Metabolism

Question 1

Metabolism

Answer 1

• the sum of all chemical reactions that occur in the body

- divided into catabolic and anabolic reaction

Question 2

catabolic reactions

Answer 2

break down large chemical and release energy

Question 3

anabolic reactions

Answer 3

build up large chemicals and release energy

Question 4

ingestion

Answer 4

the aquisition and consumption of food and other raw materials

Question 5

digestion

Answer 5

process of converting food into usable soluable form so it can pass through membranes in the digstive tract and enter the body

Question 6

absorption

Answer 6

passage of nutrient molecules through the lining of the digestive tract into the body
-absorbed molecules pass through cells lining the digestive tract by diffusion or active transport

Question 7

transport

Answer 7

the circulation of essential compounds required to nourish the tissues and the removal of waste products from the tissues

Question 8

assimilation

Answer 8

the building up of new tissues from digested food materials

Question 9

respiration

Answer 9

the consumption of oxygen by the body

cells use oxygen to convert glucose to ATP, a ready source of energy for cellular activities

Question 10

excretion

Answer 10

removal of waste products (like CO2, water, urea) produced during metabolic processes like respiration and assimilation

Question 11

synthesis

Answer 11

creation of complex molecules from simple ones (anabolism)

Question 12

regulation

Answer 12

• control of physiological activities
• the body’s metabolism functions to maintain its internal environment in a changing external environment
• the steady state of the internal environment is known as homeostasis and includes regulation by hormones and the nervous system
• irritability is the ability to respond to a stimulus and is part of regulation

Question 13

growth

Answer 13

an increase in size caused by cell division and synthesis of new materials

Question 14

reproduction

Answer 14

generation of additional individuals of a species

Question 15

respiration

Answer 15

involves the conversion of the chemical energy in molecular bonds into the usable energy needed to drive the process of living cells

• the cells of the human body and other organisms need energy for growth, and obtain it from aerobic respiration-respiration in presence of oxygen, which includes the intake of oxygen from the environment, the transport of oxygen in the blood, and the ultimate oxidation of fuel molecules in the cell
• involves external and internal respiration

Question 16

external respiration

Answer 16

refers to the entrance of aur into the ungs and the gas exchange between the alveoli (any of the many tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place) and the blood

Question 17

internal respiration

Answer 17

includes the exchange of gas between the blood and the cells and the extracellular processes of respiration

Question 18

fuel

Answer 18

• carbohydrates and fats are the favored fuel molecules in living cells
• as hydrogen is removed, bond energy is made available
• C-H bond is energy rich, in contrast CO2 contains little usable energy -it’s the stable, energy-exhausted end product of respiration

Question 19

dehydrogenation

Answer 19

• during respiration, high energy hydrogen atoms are removed from organic molecules, called dehydrogenation
• is an oxidation reaction
• subsequent acceptance of hydrogen by a hydrogen acceptior is the reduction component of the redox reaction
• energy released by this reduction is used to form a high-energy phosphate bond in ATP
• Although the initial oxidation step needs energy input, the net result if the redox reaction is energy production
• if all this energy was released in a single step, little could be harnessed, so the reduction occurs in a series of small steps called the electron transport chain

Question 20

electron transport chain

Answer 20

-the energy from redix reaction is harnessed in a series of small steps called the electron transport chain

Question 21

glucose catabolism

Answer 21

• the degradative oxidation of glucose occurs in 2 stages: glycolysis and cellular respiration
• aerobic: 1) decarboxylation of pyruvate 2)Krebs cycle 3) electron transport chain
• anaerobic: 1) fermentation

Question 22

Glycolysis

Answer 22

• first stage of glucose catabolism is glycolysis
• glycolysis is a series of reaction that leads to the oxidative breakdown of glucose into 2 molecules of pyruvate (the ionized form of pyruvic acid), the production of ATP, and the reduction of NAD+ into NADH
• all of these reactions occur in the cytoplasm and are mediated by specific enzymes
• 1 molecule of glucose (a 6 C moleucle), 2 molecules of pyruvate (3C molecule) are obtained
• during the sequence of reactions, 2 ATP are used (in steps 1 and 3) and 4 ATP generated (2 in steps 6 and 2 in step 9)= net production of 2 ATP per glucose molecule, called substrate level phosphorylation
• one NADH is produced per PGAL for a total of 2 NADH per glucose

Question 23

Glycolytic pathway

Answer 23

Step 1:
Glucose reacts with hexokinase-> Glucose-6-phosphate
ATP->ADP

Step 2:
Glucose-6-phosphate reacts with phosphoglucose isomerase-> Fructose-6-phosphate

Step 3:
Fructose-6-phosphate reacts with phosphofructokinase-> Fructose 1,6-biphosphate
ATP->ADP

Step 4:
Fructose 1,6-bisphosphate reacts with aldose ->Glyceraldehyde 3-phosphate (PGAL)Dihydroxyacetoe phosphate
OR
Frictose 1,6-bisphosphate->Dihydroxyacetone

Step 5:
Dihydroxyacetone phosphate->1,3-Diphosphoglycerate

Step 6:
1,3-Diphosphoglycerate->3-phosphoglycerate
ADP->ATP

Step 7:
3-Phosphoglycerate-> 2-Phosphoglycerate

Step 8:
2-Phosphoglycerate-> Phosphoenol pyruvate

Step 9:
Phosphoenol pyruvate reacts with pyruvate kinase-> pyruvate
ADP->ATP
*steps 5-9 occur twice per molecule of glucose
*2 molecules of PGAL are made per molecule of glucose, and all subsequent steps occur twice for each glucose molecule

Question 24

substrate level phosphorylation

Answer 24

-a type of phosphorylation where the synthesis of ATP is directly coupled with the degradtion of glucose without the participation of an intermediate molecule such as NAD+

Question 25

net reaction for glycolysis

Answer 25

Glucose + 2 ADP + 2Pi + 2NAD+ --> 2 Pyruvate + 2 ATP + 2 NADH + 2H+ +2H20

Question 26

Pyruvate degradation

Answer 26

- after glucose is degraded into pyruvate, most of the initial energy stored in the glucose molecule hasn't been released and is still present in the chemical bonds of pyruvate - depending on the capabilities of the organism, pyruvate degradation can proceed in one of 2 directions - under anaerobic conditions, pyruvate is reduced during fermentation - under aerobic, pyruvate is further oxidized during cellular respiration in the mitochondria

Question 27

Fermentation

Answer 27

- NAD+ is regenerated for glycolysis to continue in the absence of O2 - this is accomplished by reducing pyruvate into ethanol or lactic acid - fermentation refers to all the reactions involved in this process: glycolysis and the additional steps leading to the formation of ethanol or lactic acid - produces 2 ATP per glucose molecule - Alcohol and lactic acid fermentation

Question 28

Alcohol fermentation

Answer 28

- occurs in yeast and some bacteria - the pyruvate pruducedin glycolysis is converted into ethanol - in this way NAD+ is regenerated and glycolysis can continue

Question 29

Lactic acid fermentation

Answer 29

- occurs in certain fungi and bacteria and in the human muscle cells during strenuous activity - when the oxygen supply to muscle cells lags behind the rate of glucose catabolism, the pyruvate generated is reduced to lactic acid - as in alcohol fermentation, the NAD+ used in step 5 of glycolysis is regenerated when pyruvate is reduced

Question 30

cellular respiration

Answer 30

- most efficient catabolic pathway used by organisms to harvest energy stored in glucose - glycolysis only yeilds 2 ATP per molecule of glucose - cellular respiration yeilds 36-38 ATP - is an aerobic process - oxygen acts as final acceptor of electrons that are passed form carrier to carrier during the final stage of glucose oxidation - metabolic reactions occur in the eukaryotic mitochondrion and are catalyzed by reaction-specific enzymes - cellular respiration can be divided into 3 stages: pyruvate decarboxylation, the citric acid cycle, and the electron transport chain

Question 31

Pyruvate decarboxylation

Answer 31

- the pyruvate formed during glycolysis is transported from the cytoplasm into the mitocondrial matrix where it is decarboxylated (loses a CO2) and the acetyl group that remains is transferred to coenzyme A to form acetyle-CoA - in his process, NAD+ is reduced to NADH

Question 32

Citric acid cycle

Answer 32

-the cycle begins when: the 2-Carbon acetyl group from Acetyl-CoA combines with oxaloacetate, a 4-Carbon molecule, to from the 6-Carbon citrate through a series of reactions, 2 CO2 are released and the oxalaceate is regenerated for use in another turn of the cycle -one ATP is produced for each turn of the cycle by substrate-level phosphorylation via a GTP intermediate -electrons are also transferred to NAD+ and FAD, forming NADH and FADH2 -These coenzymes than transport the electrons to the electron transport chain, where more ATP is produced via oxidative phosphorylation -therefore, 2 of each type of molecular product at this stage of the cycle are created for each glucose molecule 2X3NADH- 6 NADH 2X1 FADH2= 2FADH2 2X1GTP (ATP)= 2 ATP

Question 33

What is produced at the end of the citric acid cycle?

Answer 33

2 of each type of molecular product at this stage of the cycle are created for each glucose molecule 2X3NADH- 6 NADH 2X1 FADH2= 2FADH2 2X1GTP (ATP)= 2 ATP

Question 34

electron transport chain

Answer 34

- a complex carrier mechanism in the inner mitochondrial membrane - during oxidative phosphorylation, ATP is produced when high-energy potential electrons are transferred from NADH and FADH2 to oxygen by a series of carrier molecules in the mitochondrial membrane - as the electrons are transferred from carrier to carrier, free energy is released, which is then used to form ATP - most molecules of the ETCare cytochromes, electron carriers that resemble hemoglobin in the structure of their active site...