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79 Cards in this Set
- Front
- Back
Cell Theory
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all living things are composed of cells
Addendum: all living cells arise from pre-existing living cells |
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Proteins that span the cell membrane are
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antipathic (hydrophobic & hydrophilic)
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Passive transport
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Depends on moving solutes from high to low concentration (diffusion)
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Simple Diffusion
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small nonpolar molecules that can move freely across the phospholipid bilayer (ex: oxygen, carbon dioxide)
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Facilitated diffusion
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makes use of a protein (think of a tube) embedded through the membrane that solutes (large &/or polar) can pass through
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Active Transport:
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required to move solutes against the concentration gradient (from low to high concentration). Requires energy (in cells, typically means molecule ATP)
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To move lots of solutes at once, the cell uses
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endocytosis to import and exocytosis to export. Both of these take advantage of the fluid nature of the membrane
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Nucleus is surrounded by
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2 membranes (a double membrane – four layers of phospholipids) called the nuclear envelope
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Function of nucleus
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genetic control center of cell, contains genome
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The ER is continuous with
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nuclear envelope
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Shape of ER
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Network of tubes & flattened sacs
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Rough ER
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Region closest to nucleus that is covered with ribosomes, giving it a rough appearance
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Function of Rough ER
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ribosomes (found on RER as well as free in cytoplasm) are molecular machines that make proteins. Site of synthesis (production) of proteins to be shipped to other organelles or other cells.
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Smooth ER
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Region furthest from the nucleus that has smooth appearance (no ribosomes)
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Function of Smooth ER
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site of protein modification and synthesis of new phospholipids, steroids, fatty acids
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Golgi Apparatus is made up of
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flattened stack of membranous sacs (called cristernae) & small membrane bound vesicles
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Function of Golgi Apparatus
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bring materials from the ER and then transport them to their final destination
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Vesicles
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act as cell's shipping containers
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Endomembrane system
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nucleus, ER, Golgi, & vesicles connecting them. Whole production line for genetic control center.
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Lysosomes and peroxisomes are involved in
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cellular digestion
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Mitochondria are
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Surrounded by two membranes: inner and outer
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Inner membrane of mitochondria
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folded extensively. Folds are called cristae. The space inside inner membrane is called the matrix.
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Folds of inner membrane of mitochondria
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cristae
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space inside inner membrane of mitochondria
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matrix
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Function of mitochondria
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powerhouse of cell. take up partially degraded fuel molecules (like sugar) and convert the sugar covalent bond energy into the covalent bonds holding ATP together
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Endosymbiosis
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bacterial origin of mitochondria
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Function of cytoskeleton
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Provide support for the cell, Allows cell to move, Used to move materials within cell
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3 types of cytoskeleton
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microtubules, microfilaments, intermediate filaments
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microtubules are made up of
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protein called tubulin
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microtubules can
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change length by adding or removing tubulin subunits at the end
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microfilaments are made up of
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protein called actin
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function of microfilaments
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stabilize shape of cell (think scaffolding)
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intermediate filaments are only found in
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multicellular organisms
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intermediate filaments are made up of
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keratin fibers
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3 things plant cells have that animal cells don't:
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central vacuole, plastids, cel wall
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function of central vacuole
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storage space for the cell. continually growing
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plastids are
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a family of organelles
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3 types of plastids
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leucoplasts, chromoplasts, chloroplasts
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leucoplasts
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lack pigment & are for storage (starch)
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chromoplasts
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are pigmented so they have color. carotenoids (orange, yellow)
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chloroplasts
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pigmented. chlorophyll (green)
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cell walls are found not only in plants but also
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single celled eukaryotic organisms (yeast)
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cell wall wraps
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around the plasma membrane
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function of cell wall
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protect & physically support the cell
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major component of cell wall
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polysaccharides
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1st law of thermodynamics
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• The Total amount of energy in the universe remains constant.
o Energy is conserved, it can be neither created nor destroyed. It can only be converted form one form to some other form. |
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2nd law of thermodynamics
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• Any organized system tends to become more disorganized over time
o Without the input of energy, entropy (the measure of a system’s disorder) will increase |
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2 sets of chemical reactions in photosynthesis
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light reactions & carbon reactions
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function of light reactions
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convert sunlight, produce ATP & electron carrier NADPH, & split water & release 02
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light reactions produce
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ATP & electron carrier NADPH
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carbon reactions use
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ATP & electrons (in NADPH) & environmental CO2 as a carbon source to produce glucose
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carbon reactions produce
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glucose
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A photosystem is a
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Collection of pigment molecules & proteins anchored together into thylakoid membrane
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Light reactions involve 2 photosystems called:
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I & II
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Photosystem I
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• Absorbs light
• 2 electrons are excited & released • lost electrons are replaced from one’s generated by photosystem II (and are now spent) • Excited electrons are stored in NADPH |
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Photosystem II
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• Absorbs light
• 2 e-‘s are excited & released • excited electrons are passed down and electron transport chain (staircases) to generate ATP • The two lost electrons are replaced by taking them from water. |
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Respiration
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how organisms use sugars for energy as well as oxygen
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Aerobic respiration uses 3 sets of chemical reactions:
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Glycolysis, Krebs cycle, Electron transport chain
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Glycolysis takes place in
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cytoplasm
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Function of glycolysis
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• Breaks glucose (6 C’s) into 2 pyruvate molecules (3 C’s)
In this process it releases ATP & stores electrons in NADH (another electron carrier) |
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Krebs Cycle takes place in
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mitochondria
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What happens in krebs cycle?
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• Pyruvates from glycolysis enter the mitochondria & are further broken down into individual carbons & released as carbon dioxide
During this process, some ATP is produced and more high energy electrons are stored in electron carriers (NADH & FADH2) |
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Electron Transport Chain
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• The high energy electrons stored in NADH & FADH2 are dumped into an electron transport chain embedded in the inner mitochondrial membrane & the energy is used to generate lots of ATP (26) + H+ (waste product)
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Transport proteins
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create passageways through which water-soluble molecules and ions pass into or out of the cell
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Enzymes
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facilitate chemical reactions
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Recognition proteins
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to identify “self” to the immune system as well as to identify different cell types in an organism (eg a bone cell’s surface is different from that of a muscle cell)
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Adhesion proteins
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to help cells attach to one another
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Receptor proteins
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involved in communication between cells (signal transduction)
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life's primary energy source
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sun
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producers trap energy from the sun and convert it into
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potential energy
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Metabolism is made up of two pathways:
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catabolic, anabolic
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catabolic pathways
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break larger molecules into smaller molecules to generate both energy (generally in the form of ATP) and building blocks
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anabolic (biosynthetic) pathways
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use the energy and building blocks to synthesize molecules required by the cell
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Endergonic
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anabolic, stores energy
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exergonic
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catabolic, releases energy
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oxidized molecule
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lost one or more electrons
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reduced molecule
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gained one or more electrons
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activation energy
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the amount of energy that reactants must absorb before a chemical reaction will begin.
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photosystem
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a unit consisting of chlorophyll a aggregated with other pigment molecules and proteins that anchor the entire complex in the thylakoid membrane
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