Biology (Chp 7-9)

Front 1

membranes are fluid

Back 1

individual molecules in the membrane have the ability to shift position

Front 2

membranes are mosaic

Back 2

they are made up of several types of molecules(most are phospholipids and proteins)

Front 3

Fluid mosaic model

Back 3

the membrane is a fluid structure with a “mosaic” of various proteins embedded in or attached to a double layer (bilayer) of phospholipids.

Front 4

How do unsaturated lipids affect cell membranes?

Back 4

Unsaturated hydrocarbon tails are “kinky” and prevent close packing so they remain fluid at lower temperatures. Cells may change the lipid content of their membranes (% of unsaturated lipids) in response to changing temperatures.

Front 5

the difference between integral and peripheral proteins?

Back 5

integral proteins are into the membrane, while peripheral proteins are attached or stick to a protein

Front 6

Integral proteins

Back 6

penetrate the hydrophobic core of the lipid bilayer

Front 7

Peripheral proteins

Back 7

are not embedded but attach to either surface of the membrane, many at integral proteins

Front 8

What is the function of the oligosaccharides found in the glycoproteins and glycolipids of cell membranes?

Back 8

These surface molecules allow cells to recognize each other. Function is that is usually branches to oligosaccarides may ttach to proteins on the outside face, forming glycoproteins, or sometimes to lipids forming glycolipids

Front 9

What is the role of cholesterol in cell membrane?

Back 9

Acts as temperature buffer; resisting changes in membrane fluidity that can be caused by changes in temperature.

Front 10

What kind of molecules pass easily through plasma membrane? Why?

Back 10

Nonpolar molecules(O2, CO2, Hydrocarbons) are hydrophobic and therefore dissolve in the lipid bilayer of the membrane and cross it easily without the aids of membrane proteins. The smaller the size of the hydrophobic molecule, the faster it crosses.

Front 11

What is a concentration gradient?

Back 11

In the absence of other forces, will diffuse from where it is more concentrates to where it is less concentrated

Front 12

Explain how transport proteins function.

Back 12

Cell membranes are impermeable to charged and polar molecules, meaning that these molecules cannot cross them spontaneously. Some transport proteins are intrinsic to cell membranes and facilitate the transport of polar molecules across the membranes. Channel proteins func. by having a a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane. Carrier proteins, hold onto their passengers and change shape in a way that shuttles them across the membrane.

Front 13

diffusion

Back 13

mechanism that can move molecules across membranes; movement of areas of high concentration to low concentration

Front 14

osmosis

Back 14

the diffusion of H2O across a selectively permeable membrane, such as a biological one

Front 15

passive transport

Back 15

diffusion of a substance across a biological membrane; osmosis specialized form of diffusion which requires no energy.

Front 16

Why does O2 continually diffuse into most healthy, living cells?

Back 16

O2 will continue diffusing into a cell as long as there is a higher concentration of O2 outside of the cell than inside the cell

Front 17

hypertonic

Back 17

has more solute than another solution; higher conc of solute

Front 18

hypotonic

Back 18

has less solute than another solution; least conc of solute

Front 19

isotonic

Back 19

has the same amount of solute as another solution

Front 20

Tonicity

Back 20

ability of a solution to cause a cell to gain or lose water.

Front 21

Animal cell happy when

Back 21

when its isotonic

Front 22

Animal cell that is hypertonic

Back 22

Shriveled; water coming out

Front 23

Animal cell that is hypotonic

Back 23

lysis it burst; water coming in

Front 24

Animal that is isotonic

Back 24

Normal; water coming in and out equally

Front 25

Plant cell happy when

Back 25

when its turgid; hypotonic

Front 26

Plant cell that is hypertonic

Back 26

plasmolyzed; water coming out

Front 27

Plant cell that is hypotonic

Back 27

turgid; water coming in

Front 28

Plant cell that is isotonic

Back 28

flaccid; water coming in and out equally

Front 29

What is facilitated diffusion?

Back 29

Can not diffuse into a cell without the help of a transport protein; form of passive transport

Front 30

How does active transport differ from passive transport?

Back 30

Passive transport does not require energy while active transport does. Also passive transport goes from higher to lower conc, while active transport goes from lower to higher conc.

Front 31

Passive transport

Back 31

when molecule travels from a higher concentration to lower concentration through a concentration gradient.

Front 32

Active transport

Back 32

when a molecule travels from a region of lower concentration to a region of higher concentration against the concentration gradient.

Front 33

How do cells maintain membrane potentials?

Back 33

The membrane potential is maintained by ion pumps( such as the Na+/K+ pump, which are electrogenic.
First, membrane potential is the voltage across a membrane. Membrane proteins tend tend to pump more(+) ion out than in and more (-) ions in than out. All these (-) molecules inside the cell make the extracellular fluid negative, which causes an electrical difference across the membrane, which is called the membrane potential.

Front 34

Membrane potential

Back 34

voltage across a membrane

Front 35

Main electrogenic pump for plants, fungi and bacteria..

Back 35

proton pump

Front 36

Main electrogenic pump for animals

Back 36

Sodium potassium pump

Front 37

Exocytosis

Back 37

cell secretes molecules by forming vesicles and fusing them with the plasma membrane

Front 38

Endocytosis

Back 38

a vesicles forms by invagination (a bending inward) of the plasma membrane

Front 39

Explain the 3 types of endocytosis.

Back 39

• Phagocytosis- cellular “eating”: forms food vacuoles and usually involves formation of pseudopodia (exm: amoebas and macrophage cells)
• Pinocytosis- cellular “drinkin”: non selective process that takes in H2O and substances in solution
• Receptor-mediated endocytosis- specific receptor proteins line the vesicle that is created from the plasma membrane

Hint 39

phagocytosis
pinocytosis
receptor mediates endocytosis

Front 40

Metabolism

Back 40

all of the chemical processes that occur in an organism (exm: polymer synthesis, hydrolysis, cellular respiration, and photosynthesis)

Front 41

Catabolism

Back 41

break down complex molecules to simpler molecules. (emx: cellular respiration breaks down glucose into CO2, H2O and E

Front 42

Anabolism

Back 42

consumes energy to build complicated molecules from simpler ones. (aka biosynthetic pathways)

Front 43

Kinetic energy

Back 43

energy of motion; relative motions of objects (exm: heat or thermal (movement of molecules) and light (movement of photons)

Front 44

Potential energy

Back 44

stored energy, due to the arrangement or position of matter (exm: chemical energy (due to the arrangement of atoms in molecules)

Front 45

1st law of thermodynamics

Back 45

Energy can be transferred and transformed, but it cannot be created or destroyed. (aka principle of conservation of energy) (exm: the chemical(potential) energy in food will be converted to the kinetic energy of the cheetahs movement; the quantity of energy always remains the same, but the quality doesn't because it may be transferred

Front 46

2nd law of thermodynamics

Back 46

every energy transfer or transformation increases the disorder (entropy) of the universe or for a process to occur spontaneously it must increase the entropy of the universe. (exm: disorder is added to the cheetah’s surroundings in the form of heat and the small molecules that are the by products of metabolism.

Front 47

If the universe is slowly running down and all systems tend toward disorder, how do living things grow and become more orderly?

Back 47

Living things decrease their own entropy by increasing the entropy of their surroundings. They get bigger through heat; as heat increases so does entropy

Front 48

T/F Spontaneous reactions increase the entropy of the universe.

Back 48

True, according to the 2nd law of thermodynamics (for a process to occur spontaneously it must increase the entropy of the universe)

Front 49

System

Back 49

the matter under study

Front 50

surroundings

Back 50

the rest o the universe

Front 51

open system

Back 51

allow E transfer btw. system and surroundings, while closed or isolated doesnt

Front 52

G- Gibbs Free Energy

Back 52

energy available for work at a given temp. in Kelvin(Temp; K+ 273 + C); its inversely proportional with S(entropy) as G decreases, S increases and vice versa, but H(enthalpy) stays the same.

Front 53

H

Back 53

total energy in a system or enthalpy

Front 54

S

Back 54

entropy; a measure of disorder

Front 55

Formula for G

Back 55

G= H-TS

Front 56

If /\G>0, what can we say about the reaction?

Back 56

This reaction is not spontaneous; , spontaneous reactions are exergonic.

Front 57

At equilibrium, what is /\G?

Back 57

For a system at equilibrium, G is at its lowest possible value in the system. /\G=0 and no work can be done.

Front 58

T/F Catabolic reactions in living systems usually produce ATP.

Back 58

True

Front 59

What is the energy of activation(EA)?

Back 59

In order for molecules to react they must collide with sufficient E to break their bonds. Its also the amt of energy needed to push the reactants over energy barrier

Front 60

What is the function of enzymes?

Back 60

Enzymes are biological catalyst than lower the Ea, most are proteins and they also speed up the rates of reactions.

Front 61

Explain induced fit.

Back 61

Induced fit brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reactions. When the substrate enters the active site, it induces a change in shape of the proteins. This change allows more weak bonds to form, causing the active site to enfold (changes its shape slightly the substrate and hold it in place.

This binding triggers a change in shape of the enzyme substrate complex, which allows for a closer fit btw. the two molecules

Front 62

What is the name of the structure that results from enzyme substrate binding?

Back 62

Enzyme substrate complex- the enzyme binds to its substrate (or substrates when 2 or more reactants).

or

Active site- specific portion of an enzyme that binds the substrate by means of multiple weak interactions.

Front 63

Cofactor

Back 63

enzymes that require the presence of another molecule in order to function properly; they can also be organic(aka coenzymes) or inorganic compounds (metal ions Zn, Fe, Cu)

Front 64

Coenzyme

Back 64

an organic molecule serving a a cofactor. Perform crucial functions for catalysis.

Front 65

Explain the difference between competitive and noncompetitive inhibition?

Back 65

Noncompetitive inhibition, do not directly compete with substrate to bind to the enzyme to the active site. Instead, they impede enzymatic reactions by binding to another part of the enzyme.

Front 66

What is allosteric regulation?

Back 66

Allosteric regulations occurs in proteins made of 2 more subunits, each with an active site or describes any case in which proteins function at one site is affected by the binding of a regulatory molecule to a separate site.

Front 67

Competitive inhibition

Back 67

mimics the substrate, competing for the active site.

Front 68

Noncompetitive inhibition

Back 68

binds to the enzyme away from the active site, altering the shape of the enzyme so that even if the substrate can bind, the active site functions less effectively.

Front 69

Cellular respiration

Back 69

Cellular Respiration- the catabolic pathways of aerobic (oxygen is consumed as a reactant along with the organic fuel) and anaerobic respirations (some prokaryotes use substances other than oxygen as reactants in a similar way the process harvests chemical energy without using oxygen at all), which breaks down organic molecules for the production of ATP. It uses carbs, fats and proteins as fuel.

Front 70

What is a redox reaction?

Back 70

A transfer of one or more electrons from one reactant to another. In a redox reaction, the loss of electrons from one substance is called oxidation, and the addition of electrons to another substance is known as reduction.

Front 71

Describe the electron transport chain and what it accomplishes. pg. 165

Back 71

Electron transport chain is a series of molecules attached to the inner membrane of mitochondria. O accepts the e-‘s, along with protons, at the end of the chain forming H2O.

Consist of a one carrier molecule to the next in a series of redox reactions, losing a small amount of energy in with each step until they finally reach oxygen.

Breaks the "fall" of electrons in the reaction into a series of smaller steps and stores some of the released energy in a form that can be used to make ATP.

Front 72

What is the role of NAD+ in cellular respiration? Bus exm pg.165

Back 72

The role of NAD+ in cellular respiration is an electron shuttle. Full name for NAD+; nocotinamide adenine dinucleotide, describes its structure; the molecule consists of two nucleotides joined together at their phosphate groups. As an electron acceptor, NAD+ functions as an oxidizing agent during respiration.

Front 73

Where do the electrons and protons removed from glucose wind up?

Back 73

The electrons and protons removed from glucose wind up are transferred to NAD+

Front 74

Explain the net energy yield of cellular respiration per molecule of glucose( include the e- shuttle).

Back 74

Net energy yield of cellular respiration per molecule of glucose; the tally adds 4 ATP produced directly by substrate level phosphorylation during glycolysis and the citric acid cycle to many more molecules of ATP generated by oxidative phosphorylation. Each NADH that transfers a pair of electrons from glucose to the electron transport chain contributes enough to the proton motive force to generate a maximum of 3 ATP.

Front 75

Explain the 2 major types of fermentation.

Back 75

• Alcohol fermentation- pyruvate is converted to ethanol(ethyl alcohol) in two steps. First, releases carbon dioxide from the pyruvate, which is converted to the 2 carbon compound aldehyde. Second, acetaldehyde is reduced by NADH to ethanol. This regenerates the supply of NAD+ needed for the continuation of glycolysis.
• Lactic acid fermentation- pyruvate is reduced directly by NADH to form lactate as an end product, with no release of O2(lactate is the ionized version of lactic acid)

Hint 75

Alcohol fermentation
Lactid acid fermentation

Front 76

Which organisms are facultative anaerobes? What does the term mean?

Back 76

An organism that makes up ATP by aerobic respiration if oxygen is present but that switch to anaerobic respiration or fermentation if oxygen is not present. (Exm: yeast; many bacteria and human muscle cells)

Front 77

What is the evidence for the early evolution of glycolysis?

Back 77

The evidence for early evolution of glycolysis is because it is the most widespread catabolic pathway. The location of the pathway in the cytoplasm infers it evolved early in the prokaryotes because no membrane bound organelles are necessary.

Front 78

How do carbohydrates, fats and proteins enter the pathways of cellular respiration?

Back 78

Carbs, fats and proteins enter the pathway of cellular respiration by glycolysis or the citric acid cycle at different place. Proteins are first broken down into amino acids. Fats are broken down into glycerol and fatty acids. The glycerol is converted to glycerladehyde phosphate and then enters glycolysis.

Front 79

What are the 3 parts of cellular respiration? pg.166

Back 79

• Glycolysis: sugar is split into two 3-C pyruvate molecules that are later converted to; this occurs in almost all living cells, starting point of fermentation or cellular respiration
• citric acid cycle (kerbs cycle); a chemical cycle that involves 8 steps that completes the metabolic breakdown of glucose molecules, begun in glycolysis by oxidizing pyruvate to carbon cioxide,; this process occurs within the mitochondria in eukaryotic cell and in the cytosol in prokaryotic cells
• Oxidative phosphorylation: the production of ATP using energy derived from the redox reactions of an electron transport chain; ineukarytic cells it happens in the inner membrane of the mitochondria, in prokaryotes happends in the plasma membrane

Hint 79

• Glycolysis
• citric acid cycle (kerbs cycle)
• Oxidative phosphorylation

Front 80

Describe the reactants and end products of the 1st part. pg. 168- 169

Back 80

The reactants are 1st: 5 are E investment stage, which require 2 ATP. At the end of the energy investment phase, 2 of the use to be glyceraldehyde 3 phosphate. It then converts to 1, 3 biophosphoglycerate, End product of glycolysis 2 molecules of pyruvate still has lots of energy.

Front 81

How, when, where and why is pyruvate changed to acetyl CoA?

Back 81

Acetyl CoA is formed from a fragment of pyruvate attached to a coenzyme; this occurs when the junctio between glycolysis and citric acid cycle occurs, which is done by the catalyzing of 3 reactions bmith the help of multienzyme complex

Front 82

Where is the electron transport chain located?

Back 82

The ETC is located in the inner membrane of the mitochodria in eukaryotic cells.

Front 83

Explain chemiosmosis.

Back 83

Chemiosmosis is energy stored in the form of a hydrogen ion gradients across a membrane that is used to drive cellular work such as the synthesis of ATP.