Harold Washington Bio 121 Test 2

Front 1

Macromolecule

Back 1

large molecules, including carbohydrates, proteins, and nucleic acids

Front 2

Polymer

Back 2

a long molecule consisting of many similar or identical building blocks linked by covalent bonds

Front 3

Monomer

Back 3

small molecules that are the repeating units that serve as building blocks of a polymer

Front 4

Dehydration reaction

Back 4

monomers are connected by a reaction in which two molecules are covalently bonded to each other, with the loss of a water molecule

Front 5

Hydrolysis

Back 5

Polymers are disassembled to monomers; breaking down a polymer; adds a water molecule, breaking a bond

Front 6

Monosaccharides

Back 6

the simplest carbohydrates; monomers from which more complex carbohydrates are built

simple sugars

Front 7

Carbohydrates

Back 7

the macromolecule that contains sugars and polymers of sugars

Front 8

Aldose

Back 8

When the location of the carbonyl group of a sugar is at the end of a carbon skeleton

Front 9

Ketose

Back 9

When the location of the carbonyl group of a sugar is within the carbon skeleton

Front 10

Triose

Back 10

A 3-carbon sugar

Front 11

Pentose

Back 11

A 5-carbon sugar

A: Ribose (component of RNA)

K: Ribulose (intermediate in photosynthesis)

Front 12

Hexose

Back 12

a 6-carbon sugar

A: Glucose (energy source for organisms)

K: Fructose (energy source for organisms)

Front 13

Disaccharide

Back 13

consists of two monosaccharides joined by a glycosidic linkage, a covalent bond formed between two monosaccharides by a dehydration reaction

Front 14

Polysaccharides

Back 14

macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages

Front 15

Some types of polysaccharides

Back 15

Starch

Glycogen

Cellulose

Chitin

Front 16

Starch

Back 16

a storage polysaccharide of plants, consists entirely of glucose monomers; plants store surplus of this as granules within chloroplasts and other plastids

Front 17

Glycogen

Back 17

storage polysaccharide in animals, consists entirely of glucose monomers; stored mainly in liver and muscle cells; hydrolysis of ___ in these cells releases glucose when the demand for sugar increases

Front 18

Cellulose

Back 18

a major component of the tough wall of plant cells; Like starch, this is a polymer of glucose, but the glycosidic linkages differ; the difference is based on two ring forms for glucose: alpha and beta

Front 19

Chitin

Back 19

The carbohydrate used by arthropods to build their exoskeletons; structure is similar to cellulose with Beta linkages, except that the glucose monomer of chitin has a nitrogen-containing appendage

Front 20

Lipids

Back 20

the one class of large biological molecules that does not include true polymers; the unifying feature is that they mix poorly, if at all, with water; hydrophobic because they consist mostly of hydrocarbons, which form nonpolar covalent bonds. Contains fats, phospholipids, and steroids

Front 21

Triglyceride

Back 21

In a fat, three fatty acids are joined to glycerol by an ester linkage

Front 22

Saturated fatty acids

Back 22

Fatty acids vary in length (number of carbons) and in the number and locations of double bonds.

______ have the maximum number of hydrogen atoms possible and no double bonds

Front 23

Unsaturated fatty acids

Back 23

Fatty acids vary in length (number of carbons) and in the number and locations of double bonds.

_____ have one or more double bonds

Front 24

Saturated fatty acids in food

Back 24

most animal fats

the hydrocarbon chains lack double bonds and their flexibility allows the fat molecules to pack tightly together

Front 25

Unsaturated fatty acids in food

Back 25

Plants and fishes

Usually liquid at room temperature; the kinks where the cis double bonds are located prevent the molecules from packing together closely enough to solidify at room temperature.

Front 26

Phospholipids

Back 26

Has a hydrophilic (polar) head and 2 hydrophobic (non-polar) tails. Similar to a fat molecule but only has 2 fatty acids attached to a glycerol rather than 3

Front 27

What happens when phospholipids are added to water?

Back 27

they self-assemble into double layered structures called bilayers, shielding their hydrophobic portions from the water

Front 28

Steroids

Back 28

Lipids characterized by a carbon skeleton consisting of four fused rings. Distinguished by the chemical groups attached to these rings.

Front 29

Cholesterol

Back 29

a type of steroid; the molecule from which other steroids are synthesized. Steroids vary in chemical groups attached to their four inter-connected rings

Front 30

Polypeptide

Back 30

a polymer of amino acids

Front 31

Polypeptide bond

Back 31

the covalent bond between amino acids

Front 32

Proteins

Back 32

a biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific 3D structure

Front 33

Protein terminus

Back 33

Each polypeptide has a unique linear sequence of amino acids, with a carboxyl end (C-terminus) and an amino end (N-terminus)

Front 34

Amino acids

Back 34

an organic molecule with both an amino group and a carboxyl group. Has an asymmetric carbon atom (alpha carbon) at its center; Four different partners are an amino group, carboxyl group, hydrogen atom, and a variable group symbolized as R

Front 35

R-group side chain

Back 35

a variable group attached to the carbon atom at the center of an amino acid

Front 36

Primary structure of a protein

Back 36

- a protein’s sequence of amino acids

- determined by inherited genetic information

Front 37

Secondary structure of a protein

Back 37

- found in most proteins, consists of coils and folds in the polypeptide chain

- Typical secondary structures are a coil called an α helix and a folded structure called a β pleated sheet

Front 38

Tertiary structure of a protein

Back 38

The overall shape of a polypeptide, resulting from interactions between the side chains of the various amino acids

Front 39

Quarternary structure of a protein

Back 39

results when two or more polypeptide chains form one macromolecule

Front 40

Sickle Cell Disease

Back 40

an inherited blood disorder, caused by the substitution of one amino acid for the normal one at a particular position in the primary structure of hemoglobin

Front 41

What happens when a protein’s primary structure changes?

Back 41

Even a slight change in primary structure can affect the protein’s shape and ability to function

Front 42

Denaturation

Back 42

If the pH, salt concentration, temperature, or other aspects of its environment are altered, the weak chemical bonds and interactions within a protein may be destroyed, causing the protein to unravel and lose its native shape.

Front 43

Renaturation

Back 43

If a denatured protein remains dissolved, this may happen when the chemical and physical aspects of its environment are restored to normal

Front 44

Chaperonin

Back 44

Protein molecules that assist in the proper folding of other proteins

Front 45

How are polypeptides folded?

Back 45

An unfolded protein enters into a chaperonin

- Cap attachment causes the cylinder to change shape

- Cap comes off and the properly folded protein is released

Front 46

Nucleic acids

Back 46

Polymers made of monomers of nucleotides

Front 47

Gene

Back 47

the amino acid sequence of a polypeptide is programmed by this unit of inheritance; consist of DNA, a nucleic acid

Front 48

DNA and RNA

Back 48

2 types of nucleic acids. Provides directions for its own replication; directs synthesis of messenger RNA and, through mRNA, controls protein synthesis

Front 49

Nucleotides

Back 49

consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups; in DNA, the sugar is deoxyribose; in RNA, the sugar is ribose

Front 50

Complementary strands of DNA

Back 50

Only certain bases in DNA pair up and form hydrogen bonds:

adenine (A) always with thymine (T),

guanine (G) always with cytosine (C)

single stranded thymine is replaced by uracil (U) so A and U pair

Front 51

Ribose

Back 51

in DNA, the sugar is deoxyribose; in RNA, the sugar is ribose

Front 52

Nucleus

Back 52

Contains most of the genes in the eukaryotic cell; Place where DNA resides; Place where DNA synthesis occurs; Place where RNA synthesis occurs

Front 53

Nuclear Envelope

Back 53

The double membrane that encloses the nucleus, separating its contents from the cytoplasm

Front 54

Nucleolus

Back 54

non-membranous structure involved in production of ribosomes

Front 55

Ribosomes

Back 55

carry out protein synthesis in two locations: In the cytosol (free); On the outside of the endoplasmic reticulum (bound)

Front 56

Endoplasmic Reticulum

Back 56

network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes

Front 57

Rough Endoplasmic Reticulum

Back 57

studded with bound ribosomes, which secrete glycoproteins; Proteins that are synthesized by bound ribosomes enter the lumen of the ______ where they are folded.; After folding is complete the ____ buds off into a transport vesicle with the proteins inside them; Distributes transport vesicles, secretory proteins surrounded by membranes; Is a membrane factory for the cell

Front 58

Smooth Endoplasmic Reticulum

Back 58

Synthesizes lipids; Metabolizes carbohydrates; Detoxifies drugs and poisons; Stores calcium ions

Front 59

Transport vesicle

Back 59

Bud off from the RER, carrying folded proteins that were synthesized and folded in the RER

Front 60

Golgi apparatus

Back 60

consists of flattened membranous sacs called cisternae; Modifies products of the ER; Modifies the sugar chains; Tags the proteins; Sorts and packages materials into transport vesicles

Front 61

Lumen

Back 61

The area in the RER where proteins are folded

Front 62

Lysosomes

Back 62

involved in intracellular digestion; a membranous sac of hydrolytic enzymes that can digest macromolecules; Hydrolytic enzymes are made by rough ER and then transferred to the Golgi apparatus for further processing.

Front 63

Mitochondria

Back 63

the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP; double membrane

Front 64

Mitochondria membranes

Back 64

They have a smooth outer membrane and an inner membrane folded into cristae; The inner membrane creates two compartments: intermembrane space and mitochondrial matrix; Cristae present a large surface area for enzymes that synthesize ATP

Front 65

Chloroplasts

Back 65

contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis. Contains flat interconnected sacs: thylakoids; In some regions, thylakoids are stacked (granum); Fluid outside of the thylakoids is the stroma; The membranes divide this space into 3 compartments: the intermembrane space, stroma, thylakoid space

Front 66

Traits of mitochondria and chloroplasts that contribute to the endosymbiotic theory

Back 66

Mitochondria and chloroplasts have similarities with bacteria: Enveloped by a double membrane; Contain free ribosomes and circular DNA molecules; Grow and reproduce somewhat independently in cells

Front 67

Endosymbiotic theory

Back 67

suggests that an early ancestor of eukaryotes engulfed an oxygen-using nonphotosynthetic prokaryotic cell; The engulfed cell formed a relationship with the host cell, becoming an endosymbiont

Front 68

Peroxisomes

Back 68

specialized metabolic compartments bounded by a single membrane; responsible for breakdown of long chain fatty acids; produce hydrogen peroxide.

Front 69

Cytoskeleton

Back 69

a network of fibers extending throughout the cytoplasm; organizes the cell’s structures and activities, anchoring many organelles; Composed of 3 types of molecular structures: Microtubules; Microfilaments; Intermediate filaments

Front 70

Microtubules

Back 70

Tubulin polymers; hollow tubes; thickest of the three components of the cytoskeleton; Shaping the cell; Guiding movement of organelles; Separating chromosomes during cell division

Front 71

Microfilaments

Back 71

Actin filaments; the thinnest components of the cytoskeleton; maintenance of cell shape; changes in cell shape; muscle contraction, cytoplasmic streaming in plant cells; cell motility, division of animal cells

Front 72

Intermediate filaments

Back 72

fibrous proteins coiled into cables; components of the cytoskeleton with diameters in a middle range; support cell shape and fix the nucleus and other organelles in place; more permanent cytoskeleton fixtures than the other two classes

Front 73

Nuclear lamina

Back 73

lines the inner surface of the nuclear envelope; maintains the shape of the nucleus

Front 74

Centrosomes

Back 74

in animal cells, microtubules grow out from this region that is often located near the nucleus; function as compression-resisting girders of the cytoskeleton

Front 75

Centrioles

Back 75

within the centrosome, there is a pair of these, each composed of microtubules

Front 76

Flagella and cilia

Back 76

microtubule-containing extensions that project from some cells

Front 77

Cell wall

Back 77

extracellular structure that distinguishes plant cells from animal cells; protects the plant cell, maintains its shape, and prevents excessive uptake of water; in plants, they are made of cellulose fibers

Front 78

Layers of cell wall

Back 78

Primary cell wall; Middle lamella: Thin layer between primary walls of adjacent cells; Secondary cell wall (in some cells)

Front 79

Central vacuole

Back 79

found in many mature plant cells, hold organic compounds and water

Front 80

Plasmodesmata

Back 80

channels between adjacent plant cells; water and small solutes (and sometimes proteins and RNA) can pass from cell to cell

Front 81

Tight Junctions

Back 81

membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

Front 82

Desmosomes

Back 82

anchoring junctions; fasten cells together into strong sheets

Front 83

Gap junctions

Back 83

communicating junctions; provide cytoplasmic channels between adjacent cells

Front 84

Cell fractionation

Back 84

takes cells apart and separates the major organelles from one another; Centrifuges fractionate cells into their component parts; Cell fractionation enables scientists to determine the functions of organelles; Biochemistry and cytology help correlate cell function with structure

Front 85

Optimum ratio for cell size

Back 85

Metabolic requirements set upper limits on the size of cells; The surface area to volume ratio of a cell is critical; As a cell increases in size, its volume grows proportionately more than its surface area

Front 86

Plasma membrane (4 parts?)

Back 86

boundary that separates the living cell from its surroundings; exhibits selective permeability, allowing some substances to cross it more easily than others

Front 87

Phospholipids in the plasma membrane- bilayer (what can pass through it)

Back 87

most abundant lipid in the plasma membrane; can exist as a stable boundary between two aqueous compartments

Front 88

Fluid mosaic model

Back 88

states that a membrane is a fluid structure with a “mosaic” of various proteins embedded in it; Proteins are not randomly distributed in the membrane

Front 89

Cholesterol within the animal cell membrane

Back 89

Cholesterol keeps the membrane at optimum fluidity; reduces membrane fluidity at moderate temperatures, but at low temperatures hinders solidification

Front 90

Carbohydrates in the plasma membrane

Back 90

may be covalently bonded to lipids or more commonly to proteins; when on the external side of the plasma membrane vary among species, individuals, and even cell types in an individual

Front 91

Peripheral protein

Back 91

bound to the surface of the membrane

Front 92

Integral protein

Back 92

penetrate the hydrophobic core

Front 93

Transmembrane protein

Back 93

integral proteins that span the full membrane

Front 94

Function of membrane proteins: Transport

Back 94

may provide a hydrophilic channel across the membrane that is selective for a particular solute

Front 95

Function of membrane proteins: Enzymatic activity

Back 95

may be an enzyme with the active site exposed to substances in the adjacent solution; can sometimes carry out steps of a metabolic pathway

Front 96

Function of membrane proteins: Signal transduction

Back 96

a membrane protein (receptor) may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone

Front 97

Function of membrane proteins: cell-cell recognition

Back 97

some serves as identification tags that are specifically recognized by membrane proteins of other cells

Front 98

Function of membrane proteins: Intercellular joining

Back 98

Membrane proteins of adjacent cells may hook together in various kinds of junctions such as gap or tight junctions

Front 99

Function of membrane proteins: Attachment to the cytoskeleton and extracellular matrix

Back 99

Microfilaments or other elements of the cytoskeleton may be noncovalently bound to the membrane proteins, a function that helps maintain cell shape and stabilizes the location of certain membrane proteins

Front 100

Highly specific channels example

Back 100

HIV must bind to the immune cell surface protein CD4 and a “co-receptor” CCR5 in order to infecta cell; HIV cannot enter the cells of resistant individuals that lack CCR5

Front 101

Diffusion

Back 101

the movement of particles of any substance so that they spread out into the available space; Molecules move from a region of high concentration to a region of low concentration; At dynamic equilibrium, as many molecules cross the membrane in one direction as in the other

Front 102

Osmosis

Back 102

diffusion of water across a selectively permeable membrane; Water diffuses across a membrane from the region of lower solute concentration to the region of higher solute concentration until the solute concentration is equal on both sides

Front 103

Tonacity

Back 103

the ability of a surrounding solution to cause a cell to gain or lose water

Front 104

Isotonic solution

Back 104

Solute concentration is the same as that inside the cell; no net water movement across the plasma membrane

Front 105

Hypotonic solution

Back 105

Solute concentration is greater than that inside the cell; cell loses water

Front 106

Hypertonic solution

Back 106

Solute concentration is less than that inside the cell; cell gains water

Front 107

Reaction of a plant cell when placed in different tonacity

Back 107

hypotonic solution, swells (normal); isotonic, there is no net movement of water into the cell and becomes limp; if hypertonic, cells lose water; cell wilts

Front 108

Reaction of a animal cell when placed in different tonacity

Back 108

hypotonic-explodes; isotonic-normal: hypertonic-shrivels

Front 109

Passive transport

Back 109

diffusion of a substance across a membrane with no energy investment

Front 110

Active transport

Back 110

uses energy (usually in the form of ATP) to move solutes against their gradients

Front 111

Facilitated diffusion

Back 111

transport proteins speed the passive movement of molecules across the plasma membrane

Front 112

Sodium potassium pump

Back 112

1) Cytoplasmic Na+ binds to the sodium-potassium pump. The affinity for Na+ is high when the protein has this shape.2) Na+ binding stimulates phosphorylation by ATP.3) Phosphorylation leads to a change in protein shape, reducing its affinity for Na+, which is released outside.4) The new shape has a high affinity for K+, which binds on the extracellular side and triggers release of the phosphate group.5) Loss of the phosphate group restores the protein’s original shape, which has a lower affinity for K+.6) K+ is released; affinity for Na+ is high again, and the cycle repeats.

Front 113

Bulk transport

Back 113

transport of large molecules like polysaccharides and proteins across the plasma membrane via vesicles; requires energy

Front 114

Exocytosis

Back 114

when transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell; Many secretory cells use this to export their products

Front 115

Endocytosis

Back 115

the cell takes in macromolecules by forming vesicles from the plasma membrane; Phagocytosis, pinocytosis, receptor-mediated

Front 116

Phagocytosis

Back 116

when a cell engulfs a particle by extending pseudopodia around it and packaging it within a membranous sac called a food vacuole

Front 117

Pinocytosis

Back 117

when a cell continually drinks droplets of extracellular fluid into tiny vesicles

Front 118

Receptor mediated

Back 118

enables a cell to acquire buik quantities of specific substances even though those substances may not be very concentrated; specific solutes bind to the protein sites in the plasma membrane