Carbs, Nucleic Acids, Lipids (11-13) Flashcards

UMN Biochemistry Midterm 2 Part. 1

1
Q

The definition of a carbohydrate, what are the basic structural components

A

3-7 carbon chain, with many hydroxyl groups (OH), and one aldehyde or ketone (polyhydroxy aldehyde or ketone)

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2
Q

Carb formula

A

Cn(H2O)n

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3
Q

Quiz Q: A carbohydrate may be defined as a molecule

A

that is an aldehyde or ketone that has more than one hydroxyl group source

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4
Q

Monosaccharide

A

Monosaccharide = single sugar, 3-7 C in length

Can form stereoisomers
Can be alpha or beta

Can be cyclic
Can be alpha or beta

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5
Q

Disaccharide

A

Disaccharide = 2 sugars linked by glycosidic bond

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6
Q

Polysaccharide

A

Polysaccharide = many sugars (>10) linked together

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7
Q

Relating to -saccharides: Glycosidic bond

A

hemiacetal and alcohol
Can be alpha or beta
(A hemiacetal is an alcohol and ether ATTACHED TO THE SAME CARBON.)

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8
Q

ID Aldehyde Functional Group

A

H-C=O

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9
Q

ID Ketone Functional Group

A

R-C-H

=O

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10
Q

ID isomers of Glucose that we should know for the exam

A

Alpha and Beta D glucose

Can someone lmk what other ones i should be able to ID

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11
Q

STARCH- polysaccharides

A

alpha D-glucose and alpha 1,4 link (OH down)
Storage
Forms helical coils / spherical particles

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12
Q

GLYCOGEN -polysaccharides

A

Alpha D-glucose and alpha 1,4 link (OH down)
Storage
More highly branched than starch

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13
Q

CELLULOSE -polysaccharide

A

Beta D-glucose and B 1,4 link (OH up)
Structural
Forms bundles - intra and interstrand hydrogen bonds
Composed of 1000s of glucose units that that due to the beta linkage can from extensive intrastrand
Interstrand hydrogen bonds

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14
Q

Stereoisomers

A

Physical properties same
Differ in way they end polarized light
Don’t interact with same binding sites on enzymes/proteins

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15
Q

Stereoisomeric forms because of chiral centers - carbon atom bonded to 4 different groups

A

Same chemical formula, different arrangements
Nonsuperimposable mirror images
Configuration about the chiral center furthest from the aldehyde or ketone determines if its in D or L configuration (most in D)

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16
Q

Cyclization

A

Monosaccharides with 5-6 carbons atoms exist in cyclic form - form internal bond between carbonyl group and hydroxyl group (hemiacetal bond)

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17
Q

The type of bond formed between monosaccharides in disaccharides and polysaccharides, how can they differ? And how can this affect the structure and properties of a polysaccharide

A

Glycosidic bond - hemiacetal + alcohol
Links monosaccharides to form disaccharides or polysaccharides
Can be alpha or beta configuration
Once bond formed, configuration is locked and results in different properties of the products

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18
Q

DNA role

A

store genetic info (ATGC)

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19
Q

DNA

Release genetic info

A

mRNA, TRNA, rRNA

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20
Q

DNA Intermediates in metabolism

A

NAD+/NADH - redox coenzymes

ATP - energy storage

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21
Q

Signaling molecules DNA

A

cAMP, cGMP

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22
Q

Sugar

DNA VS RNA

A

D-ribose (RNA)

2-deoxyribose (DNA) (missing oxygen for carbon #2)

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23
Q

Bases

DNA VS RNA

A

RNA: Adenine, Uracil, Cytosine, Guanine
DNA: Adenine, Thymine, Cytosine, Guanine

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24
Q

3 components Nucleotide

A

five carbon sugar, base, phosphate

25
Q

Nucleotides linked by phosphodiester linkages between

A

free OH (3’) and free phosphate (5’)

26
Q

Nucleic acid is a

A

polymer of nucleotides

27
Q

double strands running antiparallel, form double helix

A

DNA

28
Q

_____ bonds between strands - hold bases together (complementary base pairing)

A

Hydrogen

29
Q

For H bonds in DNA:

DONOR

A

NH groups

30
Q

For H bonds in DNA:

ACCEPTORS

A

O or N

31
Q

Alternating sugar and phosphate backbone

A

DNA

32
Q

DNA strands run

A

antiparallel (5’ to 3’ and ‘3 to 5’)
5’ has free phosphate group
3’ has free OH group

33
Q

Major and minor grooves formed in double helix - sites for _____

A

proteins to bind

34
Q

Quiz Q

The backbone of a nucleic acid molecule consists of

A

alternating sugar and phosphate groups linked by phosphodiester bonds

35
Q

RNA structure

A

Single stranded

36
Q

RNA Phosphodiester linkages between strands

A

(3’ OH and 5’ phosphate)

37
Q

Nucleic acids that are intermediates in metabolism

A

ATP, NAD+/NADH

38
Q

Roles in metabolism:

ATP

A

energy storage, cleaving phosphate releases energy that can be used to do work

39
Q

Roles in metabolism:

NAD+

A

electron acceptor, can be reduced to NADH when carbon is oxidized

40
Q

Roles in metabolism:

NADH

A

stored from of chemical energy, carries electrons, can be oxidized to release energy to make ATP (oxidative phosphorylation)

41
Q

Lipids are hydrophilic/hydrophobic, insoluble/soluble, nonpolar/polar

short or long hydrocarbon chains

A

hydrophobic, insoluble, nonpolar

Long hydrocarbon chains

42
Q

Functions of Lipids (3)

A

Energy storage
Component of cell membranes
Signaling molecules

43
Q

Basic fatty acid structure

A

Long hydrocarbon chains (16-20 carbons longs) with a single carboxylic acid at 1 end

44
Q

Basic fatty acid structure SATURATED

A

no double bonds (higher melting point, forms solids/fats)

45
Q

Basic fatty acid structure UNSATURATED

A

1 or more double bonds - creates kink - can be cis or trans (lower melting point, forms liquids/oils)

46
Q

Carboxyl group on lipids

A

HO-C=O

47
Q

Shorthand notation of a fatty acid given the structure

A

C(#carbons : #double bonds)

Count from the carboxylic acid

48
Q

Triglyceride structural components (how structure effects the properties of a triglyceride. Is it an oil or a fat?)

A

Triglyceride = glycerol backbone (CH2OH) and 3 fatty acid tails (can be different)

Saturated fatty acids - forms solid/fat, has higher melting point
Unsaturated fatty acid tails - forms liquid/oil, lower melting point

49
Q

Phospholipid structural components

A

Phospholipids have a glycerol or sphingomyelin backbone with 2 fatty acids and a phosphate and polar head group esterified to it

50
Q

Phospholipid role in membranes

A

Important components of cell membranes because of amphipathic properties - hydrophilic heads and hydrophobic tails
No unsaturated fatty acids - tight, lower permeability and fluidity
Many unsaturated fatty acids - kinked cause not to fit together tightly, higher permeability and fluidity

51
Q

Glycolipids: what is their function in a membrane

A

Glycolipids are cell signaling molecules on the the membrane

They have a sphingosine backbone

52
Q

Glycolipids: how define ABO blood group

A

Variable sugar groups serve as recognition sites on the surface of cells - example ABO blood groups have different sugars

53
Q

DO KAHN VID ON

A

ABO blood group and glycolipids

54
Q

General structure of sterols

A

Steroid nucleus - 3 6-carbon rings and 1 5-carbon ring

Rigid and planar structure

55
Q

Importance of Cholesterol in membranes and as a precursor to other molecules

A

Cholesterol is the most common sterol
Important lipid component of animal membranes
Steroid nucleus with hydrocarbon chain
Nonpolar/hydrophobic but has single OH group
Inserts into bilayer and increases rigidity
Serves as precursor for steroid hormones (signaling molecules) and bile acid

56
Q

Alpha has OH ____ configuration

A

down

57
Q

Alpha D glucose and B D glucose are ____ stereoisomers

A

cyclic

58
Q

Beta has OH ____ configuration

A

up