Term
| Tell me about Robert Hooke. |
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Definition
1665 A.D.
Invented primitive microscope
Observed “Little Boxes” (=cells) in cork
Discovered similar structures in live plants |
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Term
| Tell me about Anton van Leeuwenhoek. |
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Definition
1670 A.D.
Discovered “animalcules” in water samples
Mostly single-celled organisms
Observed blood, sperm, microscopic eggs
Countered idea of spontaneous generation
Fleas believed to emerge from dust |
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Term
| Tell me about Light Microscopy. |
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Definition
Most commonly used
Light combination to illuminate specimen
Combination of lenses magnify and focus image
Stains often used to provide contrast |
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Term
| Tell me about Electron Microscopy. |
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Definition
Beans of electrons replace light
Magnetic field focus image |
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Term
| Tell me about the Transmission Electron Microscope. |
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Definition
Electrons passed through specimen
Interior details of cell visible |
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Term
| Tell me about the Scanning Electron Microscope. |
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Definition
Electrons bounced off of specimen
3-D image produced |
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Term
| The Cell Theory. What are the three principles? |
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Definition
Developed in 1855
3 Principals
Every living organism is made up of 1 or more cells
Smallest living organisms are single cells and cells are functional units of multicellular organisms
Cells = basic unit of life
Cells arise from pre-existing cells
Cells reproduce!!! |
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Term
|
Definition
Must obtain energy and nutrients
Must eliminate waste
Must synthesize proteins and other molecules
Must reproduce
Many interact with other cells |
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Term
| What are common Features of Cells? |
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Definition
Small in size
1-100 micrometers (µm)
Aids in nutrients and waste exchange with external environment |
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Term
|
Definition
Plasma membrane
Cytoplasm
DNA & RNA4 |
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Term
|
Definition
Thin, fluid membrane that encloses cell
Phospholipid bilayer with embedded proteins |
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Term
| What is the function of plasma membrane? |
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Definition
Isolates cell contents from external environment
Regulates flow of materials in and out cell
Allows for cellular interactions with
Other cells
Enviornment |
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Term
| The Phospholipid bylayer is? |
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Definition
Hydrophilic head (water-loving)
Faces watery intracellular and extracellular environments
Hydrophobic tail (water-fearing)
Faces interior of membrane |
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Term
| How does the Phospholipid bylayer work? |
|
Definition
Maintains differences in concentrations of materials inside and outside of cell
Allows oxygen, carbon dioxide & water to move in and out of cell easily
Barrier to most hydrophilic molecules and ions |
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Term
| What are the functions of embedded proteins? |
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Definition
Facilitate communication between cell and its environment
Functions
Allow specific molecules and ions to enter and exit cell
Promote chemical reactions within cells
Join cell to other cells
Receive & respond to signals from molecules
Example: MHC (=glycoprotein)
Major Histocompatibility Complex
Allows body to recognize cell as not being foreign
Prevents immune system from attacking and killing cell |
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Term
|
Definition
Fluid and structures inside cells
membrane
Fluid = water, salts, organic
molecules
Structures = everything except for nucleus
metabolic activities occur here
Biochemical reactions that support life
Ex: Protein synthesis |
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Term
|
Definition
Genetic material in cells
“Blueprints: for
Making cell parts
Producing new cells
Passed on to offspring |
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Term
|
Definition
| Translates DNA into proteins |
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Term
| How does the Acquisition of Materials & Energy work? |
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Definition
Plasma membrane, cytoplasm, DNA & RNA all necessary for the acquisition and utilization of materials and energy for cell survival
Materials
Ex: carbon, hydrogen, nitrogen, oxygen, etc.
Must cross cell membrane to enter cell
Used in formation of biological molecules in cytoplasm |
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Term
|
Definition
| Acquired from sun or other living organisms |
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Term
| What is a Eukaryotic cell? |
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Definition
Larger in size (10-100 um)
Posses a nucleus
Contain a variety of organelles
Eukarya domain |
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Term
| What is a Prokaryotic cell? |
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Definition
Small in size (0.1-10 um)
Do not have a nucleus
Genetic material free in cytoplasm
Lack membrane- bound organelles
Bacteria and Achaea domains |
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Term
| Eukaryotic Cell General Info |
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Definition
Comprise bodies of Eukarya domain
Animals, plants, protists and fungi
Multicellular organisms (e.g. Animals, plants)
Composed of a variety of cells
Each cell type had its own specific function
Unicellular organisms (e.g. Protists)
Highly complex
All activities to sustain life of organisms performed within single cell of body
Not all eukaryotic cells possess the same structures |
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Term
| Tell me about the cell wall. |
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Definition
Not present in all eukaryotic cells
Found in: plant, fungi and protist cells
Non-living, stiff outer coating of cell
Function: Support and protect plasma membrane
Composed of:
Cellulose, protein or glassy silica (protists)
Cellulose and polysaccharides (plants)
Chitin (Fungi)
Produced by the cell itself
Ex: Plants
Cellulose secreted through plasma membrane cell wall is formed
Cell wall joins to adjacent cells via pectin
Pectin = polysaccharide with gelatinous properties
Support and protect cell
Helps plant stand upright and to defy gravity and wind
Porous to allow oxygen, carbon dioxide & water in & out of cell |
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Term
| Tell me about the cytoskeleton. |
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Definition
Anchors organelles and other structures within cell
Network of protein fibers
Microfilaments – thinnest of fibers
Intermediate Filaments – medium thickness
Microtubules – thickest of fibers |
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Term
| Cytoskeleton (info cont.) |
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Definition
Specific functions
Cell shape
Network of intermediate filaments
Cell movement
Microfilaments & microtubules assemble, disassemble and slide past each other
Ex: Ciliated organisms, sperm, muscle contractions
Organelle movement
Microfilaments & microtubules physically move organelles within cell
Cell Division
Microfilaments & microtubules |
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Term
|
Definition
Extension of plasma membrane from basal body
Basal body derived from centrioles in cytoplasm
Supported by microtubules of cytoskeleton
Characteristic 9+2 arrangement
9 pairs of fused microtubules in a ring
2 infused microtubules in center of ring |
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Term
| How do Cilia and Flagella move? |
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Definition
Function: Movement (Often continuous)
Requires energy released from ATP
“arms” of protein join microtubules in ring
Flexing of arms slides microtubules past each other
Results in bending of cilia or flagella
Cilia: Rowing movement
Ex: Cilia in trachea (Windpipe)
Keep foreign particles out of lungs
Flagella: wavelike movement
Ex: Flagella on sperm
Propels sperm towards egg |
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Term
|
Definition
Cilia
Short in length
Many on cell
Rowing motion
Uses
Swimming
Ex: Paramecium
Movement of fluids and particles
Ex: Oyster gills
Ex: Mammalian oviducts
Flagella
Long in length
Few on cell
Wavelike motion
Uses
Swimming
Ex: Sperm
Ex: Giardia |
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Term
| Tell me about the nucleus. |
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Definition
Largest organelle in cell
Control center of cell (=Brain of cell)
Houses DNA
Consists of 3 parts
Nuclear envelope
Chromatin
Nucleolus |
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Term
| Tell me about the Nuclear Envelope. |
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Definition
Isolates nucleus from rest of cell
Double membrane with nucleus pores
Nuclear pores
Allow water, ion & small molecules into nucleus
Lined with nuclear pore complex proteins
Regulate passage of large molecules
Ex: proteins and RNA
Rhyibosomes also found on exterior surface of membrane |
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Term
|
Definition
Fibrous complex of DNA and protein
Long, thin threads tangled up within nucleus
Important in cell division(=cell reproduction)
Become condensed and coiled = chromosomes
Chromosomes carry DNA (=blueprints) to new cell |
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Term
| Tell me about the Nucleolus. |
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Definition
little nuclei”
Each nucleus must have at least 1 nucleolus
Dense spherical bodies containing:
DNA
Ribosomal RNA (rRNA)
Proteins
Ribosomes (in varying levels of synthesis)
Function: Site of ribosomes synthesis |
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Term
|
Definition
Small particles of RNA + proteins
Polyribosomes = many ribosomes clustered on mRNA
Composed of 1 large subunit and 1 small subunit
Synthesized in nucleolous
Leave once completely synthesized
Found:
in nucleous
on nuclear envelope
Free and in/on structures in cytoplasm
Function: protein synthesis in cytoplasm
Subunits combine and work together |
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Term
| How does DNA get out of nucleus to be synthesized into proteins in cytoplasm? |
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Definition
Copies of DNA are transported through nuclear membrane
To do this:
Genetic info from DNA is copied into messenger RNA (mRNA)
mRNA passes through pores in nuclear envelope
Once in cytoplasm:
Ribosomes atttach to mRNA along with transfer RNA (tRNA) to synthesize proteins |
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Term
| What are the Components of the Cytoplasm? |
|
Definition
System of membranes
Endoplasmic reticulum
Golgi Apparatus
Vesicles
Vacuoles
Food vacuoles
Contractile vacuoles
Central vacuoles
Mitochondria
Chloroplasts
Plastids |
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Term
| What are the System of Membranes, and their functions? |
|
Definition
Fluid membranes fused with one another
Create separate, specialized compartments within cell
Compartments capable of:
Interconnecting with each other
Exchanging pieces of membrane with each other
transferring contents amongst each other
Utilizes vesicles (=membrane bound sacs) to move contents to other compartments or entirely out of cell
or
Functions
Separate biochemical reactions from one another
Enable a variety of different molecules to be processe |
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Term
| Tell me about the Endoplasmic Reticulum (ER. |
|
Definition
Series of interconnected membranes
Network of flattened sacs and tunnels
Function
Site for protein and lipid synthesis
Contain enzymes for detoxification and acquiring energy
Storage of calcium
2 Types
Smooth endoplasmic reticulum (Smooth ER)
Rough endoplasmic reticulum (Rough ER) |
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Term
|
Definition
Lack ribosomes
Specialized activities
synthesized lipids (steroids, phospholipids)
Contain enzymes for detoxification
Abundant in liver cells
Drugs, alcohol & biological by-products (e.g. ammonia)
Contain enzymes to get energy from glycogen
Stores calcium
large amounts needed for muscle contractions |
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|
Term
|
Definition
Ribosomes attached
Functions
Site of protein synthesis
Ex: Embedded proteins in plasma membrane
Ex: Digestive enzymes
Transport proteins through channels and vesicles to other organelles
Proteins collect in pockets of membrane that bud off as vesicles |
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Term
| What is Golgi Apparatus / Complex, and the function of it? |
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Definition
Stack of flattened, interconnected sacs
Derived from endoplasmic reticulum
Interact with vesicles from rough ER
Functions:
Sort proteins from ER based on type and destination
Ex: Digestive enzymes, hormones, etc.
Modify products from ER
Add sugars to fats and proteins
Ex: Carbohydrates added glycoproteins (E.g. antibodies)
Break down proteins into smaller peptides
Package materials into vesicles and distribute throughout cell |
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Term
| What are lysosomes and their functions? |
|
Definition
Specialized membrane bound vesicles
Contain digestive enzymes
Break down of proteins, fats and carbohydrates
Formed by Golgi
Function
Digestive food particles
Food enclosed in vacuoles that merge with lysosomes
Enzymes digest food into smaller molecules used by cell
Ex: amino acids, monosaccharaides, fatty acids
Digestive defective organelles
Molecules recycled |
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|
Term
|
Definition
Membrane bound sacs used for transport
Fluid filled and contain various molecules
Similar to vesicles, but larger in size
May be temporary or permanent
Temporary
Food Vacuoles
Permanent
Contractile vacuoles
Central Vacuoles |
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Term
| What are food vacuoles and how do they function? |
|
Definition
Temporary vacuole
Formed during phagocytosis
Process of engulfing particles outside of cells
Membrane derived from plasma membrane
Merge with lysosomes for food digestion |
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Term
| What are contractile vacuoles and how do they function? |
|
Definition
permanent vacuole
Not found in all Eukaryotic cells
Found in many unicellular, freshwater organisms
Ex: Paramecium
Composed of: collecting ducts, central reservoir and tube leading to plasma membrane
Function: to regulate water content of cell
Pumps excess water out of cell to prevent cell from rupturing |
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Term
| What and how do central vacuoles function? |
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Definition
Permanent vacuole
Not found in all Eukaryotic cells
Found in plant cells
Large, water-filled vacuole
water pressure provides support for cell
Functions:
To balance cell’s water content
Dump site for hazardous waste within cell
Storage of poisonous substance
Ex: sulfuric acid - deters animals from eating plant
Storage of |
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Term
| Tell me about the mitochondria. |
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Definition
Double membrane organelle
Outer membrane
Inner membrane with cristae (=folds)
Inner membrane space between membranes
Matrix= innermost compartment
Ribosomes and circular DNA |
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Term
| What is mitochondria and how does it function? |
|
Definition
Found in all Eukaryotic cells
“Powerhouses” of cell
Found in large numbers in metabolically active cells
Ex: Muscle
Functions
Extract energy from food molecules
Aerobic reactions (uses oxygen)
Storage energy as ATP (=produces ATP)
Generates~ 16 times more ATP than anaerobic reactions |
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|
Term
| Tell me about chloroplasts. |
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Definition
Similar to mitochondria
Only found in photosynthetic organisms
Function: energy capture and storage
Double membrane organelle
Outer membrane
Inner membrane - encloses stroma (=fluid)
Stroma contains grana
Grana =stacks of membranous sacs
Thylakoid = individual sacs
Contain chlorophyll (= green pigment in plants)
Capture sun’s energy
Transfers energy to other molecules and AT |
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Term
| Tell me about the Endosymbiotic Hypothesis. |
|
Definition
Mitochondria and chloroplasts evolved from prokaryotic bacteria that lived in cytoplasm of other prokaryotic cells
Endosymbiotic relationship between these organisms
Precursor to eukaryotic cells
Supportive evidence:
Similar in size to prokaryotic cells
Surrounded by double membrane
Synthesize ATP
Possess DNA and ribosomes similar to prokaryotes
Replicate independently within cell
Must arise from an existing mitochondria or chloroplast
Cell cannot make these from scratch! |
|
|
Term
|
Definition
Found in plants and photosynthetic protists
Function: storage
Molecules (e.g. pigments)
Photosynthetic products
Made during summer, to use during winter
Starch
Chloroplasts= specialized plastids |
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|
Term
|
Definition
Share many of the same structures, but not all!!!
Plant cells
Have a cell wall
Contain
chloroplasts
plastids
Central vacuole
Lack
Centrioles
Cilia
Animal cells
Lack cell wall
Lack
Chloroplasts
Plastids
Central vacuole
Contain
Centrioles
Cilia (most cells) |
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|
Term
| Prokaryotic Cell General Info. |
|
Definition
Small in size (1-10um)
Shapes vary
Rod-shaped bacilli
Spherical cocci
Spiral-shaped spirilla
Majority have cell wall
May have capsule or slime layer for adhering to surfaces
May have pili (=surface proteins) extending out from wall
Sex pili exchange DNA between bacterial cells
No Cilia, but some have flagella
Simpler internal structures |
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Term
| Internal Structures of Prokaryotes. |
|
Definition
May have membranes to organize enzymes
Enzymes situated in a specific sequence
Promotes biological reactions to occur in order
Ex: photosynthetic bacteria
Photosynthesis occurs in membrane region
Light-capturing proteins and enzymes embedded on membrane |
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|
Term
Internal structures (cont.)
(nucleoid,plasmids) |
|
Definition
Lack membrane bound organelles
Nucleoid
Central region of cell
Contains:
Single, circular chromosome
(=long, coiled DNA strand)
Plasmids
Found outside of nucleoid
Small rings of DNA
Carry genes that give cell special properties
Ex: genes that enable cell to inactivate antibodies |
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|
Term
Internal Structures (cont.)
(Ribosomes, food granules) |
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Definition
Ribosomes
Similar to ribosomes in eukaryote chloroplasts and mitochondria
Smaller in size and contain different proteins
Food granules
Store energy-rich molecules (E.g. glycogen)
Not membrane bound
Lack: Chloroplasts, mitochondria, Golgi, ER |
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Term
| Tell me about the fluidity of the membrane. |
|
Definition
Based on orientation and bonds of phospholipids
No bonds between individual phospholipids
Hydrophilic heads
Orient towards intracellular and extracellular watery environments
Form hydrogen bonds with water molecules
Hydrophobic tails
Orient towards center of membrane
Some with unsaturated fatty acids in tail
Double bonds in tail - kinks
More double bonds = more fluid membrane |
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Term
| More unsaturated fatty acids =? |
|
Definition
More double bonds
More kinks |
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Term
| Fewer unsaturated fatty acids=? |
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Definition
Fewer double bonds
Fewer kinks |
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Term
| The degree of the membrane fluidity is based on and varies how? |
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Definition
Based on:
Level of fatty acid saturation (More kinks = more fluid)
Amount of cholesterol
Stabilizes bilayer
Make membrane less permeable to water- soluble substances
Varies between cells
Allows cells to perform different functions
Allows cells to function in different environments
Ex: Cells in low temperatures tend to be less fluid
Solution: more unsaturated fatty acids and less cholesterol |
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Term
| Why is Fluidity of Bilayer Important? |
|
Definition
Cells need to be able to change shape
Stiff cells would break apart- cell death
Eukaryotic cell membranes need to be in constant motion
Membrane-enclosed compartments bring materials into cell (e.g. food vacuole)
Membrane bound organelles move materials throughout cell (e.g. lysosomes)
Membrane bound organelles merge with membranes of other organelles (e.g. ER, Golgi) |
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Term
| Cell membranes are and function how? |
|
Definition
Surround cells & organelles within eukaryotic cells
Function of components
Phospholipid bilayer
Isolate cell contents from environment
Embedded proteins
Allow communication between cells
Create attachments in and break cells
Regulate biochemical reactions
Transport essential substances
Between cell and environment
Between organelles and cytoplasm |
|
|
Term
| Isolation of Cell Contents are and what do they do? |
|
Definition
Phospholipid bilayer:
Separates cytoplasm from extracellular environment
Maintains integrity of cytoplasm
Selective and incomplete
Hydrophilic biological molecules (Polar & water soluble)
Cannot pass through nonpolar, hydrophobic region of phospholipid bilayer
Ex: salts, sugars, amino acids
Small molecules
Can pass through phospholipid bilayer
Ex: water, oxygen, carbon dioxide
Larger, uncharged, lipid-soluble molecules
Can pass through phospholipid bilayer |
|
|
Term
| Embedded Proteins are and how do they function? |
|
Definition
1000s of different proteins possible
Many are glycoproteins (=protein with carbohydrates group)
Functions vary based on type of protein
Attachment
Communication
Receptor Proteins
Recognition Proteins
Regulate biochemical reactions
Enzymes
Transport
Channel Proteins
Carrier Proteins |
|
|
Term
| Attachment Proteins are and how do they function? |
|
Definition
Anchor cell membranes in various ways
Link cytoskeleton to extracellular matrix
Anchors cell in place within tissue
Link cytoskeleton to plasma membrane
Helps maintain cell shape
Help cells adhere to and move along surfaces
Form connections between adjacent cells |
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Term
| Receptor proteins are and? |
|
Definition
Respond to messages from other cells
Messages = molecules in bloodstream(e.g. hormones)
Conveys message to cell’s interior
Message binds to specific site on protein
Protein becomes activated (Often by changing shape)
Triggers responses in cell
Modification of protein
Chemical reactions
Cellular division
Release of molecules
Etc. |
|
|
Term
| Example of a receptor protein. |
|
Definition
Hormone: Adrenaline (Epinephrine)
“Fight or Flight Hormone”
Binds to specific receptor protein on muscle cells
Stimulate muscle cells to breakdown glycogen
Produces energy for muscle contraction |
|
|
Term
| Recognition Proteins are? example? |
|
Definition
Glycoproteins that serve as “cell makers”
Identify the cell as being “self”, not foreign
Prevent immune systems from attacking your own cells
Examples
MHC glycoprotein
Red blood cell sugar groups
Identify blood type as A,B,AB or O
During transfusions - blood types must match or immune system will attack and destroy red blood cells
Organ tissue cells
During transplants – cells must match or organ will be rejected by body |
|
|
Term
|
Definition
Proteins that promote chemical reactions to synthesize or breakdown biological molecules
Either span membrane or attach to membrane surface
Example
Enzymes for protein and carbohydrates synthesis of extracellular matrix
Web of proteins and glycoproteins just outside membrane that fills spaces between animal cells |
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|
Term
| Transport proteins are and? |
|
Definition
Regulate movement of hydrophilic molecules in & out of cell through plasma membrane
2 Types
Channel proteins
Channels that allow water molecules and certain ions to cross membrane along concentration gradient
Carrier proteins
Binding sites attach to molecules on one side of membrane, then “carry” molecule across membrane & release it on other side |
|
|
Term
|
Definition
any substance whose molecules can flow past one another
Include: gases, liquids and cell membranes |
|
|
Term
|
Definition
| substance that can be dissolved |
|
|
Term
|
Definition
fluid capable of dissolving a solute
water = universal solvent |
|
|
Term
|
Definition
| solvent containing one or more dissolved solutes |
|
|
Term
|
Definition
| amount of solute in a given amount of solvent |
|
|
Term
|
Definition
| = physical differences in properties between 2 regions |
|
|
Term
|
Definition
| Flow of energy from high temperature region to low temperature region |
|
|
Term
|
Definition
| Drives the movement of ions (Charged atoms) |
|
|
Term
|
Definition
| Movement of ions and molecules to reach a state of equilibrium |
|
|
Term
|
Definition
| difference in concentration of a substance between two parts within a fluid or across a membrane |
|
|
Term
| What is Concentration Gradient? |
|
Definition
Movement of ions and molecules from concentration to low concentration to reach equilibrium
Substance becomes evenly distributed
Ex: Dye in water
At first – dye is more concentrated in one area
Dye molecules disperse evenly throughout water
Uniform color of solution |
|
|
Term
| How does Movement Through Membranes work? |
|
Definition
Transport of ions and molecules across cell membrane is crucial for survival
Cell membrane
Selectively permeable: allows certain ions and molecules
through
Creates barrier to maintain gradients
2 ways for substances to get in & out of cell
Passive Transport
No energy required!
Substances move down concentration gradient
Energy requiring transport
Cell must expand energy to transport substances across membrane |
|
|
Term
| What is Passive Transport? |
|
Definition
Driven by differences in concentration gradients
Movement of substances across membrane until equilibrium is met
Concentration of substance is same on both sides of membrane
Types
Simple diffusion
Facilitated diffusion
Osmosis |
|
|
Term
|
Definition
Movement of:
Small, uncharged molecules
Ex: oxygen (O2), carbon dioxide (CO2)
Lipid-soluble molecules
Ex: alcohol, hormones, vitamins
Move from high concentration to low concentration
Cross membrane between phospholipids |
|
|
Term
| Facilitated Diffusion is? |
|
Definition
Movement of:
Ions (e.g. K+, Na+, Cl-, Ca2+)
Polar molecules (e.g. monosaccharides)
Too large to pass through phospholipids
Move from high concentration to low concentration
Cross membrane via transport proteins
Channel Proteins
Carrier Proteins |
|
|
Term
| Channel Proteins & Facilitated Diffusion are? |
|
Definition
Facilitate diffusion of specific ions through membrane via a channel/ pore
Interior of channel depends on ion it transports
Diameter of channel based on size of ion
Charge of lining based on charge of ion
Opposite charge of ion to attract ion
Ex: Cl- ion needs a channel lined with postivitve charges
May contain protein gate that open & close as needed |
|
|
Term
| Tell me about Carrier Proteins & Facilitated Diffusion |
|
Definition
Facilitate diffusion of molecules through membrane by binding to molecules
Active binding sites present on carrier protein
Molecule bonds with protein
Bond changes shape of protein
Change in shape allows molecule through
Molecules Only transported from high concentration to low concentrations |
|
|
Term
|
Definition
Movement of free water molecules across plasma membrane
Water molecules bound to other molecules are not “free” to move across membrane
Occurs through:
Phospholipid bilayer
Aquaporin channels
Channel proteins that transport water
Move from high concentration to low concentration
To reach equilibrium between 2 solutions |
|
|
Term
| What are Types of Solutions in Osmosis? |
|
Definition
Based on concentration of solutes within solution
If solute molecules > water molecules
Lower concentration of water = less water to give
If solute molecules< water molecules
higher concentration of water = more water to give
Determines the flow of water between 2 solutions
3 types
isotonic
hypertonic
hypotonic |
|
|
Term
|
Definition
Solutions with equal concentrations of solute
Also equal concentration of water
Movement of water: none or equal
Concentrations of solutions already at equal levels |
|
|
Term
| What are Hypertonic & Hypotonic Solutions? |
|
Definition
Hypertonic Solution
Higher concentration of solute
Lower concentration of water
less free water available to move
Hypotonic Solution
lower concentration of solute
higher concentration of water
more free water available to move
Water moves from hypotonic to hypertonic solution |
|
|
Term
| Roll of Osmosis in Cells? |
|
Definition
Extracellular fluid usually isotonic to cytoplasm
Ideal for survival of cell
If extracellular fluid is not isotonic then cells can die!
Example: Red blood cells
Isotonic extracellular fluid = no harm to cell
Hypertonic extracellular fluid = cells shrivel up and shrink
Water leaves cell due to more water
Hypotonic extracellular fluid cells swell, rupture and die
Water enters cell due to less water |
|
|
Term
| How does osmosis work in other living organisms? |
|
Definition
Unicellular organisms that live in water
Use energy to counteract osmosis
Remove excess water and salts via contractile vacuoles
Plants
Use central vacuole
Contents of vacuole hypertonic to cytoplasm
Cytoplasm is hypertonic to extracellular fluids
Water flows into cytoplasm then vacuole
Water in central vacuole provides support for plant |
|
|
Term
| Passive Transport Summary. |
|
Definition
Movement of substances across membrane
high concentration low concentration
no energy required
3 Types
Simple diffusion
Movement of molecules through bilayer
Facilitated diffusion
Movement of molecules through channel or carrier proteins
osmosis
Movement of free water through phospholipid bilayer or aquaporin channels |
|
|
Term
| Tell me about Energy Required Transport. What are the three different types? |
|
Definition
Require energy (ATP) to transport substances across membrane
Establishes concentration gradients necessary for movement of substances
Types
Active transport
Endocytosis
Exocytosis |
|
|
Term
| Tell me about active transport. |
|
Definition
Membrane proteins use energy from ATP
Movement of molecules and ions across membrane against concentration gradient
Movement from low concentration to high concentration
Used to restore concentration gradient after ions move into or out of cell |
|
|
Term
| Where does energy come from? |
|
Definition
Energy-carrying molecule = ATP
ATP donates energy to transport proteins
Energy comes from breaking bond of last phosphate group |
|
|
Term
| Tell me about Active Transport Proteins. |
|
Definition
Span width of membrane
Specialized carrier proteins
Possess 2 active binding sites
1st site – binds a particular molecule or ion
Located on protein inside or outside of membrane
2nd site – binds energy carrier molecule
Located on protein inside membrane only
Often called “Pumps”
Pump substances uphill against gradient
Low concentration to high concentration |
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Term
| What types and how do endocytosis function? |
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Definition
Engulfment of materials by the plasma membrane & transported into cell by vesicles
Movement of molecules too large to pass through membrane
Types (based on material to be transported)
Pinocytosis
Receptor-mediated endocytosis
Phagocytosis |
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Term
| What is Pinocytosis (“ Cell-drinking”)? |
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Definition
Moves liquids into cell
Process:
Small dimple forms in cell membrane
Extracellular liquid becomes surrounded by membrane
Vesicle containing liquid buds off into cytoplasm |
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Term
| What is Receptor-Mediated Endocytosis? |
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Definition
Moves specific molecules and complexes of molecules into cell
Molecule must be able to react with receptor
Ex: Packets of proteins and cholesterol
Uses specialized receptor proteins
Located in coated pits on plasma membrane
Pit deepens and membrane pinches off as coated vesicle
Molecules carried into cytoplasm of cell |
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Term
| What is Phagocytosis (“ Cell-eating”)? |
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Definition
Moves large particles into cell
Including whole microorganisms
Portions of membrane extend out and surround particle to form vesicle (= food vacuole)
Examples:
Amoebas
Extend membrane out as pseudopodia (“false feet”)
Pseudopodia fuse around prey to form food vacuole
White blood cells
Engulf and destroy foreign particles (e.g. bacteria) |
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Term
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Definition
Reverse of endocytosis
Moves materials out of cell
undigested particles and waste
Products made in cell (e.g. hormones)
Process:
Vesicle carries contents to plasma membrane
Vesicle’s membrane fuses with plasma membrane
Contents released out into extracellular fluid |
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Term
| Energy Required Transport Summary. |
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Definition
Movement of substances in or out of cell
Energy required= ATP
3 Types
Active transport
Movement of molecules and ions against concentration gradient via embedded proteins
Endocytosis
Movement of large materials into cell via
Pinocytosis – movement of fluids
Receptor- mediated endocytosis – movement of molecules
Phagocytosis – movement of
Exocytosis
Movement of large materials out of cell via vesicles |
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Term
| Tell me about Cell Connections. |
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Definition
Requires specialized on plasma membrane
Hold cells together
Avenue for communication
4 Types
Desmosomes
Tight Junctions
Gap Junctions
Plasmodesmata |
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Term
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Definition
Complex of proteins linked to intermediate filaments of cytoskeleton
Attach cells together
Found in tissues that must be resistant to tearing
Ex: skin, intestine, bladder
Very strong and flexible
Animal Cells ONLY |
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Term
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Definition
Involve attachment proteins embedded in plasma membranes
Proteins adhere together between cells
Proteins bond together tightly
Create a leak proof barrier between cells
Found in tissues that contain
a lot of water
Ex: skin, blood vessels, bladder
Animal cells ONLY |
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Term
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Definition
Involved in communication between cells
Channels of proteins that connect adjacent cells
Allow molecules to pass between cells
Hormones, nutrients, ions
Electrical signals
Very important in embryonic development
Animal cells ONLY |
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Term
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Definition
holes in cell wall lined with plasma membrane & filled with cytoplasmic fluid
Cytoplasm moves freely between cells
Carries: nutrients, water and hormones
Plant cells ONLY
Membrane-lined
channels connect
insides of adjacent cells |
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Term
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Definition
Energy = the capacity to do work
Work involves transfer of energy to an object to move it
Ex: running a marathon
energy is needed to move your arms and legs
Types of energy
potential energy= stored energy
Energy stored in molecules (e.g. sugars) & organelles
Kinetic energy= energy in action
Energy of movement
Ex: light, heat, electricity, moving object (e.g. runner) |
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Term
| Energy can be... and examples |
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Definition
Can be transformed from kinetic energy into potential energy
Examples
Photosynthesis
Kinetic potential
Kinetic energy of light is captured & stored as potential in chemical bonds of molecules
Penguin jumping into water
Potential Kinetic
Potential energy stored in chemical bonds converted to kinetic energy by muscle cells |
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Term
| What are the Laws of Thermodynamics? |
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Definition
Describe the quantity and quality of energy
1st Law of Thermodynamics
AKA: law of conservations of energy
energy can neither be created nor destroyed by ordinary processes but can change form
2nd Law of Thermodynamics
When energy is converted from one form to another, the amount of useful energy decreases
Useful energy is stroed in highly organized matter |
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Term
| 1st Law of Thermodynamics states? |
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Definition
Energy can neither be created nor destroyed
Example: your car
Initially: car’s energy is all potential energy stored in chemical bonds of fuel
As you drive: chemical bonds are broken & energy is released (potential Kinetic )
Only 25% of potential energy becomes kinetic energy
used to move car
Other 75% becomes heat |
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Term
| 2nd law of thermodynamics states? |
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Definition
Amount of useful energy decreases as energy changes form
Example: your car
Heat = less usable form of energy
Released out into environment
Useful energy is stored in highly organized matter
Example: gasoline in car
Gasoline molecule has an orderly arrangement of 8 carbon atoms usable energy
Burning of gasoline leads to a random arrangement of CO2 & H2O molecules less useable energy |
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Term
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Definition
Tendency towards disorder, randomness & less-useful energy
Countered by: energy being brought in from an outside source
Energy is used to stack the bricks up |
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Term
| How does life overcome entropy? |
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Definition
Living organisms accumulate useable energy and create orderly molecules
Get continuous input of energy from sunlight as kinetic energy
Use that energy to synthesize molecules and maintain order |
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Term
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Definition
Process that forms or breaks the bonds that hold atoms together
Convert reactants to products
Atoms and/or molecules combine to form new atoms &/or molecules
R1 + R2 P
R1 + R2 P1 + P2
Types of reactions
Exergonic= energy output
Endergonic= energy in |
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Term
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Definition
KA: Spontaneous reactions
Release energy = “Downhill” reactions
Reactants contain more energy than products
High energy reactants low energy product
Excess energy given off as heat
Example: Burning glucose (C6H12O6) |
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Term
| Endergonic Reactions are? |
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Definition
AKA: Non- spontaneous reactions
Require an input of energy (= uphill reaction)
Reactants contain less energy than products
Energy comes in from an outside sources
Example: synthesis of glucose (C6H12O6)
low energy CO2 & H2O form high energy glucose |
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Term
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Definition
Energy that gets a chemical reaction started
Required in all chemical reactions
All atoms are surrounded by negatively charged electrons
Energy is needed to force electron shells together
Amount of activation energy determines speed of reaction
Lower activation energy faster reaction
Higher activation energy slower reaction |
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Term
| Source of Energy for Reactions are? |
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Definition
Exergonic Reactions
Breakdown of sugars (E.g. Glucose)
Produces chemical energy to be used in cells
Energy can be directly used for:
Building complex molecules
Powering muscles contractions
Endergonic Reactions
Can’t use energy from glucose directly
Energy from glucose must be transferred to energy-carrier molecule (E.g. ATP)
ATP- ADP releases energy |
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Term
| Coupled Reactions are and function how? |
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Definition
Exergonic reactions provide energy for endergonic reactions
Some energy will be lost as heat (= useless energy)
Energy from exergonic reaction must be greater than energy needed for endergonic reaction
Example
Energy from glucose breakdown (exergonic) is used for protein synthesis (endergonic)
Exergonic reaction takes place in different part of cell than endergonic reaction
Energy transported within cell via ATP
Constant ATP synthesis must occur |
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Term
| Reversibility of Chemical Reactions is? |
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Definition
Reactants products
Important in living organisms
enables all metabolic demands to be met
metabolism = sum of all chemical reactions within a cell
Example: respiration
Oxygen(O2) must bind to hemoglobin for transport
If O2 can’t unbind, cells can’t use it and you will die |
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Term
| Tell me about Carbon Monoxide (CO) Poisoning. |
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Definition
Carbon monoxide = toxic gas
Produced by fuel- burning sources (cars, stoves, etc)
Symptoms: headaches, nausea, vomiting, death
What’s happening?
CO binds to hemoglobin in place of O2
O2 can’t be transported to tissues
Treatment:
100% Oxygen therapy
Reverses CO- hemoglobin bond
Must be done in time to save life |
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Term
| How To Speed Up Reactions. |
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Definition
add heat
Atoms & molecules are in constant motion at higher temperatures
electrons from neighboring atoms/ molecules collide and react with each other
Higher the temperature, faster the reaction
Add a catalyst
A molecule that speeds up a reaction without being used in the reaction |
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Term
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Definition
3 Important Properties
1. Reduce amount of activation energy needed to start reaction
2. Speed up both exergonic and endergonic reactions
Can not make endergonic reactions occur spontaneously
endergonic reactions still need energy brought in
3. Not consumed or permanently changed by reaction |
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Term
| Biological Catalysts = Enzymes are? |
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Definition
Composed primarily of proteins
Catalyze both exergonic and endergonic reactions
Properties
lower activation energy and speed up reactions
highly specific
Most enzymes only catalyze a single reaction involving specific molecules
Activity is closely regulated
Too much activity could be deadly |
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Term
| Tell me about enzyme structures. |
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Definition
3-D structure with an active site
Active Site
Formed by twisting & folding of amino acid chain
Site in which specific substrates (= reactants) enter
Determines function of enzyme
Enzyme fits together precisely with specific substrates
Ex: amylase enzyme
Only catalyzes breakdown of starch molecules
Starches are only molecule that can enter active site |
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Term
| Tell me how enzymes work. |
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Definition
Substrates enter active site in a specific orientation
Temporary bonds form between substrates and active sites
Shape of substrates and active site change
Specific chemical reaction is promoted
Substrates leave enzyme
enzyme returns to original shape |
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Term
| What are enzyme catalysts? |
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Definition
Coenzymes
Small non-protein helper molecules that bind to certain enzymes
Synthesized from water- soluble vitamins (e.g. Vit B)
Required for certain enzymes to function properly |
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Term
| What are the benefits of enzymes? |
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Definition
Lower activation energy for a reaction
Molecules synthesized or broken down in steps
Each step catalyzed by a specific enzyme
Activation energy for each step is then lowered
Overall activation energy is lowered
Allows for reactions to occur at lower body temperatures!
Control rate of energy release
sugars are not burned up all at once
Capture energy in ATP
Prevents loss of too much energy |
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Term
| Tell me about metabolic pathways. |
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Definition
Chemical reactions linked in a sequence
Each reaction is modified by a specific enzyme
Each reaction produces a specific product
Product used in following reaction until end product is reached
Involve synthesis & breakdown of molecules
Photosynthesis = produces high energy molecules
Glycolysis= breakdown glucose molecules
All pathways are directly/indirectly connected |
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Term
| Rate of reactions depend on? |
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Definition
Depends on amount of substrates or enzymes present
More substrates/enzymes faster reaction
increase substrate’s chance of binding with enzyme active site
levels increase until enzyme active sites are continuously occupied by substrate
Enzymes
Regulation of synthesis
Regulation of activity
Inhibition of activity |
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Term
| Tell me about Enzyme Activity Regulation. |
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Definition
Enzymes become active when & where needed
Some synthesized only in inactive form
Activated under specific conditions
Ex: Pepsin enzyme for protein-digestion
Inactive form (= pepsinogen) prevents enzyme from digesting cell that produced it
Activated by stomach acid (HCl) which exposes active site on enzyme
Pepsinogen + HCI-> pepsin |
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Term
| Enzyme Activity Inhibition types? |
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Definition
Inhibition = inactivation of an enzyme
Inhibition prevents
Substrate from being used up
Overabundance of product
Types of inhibition
Competitive Inhibition
Non-competitive Inhibition
Feedback Inhibition |
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Term
| Competitive Inhibition is? |
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Definition
Inhibitor molecule binds to active site instead of desired substrates
Competition for active site
Depends on concentration of substrate vs inhibitor
Reversible once substrate outnumbers & displaces product |
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Term
| Some Competitive Inhibitors are? |
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Definition
Methanol= toxic alcohol in antifreeze
Inhibitor of alcohol dehydrogenase
Methanol + alcohol dehydrogenase fomaldehyde
Can cause blindness and death
Reversed by increasing ethanol concentration
Ethanol= normal substrate for alcohol dehydrogenase
Ibuprofen(Advil)
Inhibitor of enzyme that catalyzes reactions associated with swelling pain and fever |
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Term
| Non-competitive Inhibition are? |
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Definition
Inhibitor molecule binds to a different site on enzyme & affects active site binding
Not influenced by substrate concentration
Active site becomes distorted or blocked
No competition for active site
Reversible or irreversible
AKA: Allosteric inhibition |
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Term
| Some Non-competitive Inhibitors are? |
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Definition
Nerve gases (sarin)
Permanently inhibit acetylcholinesterase
Breaks down acetylcholine to activate muscles
Acetylcholine build up & over-stimulates muscles
Can lead to to paralysis, respiratory & death
Penicillin
Inhibits bacterial enzyme that produces cell wall
Bacteria eventually bursts cell wall
Does not affect animal cells
Animal cells do not have a cell wall |
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Term
| Allosteric Regulation is? |
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Definition
Allosteric molecules bind to regulatory on enzyme
Allosteric activators – stabilize enzyme in active form
Allosteric inhibitors– stabilizes enzyme in inactive form
Regulate allosteric enzyme activity
Allosteric enzyme = enzyme that can easily easily switch from active form to inactive form
Example: ADP
Allosteric activator for ATP synthesis |
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Term
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Definition
Form of allosteric regulation
Cause metabolic pathways to stop when product concentration reaches optimal level
Enzyme at beginning of pathways is by end product of same pathway
End product = allosteric inhibitor
Once product is used up, pathway restarts
Example: ATP
Allosteric inhibitor of ATP synthesis |
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Term
| Influence of Environment on Enzymes is? |
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Definition
Enzymes only function in optimal conditions
Unfavorable conditions denatured enzyme
Loses specific 3-D configuration & ability to function
pH
Most enzymes work best in pH of 7.4
Protein-digesting pepsin prefers pH of -2.0
Protein-digesting trypsin prefers pH of -8.0
Temperature
Higher temps -> faster activity
Too high denaturation of enzyme
Colder temps halt reproduction & growth reactions in bacteria |
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