Term
| About how old is the earth thought to be? |
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Definition
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Term
| What were some of the charecteristics of early earth when early life was coming to be? |
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Definition
thin crust
reddish atmosphere
no oxygen
relativly shallow seas
atmostphere was made of of N2 CO2 CH4 NH4 and water vapor and sulfer compounds
very hot
lots of geothermic activity |
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Term
When did the first liquid H20 exist?
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Definition
| About 4 billion years ago |
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Term
| When and where did the first origin of life appear |
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Definition
| About 4 and 3.5 bya in hot springs there is evidence of thermophiles who are thought to have lived in hot springs and under sea vents in areas absent of oxygen |
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Term
| What kinds of organic molecules may have been produced in early earth that became the "buildings blocks" of life |
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Definition
amino acids
simple fatty acids
nucleotides
simple sugars |
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Term
| Why is it believed that the building blocks of life were formed in the early atmosphere? |
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Definition
| Miller Urey experiment and others where early atmosphere was simulated showed that amino acids and complex carbon molecules could be formed out of early atmosphere |
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Term
| How were early amino acid chains formed? |
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Definition
Through dehydration reactions
dehydration may have first occured in hot springs, clay, tide cycles, splash zones |
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Term
| What is the definition of life? |
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Definition
Solvent for life is water
It replicates with variability
Metabolism controls over energy and compounds
Internal homeostasis
Disequilibrium with enviroment
Membrane bound |
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Term
| What was the first second and third forms metabolsism |
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Definition
1. Fermentation 4bya
2. Photosynthesis 3.5 bya (with 02)
3. Respiration a little after 2.5 bya |
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Term
| When did cells start using fermentation as metabolsim? |
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Definition
| On the time line, bacteria that existed just a little after the origin of life |
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Term
Who were the first photosynthesizers?
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Definition
- Thick robust fossils
- in these there is evidence of imbalance of carbon isotopes
- Stromatolites fighting for light
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Term
| Why did cells start using respiration as metabolism? |
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Definition
| avoidance of 02 through detoxification |
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Term
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Definition
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Term
| How did cells respond to the appearance of 02 |
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Definition
- avoidance- in anoxic enviroments (swamps etc)
- Some developed respiration to take 02 out of commision
- Set up barriers between themselves and the 02 (membranes)
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Term
| When did first DNA appear? |
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Definition
| 2.5 bya, the nucleus protects DNA |
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Term
| When was the origin of Eukaryotic cells |
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Definition
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Term
| What is the membrane made up of in Eukaryotic cells? |
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Definition
| phospholipids made of a phosphate group with a glycerol and with fatty acid "legs". The phosphate heads are hydrophilic and polar. The tails are non-polar and hydrophobic. |
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Term
| What roll does cholesterol play in phospholipid membrane |
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Definition
| It helps to make it more fluid despite temperatures |
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Term
| What structures are made up of membranes |
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Definition
The endoplasmic reticulum
Structures within ER are
-golgi
-vesicles
lysosomes
-peroxisomes
-nucleus |
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Term
| How is ER thought to have originated |
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Definition
| Through invaginations in the membrane |
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Term
| What are some of the ways that the phospholipids conduct themselves |
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Definition
- once every two weeks one flips from one side to the other
- They move through each other at 1 cm per hour
- All rotate on their long axis
- flex their fatty acid legs
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Term
| What other kinds of stuff is in lipid membrane |
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Definition
| proteins float in bilayer and can be marked with sugar chains forming glyco protiens and sugar chains can be attatched to lipids forming glycolipids. There are also lipoproteins which are proteins bonded to lipids. Sugars act as cell identifiers. |
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Term
| How do molecules move from one side of the membrane to the other |
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Definition
- Osmosis and passive diffusion
- Active transport
- Endocytosis and exocytosis
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Term
| What kind of molecules can passively diffuse? |
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Definition
hydrophobic small molecules (02 N2 and benzene)
uncharged small molecules (H20 Urea and C02)
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Term
How does passive diffusion work?
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Definition
| Does not use ATP. Only uses concentration gradient (molecules tendency to move from area of high concentration to an area of low concentration) |
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Term
| How does active diffusion work? |
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Definition
Transport proteins push things through the membrane against concentration gradient using ATP
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Term
| What kinds of things usually pass through the cell with active diffusion? |
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Definition
Large uncharged molecules
nucleotides
sugar
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Term
| What are leak channels in the cell membrane? |
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Definition
| Proteins that have channels which allow large charged molecules and charged ions to be passed through from high to low concentration gradient without touching hydrophobic area of membrane. |
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Term
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Definition
| The uptake of material into cells by inclusion within an invagination of the plasma membrane; the uptake of solid material is phagocytosis, and that of dissolved material(fluid) is pinocytosis. |
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Term
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Definition
| A type of bulk transport out of cells in which a vacuole fuses with the plasma membrane, discharging the vacuoles contents to the outsides |
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Term
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Definition
- membrane bound digestive vesicles
- they are formed from vesicles that bud from the golgi in eukaryotic cells
- they contain digestive molecules
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Term
| How do lysosomes digest food vesicles or old organelles? |
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Definition
When lysosomes fuses with vesicle containing food, it turns on a proton pump which lowers the pH in the lysosomes and allows for the digestive enzymes to become active. This results in the degradation of the food molecules |
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Term
| How do the enzymes in lysosomes "recycle" stuff? |
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Definition
| It breaks down old organelles and recycling their component molecules, and make room for newly formed organelles. |
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Term
| How does apoptosis happen? |
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Definition
| most commonly a lysosome breaks open and enzymes are set free and can function at the pH within the cell. The enzymes eat everything and the cell dies. an example of this is all animal cells during development use apoptosis to eliminate the cells not destined to be present in the final tissue. |
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Term
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Definition
- a microbody that plays an important roll in the break of highly oxidative hydrogen peroxide by catalase
- They contain digestive and detoxifying enzymes that turn hydrogen peroxide into harmless water and oxygen
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Term
| Why is the nucleus important? |
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Definition
| It protects DNA against 02 |
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Term
| What is the basic structure of the nucleus |
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Definition
| The endoplasmic reticulum folds into two layers forming the double membrane of the nucleus(the nuclear envelope). There are nuclear pores through the membrane where two layers of the nuclear envelope pinch together. Intermediate filaments line the inside of the nuclear membrane (nuclear lamina). Nucleolus:ribosomal subunit manufacturing |
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Term
| WHat is the Golgi Apparatus? |
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Definition
| A collection of flattened stacks of membranes (each called a golgi body) in the cytoplasm of eukaryotic cells, functions in collection, packaging and distribution of molecules (usually proteins) synthesized in cell. |
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Term
| What is the eukaryotic cytoskeleton? |
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Definition
| A network of protein microfilaments and microtubules within the cytoplasm of a eukaryotic cell that maintains the shape of the cell, anchors its organelles, and is involved in animal cell motility. |
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Term
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Definition
| The material within a cell, excluding the nucleus. |
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Term
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Definition
| The fluid portion of the cytoplasm; it contains dissolved organic molecules and ions. |
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Term
| What three types of cytoskeletal fibers are usually part of the cytoskeleton of a eukaryotic cell? |
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Definition
1. Microfilaments (a.k.a actin filaments)
2. Microtubules
3. Intermediate Filaments |
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Term
| What are microfilaments (actin filaments)? |
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Definition
| Long fibers composed of two protein chains loosely twined together (like 2 strands of pearls). Each pearl or subunit is the globular protein actin. Actin molecules spontaneously form these filaments. |
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Term
| How do cells regulate the rate of actin polymerization in microfilaments? |
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Definition
| Through other proteins which act as switches, turning on polymerization movements when appropriate. |
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Term
| What do microfilaments do? |
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Definition
| Microfilaments are responsible for cellular movements such as contraction, crawling, "pinching" during division, and formation of cellular extension. |
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Term
| What is the largest cytoskeletal element? |
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Definition
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Term
| What are microtubules composed of? |
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Definition
| A ring of 13 protein protofilaments. Globular proteins consisting of dimers of α- and β-tubulin subunits polymerize to form 13 protofilaments. The protofilaments are arrayed side by side around a central core, giving the microtubule its characteristic tube shape. |
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Term
| What state are microctubules constantly in? |
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Definition
| They are in a constant state of flux, continually polymerizing and depolymerizing. |
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Term
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Definition
| They facilitate cellular movement, provide organization to the cytoplasm, and are responsible for moving materials within the cell itself. |
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Term
| What protein corresponds to microtubles and motility organelles (cilia, flagella)? |
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Definition
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Term
| What protein corresponds to microfilaments and contractile units? |
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Definition
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Term
| What proteins are associated with microtubules and motility organelles (cilia, flagella)? |
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Definition
| M.A.P.'s (Microtubule associated proteins, all MAP's are ATPases), Dynein, Kinesin |
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Term
| What proteins are associated with microfilaments and contractile units? |
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Definition
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Term
| Why are there two systems for spindle movement, and what are they? |
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Definition
Because more important functions in the cell usually have 2-3 backup systems. Redundancy can be good.
1. Sliding against MAP's (including kinesin) Spagetti
2. Depolymerization or polymerization (is the backup motion) Pacman |
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Term
| What diseases are associated with microtubules? |
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Definition
| Katagener's Syndrome- disease of the cilia, cilia not making dynein effects respiratory system, sperm cells, ovaducts, fallopian tubes |
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Term
| How are microtubules associated with cancer treatment? |
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Definition
| Chemotherapy and radiation poisons mitosis by attacking the spindles with plant toxins. Effects cells in body replicating most quickly (hair, skin, nails) because the microtubules are not working in mitosis. |
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Term
| What is the most durable element of the cytoskeleton in animal cells? |
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Definition
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Term
| What are intermediate filaments? |
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Definition
| Tough, fibrous, protein molecules twined together in an overlapping arrangement. Once formed, intermediate filaments are stable and usually do not break down. |
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Term
| What do intermediate filaments do? |
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Definition
| The impart tremendous mechanical strength to the cell. |
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Term
| What proteins define intermediate filaments? |
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Definition
Lots of proteins do, rather than a specific protein. Some examples
1. Keratin > dead skin cells, fingernails, feathers, scales
2. Lamin > one of the proteins that lines the nucleus
3. Desmin > ZDISCS in muscle cells |
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Term
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Definition
| Are microtubules organizing centers. The region surrounding a pair of centrioles. |
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Term
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Definition
| They occur in pairs, usually located at right angles to each other near the nuclear membrane. The region surrounded the pair is the centrosome. |
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Term
| What structures are all cell motions tied to? |
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Definition
| Movement of actin filaments (microfilaments), microtubules, or both. |
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Term
| What do cilia and flagella do? |
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Definition
| They power external cell movement. They undulate rather than rotate. |
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Term
| What are cilia and flagella made of? |
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Definition
| Bundles of microtubules in a 9+2 array. |
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Term
| How are cilia different than flagella? |
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Definition
| Flagella arise from a basal body (an organelle formed from a centriole). Cilia are shorter and more numerous flagella. |
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Term
| What is the extracellular matrix? |
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Definition
| Various glycoproteins that give the cells support, strength, and resilience. Animal cells are surrounded by it because they lack a cell wall. The cytoskeleton is linked by integrin proteins to the extracellular matrix. |
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Term
| What are the four components of the cell membrane? |
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Definition
1. Phospholipid bilayer- phospholipid molecules
2. Transmembrane proteins- carriers, channels, receptors
3. Interior protein network- Spectrins (determine cell shape), Clathrins (Anchor certain proteins to specific sites)
4. Cell surface markers (Glycoproteins, Glycolipid) |
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