Exam 2 Lecture 3

Question 1

Most biological macromolecules in cells are
synthesized from about

Answer 1

20? 30 common small molecules

Question 2

How many major classes of proteins are there

Answer 2

9

Question 3

what are the 9 classes of proteins

Answer 3

Enzymes
structural Proteins
Motility
Regulatory
Transport
Signaling
receptor
defensive
storage

Question 4

describe enzymes

Answer 4

serve as catalysts, increasing the rates of chemical reactions

Question 5

Describe Structural proteins

Answer 5

physical support and shape

Question 6

Describe Motility proteins —

Answer 6

contraction and movement

Question 7

Regulatory proteins

Answer 7

control and coordinate cell function

Question 8

What doesnt make protein

Answer 8

Intron

Question 9

Transport proteins

Answer 9

move substances into and out of cells

Question 10

Signaling proteins

Answer 10

communication between cells

Question 11

Receptor proteins

Answer 11

enable cells to respond to chemical
stimuli from the environment

Question 12

Defensive protein

Answer 12

protect against disease

Question 13

Storage proteins

Answer 13

reservoirs of amino acids

Question 14

do proteins ever have the same amino acid sequence?

Answer 14

No two different
proteins have the
same amino acid
sequence
Amino Acids

Question 15

How many amino acids

Answer 15

20 amino acids
( technically there are 2 other found on archaea)

Question 16

What is the structure of amino acids

Answer 16

Every amino acid has the same
basic structure

 Each has a unique side chain,
called an R group

 All amino acids except glycine
have an asymmetric α-carbon
atom

 The specific properties of
amino acids depend on the
nature of their R groups

each amino acid is unique bc of its side chain

Question 17

Which amino acid does not have an asymmetric α-carbon
atom

Answer 17

All amino acids except glycine
have an asymmetric α-carbon
atom

Question 18

Group A amino acids

Answer 18

Nine amino acids have nonpolar, hydrophobic R
groups

Question 19

Group B and C

Answer 19

The remaining eleven amino acids are hydrophilic, with R
groups that are either polar or charged at cellular pH

Polar amino acids tend to be found on the surfaces of
proteins

Question 20

Cellular pH

Answer 20

7.4

Question 21

Acidic amino acids are

Answer 21

negatively charged

Question 22

basic
amino acids are

Answer 22

positively charged

Question 23

Where are polar amino acids located

Answer 23

Polar amino acids tend to be found on the surfaces of
proteins

Question 24

Amino acids are linked
together stepwise into
a….. ( and what reactions)

Answer 24

linear polymer by
dehydration (or
condensation)
reactions

Question 25

As the three atoms
comprising the H2O are removed what type of bond is formed

Answer 25

Peptide bond ( convalent bond between the C-N)

Question 26

two termini of polypeptides

Answer 26

N - Terminus
C- Terminus

Question 27

Because of the way
peptide bonds are formed,
polypeptides have

Answer 27

Directionality

Question 28

which side is the N -terminus

Answer 28

The end with the amino
group is called the N- (or
amino) terminus

Question 29

Which side is the C - terminus

Answer 29

The end with the
carboxyl group is called
the C- (or carboxyl)
terminus

Question 30

Protein synthesis

Answer 30

The process of elongating a chain of amino acids is
called protein synthesis

Question 31

what is the name of the immediate product amino acid polymerization

Answer 31

Polypeptide

Question 32

When does a polypeptide become a protein

Answer 32

A polypeptide does not become a protein until it
has assumed a unique, stable, three-dimensional
shape and is biologically active

Question 33

Proteins that consist of a single polypeptide are

Answer 33

monomeric
proteins

Question 34

multimeric proteins

Answer 34

consist of two or
more polypeptides

Question 35

homomultimeric vs heteromultimeric protein

Answer 35

different vs same subunits

If the chains are identical, it would be homomultimer. If the chains were different, it would be a heteromultimer. Hemoglobin is an example of a heteromultimer having two alpha and two beta chains making up a tetrameric structure.

Question 36

Dimers

Answer 36

proteins consisting of two polypeptides

Question 37

trimers

Answer 37

proteins consisting of three polypeptides

Question 38

what type of bonds are needed for protein to adopt its proper shape or conformation?
define amino residiues

Answer 38

both covalent and noncovalent interactions

^ also required for polypeptides to form multimeric proteins

The interactions involve carboxyl,
amino, and R groups of the amino
acids, called amino acid residues
once incorporated into a
polypeptide

Question 39

disulfide Bonds
how to form and break
type of bond

Answer 39

Covalent disulfide bonds form between the sulfur
atoms of two cysteine residues
 They form through the removal of two hydrogen ions
(oxidation) and can be broken only by the addition of
two hydrogens (reduction)
 Once formed, disulfide bonds confer considerable
stability to the protein conformation

Question 40

categories of disulfide Bonds

Answer 40

Intramolecular disulfide bonds

Intermolecular disulfide bonds

they link the two polypeptides together

Question 41

Intramolecular disulfide bonds

Answer 41

form between cysteines
in the same polypeptide

Question 42

Intermolecular disulfide bonds

Answer 42

form between cysteines
in two different polypeptides

Question 43

what types of bonds are Noncovalent bonds and
interactions

Answer 43

include hydrogen
bonds, ionic bonds, van der
Waals interactions, and
hydrophobic interactions
 These are individually weaker
than covalent bonds but
collectively can strongly
influence protein structure and
stability

Question 44

what type of bond forms between amino acids via the R chain

Answer 44

hydrogen Bonds Form in water and between amino
acids in a polypeptide chain via their R groups

Question 45

Hydrogen bond donors

Answer 45

(e.g., hydroxyl or amino
groups) have hydrogen atoms covalently linked to
more electronegative atoms

Question 46

Hydrogen bond acceptors

Answer 46

(e.g., carbonyl or sulfhydryl
groups) have an electronegative atom that attracts the
donor hydrogen

Question 47

Ionic Bonds

Answer 47

Ionic bonds, or electrostatic interactions, form
between positively and negatively charged R groups
 They exert attractive forces over longer distances than
some of the other noncovalent interactions
 Because they depend on the charge on the R groups,
changes in pH can disrupt ionic bonds

Question 48

Van Der Waals Interactions

Answer 48

 Molecules with nonpolar covalent bonds may have
transient positively and negatively charged regions

 These are called dipoles, and two molecules with
dipoles will be attracted to one another if they are
close enough

 This transient interaction is called a van der Waals
interaction or van der Waals force

Question 49

Hydrophobic Interactions

Answer 49

A hydrophobic interaction is the tendency of
hydrophobic molecules or parts of molecules to be
excluded from interactions with water

Protein folding is a balance between the tendency of
hydrophilic groups to interact with water and of
hydrophobic groups to avoid interaction with water

Question 50

Amino acids with hydrophobic side chains tend to be found

Answer 50

within proteins

Question 51

Primary protein structure

Answer 51

amino acid sequence

Question 52

secondary Protein structure

Answer 52

local folding of polypeptide

Question 53

tertiary Protein structure

Answer 53

three dimensional conformation

Question 54

quaternary structure

Answer 54

interactions between
monomeric proteins to form a multimeric unit

Question 55

Table 3-3

Answer 55

slide 8

Question 56

amino acid residues

Answer 56

The interactions involve carboxyl,
amino, and R groups of the amino
acids, are called amino acid residues
once incorporated into a
polypeptide

Question 57

what is an amino acid residue

Answer 57

a residue refers to a single unit that makes up a polymer, such as an amino acid in a polypeptide or protein

Question 58

oxidation

Answer 58

Disulfied Bonds form through the removal of two hydrogen ions
(oxidation)

Question 59

reduction

Answer 59

the addition of
two hydrogens (reduction)breaks disulfied bonds

Question 60

why are disulfide bonds important ?

Answer 60

they help proteins fold into their three dimensional protein structure

Question 61

why is cysteine important

Answer 61

Cysteine residues often play essential roles in protein structure and function by conferring stability through disulfide bond formation, maintaining proper maturation and localization through protein-protein intermolecular interactions, or providing a thiol group for reactions with molecular substrates

Question 62

How does pH affect ionic bonds

Answer 62

Because they depend on the charge on the R groups,
changes in pH can disrupt ionic bonds

Question 63

What type of bond and interactions are involved in the primary structure of protein folding
( state structure too)

Answer 63

strucutre: amino acid sequence

B/I: covalent peptide bonds

Question 64

What type of bond and interactions are involved in the secondary structure of protein folding
( state structure too)

Answer 64

Structure: folding into alpha helix and beta sheets or random coil

B/I = Hydrogen bonds between NH and CO groups of peptide bond in the backbone

Question 65

What type of bond and interactions are involved in the tertiary structure of protein folding
( state structure too)

Answer 65

structure: three dimensional folding of a single polypeptide chain

B/I disulfide bonds, hydrogen bonds, ionic, van der wall interactions, hydrophobic interactions

Question 66

What type of bond and interactions are involved in the quaternary structure of protein folding
( state structure too)

Answer 66

Structure: association of multiple polypeptides to form a multimeric protein

B/I disulfide bonds, hydrogen bonds, ionic, van der wall interactions, hydrophobic interactions

Question 67

By convention, amino acid sequences are written from

Answer 67

the N-
terminus to the C-terminus, the direction in which the
polypeptide was synthesized

Question 68

The first protein to have its amino acid sequence determined
was

Answer 68

the hormone insulin

Question 69

Insulin consists of

Answer 69

one A and one B subunit with 21 and 30
amino acids, respectively

Question 70

Primary structure refers to

Answer 70

the amino acid sequence

Question 71

who is Sanger

Answer 71

Sanger obtained the Nobel Prize for his work on
the insulin protein sequence
 He cleaved the protein into smaller fragments and
analyzed the amino acid order within individual
overlapping fragments
 Sanger’s work paved the way for the sequencing of
hundreds of other proteins and for advancements
in the methods used for sequencing proteins

Question 72

what is the importance of the primary structure

Answer 72

Genetically and Structurally

Primary structure is important genetically because
the sequence is specified by the order of
nucleotides in the corresponding messenger RNA

 It is important structurally because the order and
identity of amino acids directs the formation of the
higher-order (secondary and tertiary) structures

Question 73

describe The secondary structure

Answer 73

The secondary structure of a protein describes
local regions of structure that result from hydrogen
bonding between NH and CO groups along the
polypeptide backbone
 These result in two major patterns, the α helix and
the β sheet

Question 74

The α helix

what does it consist of ?

Answer 74

The α helix is spiral in shape,
consisting of the peptide
backbone, with R groups
jutting out from the spiral

 There are 3.6 amino acids
per turn of the helix

 A hydrogen bond forms
between the NH group of one
amino acid and the CO group
of a second amino acid that is
one turn away from the first

Question 75

the b sheet

Answer 75

The β sheet is an
extended sheet-like
conformation with
successive atoms of the
polypeptide chain located
at “peaks” or “troughs”
 The R groups jut out on
alternating sides of the
sheet
 Because of the formation
of peaks and troughs, it is
sometimes referred to as
a β-pleated sheet

The β sheet is characterized by a maximum of
hydrogen bonding, but β sheet formation may
involve different polypeptides or different regions of
a single polypeptide
 If the parts of polypeptides forming the β sheet
have the same polarity (relative to the N- and C-
termini), they are called parallel
 If the parts of polypeptides forming the β sheet
have opposite polarity, they are called antiparallel

Question 76

If the parts of polypeptides forming the β sheet
have the same polarity they are called

Answer 76

parallel

C. C
|. |
|. |
N N

Question 77

If the parts of polypeptides forming the β sheet
have opposite polarity, they are called

Answer 77

antiparallel

C. N
|. |
|. |
N C

Question 78

do all amino acids form the same Secondary Structure? If not which form alpha and which form beta?

Answer 78

Certain amino acids (e.g., leucine, methionine,
glutamate) tend to form α helices, whereas others
(e.g., isoleucine, valine, phenylalanine) tend to form
β sheets

Question 79

Proline cannot form

Answer 79

hydrogen bonds and tends to
disrupt α helix structures by introducing a bend in
the helix

Question 80

What are motifs

Answer 80

Certain combinations of α
helices and β sheets have been
identified in many proteins
These units of secondary
structure consist of short
stretches of α helices and β
sheets and are called motifs
 Examples include the β–α–β,
the hairpin loop, and the helix-
turn-helix motifs

Question 81

Describe tertiary structure

Answer 81

The tertiary structure reflects the unique aspect of
the amino acid sequence because it depends on
interactions of the R groups

 Tertiary structure is neither repetitive nor easy to
predict

It results from the sum of hydrophobic residues
avoiding water, hydrophilic residues interacting with
water, the repulsion of similarly charged residues,
and attraction between oppositely charged residues

Question 82

Native Conformation

Answer 82

The most stable possible three-dimensional
structure of a particular polypeptide is called the
native conformation

always active

Question 83

Proteins can be divided into two broad categories

Answer 83

Fibrous proteins
 Globular proteins

Question 84

describe Fibrous proteins

Answer 84

Fibrous proteins have extensive
regions of secondary structure,
giving them a highly ordered,
repetitive structure
 Some examples include
Fibroin proteins of silk
Keratin proteins of hair and wool
Collagen found in tendons and
skin
Elastin found in ligaments and
blood vessels

Question 85

describe globular proteins

Answer 85

Most proteins are
globular proteins that
are folded into
compact structures
 Each type of globular
protein has its own
unique tertiary
structure
 Most enzymes are
globular proteins

Question 86

how are peptide bonds broken

Answer 86

hydrolysis

Question 87

how many amino acids are there per turn of the helix

Answer 87

3.6 amino acids

Question 88

β sheet aka

Answer 88

β-pleated sheet

Question 89

our hair is mostly

Answer 89

alpha helices

Question 90

a protein can have a similar sequence but different folding =

Answer 90

different function

Question 91

Globular proteins havea secondary structure that can be mainly

Answer 91

α helical, mainly β
sheet, or a mixture of both structures

Question 92

Many globular proteins consists of a number of segments called

Answer 92

domains

Question 93

What is a domain in a protein

Answer 93

A domain is a discrete, locally folded unit of tertiary structure,
usually with a specific function
 A domain is typically 50–350 amino acids long, with regions of
α helices and β sheets packed together

Question 94

Proteins with similar functions often
share

Answer 94

a common domain

Question 95

Proteins with multiple functions
usually have

Answer 95

a separate domain for each function, like modular units
from which globular proteins are
constructed

Question 96

How can the primary structure help predict tertiary structure

Answer 96

primary structure determines the
final folded shape of a protein

Question 97

can we predict all aspects of protein folding

Answer 97

we are still not able to predict exactly
how a given protein will fold, especially for larger proteins

Question 98

what is the quaternary structure

Answer 98

The quaternary structure of a protein is the level
of organization concerned with subunit interactions
and assembly

The term applies specifically to multimeric proteins

Some proteins consist of multiple identical subunits;
others, such as hemoglobin, contain two or more
types of polypeptides

Question 99

quaternary strucutre applies specifically to

Answer 99

multimeric proteins

( 2 or more polypeptides - one would j be tertiary structure)

Question 100

the process of creating a quaternary structure is usually

Answer 100

spontaneous however smt molecular chaperones are required to assist the process

Question 101

Higher Levels of Assembly in proteins ( fix card)

Answer 101

A higher level of assembly is possible in the case of
proteins (often enzymes) that are organized into
multiprotein complexes
 Each protein in the complex may be involved
sequentially in a common multistep process
 An example is the pyruvate dehydrogenase
complex, in which three enzymes and five other
proteins form a multienzyme complex

Question 102

function of nucleic acids

Answer 102

store, transmit, and express genetic info

Question 103

structure of nucleic acids

Answer 103

linear polymers of nucleotides

Question 104

DNA stands for

Answer 104

deoxyribonucleic acid

Question 105

RNA stands for

Answer 105

ribonucleic acid

Question 106

DNA and RNA differences

Answer 106

DNA and RNA differ chemically and in their role in
the cell

 RNA contains the five-carbon sugar ribose, and
DNA contains the related sugar deoxyribose
 DNA serves as the repository of genetic
information, whereas RNA plays several roles in
expressing that information

Question 107

KNow strucutral difference in DNA and RNA

Answer 107

slide 16

Question 108

monomeric unit of DNA and RNA

Answer 108

nucleotides
Each nucleotide consists of a five-carbon sugar to which a
phosphate group and N-containing aromatic base are attached

Question 109

Each base of a nucleotide is either a

Answer 109

purine and pyrimidine

Question 110

Purines are

Answer 110

adenine (A) and guanine (G)

Question 111

Pyrimidines are

Answer 111

thymine (T) and cytosine (C), and
in RNA, uracil (U)

Question 112

The sugar-base portion without the phosphate
group is called

Answer 112

nucleoside

Question 113

nucleoside

Answer 113

The sugar-base portion without the phosphate
group

Question 114

know how they are names table 3.4

Question 115

Nomenclature slide

Answer 115

page 17

Question 116

the polymers of genetic information

Answer 116

Nucleic acids are linear polymers of
nucleotides linked by a 3ʹ,5ʹ
phosphodiester bridge, a
phosphate group linked to two
adjacent nucleotides via two
phosphodiester bonds

The polynucleotide formed by this
process has a directionality with a 5ʹ
phosphate group at one end and a
3ʹ hydroxyl group at the other

Phosphodiester bonds are ester bonds that form between sugar and phosphate to form the backbone of nucleic acids

Question 117

why is it called 3’

Answer 117

third carbon of that sugar

The numbers 3′ and 5′ refer to the number of carbon atoms in a deoxyribose sugar molecule that a phosphate group binds to

Question 118

why is it called 5’

Answer 118

5 carbons attached

Question 119

Nucleotide sequences are
conventionally written in

Answer 119

the 5’ to 3’ direction

Question 120

A preexisting molecule is used to ensure that new
nucleotides are
added in the correct order
what are they?

Answer 120

(NTPs for RNA, dNTPs for DNA) ??

templates

(N refers to AGCT or AUGC)

Question 121

what is a template

Answer 121

This molecule is called a template, and correct
base pairing between the template and the
incoming nucleotide is required to specify correct
order

Question 122

what type of relationship exists between purines and pyrimidines

Answer 122

complementary

Question 123

complementary base pairing and how many bonds hold the pair

Answer 123

Complementary base
pairing allows A to
form two hydrogen
bonds with T and G
to form three
hydrogen bonds with
C

Question 124

base pairing is a

Answer 124

fundamental property of nucleic acids

Question 125

double helix model

Answer 125

Two antiparallel and complementary
strands of DNA twist around a common
axis to form a right-handed spiral
structure

Question 126

RNA is normally ( in terms of strandedness)

Answer 126

single stranded but also depends on base pairing

Question 127

RNA base pairing

Answer 127

the pairing is usually between bases in
different areas of the same molecule and is less
extensive than that of DNA

( tRNA does have areas of double strandedness)

Question 128

Watson and crick

Answer 128

postulated Double helix structure in 1953

The structure accounted for the known
physical and chemical properties of
DNA
It also suggested a mechanism for DNA
replication

Question 129

Polysaccharides are

Answer 129

are long chain polymers of
sugars and sugar derivatives

They usually consist of a single kind of repeating
unit or sometimes an alternating pattern of two
kinds

Question 130

polysacc. funciton

Answer 130

They serve primarily in structure and storage

Question 131

oligosaccharides

Answer 131

Short polymers, oligosaccharides, are sometimes
attached to cell surface proteins

Question 132

monomers of polysacc.

Answer 132

monosaccharides

Question 133

A sugar may be

Answer 133

an aldehyde, aldosugars with a terminal
carbonyl group; or ketone, ketosugars with an internal carbonyl
group

Sugars within these groups are named generically based on
how many carbon atoms they contain

Question 134

sugars with three carbons are called

Answer 134

Trioses

Question 135

sugars with 4 carbons

Answer 135

Tetroses

Question 136

5 carbon sugar

Answer 136

pentoses

Question 137

6 carbon sugar

Answer 137

hexoses

Question 138

7 carbon sugars

Answer 138

heptoses

Question 139

most common monosaccharide is

Answer 139

the
aldohexose D-glucose (C6 H12 O6)

Question 140

Common sugars are called commonly called carbohydrates because

Answer 140

the formula CnH 2nO
hydrated carbon

Question 141

For every molecule of CO 2 incorporated into a
sugar

Answer 141

One water molecule is consumed

Question 142

naming the carbons of glucose

Answer 142

and other organic
molecules) are numbered from the more oxidized,
carbonyl end

Question 143

the structure of glucose

Answer 143

come bakc to slide

Question 144

how many rings for D-glucose

Answer 144

2 rings

Question 145

know difference between alpha d - glucose and beta d-glucose

Answer 145

OH on carbon 1 is oriented down for alpha

Oh is oriented up for beta

Question 146

two rings forms of D-glucose

Answer 146

The formation of a ring by D-
glucose can result in two
alternative forms
 These depend on the spatial
orientation of the hydroxyl
group on carbon number 1
 These forms are designated
α(hydroxyl group downward)
and β (hydroxyl group upward)

Question 147

disaccharides are

Answer 147

covalently linked monosaccharides

Question 148

maltose is a disacc made up of

Answer 148

two glucose units

Question 149

lactose is a disacc. made up of

Answer 149

one glucose linked to one galactose

Question 150

sucrose is a disacc. made up of

Answer 150

one glucose linked to one fructose

Question 151

glycosidic bond

Answer 151

The linkage of disaccharides is
a glycosidic bond, formed
between two monosaccharides
by the elimination of water
 Glycosidic bonds involving the α
form of glucose are called α
glycosidic bonds (e.g.,
maltose); those involving the β
form are called β glycosidic
bonds (e.g., lactose)

Question 152

Most familiar stoarge polysacc. in plants and animal cells/ a bacterial

Answer 152

starch in plant cells
glycogen in animal cells and bacteria

Question 153

starch and glycogen consist of

Answer 153

α- D-glucose units linked by α
glycosidic bonds, involving carbons 1 and 4 (1→4)
 Occasionally α(1→6) bonds may form, allowing for
the formation of side chains (branching)

Question 154

where is starch also stored in plants

Answer 154

roots and ..?

Question 155

where does branching chains occur in polymers

Answer 155

α(1→6)

Question 156

glycogen structure
where is it stored ?

Answer 156

Glycogen is highly branched, the branches
occurring every 8–10 glucose units along the
backbone
 Glycogen is stored mainly in the liver (as a source
of glucose) and muscle tissues (as a fuel source for
muscle contraction) of animals

Bacteria also store glycogen as a glucose reserve

Question 157

starch structure

Answer 157

Starch is the glucose reserve commonly found in plant tissue
 It occurs both as unbranched amylose (10–30%) and
branched amylopectin (70–90%)
 Amylopectin has α(1→6) branches once every
12–25 glucose units and has longer side chains than glycogen

Question 158

Starch is stored as ____________ within the plastids

Answer 158

starch grains

Question 159

Chloroplasts,

Answer 159

the sites of carbon fixation and sugar
synthesis in photosynthesis

Question 160

Amyloplasts

Answer 160

plastid which are specialized for starch storage

Question 161

glycogen vs strach branching and spacing

Answer 161

glycogen = highly branched and more compact and longer branches

starch can be either way and more gaps between branches

Question 162

cellulose is …

Answer 162

The best-known structural
polysaccharide is the cellulose
found in plant cell walls

Question 163

cellulose composition

Answer 163

Cellulose, composed of repeating
monomers of
β- D-glucose, is very abundant in
plants

Question 164

mammal relationship to cellulose

Answer 164

Mammals cannot digest cellulose
(though some have
microorganisms in their digestive
systems that can)

Question 165

how does cellulose of fungal cell walls differ from that of plants

Answer 165

The cellulose of fungal cell walls differs from that of
plants and may contain either β(1→4) or β(1→3)
linkages

Question 166

Bacterial cell walls contain

Answer 166

Bacterial cell walls contain two kinds of sugars:
GlcNAc (N-acetylglucosamine) and MurNAc
(N-acetylmuramic acid)
Both are derivatives of β-glucosamine and are
linked alternately in cell walls

Question 167

what is chitin

Answer 167

polysaccharide
Chitin is found in insect exoskeletons, crustacean
shells, and fungal cell walls

Question 168

chitin composition

Answer 168

consists of GlcNAc (N-
Acetylglucosamine) units only, joined by β(1→4)
bonds

Question 169

what does polysacc. structure depend on

Answer 169

Polysaccharide Structure Depends on the
Type of Glycosidic Bonds Involved

Question 170

α and β glycosidic bonds are associated with

Answer 170

marked
structural differences

Question 171

Starch and glycogen have what type of bond

Answer 171

The most familiar storage polysaccharides are
starch in plant cells and glycogen in animal cells
and bacteria
 Both consist of α- D-glucose units linked by α
glycosidic bonds, involving carbons 1 and 4 (1→4)
 Occasionally α(1→6) bonds may form, allowing for
the formation of side chains (branching)

Starch and glycogen (α polysaccharides) form loose helices
that are not highly ordered because of the side chains

Question 172

cellulose forms what linkages

Answer 172

Cellulose (that forms β linkages) exists as rigid linear rods
that aggregate into microfibrils, about 5–20 nm in diameter

Question 173

Plant and fungal cells walls contain

Answer 173

these rigid microfibrils in
a noncellulose matrix containing other polymers
(hemicellulose, pectin) and a protein called extensin

Question 174

Lipids are not formed by

Answer 174

polymerization

Question 175

why are lipids regarded as macromolecules

Answer 175

because of their high molecular weight and their
importance in cellular structures, particularly
membranes

Question 176

features of lipids

Answer 176

Although heterogeneous, all have a hydrophobic
nature and thus little affinity for water; they are
readily soluble in nonpolar solvents such as
chloroform or ether
 They have relatively few polar groups, but some
are amphipathic, having polar and nonpolar
regions

Question 177

lipid function

Answer 177

Functions include energy storage, membrane
structure, or specific biological functions such as
signal transmission

Question 178

how many classes of lipids exist and what are the types

Answer 178

6 classes based on structure

1. Fatty acids
2. Triacylglycerols
3. Phospholipids
4. Glycolipids
5. Steroids
6. Terpines

Question 179

Describe Fatty Acids

Answer 179

Fatty acids are components of / building blocks several other kinds
of lipids
 A fatty acid is a long amphipathic, unbranched
hydrocarbon chain with a carboxyl group at one
end
 The polar carboxyl group is the “head,” and the
nonpolar hydrocarbon chain is the “tail”

Question 180

fatty acid structure

Answer 180

The hydrocarbon tails are variable in length but
usually 12 to 20 carbons long
 Even numbers of carbons are favored because
fatty acid synthesis occurs via the stepwise addition
of two-carbon units to the growing chain
 Fatty acids are highly reduced and so yield a large
amount of energy upon oxidation

Question 181

saturated fatty acid structure

Answer 181

( saturated - max number of hydrogens no double bonds)

linear structure
allows it to stack and creates blockages

In saturated fatty acids, each carbon atom in the chain is
bonded to the maximum number of hydrogens
 These have long straight chains that pack together well

Question 182

Triacylglycerol

Answer 182

3 fatty acids

Question 183

phospholipid contains

Answer 183

phosphate group

Question 184

ask what to know abt chart with lipids
on slide of main classes of lipids ( or j to go through them)

Answer 184

2 groups
fatty acoids with zero double bonds and some with at least one double bond

zero vs 1+ double bond

zero double bonds = saturated with hydrogen

other = unsaturated

number of carbons are normally in pairs and even

be somewhat familiar with the name but wont be asked ( j good to know0

Question 185

what is the structure of unsaturated fatty acids

Answer 185

Unsaturated fatty acids have one or more double bonds, so
they have bends in the chains and are less tightly packed

Question 186

what are trans fats?

Answer 186

Trans fats are a type of unsaturated fatty acid with a particular
type of double bond that causes less of a bend in the chain
 They are relatively rare in nature and are produced artificially in
shortening and margarine
 They have been linked to increased risk of heart disease and
elevated cholesterol levels

Question 187

describe how to ID a trans fat molecule

Question 188

what is the function of triacylglycerol?

Answer 188

storage

Question 189

what are triaclyglycerols?

Answer 189

Triacylglycerols, also known as triglycerides,
consist of a glycerol molecule with three fatty acids
attached to it

( know what glycerol is)

Question 190

what is glycerol?

Answer 190

Glycerol is a three-carbon alcohol with a hydroxyl
group on each carbon

Fatty acids are linked to glycerol, one at a time, by
ester bonds formed by the removal of water

Question 191

what type of. bond links fatty acids to glycerol?

Answer 191

ester bonds- formed by the removal of water

Question 192

describe the structure of Triacylglycerol

Answer 192

Monoacylglycerols contain a single fatty acid
 Diacylglycerols have two fatty acids
 The three fatty acids on a triacylglycerol may vary
in length and degree of saturation

Question 193

what is the main function of triacylglycerols?

Answer 193

energy storage

Question 194

whay are some triacylglycerols called fats? ( which ones?)

Answer 194

Triacylglycerols containing mostly saturated fats are usually
solid or semisolid at room temperature and are called fats

Question 195

what is unique about Triacylglycerols in plants

Answer 195

Triacylglycerols in plants are liquid at room temperature (e.g.,
vegetable oil) and are predominantly unsaturated

Question 196

why are phospholipids important to membrane structure?

Answer 196

Phospholipids are important to membrane structure because of their amphipathic nature
( hydrophilic and hydrophobic )

Question 197

what are the two categories of phospholipids

Answer 197

phosphoglycerides or
sphingolipids, depending
on their chemistry

Question 198

what are Phosphoglycerides?

what are their basic components/ structure?

Answer 198

Phosphoglycerides are the
predominant phospholipids in
most membranes

The basic components of
phosphoglycerides is
phosphatidic acid, which has
two fatty acids and a phosphate
group attached to a glycerol
Typical phosphoglycerides often have one
saturated and one unsaturated fatty acid
 The length and degree of saturation of the fatty
acids have profound effects on membrane fluidity

 Membrane phosphoglycerides
invariably have a small
hydrophilic alcohol linked to the
phosphate by an ester bond

Question 199

What are common alcohol groups of a Phosphoglycerid?

Answer 199

The alcohol is usually serine, ethanolamine,
choline, or inositol, which contributes to the polar
nature of the phospholipid head group

Question 200

What are Sphingolipids?

Answer 200

Sphingolipids are based on the amine
sphingosine, which has a long hydrocarbon chain
with a single site of unsaturation near the polar end
 Sphingosine can form an amide bond to a long-
chain fatty acid, resulting in a molecule called a
ceramide

A whole family of sphingolipids exists, with different
polar groups attached to the hydroxyl group of the
ceramide

Question 201

where are Sphingolipids normally found?

Answer 201

Sphingolipids are predominantly found in the outer
leaflet of the plasma membrane bilayer, often in
lipid rafts, localized domains within a membrane

Lipid rafts are important in communication between
a cell and its external environment

Question 202

what are glycolipids?

Answer 202

Glycolipids are lipids containing a carbohydrate instead of a
phospholipid and are often derivatives of sphingosine and
glycerol (glycosphingolipids)

Carbohydrate groups attached to a glycolipid may be one to six
sugar units (D-glucose, D-galactose, or N-acetyl- D-
galactosamine)
 Glycolipids occur largely on the outer monolayer of the plasma
membrane

I facilitates cell-cell communication)

Question 203

glycolipids are often derivatives of what kind of phospholipid?

Answer 203

sphingosine and
glycerol (glycosphingolipids)

Question 204

where are glycolipids located?

Answer 204

Glycolipids occur largely on the outer monolayer of the plasma
membrane

Question 205

what are steroids?

Answer 205

Steroids are derivatives of a four-
ringed hydrocarbon skeleton,
which distinguishes them from
other lipids

They are relatively nonpolar and
therefore hydrophobic
 Steroids differ from one another in
the positions of double bonds and
functional groups
 The most common steroid in
animal cells is cholestero

Question 206

what makes steroids unique from other lipids

Answer 206

they are derivatives of a four-
ringed hydrocarbon skeleton,
which distinguishes them from
other lipids

Question 207

are steroids polar or nonpolar?

Hydrophobic or hydrophilic?

Answer 207

They are relatively nonpolar and
therefore hydrophobic

Question 208

How do steroids differ from one another?

Answer 208

Steroids differ from one another in
the positions of double bonds and
functional groups

Question 209

what is the most common steroid in animal cells?

Answer 209

CHOLESTEROL

Question 210

what is cholesterol?

Answer 210

Cholesterol is insoluble and found primarily in
plasma membranes of animal cells and most
membranes of organelles
 Similar molecules are found in plant cells
(stigmasterol and sitosterol) and fungal cells
(ergosterol)

Question 211

Cholesterol is the starting material for synthesis of

Answer 211

steroid hormones
- including male and female sex
hormones, the glucocorticoids, and the
mineralocorticoid

Question 212

sex hormones include

Answer 212

estrogens produced by the
ovaries of females (e.g., estradiol) and androgens
produced by male testes (e.g., testosterone)

Question 213

what are glucocorticoids?
provide an example

Answer 213

The glucocorticoids (e.g., cortisol) are a family of
hormones that promote synthesis of glucose and
suppress inflammation

Question 214

what are Mineralocorticoids? provide an example

Answer 214

Mineralocorticoids (e.g., aldosterone) regulate ion
balance by promoting reabsorption of sodium,
chloride, and bicarbonate ions by the kidney

Question 215

Carboxyl group

Answer 215

COOH

Question 216

Fatty acids are usually how long?

Answer 216

12 - 20 carbons

( EVEN numbers are favored in the tail)
Y? bc synthesis is normally in pairs - addition of 2 carbons at a time

1-4 double bonds are possible

Question 217

for table 3-5 of fatty acids

Answer 217

be able to recognize the names are fatty acids

Question 218

double bonds in fatty acids change the structure from linear to

Answer 218

Bent

(lower melting point

Question 219

why is it called trans

Answer 219

the double bond is in a trans configuration

( are linear?)

Question 220

cis unsaturated Fatty acid

Answer 220

H on same side
( not linear)

Question 221

know different bonds in different macromolecules

Answer 221

ester in lipid linkage
glycosidic bond - polysaccaride
nucleic acids have a 3’5 phosphodiester bridge

Question 222

ask her about structure of lipid review

Answer 222

know fatty acid has hydrocvarbon tail with cooh on the end

saturated v unsaturaed

know glycerol and that three fatty acods are attached

phosphate in phosopholipid

Question 223

be able to id glycerol stucutre

Question 224

more saturated would be more or less fluid

Answer 224

less fluid bc more packed

Question 225

what Lipid rafts important

Answer 225

regions/ domains in the plasma membrane important for communication between a cell and its environment

Lipid rafts are dynamic assemblies of proteins and lipids that float freely within the liquid-disordered bilayer of cellular membranes but can also cluster to form larger, ordered platforms.

Rafts are small platforms, composed of sphingolipids and cholesterol in the outer exoplasmic leaflet, connected to phospholipids and cholesterol in the inner cytoplasmic leaflet of the lipid bilayer.

Question 226

be able to ID a glucose or sugar molecule

Answer 226

so u can ID a lipid

Question 227

dehyration vs condensation v hydrolysis vs oxidation

Answer 227

dehydration = condenstion ( h200?
oxidation = removal of 2 H
hydrolysis = additon of water
Reduction = addition of H+

Question 228

d-alanine vs I-alanine

Answer 228

same chemcial formula and carboxyl + amnio group