins in the plasma membrane allow the transport of substances into and out of cells
- glucose moves across a protein and into the cell
44
Function of the Plasma Membrane: Cell signaling
an extracellular signal binds to a receptor in the plasma membrane that activates a signal transduction pathway, leading to a cellular response
-chemical messenger coming and binding to a receptor outside of the cell setting this whole signal transduction pathway so cell can respond
45
Semiautonomous Orangelles
- Mitochondria and Chloroplasts
- grow, divide and reproduce
- not entirely autonomous
- internal component synthesis
- a little self sufficient
- some ways they operate on own
46
Mitochondria
- Main job= ATP production
- also:builds, modifies, breaks down other molecules
- double membrane
- intermembrane space, mitochondrial matrix
- own DNA and binary fission
- Binary fission is taking a pure genome and splitting it into two, a cell making a copy of itself
-power house
-it makes ATP which is energy
- metabolism- build things
-outer membrane and inner membrane - makes a lot of folds
- the space between the two is called the inner membrane space
- very inside of the matrix is filled with a liquid
-Cristae is the foldings**
0they contain their own genome- DNA inside of the nucleus and you have the mitochondrial DNA, reproduces and makes more copies of itself by binary fission
47
Chloroplasts
- Photosynthesis
- how plant makes its own organic matter, take carbon dioxide and use it to make their own carbohydrates
- plants do this, algae and certain bacteria
- Outer & inner membrane
- intermembrane space
- thylakoid membrane
- stacks of the "coins" are called thylakoids and space in between
- own DNA, use binary fission
- how it reproduces
48
Thylakoid
- has an inner and outer membrane
- each individual disc is a thylakoid membrane and collectively the stack is called a granum
- granum is made of a bunch of thylakoids stacked on top of each other
- thylakoid lumen- a liquid space in side the thylakoid
- stroma- all of the liquid space inside the membrane and outside the thylakoid
49
Endosymbiotic Theory
- Mitochondria and Chloroplasts in eukaryotes originated from endosymbiotic bacteria
- Symbiosis: 2 species live in contact with each other
- Story of how Mitochondria and Chloroplast came to be
- big idea, they are the descendants of bacteria
- what happened was that bacteria was engulfed by larger eukaryotic cells, and usually when this happens the larger cell eats the bacteria or it breaks it down
- but in this case we have larger cells engulfing bacterial cells and bacterial cells are worth more alive then dead
- instead of digesting them and using them for food and energy, they kept the bacterial cell
- endosymbiotic- you have one organism living in another, a lot is in our gut
50
Theory of Endosymbiosis
- theory- it is a theory that puts forward that our M and C are derived from ancestral bacteria
- old cells the ancestral ones do not have a M or C, these came along later in evolutionary time
- this eukaryotic cell has everything including a nucleus but it does not have a M or C
- we have an engulfment event:the large eukaryotic cell engulfs the small aerobic bacteria (oxygen for metabolism) so this is a case where instead of engulfing and digesting the aerobic bacteria, bacteria survive within the cell
- we get to the point where it is not one individual living within another, the relationship evolved that the M is not part of the cell and C comes later
51
Support for Endosymbiotic Theory
- Mitochondria and Chloroplast
- size
- double membrane
- first layer is PM second layer is when they get engulfed and get surrounded by the host membrane
- genes- circular DNA
- replication- make copies of themslevs
52
Plant Cell: Chloroplast
site of photosynthesis
BIO 111
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