Ch. 5 The Working Cell Flashcards
Energy
Capacity to perform work
- measured by how it affects matter
- makes change possible
- needed by all organism
Kinetic
Energy of motion
Potential
Stored energy
Chemical Energy
Energy used by living cells/organisms
- type of potential energy
Thermodynamics
Study of energy transformations
What is the 1st Law of Thermodynamics?
Conservation of energy. Total energy is constant. Not created or destroyed.
What is the 2nd Law of Thermodynamics?
Entropy increases. When energy is transformed, some is lost as heat.
What are the two types of chemical reaction?
Exergonic and Endergonic
Exergonic (exothermic)
Energy out. Bonds are broken and heat released by reactants.
Endergonic (endothermic)
Energy in. Bonds formed and energy is stored by products.
What is energy coupling?
Combining exothermic to then produce endothermic. One reaction provides energy for another reaction.
What are the three products of oxygen and glucose?
Water, carbon dioxide, and ATP.
Why don’t cells just use glucose?
Glucose is too big/too much and more than the body can handle (110 kcal/mole). ATP is more manageable (7.3 kcal/mole).
What is Adenosine Triphosphate (ATP)?
Universal energy currency for life. Made of adenine, ribose, and 3 phosphates.
Activation Energy (Ea)
Amount of energy required for chemical reactions to occur. Energy barrier that prevents spontaneous reactions.
What are catalysts?
Substance that speeds up chemical reactions by lowering Ea.
What is an enzyme?
A biological protein catalyst made fo amino acids. Increases the rate of a reaction but not altered by it, so reusable (reversible). Catalyzes one specific reaction determined by structure.
What is a substrate?
A reactant that enzyme works on. The molecule that will be altered as it binds to the activation site of an enzyme.
What three situations lead to denaturation?
pH concentration, salt concentration, and temperature.
What are two non-protein helps for enzymes?
Cofactors and coenzymes.
What are cofactors?
Inorganic substances such as minerals that help an enzyme catalyze a metabolic reaction.
What are coenzymes?
Organic substances such as vitamins that helps an enzyme catalyze a metabolic reaction.
What are inhibitors?
Prevent enzyme activity.
- competitive and non competitive
What is an competitive competitor?
Resembles enzyme’s substrate so it blocks substrate from the active site.
What is a non-competitive?
Doesn’t resemble substrate but it blocks the active site.
Heat
Energy of movement of molecules in a body of matter.
Entropy
Measure of disorder
What is cellular respiration?
Energy releasing chemical breakdown of food molecules (glucose) and the storage of PE in form that cells can use to perform work (ATP)
What is cellular metabolism?
Chemical activities of cells
What is phosphorylation?
The transfer of a phosphate group usually from aTP to a molecule
What happens to ATP after hydrolysis?
A phosphate is removed. ATP turns into ADP. Energy is released.
What is negative feedback?
A controle mechanism so the reaction is inhibited by it’s products. The higher concentration of products then product inhibits process that made them.
Selective permeability
Property of biological membranes that allows some substances to cross more easily than other s and blocks the passage of other substances altogether.
What is the fluid mosaic?
Description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer of phospholipid.
What forms the phospholipid bilayer?
Phospholipid where head (phosphate) with is polar and a tail (2 fatty acid) which is non polar.
What is a receptor?
On or in a cell, a specific protein molecule whose shape fits that of a specific molecular messenger.
What is signal transduction?
In cell biology, a series of molecular changes that converts a signal on a target cell’s surface into a specific response inside a cell
What is diffusion?
Spontaneous movement of particles of any kind of where they are high concentrated to where they are low concentrated.
- passive transport
What is passive transport?
Diffusion of a substance across a biological membrane without any input of energy.
What is a concentration gradient?
Increase and decrease in the density of a chemical substance in an area.
- diffuse till equilibrium
Osmosis
Movement of water across a selectively permeable membrane
Hypertonic
Two solutions, one with greater solute concentration
- Cells will shrivel/die in this
Hypotonic
Two solutions, one with lower solute concentration
- Animal cells will grain water, swell, pop (lyse)
- Plant cells will be healthiest (cell wall prevents pop)
Isotonic
Solution having the same solute concentration as another
- Animal cell is isotonic
- Plant cell is flaccid and will wilt
Osmoregulation
Control of the gain/loss of water and dissolved solutes in an organism.
Facilitated Diffusion
The passage of a substance across a biological membrane down its concentration gradient, aided by specific transport protein via pore
- passive transport
Active Transport
The movement of a substance across a biological membrane against its concentration gradient, aided by a specific transport protein and requiring input of energy (ATP)
Exocytosis
Movement of materials out of a cytoplasm of a cell via membranous vesicles or vacuoles
Endocytosis
Movement of materials into the cytoplasm of a cell via membranous vesicles/vacuoles.
Phagocytosis
Cellular “eating”
- a cell engulfs macromolecules or cells/particles into its cytoplasm
Pinocytosis
Cellular “drinking”
- cell fluid and dissolved solutes into small membranous vesicles
Receptor-mediated endocytosis
Moment of specific molecules into a cell by the inward budding of membranous vesicles; contains proteins with receptor sites specific to the molecules being taken in
What is the primary role of mitochondria an chloroplast?
Harvest energy for cellular work
What is the internal membranes responsible for?
1) Structure, building of organelles
2) Partition the cell, create order
3) Provide surface area for reactions
What are the factors for selective permeability?
Size (Smaller is easier to get in) Lipid Soluble (More lipid soluble then easier to get in and dissolves) Uncharged particle charge (has a charge more difficult)
What is apart of the membrane structure?
Phospholipid Bilayer
Proteins
Pore
Glycolipid and glycoprotein
What is the propose of glycolipid and glycoprotein?
Cell recognition (ID tags).