Chapter Five The Dynamic Cell

Front 1

Energy

Back 1

is defined as the capacity to do work

Front 2

Potential energy

Back 2

is stored energy

Front 3

Kinetic energy

Back 3

is the energy of motion

Front 4

Calorie

Back 4

the amount of heat to raise the temperature of a gram of water one degree Celsius

Front 5

Kilocalories

Back 5

1000 calories used on nutrition label charts to describe a calorie

Front 6

Energy laws

Back 6

two which are called the laws of Thermodynamics

Front 7

Law 1 of Thermodynamics

Back 7

Energy cannot be created or destroyed but it can be changed from one form to another

Front 8

Law 2 of Thermodynamics

Back 8

Energy cannot be changed from one to another without a loss of usable energy ---Every conversion of results in the loss of usable energy in the form of heat

Front 9

entropy

Back 9

relates to the relative amount of disorganization the only way to bring about or maintain order is to add more energy

Front 10

ATP (adenosine triphosphate )

Back 10

is the energy currency of cells. cells use ATP to carry out nearly all of its activities, including synthesizing proteins, transporting ion across the plasma membranes, and causing organelles and cilia to move

Front 11

ATP is a nucleotide

Back 11

it contains adonosine,triphosphate the suger ribose and nitrogen (adenine)

Front 12

ATP

Back 12

easily loses the last Phosphate
ATP ---ADP + P this is more stable and energy is released as ATP breaks down

Front 13

ATP CYCLE

Back 13

ATP holds energy only for a short time before it is used in a reaction that uses energy. Then is rebuilt from ADP + P. Each ATP molecule undergoes about 10,000 cycles of synthesis and breakdown daily

Front 14

Our body uses about

Back 14

40kg (88 lbs ) of ATP daily is very nature as an effective energy carrier keeps it from storing energy

Front 15

ATP is rebuilt by

Back 15

cellular respiration and used to rebuild ATP mostly in the mitochondria

Front 16

ATP releases energy quickly

Back 16

which facilitates the speed of enzymatic reactions

Front 17

When ATP becomes ADP + P

Back 17

the amount of energy released is usually just enough for a biological purpose. Breaking down an entire carbohydrate or fat molecule would be wasteful since it would release more energy then needed

Front 18

The structure of ATP allows

Back 18

its breakdown to be easily coupled to an energy-requiring reaction

Front 19

Coupled reaction

Back 19

brings ATP breakdown together with a reaction that requires energy such as making a protein---the energy releasing reaction can drive the energy requiring reaction

Front 20

Muscle contraction

Back 20

myosin pull actin filament to the center of the cell and the musle shortens First mysin combines with ATP and only then does ATP breakdown to ADP + P the release of ADP +P from the molecule causes myosin to change shape and pull on the actin filiment

Front 21

Reactions do not occur

Back 21

haphazardly in cells chemical reactions in a cell usually occur in a particular order

Front 22

Metabolic pathway

Back 22

a series of linked reactions Metabolic pathway begin with a particular reactant and terminate with a product

Front 23

enzymes

Back 23

which are protein molecules that function as organic cataLYSTS TO SPEED CHEMICAL REACTIONS---enzymes can only speed reactions that are possible to begin with.

Front 24

molecules acted on by an enzyme are called

Back 24

substrates an enzyme converts substrates into products

Front 25

Active site

Back 25

small part of the enzyme at the active site the substrate fits into the enzyme seemingly as a key fits a lock most enzymes can fit only one substrate

Front 26

Induced fit model

Back 26

the active site undergoes a slight change in shape in order to accommodate the substrate(s) this facilitates the reaction that occurs and the active site returns to its original shape

Front 27

Enzyme inhibition

Back 27

occurs when an active enzyme is prevented from combining with its substrate

Front 28

Feedback inhibition

Back 28

when a product is in abundance, it competes with the substrate for the enzyme's active site. as the product is used up inhibition is reduced and then more product can be produced therefore the product stays within a certain range

Front 29

energy of activation

Back 29

enzymes lowers the amount of energy required for a reaction to occur

Front 30

Solution

Back 30

contains both a solute and a solvent----ie salt (solute) in water (solvent)

Front 31

Facilitated diffusion

Back 31

occurs when an ion or molecule diffuses across a membrane faster then expected either by way of a specific channel protein or with the assistance of a carrier protein

Front 32

Water, a polar molecule, moves across the membrane through channels called

Back 32

aquaporins this is why water can cross a membrane much faster than expected

Front 33

Osmosis

Back 33

is the diffusion of water across a semipermeable membrane, from an area of higher concentration to an area of lower concentration

Front 34

isotonic solutions(iso same as)

Back 34

in which cells neither gains nor loses water that is the concentration of water is the same on both sides of the membrane

Front 35

Hypotonic solution (hypo less then)

Back 35

cells placed in this solution gain water outside the cell the concentration of water is greater than inside the cell--the cell will take on water and can burst

Front 36

Hypertonic solution (hyper more than)

Back 36

Cells put in this type of solution lose water outside the cell, the concentration of solute is higher and the concentration of water is lower Animal cells shrink plant cells also shrink from the cell wall called plasmolysis

Front 37

Hypertonic solution (hyper more than)

Back 37

Cells put in this type of solution lose water outside the cell, the concentration of solute is higher and the concentration of water is lower Animal cells shrink plant cells also shrink from the cell wall called plasmolysis

Front 38

Turgur pressure

Back 38

is important to plant cells this helps them to stand

Front 39

Plasmolysis

Back 39

shrinking of the cytoplasm due to osmosis in plants----cut flowers placed in salty water will wilt due to plasmolysis

Front 40

Active transport

Back 40

during active transport molecules or ions move through the plasma membrane accumulating on one side of the cell

Front 41

Sodium-potassium pump

Back 41

is a special protein that is vital in nerve conduction, undergoes a change in shape that allows it to combine alternately with sodium ions and potassium ions

Front 42

Exocytosis

Back 42

digestive enzymes and hormones use use moleculesd transported out of the cell

Front 43

Endocytosis

Back 43

when sells take in substances by vesicle formation

Front 44

If the material taken in is large , such as a food particle or another cell the process is called

Back 44

phagocytosis

Front 45

Pinocytosis

Back 45

occurs when vesicles from around a liquid or very small particles

Front 46

Receptor-mediated endocytosis

Back 46

receptors for a particular substances are found at one location in the plasma membrane called the coated pit These are more selective and much more efficient then ordinary pinocytosis

Front 47

Exocytosis

Back 47

digestive enzymes and hormones use use moleculesd transported out of the cell

Front 48

Endocytosis

Back 48

when sells take in substances by vesicle formation

Front 49

If the material taken in is large , such as a food particle or another cell the process is called

Back 49

phagocytosis

Front 50

Pinocytosis

Back 50

occurs when vesicles from around a liquid or very small particles

Front 51

Receptor-mediated endocytosis

Back 51

receptors for a particular substances are found at one location in the plasma membrane called the coated pit These are more selective and much more efficient then ordinary pinocytosis