ch.25 metabolism

what happens when there is not enough oxygen for cellular respiration?

anaerobic reactions

what are the folds contained in the inner membrane of mitochondria?

cristae

what is the mitochondrial matrix?

fluid within mitochondria

mitochondria has its own ____ that enable ____?

DNA/RNA; protein synthesis

metabolism

is a sum of all chemical reactions in a human body.

=catabolism + anabolism

catabolism

is breaking complex molecules (like digesting food, or breaking glucose to make ATP)

anabolism

building complex molecules & usually consumes energy during the process.

what are some processes considered catabolic?

glycolysis, beta-oxidation, krebs cycle, lipolysis

what are oxidation-reduction reactions (redox reactions)?

chemical reactions that transfer electrons between reactants.

Reduction & oxidation reactions are always….

together, one substance is oxidized & another is reduced.

  Reducing agent becomes _____ while the oxidizing agent becomes _____

oxidized; reduced

  In oxidation a substance____ electrons (oxidized) while in reduction a substance _____ electrons (reduced)

loses; gains

redox reactions release what?

energy because they lead to formation of more stable molecules.

carbohydrates

• Produces ATP.

• Synthesizes amino acids.

• Forms glycogen.

• Produces triglycerides.

what are lipids?

oxidized to make ATP, stored in adipose tissue, precursor to vitamins & hormones, components of cell membrane, heat & chemical insulation

proteins function as?

enzymes & insulin

nucleic acids form?

nucleotides for DNA & RNA

Which nutrient molecule is the universal energy source and is preferred by nerve cells?

ATP (adenosine triphosphate)

List the steps of aerobic respiration using glucose. How many ATP molecules are made at each step?

a)     Glycolysis (2ATP)

b)     Krebs cycle (2ATP)

c)     Electron transport chain (34 ATP)

how many ATP molecules are made in aerobic respiration total ?

38

glycolysis reactants & products

C6H12O6 + 2ATP + 2NAD → 2 pyruvates + 4ATP + 2NADH

krebs cycle reactants & products

 2 Acetyl CoA + 6NAD + 2FAD + 2ADP + 2P → 4CO2 + 6NADH +6H + 2FADH2 +2ATP

electron transport chain / oxidative phosphorylation reactants & products

8NADH + 2FADH2 + 34ADP + 34P →34 ATP + 6H2O + 8NAD + 2FAD

How is cellular respiration regulated?

by pyruvic acid

Name the key enzyme that regulates the rate of glycolysis and explain how it works.

Phosphofructokinase produces ATP rapidly during high activity & stores glucose as glycogen for storage during low activity.

Which enzyme makes the majority of ATP in human cells and where specifically is it located?

ATP synthase in the mitochondria intermembrane space.

what is oxygen’s role?

it’s the final electron acceptor for hydrogen in the electron transport chain & maintains the flow of electrons which creates the hydrogen ion gradient needed for ATP synthase to function.

due to oxygen all these phases can occur

glycolysis, formation of acetyl coenzyme A, the Krebs cycle & the electron transport chain.

where is oxygen used?

during the Krebs cycle & electron transport chain

chemiosmosis

• The use of energy in a H+ gradient to drive cellular work.

• ATP production during cellular respiration.

where does chemiosmosis happen?

in the electron transport chain in mitochondria during cellular respiration.

what is the final electron acceptor?

the molecule that binds with hydrogen at the end of the electron transport.

what is final electron acceptor for aerobic respiration?

oxygen

what is final electron acceptor for fermentation?

none

what does fermentation allow?

production of some ATP without the use of oxygen.

how many ATPs are produced per glucose molecule

2

what happens during Lactic acid fermentation?

pyruvate is reduced to NADH, forming lactic acid as an end product with no release of CO2.this process happens in some bacteria, fungi & human cells.

what happens during Alcohol fermentation?

pyruvate is converted to ethanol & CO2; this process happens in yeast.

glycolysis

(splitting of sugar) breaks down glucose into 2 molecules of pyruvic acid

glycogenesis

happen in skeletal muscle cells (75%) & liver cells & be stimulated by insulin

Glycogenolysis

happen in liver from hepatocytes & skeletal muscle cells & is stimulated by glucagon & epinephrine.

Gluconeogenesis

happen in liver cells & kidney cortex cells & stimulated by glucagon, growth hormone, epinephrine, & cortisol

mitochondria structure

Bean-shaped organelles with a double membrane.

mitochondria function

power plants of the cell & main source of ATP

carbo-loading

• Involves consuming large starchy meals before athletic events.

• Slow conversion of starch to glycogen for quick energy during activity.

• Applied in healthcare to enhance patient conditions before surgery.

triglycerides function?

o   Long term energy storage

o   Heat & mechanical insulation of internal organs.

what is cholesterol?

o   Components of cell membranes

o   Precursors to vitamins & hormones

what are phospholipids?

Components of cell membranes

Which type of lipids is the most common in diet and is mostly used for energy production?

triglycerides

lipolysis

• A process where triglycerides are split into glycerol & fatty acids, which are released into the blood.

• Stimulated by Epinephrine & norepinephrine.

lipogenesis

the conversion of glucose or amino acids into lipids, it is stimulated by insulin

lipoproteins

transport lipids in the bloodstream

Chylomicrons

carry triglycerides from the liver to adipose tissue

Very-low density lipoproteins carry

triglycerides from the liver to adipose tissue.

Low-density lipoproteins deliver

cholesterol to body cells.

High-density lipoproteins remove

excess cholesterol from body cells & transport it to the liver for elimination.

what’s considered Good cholesterol?

high density lipoproteins

what’s Bad cholesterol?

low density lipoproteins

What is accomplished by amino acid deamination? In which organ does it happen?

an amino acid can enter the Krebs cycle; It happens in the liver.

How long does absorptive stage last after you ate a meal?

4 hours

Which hormone predominates during absorptive stage?

insulin

what processes are stimulated by insulin?

facilitated diffusion of glucose to cells, active transport of amino acids into cells, glycogenesis, protein synthesis, & lipogenesis

Which hormone predominates during post-absorptive stage

glucagon

what processes are stimulated by glucagon?

glycogenolysis, lipolysis, protein breakdown, & gluconeogenesis

The role of vitamins

coenzymes & body building materials

Most common vitamins

A, D, E, K, B1, B2, B6, B12, C, Niacin, pantothenic acid, folic acid, & biotin

microelements

inorganic minerals & vitamins are organic & function as coenzymes.

vitamin A

o   maintains epithelial cells.

o   night blindness & atrophy

vitamin B1 function & diseases?

o   acts as a coenzyme to break down carbon-to-carbon bonds.

o   beriberi & polyneuritis

Vitamin B6 function & diseases?

o   coenzyme for amino acid & fat metabolism

o    dermatitis, retarded growth, & nausea

vitamin B12 function & diseases?

• Coenzyme vital for red blood cell formation, methionine synthesis, and amino acid entry into the Krebs cycle.

• Generates choline.

• Deficiency leads to pernicious anemia, neuropsychiatric abnormalities, and impaired osteoblasts.

vitamin D function & diseases?

• absorption of calcium & phosphorus from GI tract

• rickets & osteomalacia

vitamin k function & diseases?

o   coenzyme for synthesis of clotting factors

o   excessive bleeding

folic acid function & diseases?

o   Synthesizes nitrogenous bases & produces white & red blood cells.

o   Macrocytic anemia

List the major chemical elements and microelements found in cells

Calcium, phosphorus, potassium, sulfur, sodium, chloride, magnesium, iron, iodine, manganese, copper, cobalt, zinc, fluoride, selenium, chromium

examples of how some of microelements can be used.

•   Calcium & fluoride are used for bones & teeth iodine so thyroid gland can make thyroid hormones.

• Manganese activates many enzymes.

where does beta oxidation happen?

mitochondrial matrix in the liver & heart.

how does beta oxidation works?

The long fatty acid chains are broken apart & converted to acetyl CoA for the Krebs cycle or it’s converted into ketone bodies.

beta oxidation

breaks fatty acid chains to create acetyl CoA for the Krebs cycle.

what happens during lipolysis?

triglycerides are split into glycerol & fatty acids to be used to create pyruvate in glycolysis

In what circumstances will a lot of beta-oxidation happen?

When ATP is constantly used in the heart

What is role of brown fat? What makes it brown?

produces heat when you get cold & due to it having a lot of mitochondria it turns brown

Explain how the inhibitors of cellular respiration work on the example of cyanide. Why are these molecules toxic?

cyanide discontinues the later stage of the electron transport chain which causes the earlier stages to stop. This results in no ATP being made and without being able to restore ATP that person dies.

What are nutraceuticals?

Chemicals in food with medicinal instead of nutritional value, usually has no calories & effective in very small doses.

examples of nutraceuticals

o   Caffeine-in coffee, cocoa, & chocolate

o   Phytoestrogens-in soy & yams

o   Salicylic acid (similar to aspirin)-in raspberries

o   alcohol

What are the roles of cholesterol in human body?

to maintain integrity of cell membranes & precursor for the synthesis steroid hormones, bile acids, & vitamin D.

DNA and RNA are important molecules in human diet. Which foods contain them?

all foods

essential amino acids

arginine, lysine, histidine, methionine, isoleucine, phenylalanine, leucine, tryptophan, threonine, & valine.

what’s a Complete protein?

  contains enough of all essential amino acids.

Which foods contain all essential amino acids?

beef, fish, poultry, eggs, & milk

List metabolic waste products produced in human body.

CO2, H2O, O2, nitrogenous compounds, & heat

Which hormones and neural centers are involved in body temperature regulation?

the preoptic area in the hypothalamus that release TRH (releasing) so that the anterior pituitary can release TSH (stimulating).

Normal body core temperature

98.6 F (37C)

How is body temperature regulated?

• Heat generated by catabolism.

• Body adjusts heat production and loss.

• Negative feedback maintains normal body temperature.

anorexia

fixation on weight & image leading to starvation

bulimia

binge eating too much food just to vomit it up

malnutrition

lack of balanced nutrients

what is Kwashiorkor?

protein intake being deficient despite normal caloric intake

List at least 5 metabolic functions of liver.

·    Metabolize carbs, proteins, lipids, drugs, & hormones

·    Excrete bilirubin.

·    Store glycogen, vitamins, & iron

·    Activate vitamin D.

·    Synthesis of blood proteins

Which important proteins are produced by liver?

blood proteins