Chapter 25 Flashcards
1
Q
Metabolism and nutrition on homeostasis
A
harvest cheical energy from consumed nutrients to contribute to bodys growth, repair and normal functioning
2
Q
what do most food molecules supply and what do the others serve as
A
most- energy
some- building blocks
other- stored for future use
3
Q
what is metabolism
A
all the chemical reactions that occur in the body
4
Q
Metabolism is a balance of what two main types of reaction
A
catabolic and anabolic
5
Q
what is a catabolic reaction
A
break down complex molecules into simpler ones
exergonic
ex. glycolysis krebs cycle and electron transport chain
6
Q
what is anabolic reaction
A
combine simple molecules and monomers to form bodys complex structural and functional components
- generally endergonic
e. formation of peptide bonds, building fatty acids, linkage of glucose monomers to form glycogen
7
Q
what is the molecule that participates most often in energy exchanges in living cells
A
ATP
8
Q
what does ATP do
A
couples energy releasing catabolic reactions to energy requiring anabolic reactions
9
Q
what is the process of digestion of carbs in the GI tract
A
poly and disaccharides become monosaccharides (glucose fructose galactose)
hepatocytes: most fructose and galactose ->glucose
10
Q
What is the fate of glucose (4 steps)
A
- ATP production - glucose is oxidized to produce ATp or glucose can enter another metabolic pathway
- Amino acid synthesis
- glycogen synthesis - hepatocytes and muscle fibers (glycogenesis)
- triglyceride synthesis - when glycogen stores are maxed out. hepatocytes: glucose->glycerol and fatty acids->synthesis of triglycerides
11
Q
what is the synthesis of triglycerides
A
lipogenesis
12
Q
what is the 2 steps of glucose entry into cells
A
- absorption from go tract: NA+ glucose symporters (secondary active transport)
- blood to cells: GluT(facilitated diffusion) - insulin increase # of GluT4
13
Q
What is the oxidation of glucose to ATP
A
cellular respiration
14
Q
what are the4 sets of reactions in glucose catabolism
A
glycolysis, formation of Acetyl coenzyme A,
krebs cycle, electron transport chain
15
Q
what happens in glycolysis and is it anaerobic or aerobic
A
1 glucose -> 2 pyruvic acid + 2 ATP + 2 NADH + 2H (anaerobic)
16
Q
what happens in formation of Acetyl Coenzyme A
A
2 pyruvic acid - > Acetyl CoA
+ 2 CO2 + 2 NADH + 2 H+
17
Q
krebs cycle formula
A
2 Acetyl CoA -> 2ATP + 4CO2
+ 6NADH + 6H+ + 2 FADH2
18
Q
electron transport chain formula
A
10NADH + 10H+ + 2 FADH2 + 6O2
-> 32 (or34) ATP + 6H20
19
Q
What is Glycolysis
A
series of 10 reactions
20
Q
Where does glycolysis occur
A
occurs in the cell cytosol
21
Q
In glycolysis what happens
A
glucose ->2 pyretic acid
2 ATP used, 4 ATP produced
net gain 2 ATP
22
Q
what is reaction #3 of glycolsis
A
Reaction #3
Fructose-6-phosphate -> Fructose 1,6bisphosphate
Catalyzed by enzyme : PHOSPHOFRUCTOKINASE
REGULATOR OF RATE OF GLYCOLYSIS
23
Q
what determines the rate of glycolysis
A
slowest enzyme
24
Q
If ADP is high during glycolysis what happens
A
high enzyme activity
high rate glycolysis
25
if low enzyme activity during glycolysis what happen
little glycolysis
| most glucose ->glycogen
26
the fate of pyruvic acid depends on what
availability of O2
27
if aneaerobic (no O2) then what occurs with pyruvic acid and formation of acetyl CoA
2 pyruvic acid +2NADH +2H+ -> 2 lactic Acid +2NAD+
28
if aerobic (has O2) then what occurs with pyruvic acid and formation of acetyl CoA
2 pyruvic acid -> 2 Acetyl Coenzyme A
| (in mitochondrial matrix)
29
2 Pyruvic acid -> 2 Acetyl Group
catalyzed by: PURUVATE DEHYDROGENASE
| produces 2 CO2 and 2NADH + 2H+
30
2 Acetyl Group + 2 Coenzyme A ->
2 Acetyl Coenzyme A
31
Acetyl coenzyme A =
substrate for Krebs cycle
| it drives the krebs cycle
32
where does the krebs cycle occur
matrix of mitochondria
33
what happens in the krebs cycle
- a series of redox and decarboxylations
- release CO2
- chemical energy is transferred to NAD+ & FAD
- odidation of pyruvic acid derivatives
- reduction of conexzymes (NAD &FAD)
- > NADH & FADH2
- > energy carries into electron transport chain
- 12 molecules of ATP generated
- release of CO2
34
2 acetyl CoA - > 6 NADH + 6H+ + 2 FADH2 + 4CO2 + 2ATP
krebs cycle
35
where does electron transport chain occur
inner mitochondrial membrane
36
what happens to the carriers in chain during ETC
1. reduced as puck up electrons
| 2. oxidized as gives up electrons
37
exergonic reaction in ETC release energy to make
ATP
38
Brief summary of ETC
```
(1) Energy from NADH + H+ passed along
the transport chain, used to pump H+ into
Inter mitochondrial membrane space
(proton pump)
(2) ->High H+ concentration in space
(3) H+ diffusion down H+ concentration
gradient drives ATP synthase to make ATP
```
39
in glycolysis and krebs cycle what happens to coenzymes
pumped across intermitochondrial membraine and then come back in to make ATP
40
what produced in catabolism is
metabolic water
41
carbohydrate metabolism or catabolism formula
C6H12O6 + 6 O2 + 38 ADP + 38Pi --> 6 CO2 + 6 H2O + 38 ATP
42
(anabolism) glucose storage is called ____ because what
glycogenesis because glucose can be stored as glycogen
43
(anabolism) how does glycogenesis occur
insulins stimulates hepatocytes and skeletal muscle to perform glycogenesis
44
(anabolism) What is glucose release called
glycogenolysis
45
(anabolism) glycogen can be broke down into ____ for use by _____
glucose
| hepatocytes
46
(anabolism) ___ and ____ activate enzyme phosphorylase (NB phosphates is absent in skeletal muscle)
glucagon and epinephrine
47
(anabolism) Glucose from proteins and fats is called
glucoeogenesis
48
(anabolism) when live is low on glycogen this means
time to eat
49
(anabolism) if you don't eat what happens to your body
it starts catabolizing triglycerides and proteins
50
(anabolism) Amino acids - > pyruvic acid -> ??
glucose or krebs cycle
51
(anabolism) Triglycerides -> glycerol -> glyceraldehyde 3-phosphate -> ??
pyretic acid or gluconeogenesis
52
Lipid metabolism is what
transport of lipids in the blood
53
When lipids are transported to the blood what happens
made more water-soluble by combination with proteins
| ->lipoproteins act as transport vesicles
54
(Lipid metabolism) Outer shell is
protiens phospholipids and cholesterol
55
(lipid metabolism) inner core
triglycerides
56
what are the proteins in the outer shell
apoproteins (Apo A->E)
57
(Lipid Metabolims) what do chylomicrons do
transport dietary lipid to adipose tissue for storage
58
in lipid metabolism what does Apo-C2 do
- >activates endothelial lipoprotein lipase
| - >removal of fatty acids by adipocytes for synthesis and storage of triglycerides.
59
in lipid metabolism what does Apo E do
- >docking protein.
| - >Removal of chylomicron by hepatocytes.
60
in lipid metabolism what does Apo-C2 do
-> activates endothelial lipoprotein lipase
| As they deposit their triglycerides VLDLs -> LDLs
61
What are VLDLs
very low density lipoproteins which are formed in hepatocytes
endogeneous lipids
62
LDLS carry out how much of total cholesterol in blood
75%
63
Cholesteol is used for what
membrane repair and steroid hormone synthesis
64
Excess LDLs can lead to what
fatty deposits on artery smooth muscles which means bad cholesterol
65
High fat diet can lead to
high levels of VLDLs which means high levels of LDLs leading to bad cholesterol
66
what do HDLs do
remove excess cholesterol from blood/cells to liver for elmination
67
What are are the 2 sources of cholesterol
food and synthesis in hepatocytes
68
what are the desirable levels
problem levels
and solutions for cholesterol and LDL VLDLs
-Desirable Levels: TC=under 200mg/dL LDL=under 130mg/dL
HDL =over 40mg/dL VLDL=10-190mg/dL
-Problem Levels: TC above 200mg/dL heart attack risk x2 per 50mg/dL over
Ratio TC:HDL predicts coronary artery disease (above 4 undesirable)
-Solutions: Diet, Exercise (increases HDLs),
Drugs (enhance excretion, block synthesis)
69
what are the Lipid profile test measures:
Total Cholesterol (TC), HDLs, VLDLs. LDLs calculated
70
What do statens do
influence cholesterol production within cells, common for HBP medicine
71
What occurs during triglyceride storage
- Adipose tissue removes triglycerides from chylomicrons and VLDLs
- Stored until needed elsewhere for ATP synthesis
- Stored more readily than glycerol
- Stored triglycerides = 98% bodys source of energy
- Continually being broken down and resynthesized.
72
Lipid Catabolism is called what and what occurs
- Lipolysis
- Triglyceride ->glycerol and fatty acids
- Catalyzed by lipases
- Enhanced by hormones
73
Glycerol and Fatty acids are catabolized by
different pathways.
74
(lipid metabolism glycerol catabolism)
if cell ATP supply is high, what occurs?
if cell ATP supply is low, what occurs?
further converted to glucose
further catabolized to pyruvic acid
75
Glycerol ->
Glyceraldehyde 3-phosphate
76
Fatty acids ->
beta oxidation in mitochondrial matrix (high ATP production)
77
you can make much more ATP from
fat
78
potential energy is stored as
fat (vast majority)
79
2C fragments attach to coenzyme A ->
acetyl CoA -> krebs cycle
80
during digestion proteins ->
amino acids
81
after digestion what happens to amino acids
they reassemble into proteins
82
what do several proteins serve as
structural components of the body (collagen, elastin, keratin)
83
What happens during protein catabolism
- Proteins from worn out cells broken down into amino acids
- Some amino acids converted to other amino acids then to proteins.
- Hepatocytes convert amino acids fatty acids, Ketone bodies, glucose.
- Small amounts of amino acids can be used in for the Krebs cycle
- BUT must be first converted into a molecule that is part of the Krebs cycle or into a molecule that can enter the Krebs cycle.
- Amino acid must be DEAMINATED (removal of amino group)
- Deamination in liver produces ammonia (excreted as urea by kidneys).
84
active transport of amino acids into body cells is stimulated by
insuline like growth factors and insulin
85
many proteins function as ___ ; others involved in transportation(hemoglobin) or serve as ____
enzymes
| antibodies
86
protein anabolism occurs on
ribosome
87
What occurs during protein anabolism
- Formation of new proteins from amino acids.
- Carried out by ribosomes, directed by the cells DNA
- Stimulated by: insulin like growth factors, thyroid hormones T3 & T4, insulin, estrogen, testosterone
88
How many different types of amino acids are in the body
20
89
how many essential amino acids must be present in diet
10
90
Non essential amino acids are synthesize by
body cells->formed by transamination
91
what is transamination
transfer of an amino group from an amino acid to pyretic acid or to an acid in krebs cycle
92
when can protein synthesis occur rapidly
when the appropriate essential and non essential amino acids are present
93
Regulation of metabolic reactions depends on:
1) Chemical environment (e.g. ATP and Oxygen levels)
| 2) Body Signals (nervous and endocrine)
94
Some aspects of metabolism depend on
time passage after a meal
95
what are the two states of metabolism
absorptive state and post absorptive state
96
what occurs during absorptive state
- Approx 0-4 hours after a meal
- Ingested nutrients are entering the blood stream
- Glucose readily available for ATP production
97
what occurs during post absorptive state
- Approx 4 hours onwards after a meal
- Absorption from GI tract is complete
- Energy needs have been met by fuels already in body
- Critical for continued glucose supply for ATP production
98
After meal what do nutrients do
enter blood
99
ingested food reaches blood stream as what
glucose, amino acids, triglycerides
100
What are 2 metabolic hallmarks of absorptive state
oxidation of glucose for ATP prod.
| -storage of excess fuel molecules for future between meal use
101
how much glucose is used to produce ATP
about 50%
102
When glucose enters hepatocytes what happens
converted into glycogen
| small amount used for synthesis of fatty acids
103
Where do most fatty acids go
packaged into VLDLs which carry lipid to adipose for storage
104
How much glucose that is picked up by liver is converted to triglycerides for storage
40%
105
dietary lipids become
adipose storage
106
what are blood glucose levels maintained
glucose production and conservation
107
Major reactions of post absorptive state are
1) Breakdown of liver glycogen
2) Lipolysis
3) Gluconeogenesis (lactic acid)
4) Gluconeogenesis (amino acids)
major adjustment made to produce ATP without glucose
5) Oxidation of Fatty Acids
6) Oxidation of Lactic Acid
7) Oxidation of Amino Acids
8) Oxidation of Ketone Bodies
9) Breakdown of Muscle glycogen
108
Body produces more or less heat based on what
rate of metabolic reactions
109
homeostsis of body temp can only be maintained if what
rate of heat loss equals rate of heat produced by metabolism
110
Energy from heat(temp) is expressed in what units
calories
111
1 calorie = what??
the heat required to raise the temp of 1 gram of water by 1 degree C
112
100 calories = what?
1 kilocalorie or 1 calories
113
What factors effect metabolic rate
- To measure metabolic rate, must be measured under standard conditions.
- Quiet, resting, fasting condition = basal state
- Thus, metabolic rate recorded = basal metabolic rate
- Calculated from oxygen used per kilocalorie of food metabolized
114
approx how many cal/day for body weigh in males and females
1200-1800 or 24(22) cal/kg
115
What are the 4 ways heat is transferred from body to surroundings
conduction, convection, radiation, and evaporation
116
what is conduction
Occurs between materials that are in direct contact
(approx 3% heat lost via conduction –clothes, chairs, etc)
(Heat can be gained by conduction – having a hot bath
117
what is convection
Transfer of heat by movement of a fluid (gas or liquid)
| approx 15% heat lost via conduction – skin warming air
118
what is radiation
Transfer of heat as infrared rays from hot to cold objects
(approx 60% heat lost via radiation)
-if surrounding areas warmer than you, you absorb more heat then you lose
119
what is evaporation
Conversion of a liquid to a vapor
| approx 22% heat lost via evaporation – exhaled air / sweating
120
Hypothalami thermastat is where
Preoptic area of anterior hypothalamus
| - group of neurons - body thermostat
121
how does the hypothalamic thermostat determine your temp
-Info from skin, mucus membranes and hypothalamus
-High Body Temp -> Increased AP output (i)
-Low Body Temp -> Decreases AP output (ii)
AP output -> Hypothalamic Heat losing center (i) and Heat-promoting center (ii)
122
what is thermoregulation
1.thermoreceptors in the skin and hypothalamus send nerve impulses to preoptic area and heat-promotin center in hypothalamis and hypothalamic neurosecretory cells that produce TRH
2. hypothalamus discharges nerve impulses and secret TRH stimulating thryrotrophs in Anterior pituitary gland to release thyroid stimulating hormone TSH
3. several effectors are activated
each respond in ways to increase core temp
-vasoconstriction
-adrenal medulla release hormones to increase metabolism
-shivering
-thyroid release thyroid hormone increasing metabolic rate
4. increase in body temp
5. return to homeostasis
123
if students ate 2 hours ago what is happening in metabolism
primary hormone regulating students metabolism at this point is insulin
