Biomolecules Flashcards
1
Q
What is OXIDIZED in the cell to generate ATP (3)?
A
Carbohydrates, fats, and proteins
2
Q
What happens to electrons during oxidation?
A
loss of electrons
3
Q
What happens to electrons during reduction?
A
gain of electrons
4
Q
Where does initial glycolysis occur?
A
Cytoplasm
5
Q
Where does remaining glycolysis occur?
A
the inner membrane of the mitochondria
6
Q
What are the byproducts of cellular metabolism (4)?
A
CO2, H2O, energy (ATP), and heat
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)
8
Q
What is a calorie?
A
unit of energy, the energy thatisneeded to increase the temperatureof1 gofwater by 1C at one atmosphere
9
Q
What is kilocalorie?
A
isthe energy thatisneeded to increase the temperatureof1 kgofwater by 1C
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
11
Q
When is a majority of ATP used?
A
Much used during protein synthesis to form peptide linkages between amino acids
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)
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)
14
Q
What is ATP a precursor to (2)?
A
DNA/RNA , second messenger cAMP
15
Q
What is ATP classified as?
A
nucleotide triphosphate: nitrogen base (adenine), sugar (ribose) and triphosphate
16
Q
What is the formula of ATP?
A
ATP ↔️ ADP + PO3 + ⚡️ ↔️ AMP + PO3 + ⚡️
Dephosphorylation/hydrolysis of ATP by enzymes ATPases
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
18
Q
What is the average kcal/kg for men? Women?
A
Men on average: total 39 kcal/kg; Females 34 kcal/kg
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
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
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)
22
Q
Why is monosaccharides important?
A
Are important fuel molecules as well as building blocks for nucleic acids. Hexoses.
23
Q
Monosaccharides are ______
A
water soluble
24
Q
What are examples of carbohydrates (4)?
A
- Glucose (Glycogen)
- Fructose
- Galactose
- Ribose
25
What is ribose?
the carbohydrate component of the nucleic acids- 5 C molecule
26
What is the most important disaccharides for human biology?
Sucrose, Lactose and Maltose
27
What is sucrose?
glucose and fructose
28
What is lactose?
glucose and galactose
29
What is maltose?
2 glucose molecules
30
How are disaccharides broken down?
Broken down into monosaccharides in the small intestines and carried to the liver via the portal vein
31
What is the site of carbohydrate metabolism?
Liver is the site of carbohydrate metabolism: regulation, storage (glycogen), conversion of glucose from galactose/fructose, which produce same amount of energy
32
What is glucose?
the predominant (not only) source to produce ATP
33
What is glycogen?
Long polymers similar to starch: how glucose stored (not stored in its free form)
34
How much glycogen is stored?
Up to 90% of the glucose from a meal can be stored as glycogen
35
Why is glycogen released?
Released during fasting from the liver and strenuous exercise from muscle
36
What is glycogen phosphorylase?
Enzyme: glycogen phosphorylase converts glycogen to glucose derivatives (glucose-1-phosphate)
37
What are examples of lipids?
waxes, sterols, fat-soluble vitamins, triglycerides (fat), phospholipids, and other substances
38
What type of organic molecules are lipids?
Hydrophobic
39
What are fatty acids?
carboxylic acids- long chains that can be saturated/unsaturated
40
How are lipids absorbed?
from the GI tract as chylomicrons via lymph system
41
How are lipids removed from circulation?
From tissues (adipose, liver, skeletal, heart) via lipoprotein lipase
42
What is lipoprotein lipase?
extracellular enzyme- allows free fatty acid across cell membrane
43
What are chylomicrons?
Consist of phospholipid and apolipoproteins on the outer surface and triglycerides and cholesterol (vary in size) inside
44
What is cholesterol?
is considered a lipid although does not contain fatty acids (cell membrane, hormones) Hydrocarbon rings. Sterol.
45
What is lipoproteins?
are part lipid, part protein
46
How is lipoproteins synthesized?
Synthesized by hepatocytes
47
What is VLDL and LDL?
contains most of the cholesterol in plasma
48
What is HDL?
sends excess cholesterol from the peripheral tissue back to the liver to be excreted in bile
49
What are triglycerides?
tremendous source of energy- liberated as 3 fatty acids and glycerol
50
How are triglycerides liberated?
hydrolysis from adipose and carried to cells by mainly by VLDL and albumin (lipase)
51
What stimulates triglycerides?
low glucose levels
52
What is the back bones of triglycerides?
Glycerol is a sugar alcohol that binds fatty acids together
53
What is the functions of triglycerides (2)?
Either used as fuel or restored as triglycerides
54
What are examples of triglycerides (2)?
Tristearin and Glycerol
55
Are fatty acids the same as fats?
No
56
What are saturated fatty acids?
have carbon chains that contain only carbon-carbon single bonds (close carbon bonds resistant to enzymatic activity)
57
What are unsaturated fatty acids?
have carbon chains that contain at least one carbon-carbon double bond
58
What are essential fatty acids?
must be consumed, essential for biological functions
59
What are the types of phospholipids (3)?
lecithin, cephalins, sphingomyelin
60
What are phospholipids important for (4)?
Cell membranes, transport molecules for cholesterol, thromboplastin (clotting), myelin
61
What is the structure of phosppholipids?
Contain one or more fatty acid molecules (diacylglyerol) and one phosphoric acid radial (usually with a N base)
62
What is the solubility of phospholipids?
All lipid soluble, transported as lipoproteins, used throughout the body for structural purposes
63
Where are phospholipids form?
Formed in all cells, primarily in the liver (90%)
64
How are phospholipids formed?
Formation tied to metabolism: increased formation with increased triglyceride deposition in the liver
65
What is lecithin?
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
What are the tails of phospholipids?
have long greasy tails and are hydrophobic (saturated and unsaturated fatty acid)
67
Does a phosphate group alone attached to a diaglycerol form a phospholipid?
No, it is phosphatidate (diacylglycerol 3-phosphate), the precursor of phospholipids
68
What are the two important phospholipids in plasma membranes?
Phosphatidylcholine and phosphatidylserine
69
What are steroids?
Biologically active compounds, play a variety of roles in living systems.
70
What is the solubility of steroids?
Hydrophobic, lipid molecules
71
How are steroids important?
Important component of cell membrane and cell signaling molecules (hormones)
72
What is the structure of steroids?
3 cyclohexane and 1 cyclopentane rings (Steroid nucleus)
73
What are steroids dependent on?
vary dependent on the side chains functional groups and oxidation of the ring structure
74
What is the most common steroid? What is it the precursor to (7)?
Cholesterol is the most common steroid and is the precursor to vitamin D, testosterone, estrogen, progesterone, aldosterone, cortisol, and bile salts
75
Where is cholesterol formed?
Liver (Exogenous sourced from diet)
76
What determines the amount of cholesterol in the body (5)?
- 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
What effect does a high saturated fat have on cholesterol levels?
15-25% due to fat deposition in liver and increased production of Acetyl CoA to produce cholesterol
78
What is the major function of cholesterol?
form cholic acid in the liver for bile (80%)
79
What relationship between adrenocortical hormones and cholesterol?
that are cholesterol/steroid based: sex hormones, aldosterone, cortisol
80
What are some examples of steriods (4)?
Cortisol. aldosterone, testosterone and estradiol
81
What is formed from arachidonic acid?
Prostaglandin
82
What is eiconsanoids?
Unsaturated carboxylic lipid compounds that are physiologically active in the body- hormone-like qualities, formed from 20-chain polyunsaturated fatty acids
83
What do eiconsanoids form?
Arachidonic acid metabolites
84
What is eiconsanoids important in?
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
What are the subclasses of eiconsanoids (3)?
Prostaglandins, thromboxanes, leukotrines
86
What are prostaglandins?
systemic, all throughout the body
87
What are thromboxanes?
mainly platelets but also lungs
88
What is leukotrienes?
mainly lungs
89
How are eiconsanoids liberated (2)?
Arachidonic acid liberated from cell membrane after stimulus (ex: cytokines) or damage from the structural glycerol of the cell membrane via phospholipase A2
90
What synthesizes eiconsanoids?
Prostaglandins are synthesized in vivo by almost all cells in the body from mainly the unsaturated fatty acid arachidonic acid
91
What enzyme further oxidizes the fatty acid?
cyclooxygenase enzyme
92
What three pathways can a does a liberated arachidonic acid follow?
lipoxygenase pathway, cyclooxygenase (COX) pathway, Cytochrome P450 monooxygenase system
93
What is components of the lipoxygenase pathway,?
leukotrienes, lipoxins, HETE’s (hydroxyeicosatetraenoic acids
94
What is the components of the cyclooxygenase (COX) pathway?
prostaglandins, thromboxane, prostacyclin
95
What is the components of the Cytochrome P450 monooxygenase system?
cis-epoxyeicosatrienoic acids and other HETE’s
96
Understand the Cyclooxygenase inflammatory process.
Slide 62
97
What are some functions of proteins?
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
What are proteins polymers of?
relatively simple organic compounds called amino acids joined together by peptide bonds.
99
What is the structure of amino acids?
Amino acids contain two organic functional groups: an amine group and a carboxylic acid group
100
What gives an amino acid its unique chemical and physical properties?
Each amino acid has a unique side chain that gives the amino acid its characteristic
101
What determines the characteristics of amino acids?
The R group determines the characteristics (size, polarity, and pH)
102
How many amino acids are there?
20
103
What are dietary proteins broken down to?
Dietary protein broken down by various enzyme to peptides for absorption (Na+ dependent amino acids transporters)
104
What synthesizes nonessential amino acids?
α-keto acid
105
How do amino acids move in and out of the cells?
active/facilitated transport (too large)
106
What happens when proteins enter the bloodstream?
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
How can proteins be decomposed?
Can easily be decomposed back to base forms and transported out of cells if a particular amino acid level drops
108
What happens to excess proteins?
degraded into other products, used for energy or stored as glycogen or fat
109
What are the amino acids?
Glycine, alanine, valine, cysteine, proline, leucine, isolecuine, methionine, tryptophan, phenylalanine, lysine, arginine, histidine, serine, theronine, tyrosine, aspargine, glutamine, aspartic acid and glutamic acid
110
What are the three methods for glucose transport into the cell?
Facilitated Diffusion, Primary Active Transport and Secondary Active Transport/Co-transport System
111
What is facilitated diffusion?
against or along concentration gradient using carrier proteins)- passive process
112
Which carrier protein is used in facilitated diffusion of glucose?
GLUT (glucose transport)
113
What is primary active transport?
Carrier proteins use ATP to pump into the cell
| Ex. Small intestines with digestion
114
What is Secondary Active Transport/Co-transport System?
conformational change of a protein occurs with both Na+ and glucose- both have large concentration gradients extracellularly
115
What glucose transport is important?
Sodium dependent glucose transporters (SGLT)
116
Where does Secondary Active Transport/Co-transport System commonly occur?
Small intestine, heart, kidneys and certain other organs
117
What is moved by facilitated diffusion?
RBC and throughout the body
| How many amino acids move across the cell
118
What is the relationship of simple diffusion versus facilitated?
Amount of diffusion not proportional to concentration difference as with simple diffusion
119
How does glucose travel into the cell?
Glucose must be transported through cell membranes via carrier-mediated diffusion- enhanced by insulin (driven by diffusion- GLUT 2)
120
Where is insulin produced?
produced in the pancreas in the Islets of Langerhans by β-cells (stored in vesicles for release)
121
What effect does increase glucose have on insulin release?
Increase glucose results in depolarization and release of insulin vesicles
122
How does insulin circulate the blood?
Circulates in the blood almost entirely in unbound form
123
What is the plasma half life of insulin?
Plasma half-life ~6 min, cleared from circulation within 10-15min
124
What degrades insulin?
Degraded by insulinase primarily in the liver (except insulin that combines with receptors)
125
What are some types of insulin?
Pharmacologic IV regular insulin
| and Manufactured recombinant DNA
126
Why does the pharmacological effects of insulin last 30-60 minutes despite a short half life?
Tightly bound to receptors, Despite elimination half-time 5-10 minutes, pharmacologic effect lasts 30-60 minutes
127
What is the structure of insulin receptors?
Combination of 4 subunits held together by disulfide linkages:
- Two alpha subunits that lie entirely outside the cell membrane
- Two beta subunits that penetrate through the membrane into the cell cytoplasm
128
The alpha subunits lie ______; whereas the beta subunits of insulin receptors lie ______
lie entirely outside the cell membrane; through the membrane into the cell cytoplasm
129
Describe the binding of the insulin receptors.
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
What are tyrosine kinase?
which causes phosphorylation that ↑ or ↓ enzyme activity and mediates the effects on glucose, fat, and protein metabolism
131
What effect does tyrosine kinase have on insulin receptors?
Increase number of GLUT 4 receptors to cell surface
132
Insulin receptor binding causes both ____ and ___ effects
fast and slow effects
133
What is a fast response of insulin receptor binding?
80% of cells increase their uptake of glucose, esp. muscle and adipose cells but not most neurons
134
What is important about brain cells?
Brain cells only* use glucose for energy-Obligate glucose organ
135
Fast effect insulin receptor binding: What happens to cell membranes?
Cell membranes become more permeable to amino acids and potassium and phosphate ions
136
What does insulin promote?
glucose uptake by cells and synthesis of glycogen and fat
137
What does glucagon promote?
glycogenolysis
138
Insulin causes rapid transport of glucose into ______ cells
muscle
139
How is glucose trapped in the cell?
Glucose is converted to Glucose-6-phosphate by Glucokinase which “traps” glucose inside the cell
140
What must happen to trapped glucose if it wants to get out of the cell?
Has to be liberated back to glucose (glucose phosphatase) to travel in the bloodstream
141
How is glucose stored in the liver?
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
What does glucagon promote?
glyocgenolysis, promotes conversion of glycogen back to G-1P and G-6-P.
143
What is glucagon produced by?
pancreatic α-cells
144
What happens to excess glucose?
Glucose is not left free- quickly used for ATP or stored as glycogen or fatty acids
145
What converts glucose to glucose-6-p?
Hexokinase and glucokinase
146
What converts glucose-6-p into glucose-1-p?
phosphoglucomutase
147
What converts glucose 1-p to glycogen?
Glycogen synthase
148
What converts glycogen to glucose-1-P?
Glycogen phosphorylase
149
What converts glucose-6-P to glucose?
Glucose phosphatase
