Bio ch 4
Card Set Information
Bio ch 4
What is a catabolic reactions?
A cellular reaction that breaks down complex molecules such as sugar to make their energy available for cellular work
what is an anabolic reactions?
metabolic reaction that requires energy to assemble simple substances into more complex molecules
what is an exergonic reactions?
reaction that has a negative changeG because it releases free energy
what is an endogonic reactions?
reaction that can proceed only if free energy is supplied
What is potential energy?
Energy that is stored
what is kinetic energy?
Energy of motion
What is the 1st law of thermodynamics
The amount of energy in the universe is constant
energy can be transferred and transformed but it cannot be created or destroyed
what is the second law of thermodynamics?
the entropy of the universe increases with every energy transfer or transformation
During every (g) transfer or transformation, some (G) is unusable and is often lost as heat
What is a spontaneous process?
can perform work only when its moving towards equillibrium
Occurs without outside help
More free(G)--->less stable--->greater work capacity
What are the three types of cellular work?
What is an enzyme?
Protein that accelerates the rate of a cellular reaction
what do enzymes do?
speed up reactions by lowering the activation energy required to start the reaction.
what is an active site?
The region of an enzyme to which substrates bind and where catalysis occurs
what is a substrate?
the particular reacting molecule or molecular group that an enzyme catalyzes
What is a product?
An atom or molecule leaving a chemical reaction
The end result of a chemical reaction
what is meant by the enzyme-substrate complex?
When substrate binds to active site of the enzyme and is ready for reaction to occur
What is activation energy?
The intial imput energy needed to start a reactoin
What are some examples of environmental factors that affect enzyme activity?
chemicals that specifically influence enzymes
What is entropy?
Disorder in Thermodynamics
What is ATP?
what is phosphorylation?
The addition of a phosphate group to a molecule
what are energy couples reactoins?
The process in living cells by which the hydrolysis of ATP is coupled to an endergonic reaction so that energy is not wasted as heat
what is passive transport?
The transport of substances across cell membranes without expenditure of energy, as in diffusion
what is active transport?
The mechanism by which ions and molecules move against the concentration gradient across a membrane, from the side with the lower concentration to the side with the higher concentration
what is facilitated transport?
Mechanism by which polar and charged molecules diffuse across membranes with the help of transport proteins
what is bulk transport?
mechanism by which extracellular water is taken into a cell toegether with any molecules that happen to be in solution in the water
what is exocytosis?
In Eukaryotes, the process by which a secretory vesicle fuses with the plasma membrane and releases the vesicle contents to the exterior
what is endocytosis?
In Eukaryotes, the process by which molecules are brought into the cell from the exterior involving a bulging in of the plasma membrane that pinches off to form an endocytic vesicle
what is phagocytosis?
Process in which some types of cells engulf bacteria or other cellular debris to break them down
What are ribozymes?
An RNA-based catalyst that is part of the biochemical machinery of all cells