Grade 12 biology unit 2
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Quizlet based on my 12th grade biology, unit 2 notes, quizzes, research, labs, gizmos, stse assignments, etc. Sorry for any incorrect content, misspellings or more! I used to make quizlets with the username "hrheinst6570" if anyone is looking for more content to study with
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177 Terms
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How to label diagram
\-labeling outside of diagram
\-all labels on one side
\-titles are underlined
\-titles are on top of diagram
\-enlargement/magnification value of microscope included
\-enlargement/magnification value of microscope under diagram
\-all labels should be parallel to each other (using diagonal straight lines, bringing them to an end, and then drawing another connected straight line is acceptable )
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\-interactive labeling website =
https://learnful.ca/project/cell-diagrams-labelling-activity
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\-all labels on one side
\-titles are underlined
\-titles are on top of diagram
\-enlargement/magnification value of microscope included
\-enlargement/magnification value of microscope under diagram
\-all labels should be parallel to each other (using diagonal straight lines, bringing them to an end, and then drawing another connected straight line is acceptable )
\
\-interactive labeling website =
https://learnful.ca/project/cell-diagrams-labelling-activity
\
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what is a cell
\-most basic unit of any living thing
\-variety of shapes and sizes
\-typically size ranges from 5-50 micrometers in diameter
\-exist in aqueous medium
\-have specific tasks
\-all cells have two characteristics in common
\-variety of shapes and sizes
\-typically size ranges from 5-50 micrometers in diameter
\-exist in aqueous medium
\-have specific tasks
\-all cells have two characteristics in common
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what two characteristics do all cells have in common
\-surrounded by a barrier called a cell membrane
\-at some point in their lives they contain DNA (biological information)
\-at some point in their lives they contain DNA (biological information)
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metric prefixes
\-mega
\-kilo
\-centi
\-milli
\-micro
\-nano
\-pico
\-kilo
\-centi
\-milli
\-micro
\-nano
\-pico
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mega
\-symbol: M
\-multiplier: 1,000,000
\-exponential: 10^6
\-multiplier: 1,000,000
\-exponential: 10^6
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kilo
\-symbol: k
\-multiplier: 1,000
\-exponential: 10^3
\-multiplier: 1,000
\-exponential: 10^3
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centi
\-symbol: c
\-multiplier: 0.01
\-exponential: 10^-2
\-multiplier: 0.01
\-exponential: 10^-2
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milli
\-symbol: m
\-multiplier: 0.001
\-exponential: 10^-3
\-multiplier: 0.001
\-exponential: 10^-3
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micro
\-symbol: µ
\-multiplier: 0.000001
\-exponential: 10^-6
\-multiplier: 0.000001
\-exponential: 10^-6
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nano
\-symbol: n
\-multiplier: 0.000000001
\-exponential: 10^-9
\-multiplier: 0.000000001
\-exponential: 10^-9
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pico
\-symbol: p
\-multiplier: 0.000000000001
\-exponential: 10^-12
\-multiplier: 0.000000000001
\-exponential: 10^-12
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The cell theory
\-all living things are composed of one or more cells (each cell has a different set of functions)
\-cells are the basic structural and functional units of life
\-all cells arise from the division of pre-existing cells
\-the activities of an entire organism depends on the total activities of its independent cells
\-cells are the basic structural and functional units of life
\-all cells arise from the division of pre-existing cells
\-the activities of an entire organism depends on the total activities of its independent cells
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two broad categories that cells fall into (identify and explain why)
\-prokaryotes
\-eukaryotes
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\-depending on whether they contain a nucleus
\-eukaryotes
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\-depending on whether they contain a nucleus
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Nucleus
large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA = controls cells activities
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Eukaryotes
\-The category of cells that contain nuclei
\-possess a nucleus
\-have many membrane-bound organelles
\-e.g. protists, fungi, animals, plants
\-possess a nucleus
\-have many membrane-bound organelles
\-e.g. protists, fungi, animals, plants
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prokaryotes
\-the category of cells that do not contain nuclei; genetic material is simply found within the cell, not separated from other cellular structures
\-do not have a true nucleus
\-lack many organelles
\-e.g. bacteria
\-do not have a true nucleus
\-lack many organelles
\-e.g. bacteria
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Further prokaryotic cell components
\-lack nucleus
\-include kingdoms: archaebacteria, eubacteria
\-small, simpler cells 1-10mm
\-circular DNA, not membrane-bound
\-cell division not by mitosis of meiosis
\-have no mitochondria nor membrane-bound organelles
\-many are anaerobic (don’t require oxygen
\-include kingdoms: archaebacteria, eubacteria
\-small, simpler cells 1-10mm
\-circular DNA, not membrane-bound
\-cell division not by mitosis of meiosis
\-have no mitochondria nor membrane-bound organelles
\-many are anaerobic (don’t require oxygen
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Further eukaryotic cell components
\-have nucleus
\-include kingdoms: fungi, protista, animalia, plantae
\-larger, more complex 100-1000mm
\-DNA in a membrane-bound nucleus
\-cell division by mitosis/meiosis
\-do have mitochondria and membrane-bound organelles
\-many are aerobic (require oxygen)
\-include kingdoms: fungi, protista, animalia, plantae
\-larger, more complex 100-1000mm
\-DNA in a membrane-bound nucleus
\-cell division by mitosis/meiosis
\-do have mitochondria and membrane-bound organelles
\-many are aerobic (require oxygen)
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Needs of cells
\-cells need to live
\-need food, liquid, get rid of waste products
\-need oxygen to survive and need to get rid of carbon dioxide
\-need food, liquid, get rid of waste products
\-need oxygen to survive and need to get rid of carbon dioxide
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cell membrane
\-every cell in your body has a cell membrane
\-cell membrane surrounds the cell and allows substances to pass in and out of cell
\-membrane is made up of lips called phospholipids, arranged in two layers
\-this structure is referred to as a phospholipid bilayer
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\-semipermeable (selective permeable)
\-composed of a phospholipid bilayer
\-hydrophilic “heads”/hydrophobic “tails”
\-flexible (due to weak intermolecular forces between the membrane lipids)
\-a “fluid mosaic” (composed of lipids bilayer \[polar head, non-polar tails\], proteins and carbohydrates arranged in fluid mosaic structure)
\-cell membrane surrounds the cell and allows substances to pass in and out of cell
\-membrane is made up of lips called phospholipids, arranged in two layers
\-this structure is referred to as a phospholipid bilayer
\
\-semipermeable (selective permeable)
\-composed of a phospholipid bilayer
\-hydrophilic “heads”/hydrophobic “tails”
\-flexible (due to weak intermolecular forces between the membrane lipids)
\-a “fluid mosaic” (composed of lipids bilayer \[polar head, non-polar tails\], proteins and carbohydrates arranged in fluid mosaic structure)
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components of cell membrane
\-hydrophobic end
\-hydrophilic end
\-phosphate group
\-fatty acids
\-phospholipids
\-intracellular fluid (ICF)
\-extracellular fluid (ECF)
\-hydrophilic end
\-phosphate group
\-fatty acids
\-phospholipids
\-intracellular fluid (ICF)
\-extracellular fluid (ECF)
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cell membrane tasks
\-separates ECF from ICF
\-separates the interior of cell from the outside environment
\-gives support
\-control what enters and leaves the cell (selectively permeable)
\-allows some substances to pass (permeable)
\-separates the interior of cell from the outside environment
\-gives support
\-control what enters and leaves the cell (selectively permeable)
\-allows some substances to pass (permeable)
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intracellular fluid (ICF)
\-cytosol
\-the aqueous portion of the cytoplasm consisting of water, dissolved ions, and molecules
\-cytoplasm includes the cytosol and organelles
\-the aqueous portion of the cytoplasm consisting of water, dissolved ions, and molecules
\-cytoplasm includes the cytosol and organelles
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extracellular fluid (ECF)
-all fluid outside the cell
\-two subcategories of ECF
\-two subcategories of ECF
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two subcategories of ECF
\-interstitial fluid
\-blood plasma
\-blood plasma
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interstitial fluid
water, cellular reactants and products, and other substances. it bathes and surrounds the cells of the body, and provides a means of delivering materials to the cells, and removal of metabolic waste
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blood plasma
the watery fluid found inside the vascular system that transports components of blood and other substances
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body water components by percentage
\-33% extracellular
\-66% intracellular
\-66% intracellular
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extracellular fluid components by percentage
\-25% interstitial
\-8% plasma
\-8% plasma
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Intracellular environment (definition)
area inside the cell
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extracellular environment (definition)
area outside the cell
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fluid mosaic model
\-phospholipids are the basic framework
\-macromolecules are embedded on the surface and within (e.g. proteins, glycoproteins, cholesterol, glycolipids)
\-molecules attached and embedded move to different locations on the membrane
\-macromolecules are embedded on the surface and within (e.g. proteins, glycoproteins, cholesterol, glycolipids)
\-molecules attached and embedded move to different locations on the membrane
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lipid bilayer phospholipids
\-arranged in a bilayer and are amphipathic
\-polar, hydrophilic phosphate heads facing outwards and non-polar, hydrophobic hydrocarbon tails facing inwards
\-the top region has an NH3 polar group, connected by glycerol to two fatty acid tails
\-one tail is a straight chain fatty acid (saturated), other has a kink in the tail due to a cis double bond (unsaturated)
\-kink prevents tight packing and allows movement in the lateral plane of membrane
\-hydrophobic layer acts as a barrier to all but the smallest molecules
\-polar, hydrophilic phosphate heads facing outwards and non-polar, hydrophobic hydrocarbon tails facing inwards
\-the top region has an NH3 polar group, connected by glycerol to two fatty acid tails
\-one tail is a straight chain fatty acid (saturated), other has a kink in the tail due to a cis double bond (unsaturated)
\-kink prevents tight packing and allows movement in the lateral plane of membrane
\-hydrophobic layer acts as a barrier to all but the smallest molecules
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macromolecules in phospholipid bilayer
\-cholesterol & glycolipids & glycoproteins
\-proteins
\-proteins
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function of cholesterol & glycolipids & glycoproteins in phospholipid bilayer
\-enable cells to “recognize” each other. I.e. cells can identify “intruders” such as disease-causing bacteria
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function of proteins in phospholipid bilayer
\-determine the function of the membrane
\-integral proteins
\-peripheral proteins
\-integral proteins
\-peripheral proteins
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transmembrane proteins (integral proteins)
\-integral proteins are embedded to provide transport
\-within the lipid bilayer and are amphipathic
\-contain residues with hydrophobic side chains that interact with fatty acid groups of the membrane phospholipids
\-can have form 4 to several 100 residues
\-main functions are to act as a transporter across the membrane wall for large molecules, polar molecules, and ions. They are able to do so because they are amphipathic and are stationary in the lipid bilayer of the membrane
\-within the lipid bilayer and are amphipathic
\-contain residues with hydrophobic side chains that interact with fatty acid groups of the membrane phospholipids
\-can have form 4 to several 100 residues
\-main functions are to act as a transporter across the membrane wall for large molecules, polar molecules, and ions. They are able to do so because they are amphipathic and are stationary in the lipid bilayer of the membrane
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peripheral proteins
\-peripheral proteins links with the integral protein to the cytoskeleton providing support
\-bound to the membrane indirectly by interactions with integral membrane proteins of directly by interactions with lipid polar head groups
\-bound to the membrane indirectly by interactions with integral membrane proteins of directly by interactions with lipid polar head groups
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factors affecting the fluidity of a phospholipid bilayer
\-increase temperature = increase permeability (unwater molecules may pass)
\-decrease temperature
\-presence of double bonds in the fatty acid “tails” allows for more space
\-decrease temperature
\-presence of double bonds in the fatty acid “tails” allows for more space
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membrane protein functions
1\.) hormone binding sites (act as hormone receptors)
2\.) as enzymes with the active site on the outside
3\.) cell adhesion to form tight junctions between groups of cells in tissues & organs
4\.) cell-to-cell communication - i.e. receptors for neurotransmitters at synapses
5\.) channels for passive and active transport
6\.) pumps for active transport
2\.) as enzymes with the active site on the outside
3\.) cell adhesion to form tight junctions between groups of cells in tissues & organs
4\.) cell-to-cell communication - i.e. receptors for neurotransmitters at synapses
5\.) channels for passive and active transport
6\.) pumps for active transport
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organelle areas
\-the nucleus
\-the cytoplasm
\-the surface
\-the cytoplasm
\-the surface
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organelles of the nucleus (organized into support, transport, synthesize, storage)
STORAGE/SYNTHESIZE
\-the nucleolus
SUPPORT
\-nuclear membrane
\-the nucleolus
SUPPORT
\-nuclear membrane
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organelles of the cytoplasm (organized into support, transport, synthesize, storage)
SYNTHESIZE/TRANSPORT
\-Endoplasmic reticulum (RER/SER)
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STORAGE
\-lysosomes
\-vacuoles
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SYNTHESIZE
\-mitochondria
\-ribosomes
\-chloroplasts
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TRANSPORT
\-golgi bodies
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TRANSPORT/SUPPORT
\-cyto-skeleton
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SUPPORT
\-cytosol
\-Endoplasmic reticulum (RER/SER)
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STORAGE
\-lysosomes
\-vacuoles
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SYNTHESIZE
\-mitochondria
\-ribosomes
\-chloroplasts
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TRANSPORT
\-golgi bodies
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TRANSPORT/SUPPORT
\-cyto-skeleton
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SUPPORT
\-cytosol
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organelles of the surface (organized into support, transport, synthesize, storage)
SUPPORT
\-cell wall
\-plasma membrane
\-cell wall
\-plasma membrane
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The nucleus
\-the cell nucleus acts like the brain of the cell
\-it helps control the cell’s function
\-DNA in the form of chromatin is present
\-nucleolus: denser region containing RNA for protein synthesis
\-enclosed by a porous nuclear membrane
\-it helps control the cell’s function
\-DNA in the form of chromatin is present
\-nucleolus: denser region containing RNA for protein synthesis
\-enclosed by a porous nuclear membrane
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The endoplasmic reticulum (ER)
\-membranous sheets and tubules make up the body of the endoplasmic reticulum, while rough endoplasmic reticulum has additional ribosomes lining a portion of the exterior.
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\-The rough endoplasmic reticulum is tasked with the sorting, folding, quality control, and synthesis of proteins
\-the rough ER provides a place for ribosomes to carry out protein synthesis intended for export from the cell
\-close proximity to nucleus
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\-the smooth endoplasmic reticulum is tasked with lipid synthesis and calcium storage of the cell
\-the smooth ER synthesizes lipids and lipid-containing molecules (e.g. phospholipids, and hormones)
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\-The rough endoplasmic reticulum is tasked with the sorting, folding, quality control, and synthesis of proteins
\-the rough ER provides a place for ribosomes to carry out protein synthesis intended for export from the cell
\-close proximity to nucleus
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\-the smooth endoplasmic reticulum is tasked with lipid synthesis and calcium storage of the cell
\-the smooth ER synthesizes lipids and lipid-containing molecules (e.g. phospholipids, and hormones)
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Lysosomes
\-contains digestive enzymes that break down parts of the cell that are old of no longer needed
\-recycles macromolecules for reuse in the cell
\-transports undigested material to cell membrane for removal
\-cell breaks down if lysosome explodes
\-tasked with digestion of proteins, lipids, carbohydrates, and other complex molecules
\-recycles macromolecules for reuse in the cell
\-transports undigested material to cell membrane for removal
\-cell breaks down if lysosome explodes
\-tasked with digestion of proteins, lipids, carbohydrates, and other complex molecules
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peroxisomes
\-have no consistent shape, size, or number
\-consist of a phospholipid bilayer and a variety of membrane-bound proteins
\-take part in breaking down toxic materials located within a cell and completing metabolic activity by using the digestive and oxidative enzymes they contain
\-consist of a phospholipid bilayer and a variety of membrane-bound proteins
\-take part in breaking down toxic materials located within a cell and completing metabolic activity by using the digestive and oxidative enzymes they contain
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vacuoles
\-stores of oils, carbs, water, or toxins
\-higher amount of water solution in plant (turgor pressure)
\-Made of membrane-bound sacs that consist of a variety of phospholipids
\-within the membranes there are a variety of proteins.
\-Tasked with the water storage of a cell, the turgor pressure of cells, the endocytosis and exocytosis, and the storage of many different types of molecules
\-higher amount of water solution in plant (turgor pressure)
\-Made of membrane-bound sacs that consist of a variety of phospholipids
\-within the membranes there are a variety of proteins.
\-Tasked with the water storage of a cell, the turgor pressure of cells, the endocytosis and exocytosis, and the storage of many different types of molecules
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mitochondria
\-mitochondria are known as the “powerhouse” of the cell that take in nutrients, breaks them down, and creates energy for the cell. The process of creating cell energy is known as cellular respiration
\-you might find cells with several thousand mitochondria. if the cell feels it is not getting enough energy to survive, more mitochondria can be created. sometimes they can even grow, move, and combine with other mitochondria, depending on the cell’s needs
\-ATP production
\-Made of an outer and inner membrane which both consist of phospholipid layers
\-while the inner membrane has many cristae folds, the outer membrane is used to cover the surface of the organelle.
\-The mitochondria are tasked with the production of adenosine triphosphate (A.T.P.) which provides energy to the cell
\-you might find cells with several thousand mitochondria. if the cell feels it is not getting enough energy to survive, more mitochondria can be created. sometimes they can even grow, move, and combine with other mitochondria, depending on the cell’s needs
\-ATP production
\-Made of an outer and inner membrane which both consist of phospholipid layers
\-while the inner membrane has many cristae folds, the outer membrane is used to cover the surface of the organelle.
\-The mitochondria are tasked with the production of adenosine triphosphate (A.T.P.) which provides energy to the cell
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ATP stands for:
Adenosine triphosphate
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Ribosomes
\-ribosomes are the sites of protein synthesis (making)
\-usually, the proteins synthesized by the free ribosomes are utilized in the cytoplasm itself, while the protein molecules produced by the bound ribosomes (RER) are transported outside the cell
\-protein factories
\-Are made of both small and large subunits, a combination of proteins and RNA, and an mRNA molecule.
\-Ribosomes are used to translate genetic code found in the DNA of a cell into chains of amino acids, proteins
\-usually, the proteins synthesized by the free ribosomes are utilized in the cytoplasm itself, while the protein molecules produced by the bound ribosomes (RER) are transported outside the cell
\-protein factories
\-Are made of both small and large subunits, a combination of proteins and RNA, and an mRNA molecule.
\-Ribosomes are used to translate genetic code found in the DNA of a cell into chains of amino acids, proteins
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golgi bodies
\-a.k.a golgi apparatus
\-provides an area where macromolecules are tagged with labels
\-The Golgi is divided into a cis face, and a trans face location, multiple lumens and cisternae, these appearing as sacs that have been piled on top of each other and flattened.
\-Tasked with the modification and transport of proteins that are formed in the endoplasmic reticulum
\-provides an area where macromolecules are tagged with labels
\-The Golgi is divided into a cis face, and a trans face location, multiple lumens and cisternae, these appearing as sacs that have been piled on top of each other and flattened.
\-Tasked with the modification and transport of proteins that are formed in the endoplasmic reticulum
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chloroplasts
\-production of energy and sugars via photosynthesis
\-contains green chlorophyll
\-Have an oval shape, and are made of an inner and outer membrane
\-the space in the inner membrane is called the stoma, the outer membrane forms the outer surface of the chloroplast, and the space between these two is filled with a thin intermembrane.
\-Tasked with completing the production of energy by using photosynthesis
\-contains green chlorophyll
\-Have an oval shape, and are made of an inner and outer membrane
\-the space in the inner membrane is called the stoma, the outer membrane forms the outer surface of the chloroplast, and the space between these two is filled with a thin intermembrane.
\-Tasked with completing the production of energy by using photosynthesis
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centrosome
\-Consists of two centrioles, barrel-shaped bundles of microtubules, and a complex of proteins that aid in the production of more microtubules.
\-The cell is referred to as the microtubule organizing center and directs the cytoskeletal structures, proteins, and microtubules to allow for the change in the shape of cell membranes specific to animals
\-The cell is referred to as the microtubule organizing center and directs the cytoskeletal structures, proteins, and microtubules to allow for the change in the shape of cell membranes specific to animals
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cytoskeleton
\-structural support
\-composed of microtubules
\-movement of materials in and out of cells
\-composed of microtubules
\-movement of materials in and out of cells
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microtubules
\-Made of hollow tubes of repetitive protein structures, in the cytoskeleton, that are microscopic.
\-Microtubules are tasked with the division, movement of the cell, and transport of materials within the cell
\-Microtubules are tasked with the division, movement of the cell, and transport of materials within the cell
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centromeres
\-Part of a chromosome that forms spindle fibers which are a network of filaments.
\-Play a key role in cell division, the created spindle fibers connect to sister chromatids and pull them to the opposite poles of a cell
\-Play a key role in cell division, the created spindle fibers connect to sister chromatids and pull them to the opposite poles of a cell
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differences between plant & animal cells
PLANT CELLS:
\-tend to be more rectangular
\-large vacuoles have lots of fluid that presses up against the cell membrane = creates turgor pressure (help keep plant upright)
\-cell wall also helps keep plants upright
\-have chloroplasts so cells can create food via photosynthesis
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ANIMAL CELLS:
\-tend to be round
\-small vacuoles (no turgor pressure)
\-no cell wall; just the cell membrane
\-no chloroplasts (animal cells cannot create their own food via photosynthesis)
\-tend to be more rectangular
\-large vacuoles have lots of fluid that presses up against the cell membrane = creates turgor pressure (help keep plant upright)
\-cell wall also helps keep plants upright
\-have chloroplasts so cells can create food via photosynthesis
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ANIMAL CELLS:
\-tend to be round
\-small vacuoles (no turgor pressure)
\-no cell wall; just the cell membrane
\-no chloroplasts (animal cells cannot create their own food via photosynthesis)
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Imaging technologies
\-the eye
\-light microscopy
\-electron microscopes (EM)
\-x-ray crystallography
\-cell tagging
\-light microscopy
\-electron microscopes (EM)
\-x-ray crystallography
\-cell tagging
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membrane function
\-to protect the cell from its environment
\-to select which substances can enter or leave the cell
\-to allow cell-to-cell communication
\-to preform specific biochemical reactions
\-to select which substances can enter or leave the cell
\-to allow cell-to-cell communication
\-to preform specific biochemical reactions
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cells are able to get nutrients through which two methods?
\-passive transport
\-active transport
\-active transport
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passive transport
\-simple diffusion
\-facilitated diffusion
\-osmosis
\-facilitated diffusion
\-osmosis
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solutes
substances that are dissolved in fluid to form a solution
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solvent
the liquid that the solutes are in
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diffusion definition
\-the tendency of molecules of ions to move from area that is more concentrated to one that is less concentrated
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equilibrium
\-equal concentration of particles in all areas
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concentration gradient
\-net movement from area of high concentration to low concentration
\-difference between concentration on inside of membrane and outside
\-difference between concentration on inside of membrane and outside
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passive transport
movement along the concentration gradient (without input of energy)
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dynamic equilibrium
once there are an equal number of molecules on each side of the cell membrane
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diffusion
\-solute molecules moving from an area of high concentration to an area of low concentration
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\-random motion drives diffusion
\-movement is based on kinetic energy (speed), charge, and mass of molecules
\-equilibrium is reached when there is an even distribution of solute molecules
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\-random motion drives diffusion
\-movement is based on kinetic energy (speed), charge, and mass of molecules
\-equilibrium is reached when there is an even distribution of solute molecules
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factors that determine diffusion of molecules through cell membrane
\-molecule size; large molecules cannot squeeze through tightly packed phospholipids easy, rate of diffusion decreases with size
\-molecule polarity; small polar molecules can pass but diffuse slower than non polar molecules
\-size of concentration difference
\-distance must travel (greater distance, slower diffusion)
\-charged molecules and ions cannot diffuse across
\-temperature; high temperature increased diffusion
\-pressure; high pressure increased diffusion
\-characteristics of the solvent (e.g. density of solvent \[more dense, decreased diffusion\])
\-mass of substance travelling; greater mass = decreased diffusion
\-characteristics of barrier (surface area, thickness, thinness)
\-molecule polarity; small polar molecules can pass but diffuse slower than non polar molecules
\-size of concentration difference
\-distance must travel (greater distance, slower diffusion)
\-charged molecules and ions cannot diffuse across
\-temperature; high temperature increased diffusion
\-pressure; high pressure increased diffusion
\-characteristics of the solvent (e.g. density of solvent \[more dense, decreased diffusion\])
\-mass of substance travelling; greater mass = decreased diffusion
\-characteristics of barrier (surface area, thickness, thinness)
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diffusion and the problem of size
-the rate of exchange of substances depends on the organism’s surface area that is in contact with the surroundings
\-the requirements for materials depends on the volume of the organism
\-therefore, the ability to meet the requirements depends on the surface are : volume ratio
\-the requirements for materials depends on the volume of the organism
\-therefore, the ability to meet the requirements depends on the surface are : volume ratio
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osmosis definition
\-the movement of water molecules across biological membranes, which are semi-permeable, from an area of higher concentration to an area of lower concentration
\-diffusion of water through a selectively permeable/semi-permeable membrane
\-diffusion of water through a selectively permeable/semi-permeable membrane
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osmosis
\-the aqueous cytoplasm is a solvent for cellular molecules and ions
\-cells must maintain enough water to enable cellular processes
\-but cells interact with extracellular fluid - and the composition of extracellular fluid changes all the time
* if too much extracellular fluid (water) enters a cell = cell swells
* if too much water leaves a cell = cell shrinks
\-regulation of water entry is critically important to a cell
\-cells must maintain enough water to enable cellular processes
\-but cells interact with extracellular fluid - and the composition of extracellular fluid changes all the time
* if too much extracellular fluid (water) enters a cell = cell swells
* if too much water leaves a cell = cell shrinks
\-regulation of water entry is critically important to a cell
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osmosis (in action)
\-water can easily pass through the phospholipid bilayer
\-water molecules always pass from the side of membrane with higher concentration of water and less of solute to side with low concentration of water and high solute until reach equilibrium
\-water molecules always pass from the side of membrane with higher concentration of water and less of solute to side with low concentration of water and high solute until reach equilibrium
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semi-permeable
\-permeable to solvents (e.g. water), but not to large molecules
\-high (water) to low (water)
\-high (water) to low (water)
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dissolved molecules are called
solutes (e.g. glucose, starch)
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in osmosis what is the solvent and what is the solute
\-water = solvent
\-glucose, starch = solutes
\-glucose, starch = solutes
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what happens to water level as a dilute solution and concentrated solution reaches equilibrium across a membrane
the water level rises on the side of the concentrated solution until concentrations become equal
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hypertonic environment
high solute, low solvent
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hypotonic environment
high solvent, low solute
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isotonic environment
solute = solvent
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hypertonic solution
the fluid surrounding a cell has higher solute concentration than cytoplasm of cell - water diffuses out of cell
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isotonic solution
the concentration of solutes in the fluid surrounding the cell is the same as it is in the cell’s cytoplasm - no water movement
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hypotonic solution
the solute concentration of the fluid surrounding the cell is less than cell’s cytoplasm - water diffuses into the cell
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concentration
measure of how much solute is present per volume of solvent
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plant cells - osmosis
\-the cell absorbs water by osmosis
\-the cell wall stops the cell from over expanding
\-the cell wall stops the cell from over expanding
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water potential (Ψ)
\-measurement of potential energy in water
\-water potential = pressure potential + solute potential
\-Ψ = ΨP + ΨS
\-adding solute lowers water potential
\-exerting pressure raises water potential
\-e.g. if water moves towards a solute,
* -3 (Ψ) = 0 (ΨP) + -3 (ΨS)
\-water travels to areas of lower water potential
* 0 (Ψ) = 3 (ΨP) + -3 (ΨS)
* adding water to solute creates pressure within solute
\-turgor pressure
\-water potential = pressure potential + solute potential
\-Ψ = ΨP + ΨS
\-adding solute lowers water potential
\-exerting pressure raises water potential
\-e.g. if water moves towards a solute,
* -3 (Ψ) = 0 (ΨP) + -3 (ΨS)
\-water travels to areas of lower water potential
* 0 (Ψ) = 3 (ΨP) + -3 (ΨS)
* adding water to solute creates pressure within solute
\-turgor pressure
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Turgor pressure
the force within the cell that pushes the plasma membrane against the cell wall. It is also called hydrostatic pressure, and is defined as the pressure in a fluid measured at a certain point within itself when at equilibrium
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what solution do animal and plant cells prefer
\-animal: isotonic
\-plant: hypotonic
\-plant: hypotonic
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tonicity
\-refers to what the cell does in a certain environment
\-if the environment is hypertonic, the cell will shrink due to water leaving the cell
\-hypotonic means water enters the cell makes it to expand and possibly explode
\-if the environment is hypertonic, the cell will shrink due to water leaving the cell
\-hypotonic means water enters the cell makes it to expand and possibly explode
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osmolality
\-refers to the relative concentration of two solutions
\-hyperosmotic, means the concentration of solutes outside the cell is greater than the concentration inside the cell
\-hyperosmotic, means the concentration of solutes outside the cell is greater than the concentration inside the cell
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facilitated diffusion
\-occurs when molecules or ions enter cells through channels (along their concentration gradient) that exist in special transport proteins (channel proteins) that span membrane
\-passive transport - no energy from ATP required
\-transport follows the concentration gradient (movement from high concentration to low) but molecules need help to pass through membrane
\-passive transport - no energy from ATP required
\-transport follows the concentration gradient (movement from high concentration to low) but molecules need help to pass through membrane
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channel proteins
\-have hydrophilic interior where polar molecules or ions can pass and exterior consists of amino acids with non polar side chains
\-some have gates that open and close
\-some have gates that open and close
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carrier proteins
\-bind to the molecule and transport across membrane along concentration gradient
\-rate of diffusion is lower because can only carry so many at a time
\-exterior composed of non-polar amino acids, interior lined with amino acids
\-rate of diffusion is lower because can only carry so many at a time
\-exterior composed of non-polar amino acids, interior lined with amino acids
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cell membrane transport - active transport example
Na+/K+ pump (sodium potassium pump)
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Na+/K+ pump
\-input of ATP energy needed
\-helps maintain resting membrane potential
\-initially open to the inside of the cell, binding room for three sodium ions
\-ATP changes configuration of channel, shape change causes pump to open to outside.
\-sodium ions are pushed to the outside
\-has two binding sites for potassium ions
\-phosphate group (released from ATP) is released and pump reverts back to original position (open to inside of cell)
\-moves sodium and potassium against their concentration gradients (moves ions from low concentration to high concentration)
\-moves 3 positive ions out for every 2 positive ions in
\-causes electrochemical gradient
\-cells have more potassium transport channels to allow potassium to escape
\-helps maintain resting membrane potential
\-initially open to the inside of the cell, binding room for three sodium ions
\-ATP changes configuration of channel, shape change causes pump to open to outside.
\-sodium ions are pushed to the outside
\-has two binding sites for potassium ions
\-phosphate group (released from ATP) is released and pump reverts back to original position (open to inside of cell)
\-moves sodium and potassium against their concentration gradients (moves ions from low concentration to high concentration)
\-moves 3 positive ions out for every 2 positive ions in
\-causes electrochemical gradient
\-cells have more potassium transport channels to allow potassium to escape
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resting membrane potential
\-involves electric potential; difference between the electrical voltage inside and outside of the cell
\-all cells have their own resting potential
\-generally most cells are more negative inside the cell than outside the cell while resting
\-all cells have their own resting potential
\-generally most cells are more negative inside the cell than outside the cell while resting
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action membrane potential
\-when cells are not resting
\-active and higher potential than when resting
\-active and higher potential than when resting