Exam 3 Flashcards
1
Q
What is metabolism?
A
The sum of all chemical and physical processes by which the body breaks down and builds up molecules, utilizing energy from nutrients.
2
Q
What does the human body obtain energy from?
A
Nutrients in foods.
3
Q
What is the primary energy currency of the cell?
A
Adenosine triphosphate (ATP).
4
Q
What are the two main types of metabolic reactions?
A
Anabolic reactions and Catabolic reactions
5
Q
Define anabolic reactions.
A
Building body compounds that require energy.
6
Q
Define catabolic reactions.
A
Breaking down body compounds that release energy.
7
Q
What are the energy-producing catabolic pathways?
A
- Glycolysis
- Citric acid cycle
- Electron transport chain
8
Q
What are the energy-expending anabolic pathways?
A
- Lipogenesis
- Gluconeogenesis
- Protein synthesis
- Synthesis of glycogen
9
Q
What initiates the series of catabolic reactions to produce energy?
A
Digestion.
10
Q
What role do enzymes play in metabolic reactions?
A
They act as facilitators of metabolic reactions.
11
Q
What are coenzymes?
A
Substances that associate with enzymes; many vitamins and minerals serve as coenzymes.
12
Q
What is cellular respiration?
A
The process by which pyruvate is oxidized to H2O and CO2, generating ATP.
13
Q
What are the stages of cellular respiration?
A
- Stage 1: Oxidation of fuels to acetyl-CoA
- Stage 2: Oxidation of acetyl groups to CO2 in the citric acid cycle
- Stage 3: Electron transfer chain and oxidative phosphorylation
14
Q
What is produced during each turn of the citric acid cycle?
A
- 3 NADH
- 1 FADH2
- 1 GTP (equivalent to 1 ATP)
15
Q
What is the primary site for ATP synthesis?
A
Electron transport chain.
16
Q
What can lactate build-up cause?
A
Muscle fatigue.
17
Q
What is the metabolic fate of carbohydrates?
A
- Digested and absorbed as simple sugars
- Travel to the liver
- Used by cells or stored as glycogen in muscle
- Converted to fat and stored in adipose tissue
18
Q
What regulates metabolism?
A
- Hormones (e.g. insulin, glucagon)
- Blood glucose concentration
- Cellular ATP concentration
- Liver
- Enzyme availability
19
Q
Fill in the blank: The conversion of pyruvate to _______ is an irreversible reaction in the mitochondria.
A
Acetyl-CoA
20
Q
True or False: Glycolysis occurs in the mitochondria.
A
False.
21
Q
What is produced when pyruvate is converted to lactate?
A
NADH is used in the process.
22
Q
What happens during the electron transport chain?
A
NADH and FADH2 are converted to ATP and water.
23
Q
What must be removed from amino acids for the body to use them as fuel?
A
The amino group
This process is essential for the utilization of amino acids in energy metabolism.
24
Q
How is nitrogen excreted from the body?
A
As urea
Urea is produced in the liver and is a primary way the body eliminates excess nitrogen.
25
What toxic substance is formed when the amino group is catabolized?
Ammonia
## Footnote
Ammonia is highly toxic to cells and must be converted to urea for safe excretion.
26
What organ excretes ammonia via the urea cycle?
Liver
## Footnote
The liver is crucial in detoxifying ammonia and converting it to urea.
27
What can the remaining carbon skeleton of amino acids be used for?
As fuel
## Footnote
The carbon skeleton can be utilized in various metabolic pathways for energy production.
28
What is gluconeogenesis?
Formation of new glucose
## Footnote
This process is vital for maintaining blood glucose levels, especially during fasting.
29
What is the starting material for gluconeogenesis?
Carbon skeletons of some amino acids, lactate, glycerol, or pyruvate
## Footnote
These substrates are critical for the synthesis of glucose in the liver and kidneys.
30
Where does gluconeogenesis primarily occur?
In the liver or kidney
## Footnote
These organs play a key role in regulating glucose levels in the body.
31
What is required for the reversal of the glycolysis pathway to glucose?
ATP
## Footnote
Energy input is necessary for gluconeogenesis to occur.
32
Which metabolic process occurs when amino acids are consumed in excess?
Synthesis of lipids (fat)
## Footnote
Excess amino acids can be converted to fat and stored in adipose tissue.
33
What happens to proteins in food during digestion?
They are digested and absorbed as amino acids
## Footnote
This allows the body to utilize the building blocks for various metabolic functions.
34
How do amino acids travel after being absorbed?
They travel to the liver and through the bloodstream to cells
## Footnote
This transportation is essential for anabolism and energy production.
35
What role do hormones play in metabolism?
They regulate metabolism
## Footnote
Hormones like insulin and glucagon are key regulators of metabolic processes.
36
What factors influence metabolism?
Blood glucose concentration, cellular ATP concentration, liver, enzyme availability
## Footnote
These factors collectively determine metabolic rate and efficiency.
37
What is lipolysis?
The breakdown of triglycerides in adipose tissue into glycerol and free fatty acids
## Footnote
Lipolysis is a crucial process for mobilizing stored energy in the form of fat.
38
What are the end products of lipolysis?
Glycerol and free fatty acids
## Footnote
These products can be utilized for energy production or converted into glucose.
39
What happens to the fatty acids after lipolysis?
They are taken up by other cells and used to provide energy through beta-oxidation, Citric Acid Cycle, and the electron transport chain
## Footnote
This process is essential for energy production in the body.
40
What can glycerol from triglycerides be converted into?
Glucose
## Footnote
Glycerol can enter the glycolysis pathway following gluconeogenesis.
41
Where does beta-oxidation occur?
In the mitochondrion
## Footnote
Beta-oxidation is the process of breaking down fatty acids into acetyl-CoA.
42
What is produced during each split of fatty acid in beta-oxidation?
One NADH and one FADH2
## Footnote
These are important electron carriers used in the electron transport chain.
43
What is the energy efficiency of capturing chemical energy as ATP?
40%
## Footnote
The remaining 60% escapes as heat, highlighting the efficiency of biological energy conversion.
44
How much chemical energy does an automobile capture from gas?
10%
## Footnote
This contrasts sharply with the energy efficiency of biological systems.
45
What factors regulate metabolism?
* Hormones (e.g. insulin, glucagon)
* Blood glucose concentration
* Cellular ATP concentration
* Liver
* Enzyme availability
## Footnote
These factors interact closely to maintain metabolic homeostasis.
46
What is alcohol?
Class of organic compounds containing hydroxyl (OH) groups.
47
Name two examples of alcohol.
* Glycerol
* Ethanol
48
What is the role of alcohol as a lipid solvent?
Affects cell membrane and can cause liver cell damage.
49
Is alcohol toxic in small amounts?
Yes.
50
What constitutes one standard drink?
Approximately 0.5 fl oz (14 grams) of pure alcohol.
51
What does proof measure?
The alcohol content of a liquid.
52
How is ethanol absorbed into the blood?
* Skin
* Lungs
* Ingestion
53
What is the maximum absorption percentage of alcohol in the stomach?
20%.
54
What is the minimum absorption percentage of alcohol in the small intestine?
80%.
55
Where does alcohol metabolism primarily occur?
Stomach and liver.
56
What enzyme acts on 80%-90% of alcohol consumed?
Alcohol dehydrogenase (ADH).
57
Why do women metabolize alcohol differently than men?
Women have less alcohol dehydrogenase and less body water.
58
What factors influence alcohol metabolism?
* Ethnicity
* Body size
* Age
* Food consumption
* Physical condition
59
What percentage of total hepatic ethanol uptake is processed by the alcohol dehydrogenase system?
80%-90%.
60
What toxic substance is ethanol catalyzed to?
Acetaldehyde.
61
What does acetaldehyde do in the body?
* Increases lipid synthesis
* Decreases lipid oxidation
* Causes inflammation
62
How does acetaldehyde affect DNA?
Binds to proteins and DNA, causing protein malfunction and mutations.
63
What is the consequence of irreversible DNA damage from acetaldehyde?
Increased risk of cancer.
64
What is the role of the antidiuretic hormone (ADH)?
Stimulates cells to retain water.
65
How does alcohol affect the production of antidiuretic hormone?
Depresses production, leading to increased urination.
66
How many kcal does alcohol provide per gram?
7 kcal/gram.
67
What is considered moderate alcohol consumption for women?
Average of ≤ 1 standard drink/day.
68
What is considered moderate alcohol consumption for men?
Average of ≤ 2 standard drinks/day.
69
What are some effects of chronic and excess alcohol consumption?
* Depressed nervous system
* Toxicity to liver and other cells
* Health and social problems
70
What potential health benefits are associated with moderate alcohol consumption?
* Reduced cardiovascular risks
* Increased HDL
* Decreased LDL
* Reduced abnormal blood clots
71
What is resveratrol?
A phytochemical found in red wines, grapes, and nuts.
72
What chronic diseases may resveratrol lower the risk for?
* Diabetes
* Heart disease
* Liver disease
73
What health risks are linked to alcohol consumption?
* Cancer
* Hypertension
* Hemorrhagic stroke
74
What effect does alcohol have on energy intake?
May increase total energy intake, leading to overweight or obesity.
75
True or False: Alcoholic beverages trigger the satiety response.
False.
76
What are potential interactions between alcohol and drugs?
* Magnifies effects of certain drugs
* Increases metabolism of some drugs
* Increases risk of GI bleeding
77
What happens to acetaldehyde in alcohol abuse?
Converted to Acetyl CoA, increasing fatty acid synthesis.
78
What condition is characterized by fat deposition in the liver due to alcohol?
Fatty liver.
79
What is fibrosis in the context of alcohol consumption?
Formation of scar tissue in the liver.
80
What severe liver condition can result from alcohol abuse?
Cirrhosis.
81
Who should always avoid drinking alcohol?
* Pregnant women
* Breastfeeding women
* People with a history of alcoholism
* Those taking medications that interact with alcohol
* Individuals driving or operating machinery
