Biochemistry Flashcards

1
Q

Cohesion

A

the sticking together of particles of the same substance.

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2
Q

surface tension

A

A measure of how difficult it is to stretch or break the surface of a liquid

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3
Q

water properties

A

-High heat capacity
-molecules of water cling together (high cohesion)
-high surface tension
-frozen water is less dense than liquid water (water anomaly)

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4
Q

Monomer

A

a small chemical unit that makes up a polymer

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5
Q

Polymer

A

A long molecule consisting of many monomers linked together.

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6
Q

Carbohydrates

A

a family of molecules that are made mainly of oxygen, hydrogen and carbon.
suffix: “OSE”
general formula: (CH₂O)n

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7
Q

Monosaccharides

A

the monomers that compose all carbohydrates.
general formula: (CH₂O)n
n is a number between 3 to 6, therefore there are three types of monosaccharides:
Triose: 3 carbons in the backbone
pentose- 5 carbons in the backbone
hexose- 6 carbons in the backbone

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8
Q

How many fatty acids chains are found in phospholipids?

A

2

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9
Q

Water polarity

A

Negative dipole on the oxygen atom
Portage dipole on the hydrogen atoms

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10
Q

How many hydrogen bonds can a water molecule form?

A

4 bonds

1 from each hydrogen
2 from the oxygen

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11
Q

Why does the cohesion in water very high?

A

Because of the dipole-dipole forces and the hydrogen bonds they form.

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12
Q

What are macromolecules?

A

Built by repetitive molecules called monomer, and are linked together to form a large molecule called polymer.
Monomers are not always identical to each other
Polymers can be in different lengths

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13
Q

What types of macromolecules exist in biochemistry?

A

4 kinds:
- proteins
- nucleic acid
- carbohydrates/ polysaccharides (sugar)
- lipids

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14
Q

What type of monomers form protein?

A

Amino acids

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15
Q

What type of monomers form nucleic acid?

A

Nucleotides

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16
Q

What type of monomers form carbohydrates?

A

Monosaccharides

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17
Q

What type of subunits form lipids?

A

Fatty acids

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18
Q

Which of the macromolecules is not a polymer?

A

Lipids

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19
Q

What is the general formula of carbohydrates?

A

( CH2O )n

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20
Q

What are the main functions of carbohydrates?

A
  • Energy source
  • mechanical support
  • building blocks
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21
Q

What are the main types of monosaccharides?

A
  • Trioses (3 carbon sugar)
  • Pentoses (5 carbon sugar) → ribose, deoxyribose
  • Hexoses (6 carbon sugar) → glucose
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22
Q

What is the structure of monosaccharides?

A

Ketone or aldehyde
Depends on their location on the carbonyl

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23
Q

What are structural isomers?

A

Same chemical composition, but differ in the place of the carbonyl group and in the place/ orientation of the OH group

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24
Q

What are stereo isomers in saccharides?

A

Almost Mirror image of one another
2 forms:
D- form
L-form

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25
Q

What happens to monosaccharides in water?

A

They will always close to a ring.
The ring will always dose by the oxygen.
The carbon outside of the ring will always be last!

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26
Q

What is the difference between a-glucose and b-glucose?

A

A-glucose → OH below carbon no. 1

B -glucose → OH above carbon no. 1

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27
Q

A- bond (alpha bond)

A

our body can break this bond

A band between to A- glucose

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28
Q

B-bond (beta-bond)

A

A bond between a beta - glucose
# our body cannot break this bond

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29
Q

What is glucose?

A

C6H12O6
# Most impotent building block
# all living organisms can break it during cellular respiration for energy

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30
Q

What differ glucose from galactose?

A

Their OH group on carbon number 4 is in different location

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31
Q

What is fructose?

A

Fruit sugar
# differ in the location of the carbonyl group.

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32
Q

What is a condensation reaction?

A

A molecules connect by releasing a smaller molecule (like water).
Usually requires energy.

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33
Q

What is a glycosidic bond?

A

Is Made by a condensation reaction
Covalent band between 2 cyclic monosaccharides.
# an oxygen losing A hydrogen
# carbon is losing OH group

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34
Q

What is a Hydrolysis?

A

The reverse reaction to a condensation reaction.
Water is consumed to break glycosidic bond & form 2 monomers
Release energy

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35
Q

What are disaccharides?

A

Two monosaccharides linked by glycosidic bond

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36
Q

What are oligosaccharide?

A

Composed of 2-10 monosaccharides linked together

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37
Q

Where are the main types of disaccharides?

A
  • Lactose ( C12H22O11 )
  • maltose ( C12H22O11 )
  • sucrose ( C12H22O11 )
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38
Q

What Latin lactose?

A

Disaccharide
“Milk sugar”
Contain a molecule of galactose & one of glucose linked by condensation relation
Found in milk, catabolized by the enzyme lactase.

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39
Q

What is sucrose?

A

Most common disaccharide
“Table sugar”
Contains one glucose & one fructose

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40
Q

What is maltose?

A

Disaccharide
Found in germinating seeds
2 glucose molecules linked together.

41
Q

What are the main functions of polysaccharides?

A
  • Energy storage ( starch: plants, glycogen: animals)
  • building strong cellular structures
42
Q

What are the most common polysaccharides?

A
  • Glycogen
  • starch
  • cellulose
43
Q

Whet is the structure of glycogen?

A

Branched chains, each comprised of 8-12 glucose monomers
- bonds making the chains→ a (1-4) linkage
- bonds within the branches → a (1-6) linkage

44
Q

What is the main function of glycogen?

A

Energy storage
Found in the liver and muscle tissue & fungi and bacteria.

45
Q

What are the main functions of starch?

A

Energy storage in plants
# may be consumed by animals

46
Q

What is starch composed of?

A

Composed of 2 types of glucose polymers:
1. Amylose ( straight chain )
2. Amylopectin (branched chain)

47
Q

Is starch soluble?

A
  • it becomes soluble in water when it’s heated
  • through the activity o amylases
48
Q

What type of bond form cellulose?

A

B( 1 → 4) glycosidic bonds

Thee glucose chains are bonded to each other by hydrogen bonds.

49
Q

Where can we find cellulose?

A

Cell walls of green plants

50
Q

Is cellulose soluble?

A

No!! (Water insoluble )
Non digestible dietary fiber

51
Q

What are glycoprotein?

A

Small oligosaccharides covalently bonded to protein.

52
Q

What are glycolipids?

A

Small oligosaccharides covalently bonded to lipids

53
Q

What are proteoglycans?

A

A core protein bonded to many saccharide chains.

54
Q

What is differ proteoglycans from glycoprotein?

A

Size of the sugar compared to the protein groups.
Glycoprotein → small saccharide chains, most of the molecule is composed of the peptide.
Proteoglycans → small protein core, most of the molecule is composed of oligosaccharides and polysaccharides.

55
Q

What are the monomeric units in DNA?

A

Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)

56
Q

What are the monemeric units in RNA?

A

Adenine (A)
Guanine (G)
Cytosine (C)
Uracil (U)

57
Q

What defines the classification of nucleotides?

A

The number of nitrogenous rings:
Purines → contain 2 ring of 5 and 6 atoms ( A, G)
Pyrimidines → contain one ring of 6 atoms ( T, C, U)

58
Q

What is a nucleoside?

A

The complex of sugar attached to one of the nitrogenous bases without the phosphate group

59
Q

Which bond forms the nucleotide chains?

A

Phosphodiester bond.
Condensation reaction → the phosphate group is linked to the sugar

60
Q

Does the nucleotide backbone has directionality?

A

Yes.
5’ end → free phosphate group
3’ end → free OH group

61
Q

What are fatty acids?

A

Amphoteric molecule → long carbon tail and an OH group

62
Q

What are are the most familiar lipids?

A

Oils & fats

63
Q

In what way do fatty acids differ from one another?

A
  1. No. Of carbons in their hydrophobic chain (14 - 20 carbons)
  2. Degree of unsaturation
64
Q

According to what is the degree of saturation depends on?

A

→ no C = C: fully saturated
→ one C = C: monoustaturated
→ many C = C: highly unsaturated.

65
Q

How does the degree of saturation affect the packing of the molecule?

A

Double bonds form “kinks” in the molecule.
The more “kinks”, the less packed it can be with other molecules.

66
Q

In what way do oils and fats differ from each other?

A

Their state at room temp.
Fats → solid
Oil → liquid

67
Q

What type of link is between alcohol and fatty acids?

A

Condensation reaction creating an ester bond (r- coor)

68
Q

What is glycerol?

A

Simple organic molecule

# part of the alcohol family - contains 3 hydroxyl groups
# C3H8O3

69
Q

What are triglycerides?

A

Most common lipid

#fats & oils
# composed of one glycerol molecule and 3 fatty acids by individual ester bonds.
# hydrophobic & water insoluble
# their fatty acids tails can be of different length

70
Q

What are the main roles of triglycerides?

A
  1. ** energy storage** - when the body doesn’t have available sugar to use it can break the fatty acid and make glucose for use.
  2. ** insolation** - homeostasis ( core temp.)
  3. Water source - during respiration , triglycerides can be converted to carbon dioxide and water.
71
Q

What are phospholipids?

A

Amphoteric molecule → hydrophilic region (phosphate group bonded to glycerol ), hydrophobic area (2 fatty acids )

72
Q

What is the west important role of phospholipids?

A

Form the double layered lipid membrane het surrounds all living cells.

73
Q

What happens to phospholipids in aqueous environment?

A

The fatty herds organize in two layers.
The hydrophobic layer point award one another, the hydrophilic areas point outward ( micelle)

74
Q

What are sterols?

A

Structural lipids.
Found in many eukaryotic cell’s membrane.

75
Q

What are the functions of sterols?

A
  1. Structural lipids
  2. Precursors for other products - hormones, bile acids, etc…
76
Q

Wet is the structure of sterols?

A

All sterols contain carbon skeleton (steroid nucleus )→ 4 fused carbon rings ( planar rigid plane)

77
Q

How different steroids are distinguished ?

A

By the chemical groups attached to the steroid rings.

78
Q

What are steroids?

A

A family of hormones ( sterol derivatives)
# cholesterol is the most common steroid, serves as a precursor

79
Q

What do steroids affect?

A

Gene expression & metabolism

80
Q

What is the structure of amino acids?

A

** Central carbon ** (alpha carbon ) connected to:
1. Amine group - NH2
2. Carbonyl head group - COOH
3. Hydrogen atom
4. R group

81
Q

What determines the amino acid type?

A

The R group

82
Q

How many types of amino acids are there?

A

20

83
Q

What are essential amino acids?

A

9 amino acids that cannot be synthesized in the body, and therefore must be consumed from external sources, mainly through nutrition.

84
Q

To what groups can the amino acids be classified into?

A

Most important → polar vs. Non-polar
Also,
Hydrophobic & hydrophilic, acidic & basic…

85
Q

What is a zwitterion?

A

The head - base reaction will form it
both positive and negative charges in the some molecule →
carbonyl end (-)
Amine end (+)

86
Q

Whet is a peptide bond?

A

Covalent bond between amino acids to form a protein chain.
The bond forms by a condensation reaction.
The bond forms between a carboxylic acid and an amino group.
Forms the protein backbone.

87
Q

What is the directionality of the polypeptide chain?

A

N - terminus - free amino acid, always on the left side
C - terminus - free carboxylic group

88
Q

How many peptide bond can each amino acid form?

A

2!

89
Q

What is a dipeptide ?

A

Two amino heads only linked to each other.

90
Q

How many levels does the protein structure has?

A

4 levels.
Primary, secondary, tertiary and quaternary

91
Q

What does the primary structure refer to?

A

The amino acid sequence (their type and the order in which they are joined).
Only proteins of the same kind will have the same primary structure.

92
Q

What does the secondary structure refer to?

A

The formation of local substructures, based on hydrogen bonds.
# Results from the coiling (folding) of the amino acid chain because of the hydrogen bonds between the carboxylic acid and the amine group.

93
Q

What are the most common secondary structures?

A

AIpha-helix ( a- helix)
Beta pleated sheet (b- pleated sheet)

94
Q

What is the shape of the alpha helix structure?

A

A helical structure, reminds a corkscrew.
Held in place by multiple hydrogen bonds.

95
Q

How much space is created between amino acids in an alpha helix structure?

A

4 positions apart
Amino acid 1 will bond to amino acid 5

96
Q

What is the shape of a beta - pleated sheet structure?

A

Looser & straighter than a-helix.
Can be classified to two structures:
1. Anti-parallel beta sheet
2. Parallel beta sheet.

97
Q

What is a coiled coil structure?

A

Two alpha helixes can combine to form a coiled coil.
The structure is held by R group interactions.

98
Q

Heat capacity

A