Cells and Cell Processes

Topics:

B. Cells (10%)

  1. Prokaryotic and eukaryotic cells
  2. Membranes
  3. Subcellular organization
  4. Cell cycle and its regulation

C. Cellular Energetics (8%)

  1. Coupled reactions
  2. Fermentation and cellular respiration
  3. Photosynthesis

RP. There are two different types of cells. They are Prokaryotic and Eukaryotic. The chart below details the differences between them. Although it might seem like common sense by this point, it can't hurt to review! JFM. Congratulations to our first contributor!!!

compare.gif
http://click4biology.info/c4b/2/cell2.3.htm


JFMcL. Mitosis and meiosis are frequently confused. Here is a table that compares the two processes.


Comparison chart


Meiosis
Mitosis
Occurrence of Crossing Over:
Yes
No
Occurs in:
Humans, animals, plants, fungi
all organisms
Number of Daughter Cells produced:
4
2
Creates:
Sex cells only: Female egg cells or Male sperm cells
Makes everything other than sex cells
Definition:
A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell.
A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell
Produces:
four haploid daughter cells
two diploid daughter cells
Steps:
The of meiosis are Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II.
The steps of mitosis are Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis
Discovered by:
Oscar Hertwig
Walther Flemming
Type of Reproduction:
Sexual
Asexual
Genetically:
different
identical
Cytokenesis:
Occurs in Telophase I & Telohpase II
Occurs in Telophase
Number of Divisions:
2
1
Pairing of Homologues:
Yes
No
Function:
sexual reproduction
Cellular Reproduction & general growth and repair of the body
Chromosome Number:
Reduced by half
Remains the same
Karyokenesis:
Occurs in Interphase I
Occurs in Interphase
Crossing Over:
Mixing of chromosomes
Does not occur
Centromeres Split:
The centromeres do not separate during anaphase I, but during anaphase II
The centromeres split during Anaphase
http://www.diffen.com/difference/Meiosis_vs_Mitosis

MAP
I found this animation which does a good job in visualizing the differences between mitosis and meiosis
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__comparison_of_meiosis_and_mitosis__quiz_1_.html

BEG
Meiosis
When reviewing I realized I wasn't too sure on the differences between meiosis 1 and 2. I like this video because I find it more helpful to see visual breakdown of meiosis.
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter3/animation__how_meiosis_works.html

SMM.
Endosymbiotic Theory
  • Theory that a prokaryote ingested an aerobic bacterium, and over time the bacterium became a mitochondrion, no longer able to live on its own
  • Some prokaryotes ingested cyanobacteria (photosynthetic), which became chloroplasts
  • Lynn Margulis proposed the theory
Evidence for the Endosymbiotic Theory
both mitochondria, chloroplasts, and bacteria
  • are membrane-bound, have freeribosomes
  • have similar DNA structure, sequences & processing
  • have same mode of reproduction: binary fission

I chose this topic because I couldn't remember all of the pieces of evidence, and the endosymbiotic theory is an important concept to understand, especially because of its relationship to evolution.

JFMcL. I thought it was really important to review too! Check out the video on the evolution page.


EJG
Photosynthesis:
Here's a quick interactive summary of the light vs. dark reactions of photosynthesis. I chose this topic since, for me, the difference between the two is a little fuzzy. Just click the link below! P.s., sorry the font it a little hard to read ):

http://www.wiziq.com/tutorial/6486-Light-and-Dark-reactions-in-photosynthesis

Here's a video of the Calvin cycle too! I really hope this works! If not, here's the link: http://www.youtube.com/watch?v=slm6D2VEXYs

And here's C-4 Photosynthesis! Just throwing this out there. I think this is really great to watch to review. This guy is great! Link just in case: http://www.youtube.com/watch?v=7ynX_F-SwNY&feature=relmfu


EJG
... Just one more on photosynthesis!
CAM plants
I personally need a review on this topic. I think it plays into the anatomy and adaptations of plants, as well as evolutionary advantages.


The link: http://www.youtube.com/watch?v=xp6Zj24h8uA&list=PL7A9646BC5110CF64&index=34&feature=plpp_video

EJG
Electron transport chain!
This video thoroughly explains how ADP changes to ATP via the electron transport chain and ATP synthase. This is a great review for the really specific details. This doesn't talk much about glycolysis or the Krebs cycle, it just skips ahead to the final stages of cellular respiration.



Link: http://www.youtube.com/watch?v=mfgCcFXUZRk&list=PL7A9646BC5110CF64&index=26&feature=plpp_video

JFM. Excellent videos!!! Too bad we can't show them at SHS!! But Youtube certainly has some real gems!

RP. One concept regarding plants I knew of but never fully understood was the concept of Photorespiration. This video does a good job in explaining it and its effects on the plant!
http://www.youtube.com/watch?v=EQvTEFCANTM

LJ: This website helps clarify the different types of cellular respiration (C3, C4, CAM) and it explains photorespiration well.
http://hyperphysics.phy-astr.gsu.edu/hbase/biology/phoc.html


Cell Division Overview

There are Six Phases: Prophase, Prometaphase, Metaphase, Anaphase, Telophase, and Cytokinesis

Prophase- This is when the chromatin condense into a form we know as chromosomes. The, the nuclear envelop will begin to break down to allow the chromosomes to enter the cytoplasm.

Prometaphase- It is during this phase when microtubules from the nucleus take the place of where the nucleus was located. Also, each chromosome will form two kinetochores at the centromere where one is attached to each chromatid.

Metaphase- During this phase, the chromosome will line up in the center of the cell while centrosomes align at opposite ends of the dividing cell. The centrosomes will then begin to pull apart some of the chromosomes into halves.

external image img012.gif

Anaphase- Anaphase is the phase where polar microtubules elongate and pull the daughter chromosomes to each end of the cell where there is a centromere. This phase concludes when there are two distinct groups of daughter chromosomes at opposite ends of the cell.

Telophase and Cytokinesis- After all of the chromosomes are grouped together, two new nuclear envelopes begin to develop around the new sets of chromosomes using the remains from the parent cell‘s nucleus. Once the new nuclei are completely formed, the two new sets of chromosomes condense back into chromatin. Now, they undergo DNA replication to replenish the other portion of the double helix that was lost during mitosis. The process of Cytokinesis takes care of the division of the cytoplasm. During this process, all of the other organelles are divided and placed into the new daughter cells. This process concludes the process of Cell Division.

external image 350px-Major_events_in_mitosis.svg.png

-MSL

MAP
It's important to know the differences and properties of each of these transport mechanisms across a cell membrane. This is a topic i always get confused with.
Diffusion
  • Is the random movement of molecules of any substance from an area of higher concentration of those molecules to an area of lower concentration
  • Any substance will diffuse down its concentration gradient
Passive transport
  • is the diffusion of a substance across a biological membrane from where it is more concentrated to where it is less concentrated
  • hydrocarbons, carbon dioxide and oxygen are hydrophobic substances that can pass easily across the cell membrane by passive diffusion
  • requires no energy
*Osmosis
  • the diffusion of water across a selectively permeable membrane
  • water diffuses across the membrane from the region of lower solute concentration ( that of a higher water potential) to that of a higher solute concentration (that of a lower water potential) until the solute concentrations on both sided of the membrane are equal
Facilitated diffusion
  • is the process by which ions and hydrophilic substances diffuse across the cell membrane with the help of transport proteins
  • transport proteins are specific for what they transport
  • does not reguire energy
Active transport
  • process by which substances are moved against their concentration gradient – from the side where they are less concentrated to the side where they are more concentrated (analogous to a pump moving water uphill)
  • this type of transport requires energyusually in the form of ATP
  • enables a cell to maintain internal concentrations of small solutes that differ from concentrations in its environment
  • this is how most molecules move across
  • *Example the sodium-potassium pump. A transmembrane protein pumps sodium out of the cell and potassium into the cell. *This is necessary for proper nerve transmission which we learned back in systems of the body*
*A cell has one of three water relationships with the environment around it
v In an isotonic solution there will be no net movement of water across the plasma membrane. Water crosses the plasma membrane at the same rate in both directions.
v In a hypertonic solution the cell will lose water to its surroundings due to higher concentrations of solutes outside the cell. (the hypertonic substance has a higher concentration of solute)
v In a hypotonic solution water will enter the cell because there are fewer solutes in the water surrounding the cell. ( the hypotonic substance has a lower concentration of solute)
The solution with more solute is hypertonic to the one with less solute and the solution with less solute is hypotonic to the one containing more solute.

Bulk transport (movement of large molecules) across the plasma membrane occurs by exocytosis and endocytosis
  • exocytosis: vesicles from the cell's interior fuse with the cell membrane, expelling their contents
  • endocytosis: cells form new vesicles from the plasma membrane allowing the cell to take in macromolecules.
  • Types of endocytosis:
1. phagocytosis: "cellular eating" cell wraps pseudopodia around a solid particle and brings it into cell
2 . pinocytosis: "cellular drinking" cell takes in small droplets of extracellular fluid within small vesicles
this is a combination of my own summary and parts from the reveiw book

ABM
A thing that confused me when reviewing cell signaling were the three types of membrane receptors.
1.) G-protein-coupled receptor: The signaling molecule binds to the G-protein coupled receptor and causes a change in the receptor so it is able to bind to an inactive G protein. This causes a GTP to replace a GDP which activates a G protein. The G protein can then bind to a specific enzyme and activate it and begins further works towards a specific cellular response.
external image gprotein.jpg
2.) Receptor tyrosine kinase: A signal molecule binds to the receptors and a dimer forms, where each tyrosine kinase adds a phosphate from an ATP molecule. It is then initiates a unique cellular response for each phosphorylated tyrosine. The major difference between these and g protein coupled receptors is that tyrosine kinases can activate several cellular responses.
external image Receptor-tyrosine-kinase-pic.gif
3.) Ligand-gated ion channels: Are in the membrane and signal molecules cause them to open or close which regulates the flow of specific ions.

external image img009.GIF

WJH
It can often be confusing when trying to remember the structure and functions of every type of organelle. This chart does a good job of summarizing them.

For me, the easiest way to study these is by using flashcards.
http://quizlet.com/7405630/ap-biology-cell-organelles-flash-cards/
There are some pretty good ones there, but I think you probably learn better by making your own. You can also search through Quizlet for a set of flashcards that work better for you.
http://www.uic.edu/classes/bios/bios100/lectures/07_table_2_cell_component-L.jpg
http://www.uic.edu/classes/bios/bios100/lectures/07_table_2_cell_component-L.jpg

JFMcL. I like this chart because it also emphasizes the differences in the membranes that surround organelles. It is a good reminder of the connection between structure and function. Why are the membranes different?
VBG:
While i was looking through the chapter on cells, I realized i didn't understand what phosphorylation cascade was..

Signal transduction pathways often involve a phosphorylation cascade.
Because the pathway is usually a multi-step one, the possibility of greatly
amplifying the signal exists. At each step enzymes called protein kinases
phosphorylate and thereby activate many proteins at the next level. This
cascade of phosphorylation greatly enhances the signal, allowing for a signal,
allowing for a large cellular response.

external image c11x11enzyme-cascade.jpg

MAP
This website really helped me in understanding cellular respiration. Its good for review
http://www.phschool.com/science/biology_place/biocoach/cellresp/intro.html




~ JM
Eukaryotic Cell

external image 350px-Plant_cell_structure_svg.svg.png
Prokaryotic Cell

external image 300px-Average_prokaryote_cell-_en.svg.png

RMG
So i looked at the little outline at the top and didnt remember what coupled reactions meant, so i looked it up and came up with this (feel free to help expand on this)...
Coupled Reactions: Energy transfer from one molecule to another
different types:
-exergonic reaction: reaction releases energy
-endergonic reaction: reaction requires energy
-coupled bioenergetic reaction: the energy released by the exergonic reaction is used to power the endergonic reaction.
this is different than
Coupled Pathways: the energy transfer from one metabolic pathway to another by means of ATP
different types:
- catabolic pathway (catabolism): breaking down of macromolecules, releases energy which may be used to produce ATP
- anabolic pathway (anabolism): building up of macromolecules, requires energy from ATP
-metabolism: the balance of catabolism and anabolism in the body
JFMcL. Good topic to review! It is commonly misunderstood.

TMH
I've always got cilia and flagella mixed up, so this chart helps a lot

Comparison chart


Cilia
Flagella
Length:
Short
Longer than cilia
Density:
Many (hundreds) per cell
Few (less than 10) per cell
Motion:
Wave-like, undulating, sinosoidal
Rotational, like a motor
Found in:
Eukaryotic cells
Eukaryotic and prokaryotic cells
Etymology:
Pronounced as ‘silly-ah’, is the plural of cilium. From Latin word for eyelash.
Pronounced as ‘fla-gel-ah’, is the plural of flagellum. From Latin word for whip.
Definition:
Cilia are hair like appendages extending from the surface of a living cell.
Flagella are long, threadlike appendages on the surface of a living cell.

EGR
I have found as we worked more on the cell processes, I am having a tough time remembering the products of the steps and the locations of cell respiration. This chart helped me to organize my thoughts.
external image 9.gif

It is also important to remember where these steps occur:
1. Glycolysis - cytoplasm of cell
2. Citric acid cycle - mitochondrial matrix
3. Chemiosmosis and electron transport chain - inner membrane of the mitochondria

Produces cell’s ATP
-3 steps – glycolysis (2 ATP) (anaerobic), citric acid cycle (2 ATP) (releases carbon dioxide), electron transport chain (32 ATP)
- Happens when sugar’s/glucose’s carbon bonds are broken down and energy from said carbon bonds is stored as an ATP (hi-energy phosphoric bond); after this, ATP leaves the mitochondria to be used elsewhere in the cell
- Each reaction requires specific enzymes; no reaction occurs unless the enzyme is present
- Glucose more common respiration/energy source; however, other molecules can be used for same means: other carbohydrates, proteins, lipids




KGT
Here's a chart I found that compares plant and animal cells. I found it easier to remember the differences and similarities when I could see them listed out in a chart.
Animal Cell
Plant Cell
Plasma Membrane:
only cell membrane
cell wall and a cell membrane
Microtubules/ Microfilaments:
Present
Present
Flagella:
May be found in some cells
May be found in some cells
Lysosomes:
Lysosomes occur in cytoplasm.
Lysosomes usually not evident.
Nucleus:
Present
Present
Cilia:
Present
It is very rare
Shape:
Round (irregular shape)
Rectangular (fixed shape)
Chloroplast:
Animal cells don't have chloroplasts
Plant cells have chloroplasts because they make their own food
Cytoplasm:
Present
Present
Endoplasmic Reticulum (Smooth and Rough):
Present
Present
Ribosomes:
Present
Present
Mitochondria:
Present
Present
Vacuole:
One or more small vacuoles (much smaller than plant cells).
One, large central vacuole taking up 90% of cell volume.
Centrioles:
Present in all animal cells
Only present in lower plant forms.
Plastids:
Absent
Present
Golgi Apparatus:
Present
Present
Cell wall:
Absent
Present
JFMcL. Now try your hand at labelling the diagrams!
external image blank.cell.diagram.bmp
EGR
I found the following website, and I think that it does a really good job of explaining different types of transport through cell membranes. Active, passive, and other forms of transports can seem confusing because they all sound similar, but the diagrams on this site seemed to make it clearer for me.


http://www.emc.maricopa.edu/faculty/farabee/biobk/biobooktransp.html
external image pastrans.gif
external image actrans2.gif

The information regarding the symport, antiport, and uniport is not essential for our understandings, but I thought that the diagrams were helpful.


MAP

Chemiosmosis is an energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work (generating ATP). During chemiosmosis and electron transport chain assembled in a membrane pumps protons across the membrane as electrons are passed through a series of carriers in the electron transport chain. Built into the same membrane is an ATP synthase complex. The movement of the protons down the electrochemical gradient as they pass through the ATP synthase complex provides the energy by which ATP is regenerated from ADP and phosphate.

Chemiosmosis takes place in both mitochondria and chloroplasts.

  • They both generate ATP by chemiosmosis
  • In both organelles, electron transport chains pump protons (H+) across a membrane from a region of low H+ concentration to one of high H+ concentration
  • Both move H+ from the liquid (stroma and matrix) to a membrane enclosed space
  • The protons then diffuse back across a membrane through ATP synthase, driving the synthesis of ATP
  • Some of the electron carriers, including cytochromes, are very similar in chloroplasts and mitochondria
  • The ATP synthase complexes of the two are also very similar



chem.jpg
http://bio1151.nicerweb.com/Locked/media/ch10/10_16ChemiosmosisCompared_L.jpg

However, there are key differences in this process between these organelles. Here is a chart comparing them both:

Chemiosmosis in Mitochondria (oxidative phosphorylation)
Chemiosmosis in Chloroplasts (photophosphorylation)
Source of electrons:extracted from organic molecules which are oxidized
Source of electrons:water molecules
Use chemiosmosis to transfer chemical energy from food molecules to ATP (uses energy stored in NADH or FADH2)
Do not need molecules from food to make ATP, their photosystems capture light energy and use it to drive the electrons from water to the top of the transport chain
Chloroplasts transform light energy into chemical energy in ATP (uses light energy)
The inner membrane of the mitochondria pumps protons from the mitochondrial matrix out to the intermembrane space, which then serves as a reservoir of hydrogen ions
Protons diffuse down their concentration gradient from the intermembrane space through ATP synthase to the matrix, driving ATP synthase
The thylakoid membrane of chloroplasts pumps protons from the stroma into the thylakoid spacewhich functions as the H+ reservoir
ATP is synthesized as the hydrogen ions diffuse from the thylakoid space back to the stroma through ATP synthase complexes. Thus ATP is formed in the stroma, where it is used to help drive sugar synthesis during the Calvin Cycle



Chloroplast

chemi.jpg

http://fhs-bio-wiki.pbworks.com/f/1257722651/aaaaaaaaaaa.jpg

Mitochondria

chemios.jpg

http://www.nicerweb.com/bio1151/Locked/media/ch09/09_15Chemiosmosis.jpg
this is a summary i did with most of the info coming from the book

SRF
Anaerobic respiration: Alcohol Fermentation-
5.jpg
Lactic acid fermentation-
6.jpg


BEG
  • The Krebs cycle is a series of steps (chemical reactions) that occurs in a mitochondrion.
  • The Krebs cycle begins with the entry of a 2-carbon molecule that gets delivered by acetyl CoA. The 2-carbon molecule bonds with a 4-carbon molecule forming citrate, a 6-carbon molecule. Citrate is converted (by a series of reactions) back to the 4-carbon molecule (thus it’s a cycle).
  • CO2 is removed in two of the reactions (decarboxylations).
  • ATP is produced directly in one of the reactions (substrate-level phosphorylation)
  • Hydrogen is removed in four of the reactions (oxidations).
  • For each glucose molecule (at the start of glycolysis) there will be two turns of the Krebs cycle.
  • The two turns of the cycle produce 4 CO2, 6 NADH + H+, 2 FADH2 and 2 ATP.
external image GW474H328
CCB
I thought I would post about the components of the cell membrane and its function because this is extremely important to understanding cell function and many processes that occur at a cellular level
This is the Fluid-mosaic model of the cell membrane:
877px-Cell_membrane_detailed_diagram_en_svg.png
The phospholipids are arranged in a bilayer, with their polar, hydrophilic phosphate heads facing outwards, and their non-polar, hydrophobic fatty acid tails facing each other in the middle of the bilayer. This hydrophobic layer acts as a barrier to all but the smallest molecules, effectively isolating the two sides of the membrane. This makes the membrane semipermeable. Different kinds of membranes contain phospholipids with different fatty acids, which affects the strength and flexibility of the membrane, and animal cell membranes also contain cholesterol linking the fatty acids together which stabilizes and strengthens the membrane.
The proteins can go from one side of the phospholipid bilayer to the other (integral proteins), but can also sit on the surfaces (peripheral proteins). They can slide around the membrane very quickly and collide with each other, but can never flip from one side to the other. The proteins have hydrophilic amino acids in contact with the water on the outside of membranes, and hydrophobic amino acids in contact with the fatty chains inside the membrane. Proteins comprise about 50% of the mass of membranes, and are responsible for most of the membrane's properties.
  • Proteins that span the membrane are usually involved in transporting substances across the membrane
  • Proteins on the inside surface of cell membranes are often attached to the cytoskeleton and are involved in maintaining the cell's shape, or in cell movement. They may also be enzymes, which catalyze reactions in the cytoplasm.
  • Proteins on the outside surface of cell membranes can act as receptors by having a specific binding site where hormones or other chemicals can bind. This binding then triggers other events in the cell. They may also be involved in cell signalling and cell recognition, or they may be enzymes, such as maltase in the small intestine (more in digestion).
The carbohydrates are found on the outer surface of all eukaryotic cell membranes, and are attached to the membrane proteins or sometimes to the phospholipids. Proteins with carbohydrates attached are called glycoproteins, while phospholipids with carbohydrates attached are called glycolipids. The carbohydrates are short polysaccharides composed of a variety of different monosaccharides, and form a cell coat or glycocalyx outside the cell membrane. The glycocalyx is involved in protection and cell recognition, and antigens such as the ABO antigens on blood cells are usually cell-surface glycoproteins.
Paraphrased from this:
http://www.biologymad.com/cells/cellmembrane.htm

CCA
I understand the cell cycle, but regulation of it really slips me up! This post is specifically about the specific proteins that go along with the regulation of the cell cycle.

Constant reproduction without cause would be biologically wasteful, which is why the cell cycle needs regulation. Internal regulation of the cell cycle is necessary to signal passage from one phase to the next at appropriate times. This regulation is not achieved through strict time constraints, but rather with feedback from the cell. Proteins use cues from the cell's environment to trigger the entry to and exit from the distinct phases of the cell cycle.

Cyclin-Dependent Protein Kinase (Cdks)

A Cdks is an enzyme that adds negatively charged phosphate groups to other molecules in a process called phosphorylation. Through phosphorylation, Cdks signal the cell that it is ready to pass into the next stage of the cell cycle. As their name suggests, Cyclin-Dependent Protein Kinases are dependent on cyclins, another class of regulatory proteins. Cyclins bind to Cdks, activating the Cdks to phosphorylate other molecules.

Cyclins

Cyclins are named such because they undergo a constant cycle of synthesis and degradation during cell division. When cyclins are synthesized, they act as an activating protein and bind to Cdks forming a cyclin-Cdk complex. This complex then acts as a signal to the cell to pass to the next cell cycle phase. Eventually, the cyclin degrades, deactivating the Cdk, thus signaling exit from a particular phase. There are two classes of cyclins: mitotic cyclins and G1 cyclins.

The cell stops dividing if it receives signals from density dependent inhibition, which is when cells become crowded and stop dividing. They also stop dividing is there is no anchor. Anchorage dependency is when normal cells are attached to an anchor to divide.

info from the review book and http://www.sparknotes.com/biology/cellreproduction/cellcycle/section3.rhtml

TWK
Fermentation pathways
Lactic Acid and Alcoholic fermentation. Lactic acid fermentation is the result of depleted oxygen supplies in muscle cells. It is caused by the pyruvic acid formed during glycolysis being reduced by NADH. This allows glycolysis to continue because NADH is oxidized to NAD. Alcoholic fermentation usually occurs in yeast cells. This is the process by which pyruvic acid looses a carbon, forming acetaldehyde. Acetaldehyde is then reduced by NADH forming ethyl alcohol. This process also oxidizes NADH which form NAD, allowing glycoloysis to continue. The link below has a good visual animation of the process.
http://www.phschool.com/science/biology_place/biocoach/cellresp/review5.html





As I was reviewing, I came across the need to review the similarities and differences between Photosynthesis and Cellular Respiration. Here is a chart that compares the two processes:

Fact/ Cellular Respiration/ Photosynthesis

Occurs where? Cytoplasm/Mitochondria Chloroplasts
Energy Source R:Glucose P:Sunlight
Does what? R: Strips H+ and e- from glucose to release energy P: Adds H+ and e- to sunlight to form energy
Role of O2? R: Final acceptor in ETC to form H2O P: Waste product from splitting H2O
Role of CO2? R: Waste Product P: Used to build glucose using H+ and O2(H+ from water and O2 from CO2)
Role of H2O? R: Waste product after ETC P: Replace e- in PS(2) and H+ in ETC, NADPH
Role of C6H12O6? R: Broken down to make ATP P: Formed from light, CO2, and H+ from H2O
Location and function of ETC? R: At end; make ATP P: Between PS(1) and PS(2); Make ATPfor Calvin Cycle
Source of H+ for ETC pumps? R: Glucose P: Water
Location of Proton Gradient? R: Inner Membrane Space P: Thylakoid Membrane Space

Hope this helps :)
had this all organized in columns but the default format made it bunch together. Tried to clean it up.

-MSL
CCB

For me, cell communication and cell signaling was extremely confusing. The part that sticks out to me most is signal-receptor proteins in cell membranes.

This website:http://www.mansfield.osu.edu/~sabedon/campbl11.htm has an excellent and detailed review of the entire cell communication chapter if it is a weak spot for you, and I will summarize the different signal receptors here

G-Protein Linked Receptors:
gprotein02.jpg

G proteins are signal-transduction pathways that are in an active state when they are bound to a molecule of GTP.

The G protein interacts with the receptor on the receptor's cytoplasmic side, and conformational changes in the receptor (induced by ligand attachment) results in the activation of the G protein. The G protein diffuses to and then activates a subsequent protein in the signal-transduction pathways (or the protein that is directly responsible for the response) by binding to that protein while in its own (the G protein's) active state. Subsequently, the G protein hydrolizes the GTP (to GDP) which inactivates the G protein and whatever the active G protein had activated (these activation-after-activation-after-activation pathways can get complicated). The important function of G protein inactivation is that they allow a reversibility to the G protein mediated activation of a protein, thus contributing to the dynamic nature of a cell

Tyrosine-Kinase Receptors

10.png11.png

Rather than activating G proteins following their conformational change (that follows ligand binding), tyrosine kinase receptors instead activate their own enzymatic activity, the tyrosine kinase activity and then phosphorylate themselves--the phosphorylated receptor is then recognized by cytoplasmic proteins which effect the transduction event through the cytoplasm. Part of the process of activation of tyrosine kinase activity involves a dimerization (linking together of two subunits) of the tyrosine kinase. Individual tyrosine kinase receptors are often capable of directly activating multiple transduction pathways.

Ion-gated Channel
11_07cIonChannelReceptors.jpg
With ion-channel receptors, the molecules responsible for transduction are ions (e.g., Na+ or Ca2+) that are normally found outside of cells. Here binding of a ligand to the receptor (no, the external ions themselves are not the ligands) results in an opening of a gate through the plasma membrane that allows entrance of the ions (both gate and receptor are proteins, likely one in the same protein). The increased ion concentration in the cytoplasm either propagates signal transduction or results in a direct stimulation of a response.

Really look over the diagrams and check out that website!

Chart Encompassing Glycolysis, Krebs Cycle, Oxidative Phosphorylation


This is a chart I found on a document that had automatically downloaded to my computer. I dont know how to cite it, but its nice to see and compare the different locations, functions, requirements, and products. Happy Studying!
-WMWoods

Location
Function
Requirements
Products
Glycolysis
Cytoplasm
Split Glucose
Produce ATP
NADH
Glucose, 2 ATP,
4 ADP + Pi, 2 NAD+
2 Pyruvate
2 ADP + Pi
4 ATP
2 NADH
Krebs Cycle
Matrix
Produce NADH
and FADH2
Pyruvate, 2 ADP + Pi
8 NAD+, 2 FAD+
6 CO2, 2 ATP
8 NADH,
2 FADH2
Oxidative Phosphorylation
Cristae
Cash in NADH and
FADH2 to produce ATP
NADH, FADH2
ADP + Pi, O2
NAD+, FAD
ATP, H2O
MFT

Sorry if this is late, for some reason I was having trouble getting the page to load on my computer!

In the light reactions of photosynthesis:

There are two photosystems, which are groups of pigment molecules in the thylakoid membrane.
A photosystem has two parts:
1. Light harvesting complex - made up of chlorophyll and cartenoid molecules; chlorophyll absorbs light, causing the electrons to become "excited" (in an orbital of higher potential energy)
2. Reaction center - two chlorophyll a molecules which donate electrons to the primary electron acceptor
This is the first step in the light reactions and the conversion of light to chemical energy = autotrophs

The two photosystems are photosystem I (P700) and photosystem II (P680).
Photosystem II actually acts FIRST
A lot of this information and this diagram are also in the study guide. This diagram was particularly helpful because the steps are numbered.
external image ps1_2.jpg
[SK] Photosynthesis and cellular respiration are obviously very important for the exam and I'm assuming that knowledge of products and the reactants are as well (through each cycle) and the location of each. Knowledge of the photosystems and cyclic and linear are important too, as well as the knowledge of the various organelles and differences between types of organisms (prokaryotic and eukaryotic).


SS

Heres a long list of diseases and such that stems cells can be used to treat.

http://stemcellresearchfacts.squarespace.com/research-critical-need/;jsessionid=3C0FD683D6F8914CAE844285FB482299.web143