Biology, Ch. 4 And Ch. 5

Front 1

Allosteric site

Back 1

Region of an enzyme where regulatory molecules bind.

Front 2

Redox Reaction

Back 2

One molecule accepts electrons (it becomes reduced) from another molecule (which becomes oxidized

Front 3

Cofactors

Back 3

A metal ion or a coenzyme that associates with an enzyme and is necessary for its function.

Front 4

Coenzyme

Back 4

Organic molecules that are cofactors are called coenzymes . Coenzymes carry chemical groups, atoms, or electrons from one reaction to another in metabolic pathways. - Many are modified by taking part in a reaction.

Front 5

Phosphorylization

Back 5

A reaction in which a phosphate group is transferred from one molecule to another.

Front 6

ATP

Back 6

Adenosine Tri-phosphate; nucleotide coenzyme

Front 7

Cells

Back 7

Smallest unit of life; All cells have: 1) Plasma membrane; 2) Cytoplasm; 3) Start life out with DNA

Front 8

Nucleoid

Back 8

DNA-containing region in prokaryotic cells

Front 9

Nucleus

Back 9

DNA-containing region in eukaryotic cells

Front 10

Cytoplasm

Back 10

A semifluid mixture containing cell components

Front 11

Includes: Plants, Animals, Fungi and Protists

Back 11

Eukaryotic cells

Front 12

Cell interior is divided into functional compartments (Organelles), including a nucleus.

Back 12

Eukaryotic cells

Front 13

Small, simple cells without a nucleus.

Back 13

Prokaryotic cells

Front 14

Includes Bacteria and Archaea

Back 14

Prokaryotic cell

Front 15

Are structures that carry out special metabolic functions inside a cell

Back 15

Organelles

Front 16

Lipid bilayer

Back 16

A double layer of phospholipids organized with their hydrophilic heads outwards and their hydrophobic tails inwards

Front 17

Surface-to-volume ratio

Back 17

Restricts cell size by limiting transport of nutrients adn wastes

Front 18

Cell theory

Back 18

1. All organisms consist of one or more cells; 2. A cell is the smallest unit with properties of life; 3. Each new cell arises from division of a preexisting cell. 4. Each cell passes its hereditary material to its offsprong

Front 19

Smallest and most metabolically diverse forms of life

Back 19

Prokaryotes

Front 20

Pili

Back 20

Help cells move across surfaces; "sex" pili aid in reproduction

Front 21

Ribosomes

Back 21

Organelles upon which polypeptides are assembled

Front 22

Nucleoid

Back 22

An irregularly shaped region of cytoplasm containing a single, circular DNA molecule (prokaryotes)

Front 23

Plamids

Back 23

Small circles of DNA carry a few genes that can provide advantages, such as resistance to antibiotics (prokaryotes)

Front 24

Biofilms

Back 24

Single-celled organisms sharing a secreted layer of polysaccharides and glycoproteins. May include bacteria, algae, fungi, protists, and archaeans

Front 25

All protists, fungi, plants, and animals are _____

Back 25

Eukaryotes

Front 26

Eukaryotic (“true nucleus”) cells carry out much of their metabolism inside _____

Back 26

membrane-enclosed organelles

Front 27

All of a eukaryotic cell’s DNA is in its _____

Back 27

nucleus

Front 28

The ______ controls when DNA is accessed

Back 28

nuclear envelope

Front 29

Nuclear envelope

Back 29

Two lipid bilayers pressed together as a single membrane surrounding the nucleus; outer bilayer is continuous with the ER; nuclear pores allow certain substances to pass through the membrane

Front 30

Nucleoplasm

Back 30

Viscous fluid inside the nuclear envelope, similar to cytoplasm

Front 31

Nucleolus

Back 31

A dense region in the nucleus where subunits of ribosomes are assembled from proteins and RNA

Front 32

Chromatin

Back 32

All DNA and its associated proteins in the nucleus

Front 33

Chromosome

Back 33

A single DNA molecule with its attached proteins; During cell division, chromosomes condense and become visible in micrographs; Human body cells have 46 chromosomes

Front 34

Endomembrane system

Back 34

A series of interacting organelles between the nucleus and the plasma membrane

Front 35

Makes, modifies, and transports proteins and lipids for secretion or insertion into cell membrane

Back 35

Endomembrane system

Front 36

It also destroys toxins, recycles wastes, and has other specialized functions

Back 36

Endomembrane system

Front 37

Endoplasmic reticulum (ER)

Back 37

An extension of the nuclear envelope that forms a continuous, folded compartment. There are two types: rough and smooth.

Front 38

______ (with ribosomes) folds polypeptides into their tertiary form

Back 38

Rough ER

Front 39

______ (no ribosomes) makes lipids, breaks down carbohydrates and lipids, detoxifies poisons

Back 39

Smooth ER

Front 40

Golgi body

Back 40

A folded membrane containing enzymes that finish polypeptides and lipids delivered by the ER; Packages finished products in vesicles that carry them to the plasma membrane or to lysosomes

Front 41

Small, membrane-enclosed saclike organelles that store or transport substances

Back 41

Vesicles

Front 42

Peroxisomes

Back 42

Vesicles containing enzymes that break down hydrogen peroxide, alcohol, and other toxins

Front 43

Lysosomes

Back 43

Are vesicles containing enzymes that fuse with vacuoles and digest waste materials. Lysosomal enzymes empty into the other vesicles and digest their contents into bits.

Front 44

Vacuoles

Back 44

Vesicles with various functions depending on cell type; Many isolate or dispose of waste, debris, and toxins

Front 45

Central vacuole (plant cell)

Back 45

Occupies 50 to 90 percent of a cell’s interior; Stores amino acids, sugars, ions, wastes, toxins; Fluid pressure keeps plant cells firm

Front 46

Eukaryotic cells make most of their ATP in ______

Back 46

mitochondria

Front 47

Plastids function in ______ and ______ in plants and some types of algae

Back 47

storage and photosynthesis

Front 48

Mitochondrion

Back 48

Eukaryotic organelle that makes the energy molecule ATP through aerobic respiration

Front 49

Contains two membranes, forming inner and outer compartments; buildup of hydrogen ions in the outer compartment drives ATP synthesis

Back 49

Mitochondrion

Front 50

Has its own DNA and ribosomes

Back 50

Mitochondrion

Front 51

Resembles bacteria; may have evolved through endosymbiosis

Back 51

Mitchondrion

Front 52

Includes chromoplasts, amyloplasts, and chloroplasts

Back 52

Plastids

Front 53

Chloroplasts

Back 53

Plastids specialized for photosynthesis

Front 54

Resemble photosynthetic bacteria; may have evolved by endosymbiosis

Back 54

Chloroplasts

Front 55

Thylakoids

Back 55

Inner membrane system folded into flattened disks in chloroplasts

Front 56

An interconnected system of many protein filaments – some permanent, some temporary

Back 56

Cytoskeleton

Front 57

Parts of the ______ reinforce, organize, and move cell structures, or even a whole cell

Back 57

cytoskeleton

Front 58

Microtubules

Back 58

Long, hollow cylinders made of tubulin; Form dynamic scaffolding for cell processes

Front 59

Microfilaments

Back 59

Consist mainly of the globular protein actin; make up the cell cortex

Front 60

Intermediate filaments

Back 60

Maintain cell and tissue structures

Front 61

________ allow cells to interact with each other and the environment

Back 61

Cell junctions

Front 62

In plants, __________ extend through cell walls to connect the cytoplasm of two cells

Back 62

plasmodesmata

Front 63

Animals have three types of cell junctions: ____, ____, and ______

Back 63

tight junctions, adhering junctions, gap junctions

Front 64

_______ regulate the movement of substances in and out of cells; failure of one of these proteins causes cystic fibrosis

Back 64

Transporter proteins

Front 65

Fluid mosaic model

Back 65

Fluid: Based on the behavior of Phospholipids in membranes where they remain organized as a bilayer, but they also
Drift sideways
Spin along their axis
Tails wiggle
Mosaic: Steroids, proteins and other molecules dispersed on them

Front 66

Integral membrane proteins

Back 66

Integral membrane proteins are permanently attached to the lipid bilayer.

Front 67

Peripheral membrane proteins

Back 67

These attach temporarily to one of the bilayer’s surfaces by way of interaction with lipids or other proteins.

Front 68

Membrane proteins are mostly ______

Back 68

glycoproteins

Front 69

In ___________ , the movement of a solute (and the direction of the movement) through a transport protein is driven entirely by the solute's concentration gradient.

Back 69

passive transport

Front 70

In ________ , a transport protein uses energy to pump a solute against its gradient across a cell membrane.

Back 70

active transport

Front 71

Calcium pump

Back 71

An example of an active transporter. This protein moves calcium ions across cell membranes.

Front 72

In a process called ______ , an enzyme makes a reaction run much faster than it would on its own

Back 72

catalysis

Front 73

Substrates

Back 73

Specific reactants that are altered by enzymes

Front 74

Active sites

Back 74

Pockets where substrates bind and where reactions proceed on enzymes

Front 75

Transition state

Back 75

When substrate bonds reach their breaking point and the reaction will run spontaneously to product. Enzymes can help bring on the transition state by lowering activation energy.

Front 76

uilding, rearranging, or breaking down an organic substance often occurs stepwise, in a series of reactions called a __________.

Back 76

metabolic pathway

Front 77

Both ____ and _____ metabolic pathways are common in cells.

Back 77

linear and cyclic

Front 78

The end product of a series of enzymatic reactions may inhibit the activity of one of the enzymes in the series, an effect called _______

Back 78

feedback inhibition

Front 79

Allosteric sites

Back 79

Regions of an enzyme (other than the active site) where regulatory molecules bind

Front 80

In a ______ , one molecule accepts electrons (it becomes reduced) from another molecule (which becomes oxidized)

Back 80

redox reaction

Front 81

Electron transfer chain

Back 81

An organized series of reaction steps in which membrane-bound arrays of enzymes and other molecules give up and accept electrons in turn

Front 82

Most enzymes do not function properly without assistance from metal ions or small organic molecules. Such enzyme helpers are called ____.

Back 82

cofactors

Front 83

Osmosis

Back 83

The diffusion of water across a membrane

Front 84

Turgor

Back 84

Pressure that a fluid exerts against a structure that contains it.

Front 85

Osmotic pressure

Back 85

The amount of turgor that stops osmosis

Front 86

Many types of molecules and ions can cross a lipid bilayer only with the help of ______

Back 86

transport proteins

Front 87

By processes of ________ and ________ cells take in and expel particles that are too big for transport proteins, as well as substances in bulk.

Back 87

exocytosis; endocytosis

Front 88

By _______ , a vesicle moves to the cell's surface, and the protein-studded lipid bilayer of its membrane fuses with the plasma membrane. As the ______ vesicle loses its identity, its contents are released to the surroundings.

Back 88

exocytosis

Front 89

________ is an endocytic pathway in which phagocytic cells such as amoebas engulf microorganisms, cellular debris, or other particles. In animals, macrophages and other white blood cells engulf and digest pathogenic viruses and bacteria, cancerous body cells, and other threats

Back 89

Phagocytosis

Front 90

_______ is an endocytic pathway that brings materials in bulk into the cell. It is not as selective as receptor-mediated endocytosis. An endocytic vesicle forms around a small volume of the extracellular fluid regardless of the kinds of substances dissolved in it.

Back 90

Pinocytosis

Front 91

The composition of a plasma membrane begins in the ______.

Back 91

ER

Front 92

Membrane cycling

Back 92

As long as a cell is alive, exocytosis and endocytosis continually replace and withdraw patches of its plasma membrane.

Front 93

Entropy

Back 93

A measure of how much the energy of a system is dispersed.

Front 94

First Law of Thermodynamics

Back 94

Energy cannot be created or destroyed.

Front 95

Second Law of Thermodynamics

Back 95

Energy tends to disperse spontaneously.

Front 96

Cells regenerate ATP in the _____

Back 96

ADP/ATP cycle.

Front 97

ADP/ATP cycle

Back 97

Process by which cells regenerate ATP. ADP forms when ATP loses a phosphate group, then ATP forms again as ADP gains a phosphate group

Front 98

Receptor Proteins

Back 98

Plasma membrane protein that binds to a particular substance outside of the cell.

Front 99

Adhesion Proteins

Back 99

Membrane protein that helps cells stick together in animal tissues.

Front 100

Recognition proteins

Back 100

Plasma membrane protein that identifies a cell as belonging to self (one's own body).

Front 101

______ proteins work without an energy input; a solute's movement is driven by its concentration gradient.

Back 101

Passive transport proteins

Front 102

Entropy always _____, overall.

Back 102

increases

Front 103

Enzymes are proteins, except for a few _______.

Back 103

RNAs

Front 104

______ prevents other molecules from being oxidized.

Back 104

Antioxidants

Front 105

_____ form during endocytosis, phagocytosis, and exocytosis.

Back 105

Vesicles

Front 106

In cells, the nucleotide coenzyme ______ often couples reactions that release energy with reactions that require it.

Back 106

ATP (adenosine tri-phosphate)

Front 107

ATP has three ________, and the bonds between these groups hold a lot of _______.

Back 107

phosphate groups, energy

Front 108

Importance of selective permeability

Back 108

1. Metabolism
2. Supply of raw materials
3. Removal of waste
4. Maintains volume and pH with in tolerable ranges.

Front 109

_____, _______, and _____ cross the lipid bilayer freely.

Back 109

Gases, nonpolar molecules, water

Front 110

5 factors on which rate of diffusion depends

Back 110

Size
Temperature
Steepness of the concentration gradient
Charge
Pressure

Front 111

A __________ is where two reactions occur nearly simultaneously. The first reaction must be _____ and give off energy. The second reaction is ______ and immediately uses the energy produced from the first reaction.

Back 111

coupled reaction, exergonic, endergonic

Front 112

_____ refers to the constant pinching and fusion of vesicles from the plasma membrane.

Back 112

Membrane trafficking

Front 113

Binding of the substrates at enzyme active sites may bring on the transition state by four mechanisms, which are:

Back 113

Helping substrates get together
Orienting substrates in positions that favor reaction
Inducing a fit between enzyme and substrate (induced-fit model)
Shutting out water molecules

Front 114

Raising the temperature _____ reaction rates by increasing a substrate’s energy.

Back 114

increases (But very high temperatures denature enzymes)

Front 115

Each enzyme has an optimum ___ range.

Back 115

pH (6 to 8 in humans)

Front 116

_______ pathways build molecules

Back 116

Anabolic

Front 117

______ pathways break apart molecules

Back 117

Catabolic

Front 118

____ pathways regenerate a molecule from the first step

Back 118

Cyclic

Front 119

_______ proteins temporarily attach to one of the lipid bilayer's surfaces by way of interactions with lipids or other proteins

Back 119

Peripheral membrane

Front 120

_______ proteins permanently attach to a bilayer.

Back 120

Integral membrane proteins

Front 121

Initiate change in a cell activity by responding to an outside signal (e.g., by binding a signaling molecule or absorbing light energy).

Back 121

Receptor proteins

Front 122

Adhesion proteins

Back 122

Help cells stick to one another, to cell junctions, and to extracellular matrix.

Front 123

All cell membranes have the same _______.

Back 123

phospholipid bilayer

Front 124

The nuclear envelope contains: ______, _______, and __________.

Back 124

outer membrane, lumen, inner membrane

Front 125

The nuclear envelope contains many ______, through which material enters and leaves the nucleus.

Back 125

Nuclear pore