Lecture 2-Exam 1 Flashcards
(125 cards)
1
Q
The following organic elements make up more than 97% of the mass of the human body:
A
Carbon, hydrogen, o2, nitrogen, sulfur and phosphorous
2
Q
A
2
Q
Additional element calcium which is found in what?
A
bones, teeth, cartilage and makes up an additional 2%
3
Q
The additional 2-3% is made up of what? List the ones we care about?
A
Inorganic elements: iron, zinc and copper
4
Q
What are the inorganic elements considered?
A
Micronutrients because they are needed for health but in minute quantities
5
Q
What are the nutritionally essential transition metals?
A
iron (Fe), manganese (Mn), zinc (Zn), cobalt (Co), Copper (Cu), nickel (Ni), molybdenum (Mo), vanadium (V), and chromium (Cr).
6
Q
Can transition metals be toxic? Explain?
A
- While nutritionally essential, several transition metals may be harmful if present in the body in excess
- The body makes sure there is strict control over both the uptake and excretion of transition metal ions.
7
Q
What is an example of reguation of transition metals?
A
hepcidin system for regulation of iron to avoid its accumulation to damaging levels.
◦ The appropriate regulation of hepcidin expression is dependent on the ability of the liver to sense intracellular and extracellular iron and relay these signals to the hepatocyte nucleus where hepcidin expression can be appropriately modulated to maintain homeostasis
8
Q
What do symptoms of acture metal poisoning by heavy metals or transitional metals include?
A
include abdominal pain, vomiting, muscle cramps, confusion, and numbness
9
Q
What is the treatments of transition metal toxicity?
A
Treatments include administration of metal chelating agents, diuretics, or—should kidney function be compromised—hemodialysis
10
Q
Hepcidin:
* What type of molecule?
* Is Iron excreted? Explain the process
A
- Hepcidin is hormone peptide produced in the liver
- Iron is NOT excreted. The lack of a regulated iron excretory mechanism means that body iron balance is controlled at the level of absorption from the diet.
11
Q
How is iron absorption regulated? Explain how it works
A
Iron absorption is regulated by hepcidin. Hepcidin also controls iron release from cells that recycle or store iron, thus regulating plasma iron concentrations.
12
Q
- Hepcidin exerts its effects through its receptor, the cellular iron exporter _
- Explain why hepcidin is an important regulator
A
- Missing word: Ferroportin
- Important regulators of hepcidin, and therefore of systemic iron homeostasis, include plasma iron concentrations, body iron stores, infection and inflammation, and erythropoiesis.
13
Q
What happens when hepcidin bind to ferroportin receptor?
A
- Binds to the ferroportin receptor, degrades ferroportin and traps the iron in the intestinal cells
- Ferroportin is a transmembrane protein that transports iron from the inside of a cell to the outside of the cell. Ferroportin is the only known iron exporter
14
Q
Explain where plasma iron goes
A
15
Q
What is the second most abundant metal on earth, is favorable for its oxidation- reduction characteristics?
A
Iron
16
Q
What are components involved in energy transfer?
A
Major constituent of hemoglobin, myoglobin, and many other enzymes
17
Q
80% of body iron is destined for what?
A
for bone marrow uptake (hemopoiesis)
18
Q
What is ferritin and transferrin
A
Ferritin- an intracellular Fe3+ storage protein-> can look at in labs
* Even though its intracellular, its levels in peripheral blood provide a noninvasive measure of iron overload
* Hemochromatosis
Transferrin – an extracellular Fe3+ transport protein
19
Q
What is Iron deficiency anemia
A
insufficient levels of iron affects the ability to produce hemoglobin, thus limiting the amount of functional red blood cells that can carry oxygenated blood around the body
20
Q
What are the symptoms of iron deficiency?
A
- Extreme fatigue
- Weakness
- Pale skin
- Cold hands and feet
- Inflammation or soreness of your tongue
- Brittle nails
- Unusual cravings for non-nutritive substances, such as ice, dirt or starch (pica)
- Poor appetite, especially in infants and children with iron deficiency anemia
21
Q
- Most iron is found in _ , the rest is stored as _ .
- Ferritin levels are useful to do what?
A
Most iron is found in hemoglobin, the rest is stored as ferritin. Ferritin levels are useful to assess body iron stores
22
Q
Iron needs a protein, called what? What does it do?
A
Iron needs a protein, called transferrin, to travel in the blood. Blood iron levels represent the balance between dietary intake and iron losses (menses, loss in stools, etc.).
23
Q
Iron binding capacity is calculated from what? What is it used for?
A
blood transferrin levels and is expressed as a percentage. It is used to distinguish the various types of anemia.
24
The four most frequent iron-related tests are what?
* **serum iron** - measures iron levels in serum; represents iron that is almost completely bound to transferrin;
* **transferrin** - measures levels of the iron carrier;
* **total iron binding capacity (TIBC)** - measures the transferrin capacity to bind iron
* **serum ferritin** - measures the body's ability to store iron.
25
What is hemosiderosis?
accumulation of excess hemosiderin (insoluble compound containing up to 40% iron)
26
Hemosiderosis can result from?
* Direct bleeding into the tissues that is followed by breakdown of red blood cells and release of iron to the tissues
* Destruction of red blood cells within the blood vessels, leading to release of iron into the blood followed by accumulation of iron inside the kidneys as the kidneys filter waste from the blood
27
* What are site of hemosiderosis?
* Excessive iron absorption that causes hemosiderosis is a condition called what?
* Lungs and kidneys
* Hemochromatosis
28
Hemochromatosis:
* What type of disease? How common?
* What is hyperabsorped?
* What is serum level is high? What is the treatment?
* What are symptoms?
29
From the picture of hemochromatosis:
* More common in who?
* Increased what?
* Leads to what?
* What is treatment?
* More common in males and age presentation of 50 years
* Increased intestinal iron absorption
* Leads to free radicle injury and iron deposition in paranchymal organs-> fibrosis (organ damage)
* Treatment: Regular phlebotomy and iron chelator
30
Oxygen must be delivered from lungs to peripheral tissues. How is this carried out?
This function is carried out by myoglobin and hemoglobin
31
What is myoglobin and hemoglobin?
* Myoglobin: an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals
* Hemoglobin: a **tetrameric** protein of **erythrocytes**, it interacts in a cooperative fashion that enables this transporter to offload a high proportion of bound O2 in peripheral tissues while simultaneously retaining the capacity to bind it efficiently in the lungs
32
* Both myoglobin and hemoglobin contain _
* What is heme?
* Both myoglobin and hemoglobin contain **heme**
* Heme is an iron-containing cyclic tetrapyrrole consisting of four molecules of pyrrole linked by **methyne** bridges
33
Iron is in the form of _ on a heme molecule
Fe2+
34
* Hemoglobin aids in what?
* What are some genetic disorders?
* Cyanide and carbon monoxide (CO) kill because why?
* transporting CO2 to the lungs for disposal
* Genetic disorders sickle cell and thalassemia's
* Cyanide and carbon monoxide (CO) kill because they disrupt the physiologic function of the heme proteins cytochrome oxidase and hemoglobin
35
* Hemoglobin has _ polypeptide chains and _ oxygen binding sites.
* Myoglobin is a _ polypeptide chain with _ oxygen binding site, which results in the different binding kinetics of the two proteins to oxygen.
* Hemoglobin has **four** polypeptide chains and **four** oxygen binding sites.
* Myoglobin is a **single** polypeptide chain with **one** oxygen binding site, which results in the different binding kinetics of the two proteins to oxygen.
36
Myoglobin binds to oxygen how? How does this compare to hemoglobin?
Myoglobin does so noncooperatively, unlike hemoglobin which binds to oxygen cooperatively as a result of its tetrameric nature
37
What are the graph shapes of myoglobin and hemoglobin? Why is this?
* As a result, myoglobin’s oxygen saturation curve is **hyperbolic**. Myoglobin exhibits a higher affinity for oxygen than hemoglobin. Therefore, it is very efficient at extracting oxygen from the blood and storing it
* Hemoglobin displays a **sigmoid-shaped** curve due to its cooperative binding.
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label
39
What is:
* Myoglobinuria
* Anemias
* Thalassemias
* **Myoglobinuria** – following crush injury to skeletal muscle followed by renal damage, myoglobin may appear in urine
* **Anemias** – reductions in the number of red blood cells (folic acid or vitamin B 12 deficiencies) or hemoglobin in blood, (may reflect iron deficiency)
* **Thalassemias** - partial or total absence of one or more α or β chains of hemoglobin, 3 common, α chain (α thalassemias) or β chain (β thalassemias) can be affected
40
Glycated hemoglobin is what?
is a form of hemoglobin that is chemically linked to a sugar. Most monosaccharides, including glucose, galactose and fructose, spontaneously bond with hemoglobin when present in the bloodstream
41
Glycated Hemoglobin – HbA1c provides what?
valuable information for management of diabetes mellitus
42
Glycated hemoglobin (A1C) or HgbA1c, is an effective and objective retrospective marker of what?
blood glucose control over the previous 3 months. The A1C value is determined by the 3-month lifespan of a red blood cell
43
What is the normal value ranges of Glycated Hemoglobin – HbA1c
4-5.5
44
Vitamins:
* Essential or not?
* Some can be what?
* Most vitamins need to be what?
* What are the two types of vitamins?
* Functionally essential
* Some can be synthesized by endogenous pathways, unusual conditions of precursor availability (**vitamin D and niacin**)
* **Most vitamins need to be supplied in the diet**
* Since vitamins are abundant and only required in a small amount, usually only see deficiency in malnutrition cases
* Vitamins are water soluble or fat soluble
45
Water soluble vitamin:
* What are examples? What are they precursors of?
**B vitamins**:
* folate, thiamine (B1), riboflavin, niacin, pantothenic acid, biotin, vitamin B6, and vitamin B12
* These vitamins are precursors of enzymatic cofactors, or **coenzymes**
**Vitamin C**
46
Fat soluble:
* What are the examples?
* Solube in what?
* Vitamin A and D have what?
* Vitamin E is transported by what?
* Vitamin K transported by what?
* **Vitamins A, D, E, and K** are called the fat-soluble vitamins
* soluble in organic solvents and are absorbed and transported in a manner similar to that of fats
* Vitamin A and D have carrier proteins
* Vitamin E is transported by high density HDL and LDL lipoproteins
* Vitamin K transported by VLDL
47
What is the vitamin C? Why is it important?
is a cofactor in **collagen biosynthesis** due to its role in the generation of hydroxyproline residues
* Collagen is a fundamental structural component of connective tissues such as tendons, bone matrix, and cartilage.
48
Vitamin C (ascorbate) is required in what?
synthesis of certain neurotransmitter receptors and **may contribute to host resistance to infection, very effective antioxidant (mops up oxygen free radicals)**
| Too much vit. C= diarrhea
49
* Vitamin C deficiency is termed what?
* What are symptoms?
* termed “scurvy”
* Swollen gums, ulceration, easy bruising, and impaired wound healing
50
Thiamine, B1:
* Thiamine is integral in the pathway of what?
* Thiamine is a crucial cofactor involved in what?
* converting carbohydrates into energy (ATP)
* Thiamine is a **crucial cofactor** involved in the function of converting carbohydrates into energy->or **pyruvate dehydrogenase** (forms acetyl-CoA into citric acid cycle/Kreb cycle)
51
* What is the thiamine deficiency? Seen in who and why?
* What are the symptoms?
Wernicke-Korsakoff syndrome
* Seen in chronic alcohol intake. **Alcohol inhibits conversion of thiamine to its active form, inhibits active transport of thiamine to intestinal absorption**
Symptoms: confusion, horizontal nystagmus, lateral gaze restriction
52
Loss of thiamine impairs what? What does this cause?
* Loss of thiamine impairs the biochemical process and **accumulation** of lactate and pyruvate occur
* This causes metabolic imbalances leading to **brain damage to the thalamus and hypothalamus, neurologic complications and neuronal cell death**
53
What makes things worse in wernicke korsakoff syndrome
If patient has a high glucose intake, thiamine increases too in order to assist in breakdown of glucose through the Kreb cycle – so a glucose increase can make things worse
54
Thiamine, B: Wet/dry beriberi
* Seen in who?
Seen in patients with chronic alcohol use and prolonged history of receiving TPN. **Is from a lack of dietary thiamine**
55
What is dry beriberi and wet beriberi?
**Dry Beriberi**
◦ Characterized by distal peripheral neuropathy, motor weakness, loss of deep tendon reflexes
◦ Diagnosis made by measuring serum thiamine levels
**Wet Beriberi**
◦ Includes cardiac involvement – cardiomegaly, cardiomyopathy, heart failure, peripheral edema – in addition to neuropathy
56
Riboflavin, B2:
* Important for what?
* What does deficiency cause?
* Important for red blood cell production and skin integrity
* Deficiency causes sore mouth (angular stomatitis, glossitis) and associated with reduced red blood cell glutathione reductase activity
57
Niacin, B3:
* What is it?
* What does it maintain?
* Water soluble vitamin formed from the precursor amino acid tryptophan
* Maintain integrity of kin, gut mucosa, nerves
58
Niacin, B3 can be used to do what?
used as a drug to lower cholesterol levels
* Niacin inhibits hepatocyte diacylglycerol acyltransferase-2. This action prevents the final step of triglyceride synthesis in hepatocytes, limits circulating triglycerides and LDL
* Niacin also inhibits a high density lipoprotein (HDL) catabolism receptor, which increases the levels and half life of HDL
59
Tryptophan also serves as a precursor for what? What is carcinoid syndrome?
Tryptophan also serves as a precursor for the neurotransmitter serotonin
* Carcinoid syndrome (excess serotonin production) leads to depletion of tryptophan and in turn niacin
60
Niacin deficiency is known as what?
the 3 D’s – dermatitis, diarrhea, and dementia
61
Can also see niacin deficiency in patients with history of of what/
history of chronic ETOH use, bariatric surgery, or history of prolonged treatment with isoniazid
62
What is pantothenic acid
is an **essential component of coenzyme A** and fatty acid synthesis
63
Coenzyme A plays an important role in what?
an important role in the synthesis of fat soluble vitamin as well as synthesis of steroids, carbohydrates and proteins
64
* Pantothenic acid deficiency is rare, why?
* What do symptoms include?
* Pantothenic acid deficiency is rare as readily available in egg yolk, milk, whole grains, and meat, but can be seen in patients with severe malnutrition
* Symptoms include: peripheral neuropathy (numbness/burning) dermatitis, alopecia, and enteritis
65
Folate, B9 is important for what? When is crucial?
* Important in red blood cell formation and for healthy cell growth and function.
* The nutrient is crucial during early pregnancy to reduce the risk of birth defects, congenital neural tube defect.
66
Folate is mainly found in what?
Folate is found mainly in dark green leafy vegetables, beans, peas and nuts
67
n dietary supplements and many vitamins, folate is usually in the form of what?
form of folic acid, but 5-MTHF (methylfolate) can also be used.
* Dietary supplements containing 5-MTHF might be better than folic acid for some individuals who have a gene variant called MTHFR C677T because their bodies can use this form more easily
## Footnote
Folic acid needs to be converted into folate using a specific enzyme so decrease in enzyme so you get byproducts of homocysteine (prothrombic)
68
What is b6? What is used for?
* B6 – pyridoxine – 90% is bound to muscle glycogen phosphorylase
* Essential for nerve function, blood, and antibody production
69
* What is B12? Perquiste for what?
* Obtained from what?
* Diseases such as what require parenteral doses of B12?
B12 – cyanocobalamin – essential for DNA synthesis and blood cell production
* Perquisite for folate utilization
* **Obtained from intestinal or stomach mucosa via intrinsic factor**
* Disease such as pernicious anemia (autoimmune gastric atrophy) and Crohn Disease (IBD) cause chronic malabsorption of B12 and require parenteral doses of B12
70
Vitamin A is important for what?
What are Carotenoids?
* Vitamin A is important for normal vision, the immune system, reproduction, and growth and development.
* Carotenoids are pigments that give yellow, orange, and red fruits and vegetables their color. Your body is able to convert some carotenoids into vitamin A
71
Vitamin D is what?
Vitamin D (also referred to as “**calciferol**”) is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced **endogenously when ultraviolet (UV) rays** from sunlight strike the skin and trigger vitamin D synthesis.
72
Vitamin D obtained from sun exposure, foods, and supplements is biologically inert and must undergo what?
undergo two **hydroxylations** in the body for activation. The first hydroxylation, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as “calcidiol.” The second hydroxylation occurs primarily in the kidney and forms the **physiologically active 1,25- dihydroxyvitamin D [1,25(OH)2D], also known as “calcitriol”**
73
What does Vitamin D promote? What is it needed for?
* Promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralization and to prevent hypocalcemic tetany (involuntary contraction of muscles, leading to cramps and spasms).
* It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts. Without sufficient vitamin D, bones can become thin, brittle, or misshapen.
74
Vitamin D insufficiency can cause what?
rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps protect older adults from osteoporosis.
75
Vitamin D has other roles in the body, including what?
* Including reduction of inflammation as well as modulation of such processes as cell growth, neuromuscular and immune function, and glucose metabolism.
* Many genes encoding proteins that regulate cell proliferation, differentiation, and apoptosis are modulated in part by vitamin D. Many tissues have vitamin D receptors, and some convert 25(OH)D to 1,25(OH)2D.
75
What is vitamin E?
Serum concentrations of vitamin E (alpha-tocopherol) **depend on the liver, which takes up the nutrient after the various forms are absorbed from the small intestine.**
76
Vitamin E stops what?
stops the production of ROS formed when fat undergoes oxidation. Scientists are investigating whether, by limiting free-radical production and possibly through other mechanisms, vitamin E might help prevent or delay the chronic diseases associated with free radicals
77
* What is ROS- Reactive oxygen species?
* When are we exposed to them?
* Unshared electrons are highly energetic and react rapidly with oxygen to form ROS. The body forms ROS endogenously when it converts food to energy, and antioxidants might protect cells from the damaging effects of ROS.
* The body is also exposed to free radicals from environmental exposures, such as cigarette smoke, air pollution, and ultraviolet radiation from the sun. ROS are part of signaling mechanisms among cells.
78
Vitamin K:
* Like dietary lipids and other fat-soluble vitamins, ingested vitamin K is incorporated into what? What happens after that?
* Into mixed micelles via the action of bile and pancreatic enzymes, and it is absorbed by enterocytes of the small intestine.
* From there, vitamin K is incorporated into chylomicrons, secreted into the lymphatic capillaries, transported to the liver, and repackaged into very low-density lipoproteins
79
Where is vitamin K present?
Vitamin K is present in the liver and other body tissues, including the brain, heart, pancreas, and bone
80
Vitamin K functions as what?
a coenzyme for vitamin K-dependent carboxylase, an enzyme required for the synthesis of proteins involved in hemostasis (blood clotting) and bone metabolism, and other diverse physiological functions.
81
* Prothrombin (clotting factor II) is what?
* What is warfarin?
* Prothrombin (clotting factor II) is a vitamin K-dependent protein in plasma that is directly involved in blood clotting.
* Warfarin (Coumadin®) antagonizes the activity of vitamin K and, in turn, prothrombin to thin the blood and prevent blotting. For this reason, individuals who are taking these anticoagulants need to maintain consistent vitamin K intakes.
* Also Vit K can be used to reverse Coumadin
82
What is the first law of thermodynamics?
the total energy of a system, including its surroundings, remains constant
◦ Energy cannot be created or destroyed
◦ Energy can only change from one form to another
◦ Total amount of energy in the universe remains constant
◦ During each conversion, some energy is lost as heat
83
What are extergonic and endergonic reactions?
* **Exergonic reaction**: Spontaneous, releases free energy to its surroundings
* **Endergonic reaction**: not spontaneous, require free energy from its surrounding
84
Activation energy?
* What is it?
* Exergonic reaction’s rate depends on what?
* Larger activation energy proceeds how?
◦ Extra energy required to destabilize existing bonds and initiate a chemical reaction
◦ Exergonic reaction’s rate depends on the activation energy required
◦ Larger activation energy proceeds more slowly
85
Rate can be increased 2 ways, explain?
1. Increasing energy of reacting molecules (heating)
2. Lowering activation energy of the chemical reaction
86
What are catalysts able to do?
Are able to lower activation energy by having an effect on chemical bonds (remember enzyme discussion)
87
Even though they are catalyzing reactions they cannot what?
they cannot violate laws of thermodynamics
◦ Cannot make an endergonic reaction spontaneous
◦ Endergonic reactions still require energy to proceed
88
Adenosine triphosphate is composed of what?
Composed of:
* **Ribose** – 5 carbon sugar
* **Adenine**
* Chain of **3 phosphates**
◦ Energy storage
◦ Unstable Bonds
◦ ADP – 2 phosphates
◦ AMP – 1 phosphate – lowest energy form
89
ATP is not suitable for what? What is better?
ATP not suitable for long-term energy storage
* Fats and carbohydrates better
* Cells store only a few seconds worth of ATP
90
* Cells use ATP to drive what?
* What is ΔG?
* Cells use ATP to drive endergonic reactions
* ΔG (free energy) = –7.3 kcal/mol
91
What are 2 mechanisms for synthesis of ATP?
1. **Substrate-level phosphorylation**
* Transfer phosphate group directly to ADP
* Happens during glycolysis - low yield of ATP
2. Oxidative phosphorylation: happens in the **electron transport chain (ETC)**
* reduction of oxygen to generate high-energy phosphate bonds in the form of adenosine triphosphate (ATP) – high yield of ATP
92
The complete oxidation of glucose proceeds in stages: list them and were they are located (4)
1. Glycolysis (**cytoplasm**) – does not require oxygen
2. Pyruvate oxidation (**mitochondria**)
3. Krebs cycle (**mitochondria**)
4. Electron transport chain & chemiosmosis (**mitochondrial membrane**)
93
Glycolysis:
* Most tissues have at least some requirement for what?
* What is the requirement for brain?
* Erythrocytes, which lack mitochondria, are completely reliant on what?
* The ability of glycolysis to provide ATP in the absence of oxygen allows what?
* Most tissues have at least some requirement for glucose
* This requirement is substantial in the brain—even in prolonged fasting the brain can meet no more than about 20% of its energy needs from ketone bodies
* Erythrocytes, which lack mitochondria, are completely reliant on glucose as their metabolic fuel, and metabolize it by anaerobic glycolysis.
* The ability of glycolysis to provide ATP in the absence of oxygen allows skeletal muscle to perform at very high levels of work output with insufficient oxygen
94
What does glycolysis need and produce?
95
Glycolysis allows tissues to survive anoxic episodes. What is the exception?
heart muscle, however, which is adapted for aerobic performance, has relatively low glycolytic activity and poor survival under conditions of ischemia (inadequate blood supply)
96
* In fast-growing cancer cells, glycolysis proceeds how?
* What does it produce?
* We know that lactate is used for gluconeogenesis in the liver - an energy-expensive process, which is responsible for what?
* In fast-growing cancer cells, glycolysis proceeds at a high rate, forming large amounts of pyruvate, which is reduced to lactate and exported.
* This produces a relatively acidic local environment in the tumor.
* We know that lactate is used for gluconeogenesis in the liver - an energy-expensive process, which is responsible for much of the **hypermetabolism** seen in **cancer**
97
# LONG lol
What happens during glycolysis?
98
Most cellular respiration requires O2 to produce ATP but glycolysis can produce ATP with or without O2. Explain the process
99
Oxidation Without O2: List the two ways?
1. Anaerobic respiration: Use of inorganic molecules (other than O2) as final electron acceptor (CO2)
2. Fermentation: Use of organic molecules as final electron acceptor
100
Fermentation:
* Reduces what?
* What are the two types?
101
How do you get ethanol from glucose?
Glucose→Pyruvate → Acetaldehyde→Ethanol
102
Cellular respiration, anaerobic respiration and fermentation: have different terminal electron acceptors
* Cellular respiration = O2
* Anaerobic respiration = inorganic molecule (CO2)
* Fermentation = organic molecule (ex: lactate)
103
Cellular respiration and fermentation: Have different energy yield
* Cellular respiration = 30-32 ATP per glucose
* Fermentation = 2 ATP per glucose
104
What is pyruvate oxidation
In the presence of oxygen, pyruvate is oxidized
◦ Occurs in the mitochondria in eukaryotes
◦ multienzyme complex called pyruvate dehydrogenase catalyzes the reaction
105
What are the products of pyruvate oxidation?
106
Krebs cycle:
* What is it?
* Where does it occur?
* What are the segments we care about?
107
One turn around the Kreb cycle gives us?
3 NADH
1 FADH2
1 ATP
2 CO2
108
After everything: glucose has been oxidized to?
109
Energy Yield of Glucose with Oxidative Respiration?
36 ATP per glucose for eukaryotes
110
Cellular membranes have 4 components: list them and their functions
111
Phospholipids composed of?
112
Phospholipid bilayer made up of?
* Hydrophilic heads point outward
* Hydrophobic tails point inward toward each other
113
How do things get through the cell membrane? (two ways)
Utilize proteins in the plasma membrane
◦ **Active transport:** involves the movement of molecules from lower concentration to higher concentration with the use of energy.
◦ **Passive transport**: involves the movement of molecules from higher concentration to lower concentration and no amount of energy is required
114
What are the three protein?
Channel protein, carrier protein and gated channel protein
115
What is a channel protein? Give example
* acts like a pore membrane that lets water molecules or small ions through quickly
* Water channel proteins (aquaporins)- allows water to diffuse across the membrane at a very fast rate
115
What are carrier proteins?
* transport protein specific for an ion, molecule, or group of substances
* They “carry” the ion or molecule across the membrane by changing the shape after binding the ion or molecule
116
What are Gated channel protein? Give example
* A transport protein that opens a “gate” allowing a molecule to pass through the membrane
* Have a binding site specific for a given molecule or ion – it stimulates the “gate” to open or shut
◦ **Example: sodium gated channel** in a nerve cell is stimulated by a chemical signal which causes them to open and sodium can enter the cell
◦ **Glucose** molecules are too big so they are moved via gated channels
117
Explain the difference between carrier proteins vs. channel proteins
118
Sodium-potassium pump:
* What happens with every ATP spent?
* What does the pump maintain?
* The gradient is essential for what?
119
Clinical significance of Na+/K+ ATPase (5 of them)
120
Digitalis (Digoxin):
* What is it?
* What does it increase and slow down?
* Cardiac glycoside, mechanism of action involves inhibiting the Na+/K+ ATPase pump
* Increases contractile power of the heart
* Slows ventricular rate, can assist with arrhythmia control
121
The inhibition of Na+/K+ ATPase has indirect effects on what?
on the contractile strength, or inotropy, of cardiac muscle cells.
122
If the pump is inhibited than the cellular concentration of sodium increases. Through the increase in cytoplasmic sodium concentration, what happens?
**a sodium-calcium exchanger is activated**, thereby increasing the cellular concentration of calcium.
* **Calcium** is a second messenger in many signaling/regulatory pathways. Its release into the cytoplasm of muscle cells **signals contraction** (in this example the myocytes). This increases the force with which the cell contracts.
