Biomolecules Flashcards

1
Q

What is OXIDIZED in the cell to generate ATP (3)?

A

Carbohydrates, fats, and proteins

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2
Q

What happens to electrons during oxidation?

A

loss of electrons

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3
Q

What happens to electrons during reduction?

A

gain of electrons

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4
Q

Where does initial glycolysis occur?

A

Cytoplasm

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5
Q

Where does remaining glycolysis occur?

A

the inner membrane of the mitochondria

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6
Q

What are the byproducts of cellular metabolism (4)?

A

CO2, H2O, energy (ATP), and heat

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7
Q

How many calories and ATP is generated from 1 mole of glucose?

A

1 mole of glucose (180 g) generates 686,000 calories to get 36-38 moles of ATP (each ATP requires 12K calories= 456,000 calories)

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8
Q

What is a calorie?

A

unit of energy, the energy thatisneeded to increase the temperatureof1 gofwater by 1C at one atmosphere

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9
Q

What is kilocalorie?

A

isthe energy thatisneeded to increase the temperatureof1 kgofwater by 1C

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10
Q

What is adenosine triphosphate?

A

Organic compound, ”molecular unit of currency/energy” for the body that drives MANY of the biologic processes in the body

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11
Q

When is a majority of ATP used?

A

Much used during protein synthesis to form peptide linkages between amino acids

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12
Q

How is ATP normally stored?

A

ATP itself not stored- the high energy phosphate molecules are stored as phosphocreatine within the cell (provide the buffer source to quickly “charge” ATP from ADP/AMP)

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13
Q

How is ATP produced (3)?

A

Produced by glycolysis, oxidative phosphorylation (Citric Acid Cycle/Kreb’s) and beta oxidation (fatty acids used as fuel)

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14
Q

What is ATP a precursor to (2)?

A

DNA/RNA , second messenger cAMP

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15
Q

What is ATP classified as?

A

nucleotide triphosphate: nitrogen base (adenine), sugar (ribose) and triphosphate

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16
Q

What is the formula of ATP?

A

ATP ↔️ ADP + PO3 + ⚡️ ↔️ AMP + PO3 + ⚡️

Dephosphorylation/hydrolysis of ATP by enzymes ATPases

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17
Q

How many kcal/day are required to meet basic metabolic needs? How many oxygen?

A

20 kcal/day; 250 mL/min of oxygen

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18
Q

What is the average kcal/kg for men? Women?

A

Men on average: total 39 kcal/kg; Females 34 kcal/kg

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19
Q

How many kcal/g are founded in carbohydrates/proteins; fats; alcohol?

A

Carbohydrates/proteins provide 4.1 kcal/g; fats 9.3 kcal/g; alcohol 7 kcal/g

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20
Q

What is the structure of carbohydrates?

A

Carbon compounds with large quantities of hydroxyl groups (OH), often referred to as “sugars” or saccharides

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21
Q

What is monoasaccharides?

A

the simplest carbohydrates, are polyalcohol aldehydes or ketones that have two or more hydroxyl groups vs polysaccharides (very large)

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22
Q

Why is monosaccharides important?

A

Are important fuel molecules as well as building blocks for nucleic acids. Hexoses.

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23
Q

Monosaccharides are ______

A

water soluble

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24
Q

What are examples of carbohydrates (4)?

A
  • Glucose (Glycogen)
  • Fructose
  • Galactose
  • Ribose
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25
Q

What is ribose?

A

the carbohydrate component ofthe nucleic acids- 5 C molecule

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26
Q

What is the most important disaccharides for human biology?

A

Sucrose, Lactose and Maltose

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27
Q

What is sucrose?

A

glucose and fructose

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28
Q

What is lactose?

A

glucose and galactose

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29
Q

What is maltose?

A

2 glucose molecules

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30
Q

How are disaccharides broken down?

A

Broken down into monosaccharides in the small intestines and carried to the liver via the portal vein

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31
Q

What is the site of carbohydrate metabolism?

A

Liver is the site of carbohydrate metabolism: regulation, storage (glycogen), conversion of glucose from galactose/fructose, which produce same amount of energy

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32
Q

What is glucose?

A

the predominant (not only) source to produce ATP

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33
Q

What is glycogen?

A

Long polymers similar to starch: how glucose stored (not stored in its free form)

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34
Q

How much glycogen is stored?

A

Up to 90% of the glucose from a meal can be stored as glycogen

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35
Q

Why is glycogen released?

A

Released during fasting from the liver and strenuous exercise from muscle

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36
Q

What is glycogen phosphorylase?

A

Enzyme: glycogen phosphorylase converts glycogen to glucose derivatives (glucose-1-phosphate)

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37
Q

What are examples of lipids?

A

waxes, sterols, fat-soluble vitamins, triglycerides (fat), phospholipids, and other substances

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38
Q

What type of organic molecules are lipids?

A

Hydrophobic

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39
Q

What are fatty acids?

A

carboxylic acids- long chains that can be saturated/unsaturated

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40
Q

How are lipids absorbed?

A

from the GI tract as chylomicrons via lymph system

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41
Q

How are lipids removed from circulation?

A

From tissues (adipose, liver, skeletal, heart) via lipoprotein lipase

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42
Q

What is lipoprotein lipase?

A

extracellular enzyme- allows free fatty acid across cell membrane

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43
Q

What are chylomicrons?

A

Consist of phospholipid and apolipoproteins on the outer surface and triglycerides and cholesterol (vary in size) inside

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44
Q

What is cholesterol?

A

is considered a lipid although does not contain fatty acids (cell membrane, hormones) Hydrocarbon rings. Sterol.

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45
Q

What is lipoproteins?

A

are part lipid, part protein

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46
Q

How is lipoproteins synthesized?

A

Synthesized by hepatocytes

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47
Q

What is VLDL and LDL?

A

contains most of the cholesterol in plasma

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48
Q

What is HDL?

A

sends excess cholesterol from the peripheral tissue back to the liver to be excreted in bile

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49
Q

What are triglycerides?

A

tremendous source of energy- liberated as 3 fatty acids and glycerol

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50
Q

How are triglycerides liberated?

A

hydrolysis from adipose and carried to cells by mainly by VLDL and albumin (lipase)

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51
Q

What stimulates triglycerides?

A

low glucose levels

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52
Q

What is the back bones of triglycerides?

A

Glycerol is a sugar alcohol that binds fatty acids together

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53
Q

What is the functions of triglycerides (2)?

A

Either used as fuel or restored as triglycerides

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54
Q

What are examples of triglycerides (2)?

A

Tristearin and Glycerol

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55
Q

Are fatty acids the same as fats?

A

No

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56
Q

What are saturated fatty acids?

A

have carbon chains that contain only carbon-carbon single bonds (close carbon bonds resistant to enzymatic activity)

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57
Q

What are unsaturated fatty acids?

A

have carbon chains that contain at least one carbon-carbon double bond

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58
Q

What are essential fatty acids?

A

must be consumed, essential for biological functions

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59
Q

What are the types of phospholipids (3)?

A

lecithin, cephalins, sphingomyelin

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60
Q

What are phospholipids important for (4)?

A

Cell membranes, transport molecules for cholesterol, thromboplastin (clotting), myelin

61
Q

What is the structure of phosppholipids?

A

Contain one or more fatty acid molecules (diacylglyerol) and one phosphoric acid radial (usually with a N base)

62
Q

What is the solubility of phospholipids?

A

All lipid soluble, transported as lipoproteins, used throughout the body for structural purposes

63
Q

Where are phospholipids form?

A

Formed in all cells, primarily in the liver (90%)

64
Q

How are phospholipids formed?

A

Formation tied to metabolism: increased formation with increased triglyceride deposition in the liver

65
Q

What is lecithin?

A

Requires choline: an essential nutrient in humans (body can made de novo but requires nutritional input to meet metabolic needs) (another example- acetylcholine)
Important for cell structure and controls passage of nutrients in/out the cell

66
Q

What are the tails of phospholipids?

A

have long greasy tails and are hydrophobic (saturated and unsaturated fatty acid)

67
Q

Does a phosphate group alone attached to a diaglycerol form a phospholipid?

A

No, it is phosphatidate (diacylglycerol 3-phosphate), the precursor of phospholipids

68
Q

What are the two important phospholipids in plasma membranes?

A

Phosphatidylcholine and phosphatidylserine

69
Q

What are steroids?

A

Biologically active compounds, play a variety of roles in living systems.

70
Q

What is the solubility of steroids?

A

Hydrophobic, lipid molecules

71
Q

How are steroids important?

A

Important component of cell membrane and cell signaling molecules (hormones)

72
Q

What is the structure of steroids?

A

3 cyclohexane and 1 cyclopentane rings (Steroid nucleus)

73
Q

What are steroids dependent on?

A

vary dependent on the side chains functional groups and oxidation of the ring structure

74
Q

What is the most common steroid? What is it the precursor to (7)?

A

Cholesterol isthe most commonsteroidandisthe precursor to vitamin D, testosterone, estrogen, progesterone, aldosterone, cortisol, and bile salts

75
Q

Where is cholesterol formed?

A

Liver (Exogenous sourced from diet)

76
Q

What determines the amount of cholesterol in the body (5)?

A
  • Ingested (only changes levels +/- 15%
  • Diet high saturated fat:
  • Diet of unsaturated fat: decreases (unknown mechanism)
  • Genetics, lack of insulin, excess thyroid hormone, stress
  • Role in atherosclerosis (LDL versus HDL)
77
Q

What effect does a high saturated fat have on cholesterol levels?

A

15-25% due to fat deposition in liver and increased production of Acetyl CoA to produce cholesterol

78
Q

What is the major function of cholesterol?

A

form cholic acid in the liver for bile (80%)

79
Q

What relationship between adrenocortical hormones and cholesterol?

A

that are cholesterol/steroid based: sex hormones, aldosterone, cortisol

80
Q

What are some examples of steriods (4)?

A

Cortisol. aldosterone, testosterone and estradiol

81
Q

What is formed from arachidonic acid?

A

Prostaglandin

82
Q

What is eiconsanoids?

A

Unsaturated carboxylic lipid compounds that are physiologically active in the body- hormone-like qualities, formed from 20-chain polyunsaturated fatty acids

83
Q

What do eiconsanoids form?

A

Arachidonic acid metabolites

84
Q

What is eiconsanoids important in?

A

Important in the inflammation process of the body (pro and anti-inflammatory), vasodilation, aggregation of platelets, tissues have varying receptors for them and target of pharmacology

85
Q

What are the subclasses of eiconsanoids (3)?

A

Prostaglandins, thromboxanes, leukotrines

86
Q

What are prostaglandins?

A

systemic, all throughout the body

87
Q

What are thromboxanes?

A

mainly platelets but also lungs

88
Q

What is leukotrienes?

A

mainly lungs

89
Q

How are eiconsanoids liberated (2)?

A

Arachidonic acid liberated from cell membrane after stimulus (ex: cytokines) or damage from the structural glycerol of the cell membrane via phospholipase A2

90
Q

What synthesizes eiconsanoids?

A

Prostaglandins are synthesized in vivo by almost all cells in the body from mainly the unsaturated fatty acid arachidonic acid

91
Q

What enzyme further oxidizes the fatty acid?

A

cyclooxygenase enzyme

92
Q

What three pathways can a does a liberated arachidonic acid follow?

A

lipoxygenase pathway, cyclooxygenase (COX) pathway, Cytochrome P450 monooxygenase system

93
Q

What is components of the lipoxygenase pathway,?

A

leukotrienes, lipoxins, HETE’s (hydroxyeicosatetraenoic acids

94
Q

What is the components of the cyclooxygenase (COX) pathway?

A

prostaglandins, thromboxane, prostacyclin

95
Q

What is the components of the Cytochrome P450 monooxygenase system?

A

cis-epoxyeicosatrienoic acids and other HETE’s

96
Q

Understand the Cyclooxygenase inflammatory process.

A

Slide 62

97
Q

What are some functions of proteins?

A

Proteins serve many roles in the living systems, from transport molecules such as hemoglobin, to structural and locomotion tissues, to enzymes that are necessary to catalyze virtually every chemical process that living organisms carry out.

98
Q

What are proteins polymers of?

A

relatively simple organic compounds called amino acids joined together by peptide bonds.

99
Q

What is the structure of amino acids?

A

Amino acids contain two organic functional groups: an amine group and a carboxylic acid group

100
Q

What gives an amino acid its unique chemical and physical properties?

A

Each amino acid has a unique side chain that gives the amino acid its characteristic

101
Q

What determines the characteristics of amino acids?

A

The R group determines the characteristics (size, polarity, and pH)

102
Q

How many amino acids are there?

A

20

103
Q

What are dietary proteins broken down to?

A

Dietary protein broken down by various enzyme to peptides for absorption (Na+ dependent amino acids transporters)

104
Q

What synthesizes nonessential amino acids?

A

α-keto acid

105
Q

How do amino acids move in and out of the cells?

A

active/facilitated transport (too large)

106
Q

What happens when proteins enter the bloodstream?

A

Once enters bloodstream, rapidly picked up by all cells to form various proteins- amino acids linked by peptide chains under the direction of RNA/ribosomes in the cells (protein can range 20-100,00 amino acids!)

107
Q

How can proteins be decomposed?

A

Can easily be decomposed back to base forms and transported out of cells if a particular amino acid level drops

108
Q

What happens to excess proteins?

A

degraded into other products, used for energy or stored as glycogen or fat

109
Q

What are the amino acids?

A

Glycine, alanine, valine, cysteine, proline, leucine, isolecuine, methionine, tryptophan, phenylalanine, lysine, arginine, histidine, serine, theronine, tyrosine, aspargine, glutamine, aspartic acid and glutamic acid

110
Q

What are the three methods for glucose transport into the cell?

A

Facilitated Diffusion, Primary Active Transport and Secondary Active Transport/Co-transport System

111
Q

What is facilitated diffusion?

A

against or along concentration gradient using carrier proteins)- passive process

112
Q

Which carrier protein is used in facilitated diffusion of glucose?

A

GLUT (glucose transport)

113
Q

What is primary active transport?

A

Carrier proteins use ATP to pump into the cell

Ex. Small intestines with digestion

114
Q

What is Secondary Active Transport/Co-transport System?

A

conformational change of a protein occurs with both Na+ and glucose- both have large concentration gradients extracellularly

115
Q

What glucose transport is important?

A

Sodium dependent glucose transporters (SGLT)

116
Q

Where does Secondary Active Transport/Co-transport System commonly occur?

A

Small intestine, heart, kidneys and certain other organs

117
Q

What is moved by facilitated diffusion?

A

RBC and throughout the body

How many amino acids move across the cell

118
Q

What is the relationship of simple diffusion versus facilitated?

A

Amount of diffusion not proportional to concentration difference as with simple diffusion

119
Q

How does glucose travel into the cell?

A

Glucose must be transported through cell membranes via carrier-mediated diffusion- enhanced by insulin (driven by diffusion- GLUT 2)

120
Q

Where is insulin produced?

A

produced in the pancreas in the Islets of Langerhans by β-cells (stored in vesicles for release)

121
Q

What effect does increase glucose have on insulin release?

A

Increase glucose results in depolarization and release of insulin vesicles

122
Q

How does insulin circulate the blood?

A

Circulates in the blood almost entirely in unbound form

123
Q

What is the plasma half life of insulin?

A

Plasma half-life ~6 min, cleared from circulation within 10-15min

124
Q

What degrades insulin?

A

Degraded by insulinaseprimarily in the liver (except insulin that combines with receptors)

125
Q

What are some types of insulin?

A

Pharmacologic IV regular insulin

and Manufactured recombinant DNA

126
Q

Why does the pharmacological effects of insulin last 30-60 minutes despite a short half life?

A

Tightly bound to receptors, Despite elimination half-time 5-10 minutes, pharmacologic effect lasts 30-60 minutes

127
Q

What is the structure of insulin receptors?

A

Combination of 4 subunits held together by disulfide linkages:

  • Two alpha subunits that lie entirely outside the cell membrane
  • Two beta subunitsthat penetrate through the membrane into the cell cytoplasm
128
Q

The alpha subunits lie ______; whereas the beta subunits of insulin receptors lie ______

A

lie entirely outside the cell membrane; through the membrane into the cell cytoplasm

129
Q

Describe the binding of the insulin receptors.

A

Insulin binds with α subunits on outside of the cell but because of linkages with β subunits the portions of the β subunits protruding into the cell become autophosphorylated

130
Q

What are tyrosine kinase?

A

which causes phosphorylation that ↑ or ↓ enzyme activity and mediates the effects on glucose, fat, and protein metabolism

131
Q

What effect does tyrosine kinase have on insulin receptors?

A

Increase number of GLUT 4 receptors to cell surface

132
Q

Insulin receptor binding causes both ____ and ___ effects

A

fast and slow effects

133
Q

What is a fast response of insulin receptor binding?

A

80% of cells increase their uptake of glucose, esp. muscle and adipose cells butnot most neurons

134
Q

What is important about brain cells?

A

Brain cells only* use glucose for energy-Obligate glucose organ

135
Q

Fast effect insulin receptor binding: What happens to cell membranes?

A

Cell membranes become more permeable to amino acids and potassium and phosphate ions

136
Q

What does insulin promote?

A

glucose uptake by cells and synthesis of glycogen and fat

137
Q

What does glucagon promote?

A

glycogenolysis

138
Q

Insulin causes rapid transport of glucose into ______ cells

A

muscle

139
Q

How is glucose trapped in the cell?

A

Glucose is converted to Glucose-6-phosphate by Glucokinase which “traps” glucose inside the cell

140
Q

What must happen to trapped glucose if it wants to get out of the cell?

A

Has to be liberated back to glucose (glucose phosphatase) to travel in the bloodstream

141
Q

How is glucose stored in the liver?

A

Rapidly stores glucose in the liver in the form of glycogen (some in muscle) Glucose-6-phosphate is converted to Glucose-1-Phosphate that is converted to glycogen (promoted by insulin)

142
Q

What does glucagon promote?

A

glyocgenolysis, promotes conversion of glycogen back to G-1P and G-6-P.

143
Q

What is glucagon produced by?

A

pancreatic α-cells

144
Q

What happens to excess glucose?

A

Glucose is not left free- quickly used for ATP or stored as glycogen or fatty acids

145
Q

What converts glucose to glucose-6-p?

A

Hexokinase and glucokinase

146
Q

What converts glucose-6-p into glucose-1-p?

A

phosphoglucomutase

147
Q

What converts glucose 1-p to glycogen?

A

Glycogen synthase

148
Q

What converts glycogen to glucose-1-P?

A

Glycogen phosphorylase

149
Q

What converts glucose-6-P to glucose?

A

Glucose phosphatase