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BMB 402 > Exam 3 > Flashcards

Exam 3 Flashcards

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1
Q

What is the role of the pancreas?

A

It secretes insulin in response to rising blood glucose levels

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2
Q

What does the pancreas secrete for digestion and why is it important?

A

It secretes Trypsin, Chymotrypsin, Elastase. These are digestive proteases that degrade dietary proteins in the small intestine

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3
Q

What is the role of the small intestine in digestion?

A

It is where most of the absorption occurs. It absorbs nutrients, as well as secretes peptide hormones that control eating behaviors through neuronal signaling in the brain

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4
Q

What is the role of the large intestine in digestion?

A

It absorbs water and electrolytes

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5
Q

What is the stomach’s role in digestion?

A

It prepares food for the small intestine by producing chyme, an acidic food slurry.
It secretes peptide hormones that control eating behaviors through neuronal signaling in the brain

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6
Q

What is the Liver’s role in metabolism?

A

The central processing facility and metabolic hub.
It determines the dietary nutrients and metabolic fuels to peripheral tissues.

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7
Q

Why is the liver called a glucose regulator?

A

It removes excess glucose from the blood when carb levels are high. Relies on signaling from insulin and glucagon

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8
Q

What is the portal vein?

A

It directly delivers nutrients from the small intestines to the liver so it can inactivate toxins from the diet

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9
Q

What are the 4 different fates for Glucose-6-Phosphate?

A

1.Converted to glucose and released into the blood
2.Converted to Fructose-6-P that goes thru glycolysis to form pyruvate and then acetyl CoA. From there, lipid synthesis, oxidative phosphorylation, or ketogenesis
3. Converted to 6-phospho-gluconolactone and sent to the PPP
4. Converted to Glucose-1-P and used in glycogen synthesis

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10
Q

What is the purpose of skeletal muscle in metabolism?

A

Skeletal muscle uses fatty acids, glucose, and eventually ketone bodies for energy. These muscles are utilized in rapid bursts or endurance activities. In times of starvation, they can be used as an energy source

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11
Q

What is the purpose of cardiac muscle in metabolism?

A

Cardiac muscle uses mostly fatty acids and ketones for energy, It is continually used over the course of your life. Uses aerobic respiration for energy

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12
Q

What is creatine kinase?

A

A reversible enzyme that creates phosphocreatine when the cellular ATP levels return to normal during muscle recovery.

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13
Q

What is phosphocreatine?

A

Storage molecule for potential ATP. When acted on by creatine kinase, produces creatine and ATP that can be used for energy.

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14
Q

What is the purpose of adipose tissues?

A

It secretes peptide hormones (adipokines) to regulate metabolic homeostasis
It makes up 15-25% of an individuals mass

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15
Q

What is subcutaneous fat?

A

It is located in the thighs, butt, arms, and face. More for insulation and protection.

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16
Q

What is visceral fat?

A

Located in the abdomen. Secretes adipokines. More visceral fat gives rise to a higher risk of cardiovascular disease

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17
Q

What is BMI?

A

Provides an estimation of total body fat in an average person.
It provides on measure of risk

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18
Q

How does the brain relate to metabolism?

A

It is the control center of our bodies. 20% of the O2 consumed by the body is used for oxidative phosphorylation.
Generally depends mostly on glucose- 60% of body’s glucose is used by the brain.
fatty acids does not cross BBB but ketone bodies can

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19
Q

What is the blood brain barrier?

A

Area between the brain and the capillaries that limits what molecules transverse into the brain. There are certain areas where it is less restrictive like the pineal gland for melatonin or the posterior pituitary for oxytocin and ADH

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20
Q

What is PET imaging?

A

Positron emission tomography
Uses metabolic radioactive 18F-deoxyglucose to show differences in glucose metabolism
Used to detect blood flow for tumor visualization
Tau and amyloid deposits and neurodegenerative diseases
-epilepsy, cancer, heart disease

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21
Q

How does PET imaging work?

A

Positron emitted, generates gamma rays, which are detected by the scanner.
Positron is a subatomic particle with the same mass as an electron but with a positive charge
It is an anti-electron and when it collides with an electron both are converted to energy in the form of photons
Positron emission occurs with natural isotopes

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22
Q

What is the role of the kidneys?

A

They are located on either side of the abdominal cavity
only other major organ that uses gluconeogenesis
Remove concentrated levels of urea, ketone bodies, and soluble metabolites

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23
Q

What is hemodialysis?

A

blood is filtered from a patient with poor kidneys to remove waste products

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24
Q

What is metabolic homeostasis?

A

The process of maintaining optimal metabolite concentrations and managing chemical energy reserves in tissues

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25
What are the 6 vital tissues?
Brain, liver, cardiac muscle, skeletal muscle, adipose tissue, heart
26
What is the triacylglycerol cycle?
An interorgan process that continually circulates fatty acids and triacylglycerols between adipose tissue and the liver Maintains energy-rich fatty acids in circulation so that they can be used by peripheral tissues
27
What are the two components that depend of G3P?
Systemic and intracellular
28
What is the role of Insulin?
Released by pancreatic beta cells stimulates glucose uptake in the liver, skeletal muscle and adipose tissue Activates glycogen and FA synthesis Decrease appetite through neuronal signaling
29
What is the role of glucagon?
Released by pancreatic alpha cells stimulates gluconeogenesis stimulates glycogen degradation Stimulates fatty acid export from adipose tissue when food is not available
30
What is the islet of langerhans?
A collection of cells that produce insulin, glucagon. Also has capillaries connected
31
What is PPAR signaling?
Peroxisome-proliferator-activated receptor (PPAR) nuclear receptor proteins They are metabolic sensors of lipid homeostasis It regulates gene expression in response to binding of low-affinity, fatty acid derived nutrients important in energy metabolism and insulin sensitivity
32
What is the metabolic fuel during starvation?
Blood glucose levels are maintained by degradation in liver glycogen Flux is altered in two ways: gluconeogenesis occurs fatty acids are used as fuel
33
What are the changes in metabolism during starvation?
Fatty acid release increase in gluconeogenesis increase in ketogenesis protein degredation
34
What is the purpose of leptin?
It can decrease fat storage thru signaling pathways
35
What is metabolic syndrome?
Lifestyle of prolonged positive energy imbalance Symptoms include: Abdominal obesity insulin resistance hypertension hyperlipidemia high risk for cardiovascular disease
36
What is Type I diabetes?
Insulin dependent insufficient insulin production by pancreatic beta cells, usually occurs earlier in life
37
What is Type II diabetes?
Insulin-resistant Coupled with positive energy balance (weight gain) Desensitization of insulin receptor signaling
38
What levels are high in adipocytes when lipid store are high?
TNF-alpha
39
What is the purpose of TNF-alpha?
It down regulates adiponectin and fatty acid metabolism genes as well as the inhibition of downstream insulin signaling
40
What are the 4 major classes of diabetes treatments?
1. Alpha glucosidase inhibitors (miglitol) 2.Sulfonylurea drugs, which inhibit the dependent K+ channel (Glipizide) 3.Drugs that AMPK are stimulators (metformin) 4.Ligand agonists of the nuclear receptor PPARy (thiazolidinediones)
41
What does metformin promote in skeletal and cardiac muscle?
Fatty acid oxidation glucose uptake mitochondrial biogenesis glycolysis
42
What are the three main factors that influence metabolic homeostasis?
Genetic inheritance nutrition exercise
43
What is the impact of maintaining a healthy weight?
It significantly lowers the risk of type 2 diabetes, CVD, and some types of cancer
44
What is ephedrine?
A drug used to induce weight loss it stimulates adrenergic receptor signaling through the release of NE
45
What is Lorcaserin (belviq)?
Appetite suppressant (receptor agonists for serotonin) First approved weight loss drug that targets neuronal control of food consumption and energy expenditure
46
What is Orlistat (xenical)?
A weight loss drug pancreatic lipase inhibitor triglycerides pass thru the digestive tract without being metabolized
47
What are some other weight loss methods?
Olestra which is a fat substitute in foods Caloric intake reduction- different diets
48
What types of fat lead to higher LDL levels and an increased risk of CVD?
Saturated and trans fats
49
What types of fats lower your cardiovascular risk?
Poly-unsaturated and cis fats
50
What is the glycemic index?
A numerical value indicating how fast glucose is released unto the blood after eating carb containing foods relative to the rise in the blood glucose after drinking a solution of pure glucose Foods <55 are considered healthy High glycemic index foods are associated with drop in blood glucose levels leaving feeling lethargic and can cause insulin spikes
51
What are the components of eating a healthy plate?
Veggies, fruits, healthy proteins, whole grains, water, healthy oils
52
What are the metabolic effects of physical exercise?
Significant healthy improvements can be achieved by just 30 minutes of moderate exercise a day Aerobic respiration is used for endurance sports while ATP and phosphocreatine and anaerobic respiration are used for quick bursts of energy
53
What are nucleotides used in?
energy conversion reactions signal transduction pathways coenzyme-dependent reactions genetic information storage and transfer
54
What do nucleotides consist of?
a nucleotide base a ribose ring phosphoryl group
55
Which nucleotide bases have one ring?
Pyrimidines-cytosine, thymine, uracil
56
What nucleotide bases have 2 rings?
Purines- guanine and adenine
57
What is the most abundant nucleotide?
ATP!
58
What are the functions of ATP?
Energy conversion Signal transduction coenzyme function genetic information
59
What is the nucleotide salvage pathway?
Used to resynthesizes nucleotide monophosphates from free bases energy investment is not as high as the de novo pathway PRPP is used
60
What is the common intermediate produced in purine metabolism?
inosine-5'-monophosphate (IMP)
61
How does purine synthesis differ from pyrimidine synthesis?
Purine- build the base on the sugar Pyrimidine- build base then the sugar
62
What does the first step of purine synthesis use?
PRPP
63
What does the second step of purine synthesis produce?
IMP
64
What does IMP produce?
AMP and GMP
65
What are AMP and GMP used for?
They are used to create nucleoside triphosphates for RNA and DNA synthesis
66
What inhibits Purine biosynthesis?
AMP and GMP inhibit their production from IMP. ADP and GDP inhibit the production of PRPP
67
What is uric acid and how is it excreted?
It is a product of purine degradation, gets excreted through urine.
68
What is gout?
The build up of uric acid crystals in the joints and kidneys
69
What causes gout?
A defect in the purine degredation pathway There is an increase in PRPP synthetase activity which causes an over production of IMP
70
What is Lesch-Nyhan Syndrome?
HGPRT enzyme deficiency -This enzyme is used to salvage hypoxanthine and guanine bases Rare Cuases neurologic symptoms including severe anxiety and self mutilation X-linked recessive mutation- 2X more likely in women
71
What is Adenosine Deaminase Deficiency?
It is caused by a defect in adenosine deaminase It leads to severe combined immunodeficiency disease (SCID) Only treatment is a bone marrow transplant
72
How is ADA being treated with gene therapy?
By using Human Stem cells
73
What are the characteristics of Pyrimidine metabolism?
All atoms are derived from aspartate or carbamoyl phosphate It is a 6 step process
74
What is the main product of pyrimidine biosynthesis?
UMP
75
What does UTP make?
CTP
76
What is the allosteric regulation of Pyrimidine biosynthesis?
Regulated by feedback inhibition and allosteric activation
77
What are the positive allosteric activators of Pyrimidine biosynthesis?
PRPP and ATP
78
What are the negative allosteric regulators of Pyrimidine biosynthesis?
CTP, UTP, UDP
79
What are the products of pyrimidine degradation?
NH4+, HCO3-, B-alanine, B-aminobutyrate
80
What is the purpose of 5-Fluorouracil?
It's a potent anti-cancer medication that inhibits thymidylate synthesis (dUMP->dTMP) Patients must be screened for dihydropyrimidine dehydrogenase activity
81
What are deoxyribonucleotides derived from?
They are derived from ribonucleotides in a single reaction by ribonucleotide reductase
82
What does ribonucleotide reducase require?
2 e- from NADPH
83
What is the net equation for deoxyribonucleotide metabolism?
NADPH+ H+ +nucleoside 5'-diphosphate---> H20 + deoxynucleoside 5'-diphosphate + NADP+
84
How is ribonucleotide reductase regulated?
It has substrate specificity and overall activity Allosteric effector binding regulates activity
85
What does thymidylate synthase do?
Converts dUMP to dTMP by adding a methyl group
86
What are the inhibitors of Thymidylate Synthesis?
Uracil-based compounds can be used to block activity of thymidylate synthesis This can act as potent anticancer medications Raltitrexed Methotrexate
87
What are anti-cancer drug "cocktails"?
Mixture of drugs where each drug blocks a specific process in order to maximize chances of killing the cancer cells before drug resistance begins
88
What is a gene that can mutate to form cancer?
ONCA genes
89
What are some characteristics of DNA replication?
It occurs at a high rate in order to copy the entire genome It is semiconservative ---> original duplex DNA template is separated into two strands --->Each daughter molecule contains one strand of original template ---> discovered by meselson and stahl
90
Is DNA replication unidirectional or bidirectional?
Bidirectional Two replication forks
91
What happens after the replication fork is formed?
1. Double stranded DNA is converted into single stranded DNA 2. RNA primer is added 3. RNA primer is extended
92
What is the replisome?
The complete complex of proteins and enzymes required to replicated DNA
93
What are okazaki fragments?
fragments that are synthesized while the other strand is synthesized continuously Continual strand is know as the leading strand Discontinuous strand containing okazaki fragments is known as the lagging strand
94
What is DNA Polymerase?
Enzymes responsible for the bulk of DNA synthesis There is Mg+ to cofactor for this reaction Primers are necessary
95
What is the direction of DNA synthesis?
5'-----> 3'
96
What is important about the active site of DNA polymerase?
It facilitates complimentary base pairing because of the fit
97
What is the Klenow fragment?
Cleavage of DNA polymerase I results in two fragments: 5'----->3' exonuclease activity Klenow fragment
98
What is Reverse Transcriptase?
Enzyme used to convert RNA to DNA Used in HIV replication highly prone to error no proof reading function
99
What is DNA helicase?
Separates the double stranded DNA Specific to the reaction they catalyze Involved in DNA repair and replication ATP-dependent
100
What is the Trombone model?
Coordinated DNA synthesis on the leading and lagging strand templates by two POL III core complexes is mediated by the clamp loader complex. Pol III core on the lagging strand template alternates between bound and unbound forms as each Okazaki fragment is made
101
How does prokaryotic and Eukaryotic DNA replication differ?
They use different DNA polymerases
102
What oriC?
The spot where DNA is separated to initiate replication in prokaryotes Several steps involve ATP binding or hydrolysis
103
What are termination proteins?
Makes up the termination region, where DNA replications ends. Halfway around the genome
104
How is DNA replication regulated?
Cell cycle timing
105
What is telomerase?
Adds telomeric DNA sequences to the ends of chromosomal DNA limited to undifferentiated embryonic stem cells, male germ cells, and activated lymphocytes in human Shortening is a major factor of aging
106
What are mutations?
Permanent change in DNA sequence can affect gene function can alter protein-coding sequence
107
What are somatic mutations?
Not genetically inherited result in decreased cell viability can alter genes that are regulators of cell division
108
What is the Ames test?
Biochemical test to determine if a substance is mutagenic
109
What are the different types of DNA damage?
Spontaneous deamination of C to U -improper complimentary base pairing -generates abasic site Environmental factors -UV radiation -Can result in stalled replication form and double strand break DNA alkylation
110
What is the Cytosine deamination reaction?
Water converts NH group to ketone (cytosine to uracil)
111
What is autophagy?
Repair to the cell, engulfs damaged cell products and takes them to the lysosome to be broken down -non aggregated proteins -damaged mitochondria -big molecules
112
How does DNA damage affect protein coding?
3 nucleotide bases in DNA specify an amino acid codon in RNA Mutations: Missense nonsense Silent
113
What are the mechanisms for DNA repair?
Mismatch repair Done by mismatch repair proteins MutS and MutL
114
What is the base excision repair mechanism?
It is responsible for removal and replacement of individual bases that are damaged by various chemical reactions, including damage by ROS
115
What is short-patch repair?
Involves removal and replacement of single nucleotide catalyzed DNA polymerase and DNA lyase
116
What is long-patch repair?
Involves the synthesis of up to 10 or more nucleotides using a strand displacement mechanism FEN removes the displaced strand, leaving behind a single strand nick that is sealed by DNA ligase
117
What is Nucleotide Excision Repair?
Used for large lesions that distort the helical nature of DNA
118
What are the two methods of double-strand breaks?
Homologous recombination Nonhomologous end joining- does not require DNA template strand
119
What is DNA recombination?
Homologous recombination occurs during meiosis double strand DNA breaks are required promotes diversity!
120
What is the Holliday junction?
Region of a quadruplex DNA where 4 different DNA strands come together -Branch migration -are resolved by the enzyme resolvase to separate the joined chromosomes
121
What is the lysogenic cycle?
They cause the cell to stay in tact after a bacterial infection

BMB 402 (3 decks)

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