Term
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Definition
| It's the theory on the origin of Eukaryotic cells - the theory says that cells ate other cells, but kept them alive, and they eventually evolved into organelles |
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Term
| What does the prefix "Endo-" mean? |
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Definition
| It means living inside of; "endoparasite" lives inside it's host. |
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Term
| What does "symbiosis" mean? |
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Definition
| Like "symbiotic", it means depending on each other, in a way which both organisms benefit. ("win/win" situation) |
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Term
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Definition
| A type of symbiosis where two organisms have a "win-win" situation going where they both benefit |
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Term
| Does endosymbiosis still occur today? |
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Definition
| Yes, it is common in protists |
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Term
| What evidence of endosymbiosis is there? |
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Definition
1) The mitochondria and chloroplasts look a lot like (and are similarly shaped as) free, living, bacteria.
2) Most DNA is in the cell's nucleus, but DNA can be found in organelles as well. That DNA found in organelles is circular, just as DNA in free, living, bacteria.
3. The ribosomes (protein building organelles) in mitochondria and chloroplasts have bacterial-type ribosome.
4. Both these organelles have double membrane, evidence of being eaten. |
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Term
| How do we explain other cellular evolutions if not by endosymbiosis? |
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Definition
| Thought to be results of foldings of the membrane which started to fold and mix into the cell. |
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Term
| Which two organelles do scientists believe to be products of endosymbiosis? |
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Definition
| THe Chloroplasts and Mitochondria |
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Term
| What are the two major (common) ways chemicals can get into or out of cells? |
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Definition
| 1) they can pass through the fatty, phospholipid bylayer, or (2) go through the transport proteins. |
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Term
| What are the 4 mechanisms a chemical can use to cross the cell membrane? |
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Definition
1) Diffussion
2) osmosis
3) facilitated diffusion
4) active transport |
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Term
| What does diffusion mean? |
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Definition
| Chemicals move from areas of high concentration to areas of low concentration. |
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Term
| How do cells make diffusion happen? |
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Definition
| They don't; it's a natural force like gravity and will occur on it's own. |
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Term
| What does "moving with the concentration gradient" mean? |
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Definition
| It means moving from areas of high concentration to low concentration. |
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Term
| What kind of chemicals diffuse into and out of cells? |
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Definition
| Often small chemicals, water, oxygen, carbon dioxide. |
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Term
| What is an example of diffusion? |
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Definition
| When blood cells get to your lungs, they are high in carbon dioxide and low in oxygen. The air you breathe in is high in oxygen and low in carbon dioxide, and so oxygen diffuses from high to low, and your blood cells get recharged with oxygen by diffusion and carbon dioxide will diffuse out of your blood and into your lungs. |
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Term
| What functions of the human body are directly related to diffusion? |
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Definition
| Gas movement and circulation |
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Term
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Definition
| Osmosis is a type of diffusion, where water passes through selectively permeable membranes. All of the things true for diffusion is true for osmosis as well. |
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Term
| What does "isotonic" mean? |
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Definition
| Equal concentrations of solute (disolved stuff)AND equal concentrations of water |
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Term
| What is the theory on the origin of Eurkaryotic cells called? |
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Definition
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Term
| What is the term for when two organisms have a co-dependant "win-win" relationship? |
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Definition
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Term
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Definition
| the higher concentration of solute (stuff disolved in) |
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Term
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Definition
| The lower concentration of solute (disolved stuff) |
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Term
| Something with a lower solute is called... |
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Definition
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Term
| Something with a higher solute is called... |
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Definition
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Term
| Which way does water always diffuse? Why? |
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Definition
| From Hypo- to Hyper-, because it's always moving from the bigger concentration of water to the smaller. The side with less solute by definiton has more water. |
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Term
| Why is it that often times the solute does not move? |
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Definition
| It 'should', but membranes are selectively permeable and therefore may not allow the solute to do so. |
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Term
| Is blood plasma isotonic, hypertonic, or hypotonic? |
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Definition
| Isotonic, meaning it has equal ammounts of water to disolved things. |
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Term
| What would happen if your blood plasma was Hypotonic? |
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Definition
| Hypotonic means it has a low solution of solute, so the blood cells would then be hypertonic. Water always moves from hypo to hyper, so the blood cells would swell and eventually burst (lyse) |
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Term
| What is crenation and when does it occur? |
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Definition
| Crenation is the shriveling up of blood cells and occur if the cell becomes hypotonic. The cell tries to get rid of excess water and shrivels, or becomes crenated. |
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Term
| What is facilitated diffusion? |
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Definition
| Facilitated diffusion is diffusion across a membrane with the help of a transport protein |
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Term
| What kind of chemicals use facilitated diffusion to enter cells? |
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Definition
| Chemicals that cannot cross the phospholipid bylayer. Too large (sugar, proteins) or very strongly charged (sodium, chlorine) |
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Term
| How does a cell start the process of facilitated diffusion? |
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Definition
| It doesn't; it is a passive process wherein small chemicals use a transport protein's tunnel through the membrane to get in or out of a cell. (from high to low concentrations) |
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Term
| How is active transport different from other mechanisms a chemical can use to cross a cell's membrane? |
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Definition
| It is the only way which is active, that doesn't "just happen", and the chemical moves from areas of low concentration to areas of high concentration (against the concentration gradient) |
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Term
| Which mechanism is the only to "move against the concentration gradient"? |
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Definition
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Term
| What is an example of active transport? |
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Definition
| The sodium-potassium pump, one of the first discovered, uses ATP to pump two potassiums in and three sodiums out. |
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Term
| If water is moving via osmosis, how can cells regulate water content? |
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Definition
| Through a combination of osmosis and active transport, cells can alter concentrations to cause osmosis to occur. It could move salt across the cell membrane, thus changing the solute, which, indirectly, changes the water concentration. |
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Term
| If a cell needed to remove excess water, what steps would it take to do so? |
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Definition
1. The cell would start pumping salts out of the cell, to concentrate the salt.
2. The water would leave the cell through osmosis |
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Term
| What is cystic fibrosis and how does it relate? |
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Definition
| Cystic fibrosis is a genetic disease wherein the transport protein used to get salt out of cells (to regulate water content) is formed incorrectly and thus cannot function. Because of this, sufferers of the condition have excess water in their cells and very thick bodily fluids. Since they can't regulate water, or get water into their fluids, they have the thick bodily fluids. The mucus in the lungs is very thick and heavy, it can't be moved up and out, so if bacteria grows, they get respritory infections. Digestion is a problem too, as is reproduction. |
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Term
| What are the two mechanisms for transport of chemicals without crossing the membrane? |
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Definition
| Exocytosis (chemicals "exiting" the cell) and Endocytosis (chemicals entering the cell). |
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Term
| How does exocytosis work? |
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Definition
| Chemicals leaving the cell are wrapped up in a vacuole or membrane sac, made of phospholipid bylayer. That vacuole gets pushed up to the edge of the cell using the cytoskeleton. When the vacuole and cell membrane touch, they combine. The cytoskeleton will pull and open up the bylayer. The contents inside spill outside the cell, but never went through the membrane. |
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Term
| How does endocytosis work? |
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Definition
| The cell forms a dimple, and when the chemical bounces into the dimple, the cytoskeleton will pinch the dimple closed, and pull the chemical inside. |
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Term
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Definition
| A type of endocytosis, when cells are eating large food sources or even anentire cell. |
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Term
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Definition
| Another type of endocytosis, of chemicals, things smaller than food. |
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Term
| What is a drawback of Pinocytosis? |
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Definition
| If there is not very much of the chemical the cell needs, the dimple may come back "empty" |
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Term
| What is Receptor-mediated endocytosis? |
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Definition
| A specialized type of endocytosis. Receptor proteins stick out of the membrane and will bind to the chemical needed. The cell will make a pit but won't pinch off until all the proteins are full. |
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Term
| Why is receptor-mediated endocytosis so important to humans? |
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Definition
| Receptor-mediated cytosis is a mechanism to remove cholesterol-causing LDL's from our blood. If it doesn't work properly, it's linked to many kinds of heart disease, as well as stroke, heart attacks, etc. |
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