Biochemistry A Flashcards

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1
Q

Metabolism

A

An organism’s net sum of reactions, the result of enzyme catalyzed biological pathways

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2
Q

Catabolic Reactions

A

Breaking down complex polymers into monomers, releases energy

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3
Q

Anabolic Reactions

A

Monomers are synthesized to form a polymer, requires energy

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4
Q

Examples of Anabolic Reactions

A

Photosynthesis, DNA replication, protein synthesis

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5
Q

Condensation Reaction (Dehydration Synthesis)

A

Two molecules covalently bonded to each other through the loss of water

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6
Q

Hydrolysis Reaction

A

A covalent bond is broken through the addition of water

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7
Q

Carbohydrates

A

Carbon, hydrogen and oxygen in a specific ratio. Categorized as monosaccharides, disaccharides and polysaccharides.

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8
Q

Carbohydrates Functions (2)

A

Provide energy storage and building blocks of life

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9
Q

Prefix in front of -ose indicates…

A

Number of carbon atoms in each molecule, e.g. triose has three carbon molecules

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10
Q

Monossacharides

A

Simple ring shaped sugar molecule, basic unit of carbohydrates

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11
Q

Isomers

A

Have the same formula but are structurally different, e.g. glucose, fructose and galactose

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12
Q

DIssacharides

A

2 monosaccharides bonded by a glycosidic bond

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13
Q

Sucrose

A

Fructose + glucose

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14
Q

Lactose

A

Galactose + glucose

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15
Q

Maltose

A

2 glucose molecules

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16
Q

Polyssacharides

A

Long chains of three or more monosaccharides

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17
Q

Starch in plants and glycogen in animals are responsible for …

A

Energy storage

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18
Q

Cellulose in plants and chitin in fungi and arthropods are responsible for forming…

A

Structure

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19
Q

Cellulose

A

Plant source, beta glucose subunit, 1 - 4 bonding, no branching

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20
Q

Starch: amylose

A

Plant source, alpha glucose subunit, 1 - 4 bonding, no branching

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21
Q

Starch: amylopectin

A

Plant source, alpha glucose subunit, 1 - 4 and 6 bonding, branching evry 20 subunits

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22
Q

Glycogen

A

Animal source, alpha glucose subunit, 1 - 4 and 6 bonding, branching every 10 subunits

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23
Q

Lipids

A

Carbon, hydrogen and oxygen atoms in an unfixed ratio. Can be phospholipids, triglycerides, steroids, and waxes.

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24
Q

Types of Lipids

A

Phospholipids (only lipid that contains phosphorus), e.g. lecithin, plasma membrane structure

Triglycerides: fats, oils, long term energy storage

Steroids: cholesterol, testosterone and estrogen: membrane component and sex hormones

Waxes: cuticle: protective covering

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25
Q

Five functions of lipids

A

Cell membrane component, long term energy storage, insulation, organ cushioning, structural component of hormones

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26
Q

Structure of a triglyceride

A

1 glycerol molecule, fatty acid chains

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27
Q

Ester Linkage

A

Binds the glycerol molecule to the hydrocarbon chains

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28
Q

Lipids are differentiated based on the level of…

A

Hydration of the carbon atoms in the fatty acid chain

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29
Q

Saturated Lipids

A

All carbons have the maximum number of hydrogen atoms

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30
Q

Monounsaturated

A

Only one double bond between carbons

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31
Q

Polyunsaturated

A

More than one double bond

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32
Q

Why are saturated lipids less healthy than unsaturated lipids?

A

Saturated lipids are harder to break down and absorb because they tend to be solid at room temperature by forming London dispersion forces that are difficult to break apart completely. The bends in unsaturated lipids help membrane fluidity and prevent stacking

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33
Q

Hydrogenation

A

Make a lipid more solid (creation of saturated lipids)

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34
Q

Cis vs trans fats

A

Cis lipids have hydrogens on the same size, causing kinks. Trans fats have hydrogens on opposing sides, resulting in a linear chain.

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35
Q

Why are trans fats desirable?

A

They are more stable at higher temepratures, last longer and taste better

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36
Q

Protein

A

Polymer made of amino acids constructed by nitrogen, carbon, hydrogen, oxygen and sulfur atoms. Structured as polypeptides

37
Q

Amino acids are formed by an …

A

Amino group, a carboxyl group, a hydrogen atom and a random group

38
Q

The R (variant) group of an amino acid determines…

A

The physical and chemical properties of the amino acid.

39
Q

Essential vs Nonessential Amino Acids

A

9 essential obtained from food, 12 nonessential made by cells

40
Q

Dehydration Synthesis for forming Peptide Bonds

A

The carboxylic acid loses an oxygen atom, and the amine loses two hydrogen atoms

41
Q

Primary Protein

A

A chain of amino acids held together by peptide bonds that form between an amino group and a carboxyl group

42
Q

Secondary Protein

A

Amino acids linked together by hydrogen bonding. Alpha helices and beta pleated sheets form

43
Q

Alpha Helix

A

Hydrogen bonding between amino acids some distance apart, forming a spiral

44
Q

Beta Pleated Sheet

A

Hydrogen bonding between opposing amino acids of a chain , resulting in kinks

45
Q

Tertiary Protein

A

Attractions form between alpha helices and beta pleated sheets to form a 3D shape. Bound together by disulfide bridges, ionic interactions, hydrophobic interactions, intermolecular forces.

46
Q

Quaternary Protein

A

Multiple tertiary protein clusters bound together: multi - subunit. Contains more than one AA chain.

47
Q

Fibrous Proteins

A

Only found in animals, form long protein filaments, usually structural proteins, generally water - insoluble due to the hydrophobic R groups sticking out. Example: collagen

48
Q

Globular Proteins

A

Compact and rounded, generally soluble due to the hydrophobic groups clustered inside, can form dipole - dipole bonds

49
Q

The Proteome

A

An organism’s entire set of proteins

50
Q

How are proteins made?

A

DNA are transcribed into mRNA, which are translated into polypeptides, which are modified into proteins

51
Q

One gene can code for x polypeptide

A

More than one

52
Q

Compare the size of the proteome and the genome

A

The proteome is much larger

53
Q

3 possible ways in which one gene can code for more than one polypeptide

A

1, Genes may be alternatively spliced
2. Genes encoding non mRNA sequences may be transcribed but never translated
3. Genes may be mutated (contain a different base sequence) and produce a different polypeptide

54
Q

6 Functions of Proteins

A
  1. Structure: collagen muscles
  2. Enzymatic (catalysts for all biochemical reactions)
  3. Messaging (protein hormones)
  4. Transportation (channels and carriers)
  5. Defense as antibodies
  6. Emergency energy source
55
Q

Protein denaturation occurs when … structure(s) are lost

A

Secondary, tertiary and quaternary

56
Q

Deviations from the x or y cause protein denaturation

A

Optimal pH or temperature

57
Q

Effects of Protein Denaturation

A

H bonds lost, active sites lose their shape, enzymatic properties lost

58
Q

Examples of Proteins

A

Rubisco, insulin, immunoglobulin, rhodopsin, collagen, spider silk

59
Q

Protein Denaturation: Temperature

A

Large rises of energy change the interactions between the aminoi acids. Peptide bonds remain intact, conserving the primary structure

60
Q

Protein Denaturation: pH

A

Break the bonds between nonadjacent bonds

61
Q

Purpose of having an activation energy

A

Preventing random reactions from occuring

62
Q

Enzyme Catalyzed Catabolic Reaction

A

The substrate enters the active site, forming an enzyme - substrate complex. Degradation occurs, breaking down the substrate into smaller counterparts before it leaves the enzyme

63
Q

Changes in energy level during a catabolic reaction

A

Reactants have more energy than products, resulting in a net energy release (negative value)

64
Q

Enzyme Catalyzed Anabolic Reaction

A

Reactants have less energy than products, resulting in the need to input energy (positive value)

65
Q

The active site lowers the activation energy by…

A

Orienting the substrate correctly and covalently bonding to the substrate

66
Q

2 models proposed for substrate - enzyme binding

A

Lock and key and induced fit

67
Q

The Lock - and Key Model

A

Enzymes are very rigid and specific to only one type of substrate

68
Q

The Induced Fit Model

A

The enzyme undergoes some conformational change to mold to the substrate, more flexible and increases efficiency by increasing the reactivity of the substrate. The enzyme is still highly specific but not just to one

69
Q

Types of Enzyme Regulation

A

Competitive and non - competitive inhibition

70
Q

Competitive Inhibition

A

A competitve inhibitor, a molecule that competes for the active sites, is structurally and chemically similar to the substrate and blocks the active site. If it stays permanently, the reaction doesn’t occur; if it stays temporarily, the reaction is slowed down

71
Q

Example of Competitive Inhibition

A

Heavy metal poisoning: mercury and iron

72
Q

Non - competitive (allosteric) inhibition

A

A molecule binds to the enzyme on an allosteric site, causing a conformational change to the active site

73
Q

Increasing the concentration of the substrate only increases the possibility of the reaction occuring if the inhibitor is…

A

Competitive

74
Q

Graph of substrate concentration against rate of reaction for a normal enzyme, competitve inhibitor and a noncompetitive inhibitor

A

Competitve inhibitor: curve is slower than normal enzyme but plateaus with the normal enzyme. Noncompetitive: curve is slower than competitive inhibitor and plateaus lower.

75
Q

End Product Inhibition of Isoleucine

A

Threonine is the initial reactant. In the first step, threonine is converted into an intermediate compound by the enzyme threonine deaminase. It is catalyzed by multiple different enzymes to become intermediate molecules until it becomes isoleucine, the end product. As isoleucine levels rise, it binds to an allosteric site on threonine deaminase to inhibit it.

76
Q

Purpose of end product inhibition

A

To ensure that the reaction only proceeds when end product is low

77
Q

Benefits of enzymes in industry

A

Speed up reactions, display great specificity, cost - effective

78
Q

Challenge of using enzymes in industry

A

Removing the enzyme once the desired compound is synthesized

79
Q

Immobilized Enzymes

A

Enzymes that are held by a container attached to a support over which a substrate is passed through and converted into desired products

80
Q

Applications of Enzymes in Industry

A

Biofuels (decomposing carbohydrates), medicine (diagnosis), biotechnology (gene splicing), food production (beer and dairy products), textiles (fibers), paper (wood)

81
Q

Advantages of Immobilized Enzymes

A

Resuable, the ability to immediately terminate a rearction by removing the enzymes, the ability to stop random reactions from initiating, enzymes are stable, products don’t contain the enzymes, low energy requirement

82
Q

Production of Lactose - Free Milk

A

Milk containing lactose is pour into immobilize lactase, converting lactose into glucose and galactose

83
Q

Water vs Methane

A

Water has higher melting and boiling points, higher cohesion (H bonding). Methane is nonpolar while water is polar. Methane is tetrahedral, water is bent. Water can dissolve nutrients; dissolution necessary for metabolic reactions to start: not possible with methane

84
Q

Water Properties

A

Cohesion and adhesion (sticking to its own molecules and other molecules through hydrogen bonds), high surface tension (H bonds form spherical shape with strong collective force to minimize area to volume ratio), high specific heat capacity due to large quantity of energy needed to disrupt H bonds, ionic and polar (universal solvent)

85
Q

Water’s Cooling Effect

A

High latent heat of vaporization: cools skin during evaporation by taking heat with it

86
Q

Urea’s Chemical Composition

A

Co(NH2)2

87
Q

Properties of Urea

A

Non - toxic, highly soluble organic compound, used to excrete potentially toxic nitrogen, shows that the synthesis of organic compounds from inorganic molecules is possible, disproved the theory of vitalism

88
Q

Solubility of Biological Molecules Found in Blood

A

Glucose: polar. Lipid: nonpolar, transported by lipoproteins. Amino acids: depends on R group and size, transported in lower concentrations if hydrophobic. Oxygen: needs hemoglobin, soluble in small amount. CO2 and NaCl both soluble.