Chapter 4 - Life's Energy

Question 1

Energy

Answer 1

The ability to do work - to move matter.

Question 2

Potential energy

Answer 2

stored energy available to do work. Examples: chemical energy, stored in bonds; concentration gradient across a membrane; bike at the top of a hill; energy bar.

Question 3

Kinetic Energy

Answer 3

Energy in motion; any moving object possesses this form of energy. Examples: light and sound; thermal heat; moving objects

Question 4

Calorie (cal)

Answer 4

the amount of energy required to raise the temperature of 1 gram of water from 14.5 degrees C to 15.5 degrees C.

Question 5

Kilocalorie (kcal)

Answer 5

the measurement for energy content in food; one kilocalorie equals 1,000 calories. 1 Food calorie (with Capitol C) is in reality in kilocalorie, not 1 calorie.

Question 6

Thermodynamics

Answer 6

the study of energy transformations

Question 7

First Law of Thermodynamics

Answer 7

The law of energy conservation. It states that: energy cannot be created or destroyed, although energy can be converted to other forms. this means the total amount of energy in the universe does NOT change.

Question 8

Two most important energy transformations:

Answer 8

Photosynthesis and cellular respiration.

Question 9

Photosynthesis, nutshell explanation:

Answer 9

plants and some microbes use carbon dioxide, water, and the kinetic energy in sunlight to produce sugars that are assembled into glucose and other carbohydrates.

Question 10

Cellular Respiration, nutshell explanation:

Answer 10

Energy-rich glucose molecules change back to carbon dioxide and water, liberating the energy necessary to power life.

Question 11

Second Law of Thermodynamics

Answer 11

States that all energy transformations are inefficient because every reaction loses some energy to the surroundings as heat.

Question 12

Entropy

Answer 12

the measure of the randomness of the disorder and loss of heat/energy in the universe. Organisms can increase in complexity as long as something else decreases in complexity by a greater amount.

Question 13

Metabolism

Answer 13

All of the chemical reactions in cells. Each reaction rearranges atoms into new compounds and each reaction either absorbs or releases new energy.

Question 14

Endergonic reactions

Answer 14

Requires an input of energy to proceed. The products contain MORE energy than the reactants…typically build complex molecules from simpler components. Photosynthesis thesis is an example of this - Glucose contains more potential energy than what goes into the reaction, which is water and carbon dioxide.

Question 15

Exergonic reactions

Answer 15

Reaction releases energy. Products contain LESS energy than the reactants…typically break down large, complex molecules into their simpler components. Cellular respiration is an example - water and carbon dioxide have less potential energy than what goes into it, which is glucose.

Question 16

Oxidation-reduction (redox) reactions

Answer 16

transfer energized electrons from one molecule to another

Question 17

Oxidation

Answer 17

A loss of electrons - and a corresponding loss of energy - from a molecule, an atom, or an ion. An electron donor is “being oxidized” when it donates (an) electron(s) to another molecule, etc. this half of the chemical reaction is an exergonic reaction, since energy is being removed.

Question 18

Reduction

Answer 18

A gain of electrons - and a corresponding gain of energy. The electron receiver is “being reduced” when it receives (an) electron(s) from a molecule that is being oxidized. This half of the chemical reaction is an endergonic reaction, since energy is being added.

Question 19

Electron Transport Chain

Answer 19

Each protein accepts an electron from the molecule before it and passes it on to the next. These molecules act as electron carriers.

Question 20

Adenosine Triphosphate (ATP)

Answer 20

A molecule whose covalent bonds temporarily store much of the energy that is released during exergonic reactions just long enough to power subsequent endergonic reactions. In eukaryotic cells, the mitochondria produces most of a cell’s ATP. ATP is the “go-between” that links endergonic and exergonic chemical reactions

Question 21

Components of ATP:

Answer 21

Nitrogen-containing base adenine
5-carbon sugar ribose
3-phosphate groups, which each have a negatively charged oxygen atom.

Question 22

Coupled reactions

Answer 22

Simultaneous reactions in which one provides the energy that drives the other.

Question 23

Phosphorylating

Answer 23

When a cell transfers its phosphate group to another molecule.

Question 24

Enzyme

Answer 24

an organic molecule that catalyzes (speeds up) a chemical reaction without being consumed. Most are proteins, although some are made from RNA.

Question 25

Activation energy

Answer 25

The amount of energy required to start a reaction.

Question 26

How an enzyme works:

Answer 26

Enzymes bring reactants (substrates) into contact with one another, so that less energy is required for the reaction to proceed.

Question 27

active site

Answer 27

The region to which the substrates bind - substrates fit like puzzle pieces onto the enzyme, an example of how enzymes are specific to each substrate.

Question 28

Inhibitors to enzyme activity

Answer 28

If the pH, salt content, or temperature are too high or too low, this can denature the enzyme and it will stop working.

Question 29

Cofactors

Answer 29

nonprotein "helpers" for enzymes...substances that must be present for an enzyme to catalyze a chemical reaction. Are often oxidized or reduced during the reaction, but are not consumed and return to their original state the reaction is complete.

Question 30

Negative feedback

Answer 30

Used to help regulate a metabolic pathway - also called feedback inhibition, in which a change triggers action that reverses change. Works in two main ways: noncompetitive inhibition, and competitive inhibition

Question 31

Noncompetitive Inhibition

Answer 31

Product molecules bind to the enzyme at a location OTHER than the active site, in a way that alters the enzyme's shape so it can no lo get bind the substrate.

Question 32

Competitive Inhibition

Answer 32

The product of a reaction binds to the enzyme's ACTIVE SITE, preventing it from binding to another substrate.

Question 33

Enzyme Inhibitors

Answer 33

Noncompetitive inhibition and competitive inhibition

Question 34

Positive feedback

Answer 34

a process that reinforces an existing condition...an example is blood clotting; once the clot forms, the reactions accelerate, which further stimulates the clotting, speeding up the reactions even more. eventually negative feedback kicks in, however, shutting the pathway down. **positive feedback is MUCH rarer in orgs isms than negative feedback**

Question 35

Selectively permeable

Answer 35

Means that some substances pass through the phospholipid bilayer, and others require help to pass through from proteins. The presence of proteins in a phospholipid bilayer are what make it selective permeable

Question 36

Gradient

Answer 36

Describes any differences in concentration solution between two neighboring regions.

Question 37

Concentration gradient

Answer 37

When a solute is more concentrated in one region than in a neighboring region. If a substance moves from an area where it is more concentrated to an area where it is less concentrated, it is said to be "moving down" or "following" its concentration gradient.

Question 38

Passive transport

Answer 38

when a substance moves from across a membrane without the direct expenditure of energy. ALL forms of passive transport involve diffusion.

Question 39

Diffusion

Answer 39

The spontaneous movement of a substance from a region where it is more concentrated to a region where it is less concentrated. Diffusion is passive transport, because it does NOT require any energy output.

Question 40

Simple diffusion

Answer 40

A form of passive transport, where a substance moves down its concentration gradient without the use of a transport protein. Small, non polar molecules that can freely pass through the membrane.

Question 41

Osmosis

Answer 41

The simple diffusion of water across a selective permeable membrane. Water will diffuse down its own concentration gradient toward where the high solute concentration it.

Question 42

Isotonic

Answer 42

When a cell's interior solute concentration is the same as the concentration outside of the cell.

Question 43

Hypotonic

Answer 43

When the solute concentration outside of a cell is lower than the concentration inside of the cell. Water moves inside the cell from outside, cells plump up and can even burst.

Question 44

Hypertonic

Answer 44

When the solute concentration outside of a cell is higher than the concentration inside of the cell. Water moves outside the cell from the inside, cells shrink and can even die due to loss of water.

Question 45

Turgor pressure

Answer 45

The resulting force of water against the cell wall in plant cells

Question 46

Facilitated diffusion

Answer 46

A form of passive transport in which a membrane protein assists the movement of a polar solute DOWN its concentration gradient. Facilitated diffusion releases e energy because the solute moves from where it is more concentrated to where it is less concentrated.

Question 47

Active transport

Answer 47

When a cell uses a transport protein to move a substance AGAINST its concentration gradient, from where it is less concentrated to where it is more concentrated. Cells expend energy and use ATP when this type of transport takes place.

Question 48

Sodium-potassium pump

Answer 48

A protein use in the membranes of most animal cells, and helps facilitate active transport. It uses ATP as an energy source to expel three NA+ for every two K+ it admits.

Question 49

Transport vesicle

Answer 49

Helps transport large particles or groups of small particles across a cell membrane. A small sac that can pinch off, or fuse with, a cell membrane.

Question 50

Endocytosis

Answer 50

A process in which a cell membrane engulfs fluids and large molecules to bring them into a cell. Two main forms are Pinocytosis and Phagocytosis

Question 51

Phagocytosis

Answer 51

When the cell captures and engulfs large particles, such as debris or even another cell. The vesicle forms with a lysosome, and hydrolytic enzymes dismantle the cargo.

Question 52

Pinocytosis

Answer 52

When the cell engulfs small amounts of fluids and dissolved particles.

Question 53

Exocytosis

Answer 53

The opposite of endocytosis, exocytosis uses vesicles to transport fluids and large particles OUT of the cell