LECTURE 7: THE WORKING CELL

energy

defined as the capacity to cause change

chemical energy

arises from the arrangement of atoms and can be released by a chemical reaction.

thermodynamics

the study of transformations of energy, using heat as the most convenient form of measurement energy.

kinetic energy

energy of motion

potential energy

the energy an object has because of its location or structure

heat

a type of kinetic energy contained in the random motion of atoms and molecules

entropy

a measure of the amount of disorder, or randomness, in a system.

calories

the amount of energy that can raise the temperature of 1 gram of water by 1°C

1000 calories

how many calories are in a 1 kilocalories(kcal)?

ATP

acts like an energy shuttle, storing energy obtained from food and then releasing it as needed at a later time.

adenosine triphosphate

ATP stands for

ATP power

release the phosphate at the tip of the triphosphate tail that makes energy available to working cells.

ADP

two phosphate groups.

enzymes

a living organism contains a vast collection of chemicals, and countless chemical reactions constantly change the organism’s molecular makeup.

metabolism

total of all the chemical reactions in an organism

enzymes

proteins thats speed up chemical reactions without being consumes by those reactions.

activation energy

the energy that must be invested to start a reaction, it activates the reactants and triggers the chemical reaction

catalysts

accelerate particular reactions by lowering the amount of activation energy required to initiate the reaction.

substrate

the selectivity is based on the enzyme’s ability to recognize a certain reactant molecule called_________.

active site

a region of the enzyme called_________ has a shape and chemistry that fits the substrate molecule.

feedback regulation

keeps the cell from wasting resources that could be put to better use.

plasma membrane

consist of a double layer of fat with embedded proteins.

selectively permeable

all biological membranes are________- that only allow certain molecules to pass

diffusion

movement of molecules spreading out evenly into the available space.

passive transport

cell does not expend any energy for the diffusion to happen

concentration gradient

from where the substance is more concentrated to where it is less concentrated.

facilitated diffusion

assisted transport, a type of passive transport because it does not require the cell to expend energy.

osmosis

reduces the difference in solute concentrations and changes the volumes of the two solutions, water across a selectively permeable membrane is called________.

solute

a substance that is dissolved in a liquid solvent.

solution

resulting mixture is called a _________.

hypotonic solution

its concentration gradient from an area of higher concentration.

hypertonic solution

to one of lower water concentration.

isotonic

solutions of equal solute concentration

osmoregulation

control of water balance

turgor (pressure)

necessary for plants to retain their upright posture and the extended state of their leaves.

active transport

requires that a cell expendenergy to move molecules across a membrane

exocytosis

large molecules such as proteins are much too big fit through the membrane

releases waste outside the cell

vesicles

traffic into and out of the cell depends on the ability of the cell to package large inside sacs called________.

endocytosis

cell takes material in via vesicles that bud inward

phagocytosis

(cellular eating) a cell engulfs a particle and packages within a food vacuole