Biol214

Front 1

Enzymes do not affect the equilibrium of a reaction and thus can be bidirectional. True or False

Back 1

True

Front 2

List in order the 4 most abundant elements in the body.

Back 2

H > O > C > N

Front 3

Name the 3 forms of energy in biology

Back 3

Energy carriers. Macromolecules. Electrochemical Gradients

Front 4

Name the most abundant energy carrier

Back 4

ATP

Front 5

Name 3 energy carriers which release high energy electrons and H+

Back 5

NADH, FADH, NADPH

Front 6

Oxidation of organic molecules is important for energy production. True or False?

Back 6

True. Reduced compounds provide electrons.

Front 7

The loss of a C-H bond in an organic molecule is indicative of which process?

Back 7

Oxidation

Front 8

State the concept which describes different metabolic processes occurring in separate parts of the cell or organism

Back 8

Compartmentation

Front 9

What is ultimately produced in the pentose phosphate pathway?

Back 9

2 NADPH during the pathway.

Ribose-5-phosphate -> Nucleotides, coenzymes, DNA, RNA

Front 10

How are lipids processed differently to carbohydrates and protein in the GI tract?

Back 10

Need to be emulsified and incorporated into micelles to increase enzyme access

Front 11

Dietary lipids are hydrolysed by which enzymes?

Back 11

intestinal/pancreatic lipases

Front 12

Name the amphipathic molecules made from cholesterol which aid emulsification and hydrolysis of dietary lipids

Back 12

Bile salts

Front 13

Describe the basic degradation steps of dietary triacylglycerols

Back 13

TGs -> DGs + FAs -> MGs + FAs

Front 14

What are the final products of metabolised triglycrides in the intestine?

Back 14

One monoacylglycerol and two fatty acids

Front 15

Triacylglycerols combine with proteins and other lipids in mucosal cells to form what?

What are the surface proteins called?

Back 15

Lipoproteins.

Apolipoproteins

Front 16

What are lipoproteins

Back 16

Combinations of apolipoproteins and lipids:

Chylomicrons, VLDL, IDL, LDL, HDL

Front 17

Name the 4 types of lipoproteins because BIOL214 doesn't admit that IDL exists

Back 17

Chylomicrons, VLDL, LDL, HDL

and also IDL

Front 18

Describe the function of apolipoproteins

Back 18

solubilise lipids, cell targeting, receptor activation

Front 19

Which lipoprotein enters the arterial wall and leads to atherosclerosis?

Back 19

LDL

Front 20

Which lipoprotein removes excess cholesterol?

Back 20

HDL

Front 21

Name the process by which LDL is taken up by LDL receptors in the liver

Back 21

LDL receptor mediated endocytosis

Front 22

Name the drugs used to reduce circulating LDL by inhibiting HMG-COA reductase

Back 22

Statins

Front 23

Name the two types of adipose tissue in humans and give their key functions

Back 23

White - storage of TGs for ATP production

Brown - storage of TGs for thermogenesis

Front 24

Do TGs or CHO have higher energy content per unit mass?

Back 24

TGs

Front 25

What are TGs composed of?

Back 25

Glycerol backbone, fatty acids

Front 26

In adipocytes, TGs are converted to fatty acids and glycerol through which enzyme?

Back 26

Hormone Sensitive Lipase

Front 27

Describe the enzyme pathway downstream of hormone receptor activation TG mobilisation from adipocytes

Back 27

Hormone receptor -> adenylyl cyclase -> cAMP -> Protein Kinase A -> lipase

Front 28

The glycerol derived from TGs may undergo metabolism via which pathways?

The fatty acids enter which pathway?

Back 28

Glycolysis and gluconeogenesis

Beta oxidation

Front 29

Beta oxidation occurs at which carbon of the fatty acid chain?

Back 29

Beta carbon C-3, carboxyl end

Front 30

In animals, beta oxidation occurs predominantly in which organelle?

Back 30

Mitochondria

Front 31

Which enzyme links fatty acids to coenzyme A to form fatty acyl-CoA

Back 31

Fatty acyl-CoA synthase

Front 32

Fatty acids longer than 14 carbons enter the mitochondria via what process?

Back 32

Carnitine shuttle

Front 33

Beta oxidation is a repetitive 4 step process by which fatty acids are converted to what?

Back 33

Acetyl-CoA, FADH2, NADH

Notice these are all involved in krebs

Front 34

What are the 4 repetitive steps of beta oxidation?

Back 34

Oxidation

Hydration

Oxidation

Thiolysis

Front 35

What is the key intermediate molecule between lipid and carbohydrate metabolism?

Back 35

Acetyl-CoA

Front 36

Beta oxidation of unsaturated fatty acids requires additional steps involving what two enzymes?

Back 36

Isomerase and reductase

Front 37

Complete Beta oxidation of odd-chain fatty acids requires additional steps. What is the final product arising from these steps and the essential vitamin required?

Back 37

Succinyl-CoA

Vitamin B12

Front 38

Vitamin B12 deficiency prevents metabolism of fatty acids and results in what disorder?

Back 38

Odd chain fatty acids -> spinal cord degeneration

Front 39

How do inborn errors to medium chain acyl-CoA dehydrogenase impair lipid metabolism?

Back 39

Inability to oxidise 6-12 carbin fatty acids

Front 40

What step in Beta oxidation does acyl-CoA dehydrogenase catalyse?

Back 40

First. Oxidation.

Front 41

Fatty acid metabolism of gut bacteria is important to human health. T or F

Back 41

True

Front 42

Acetyl-CoA is moved from mitochondria to cytoplasm via what transporter?

Back 42

Citrate transporter

Front 43

Which enzyme converts acetyl-CoA to malonyl-CoA to begin fatty acid synthesis?

Back 43

Acetyl-CoA carboxylase

Front 44

Which multi enzyme complex catalyses fatty acid synthesis?

Back 44

Fatty acid synthase

Front 45

List the four repetitive steps of fatty acid synthesis

Back 45

Condensation

Reduction

Dehydration

Reduction

Front 46

Fatty acid synthesis terminates at which end product?

Back 46

Palmitate 16:0

Front 47

Mammals lack the ability to introduce double bonds beyond which carbon position in fatty acids?

Back 47

After carbon 9, so carbon 10 onwards

Front 48

Which enzyme introduces double bonds into fatty acids?

Back 48

Fatty acyl-CoA desaturase

Front 49

Which enzyme is the key control point of fatty acid metabolism?

Back 49

Acetyl-CoA carboxylase?

Front 50

True or False: Triacylglycerol and glycerophospholipid synthesis share a common start point?

Back 50

True

Front 51

What is the starting point for triacylglycerol and glycerophospholipid synthesis?

Back 51

Phosphatidate

Front 52

What precursor molecules give rise to phosphatidate?

Back 52

Glycerol-3-phosphate and fatty acyl-CoA

Front 53

Fatty acyl-CoA and acyl-CoA synthase are involved in phosphatidate synthesis. What else are these compounds involved in, in lipid metabolism?

Back 53

Fatty acid degradation/Beta oxidation (carnitine shuttle)

Front 54

Which sphingolipid is the starting point for the synthesis of other sphingolipids?

Back 54

Ceramide

Front 55

Which two key substrates are required for the synthesis of sphingosine?

Back 55

Palmitoyl-CoA

Serine

Front 56

Sphingosine and fatty acyl-CoA form what?

Back 56

Ceramide

Front 57

Ketone body formation occurs mainly in which organ?

Back 57

Liver

Front 58

Name the end product of Beta oxidation which also serves as the starting point for ketone body synthesis?

Back 58

Acetyl-CoA

Front 59

In lipid metabolism, acetone, acetoacetate and D-B-hydroxybutyrate are types of what?

Back 59

Ketone bodies

Front 60

Ketone body production occurs mainly in the liver due to high levels of which enzyme?

Back 60

HMG-CoA synthase

Front 61

What two health conditions are often associated with increased ketone body formation?

Back 61

Starvation (also ketosis)

Diabetes

Front 62

Why does ketone body formation increase in starvation and diabetes?

Back 62

Increased gluconeogenesis depletes TCA cycle intermediates to prevent FA-derived acetyl-coa from TCA cycle entry

Front 63

Eicosanoids are derived from what membrane phospholipid-derived fatty acid?

Back 63

Arachidonate

Front 64

Arachidonate is derived from what type of fatty acids?

Back 64

Essential omega fatty acids

Front 65

What enzyme causes the release of arachidonate from membrane phospholipid?

Back 65

Phospholipase A2

Front 66

List the 3 major classes of eicosanoids

Back 66

Prostaglandins

Thromboxanes

Leukotrienes

Front 67

What enzyme converts arachidonate into prostaglandins and thromboxanes?

Back 67

Cyclooxygenase (prostaglandin H2 synthase)

Front 68

What enzyme group converts arachidonate to leukotrienes?

Back 68

Lipooxygenases

Front 69

What group of common household drugs prevent prostaglandin and thromboxane synthesis?

Back 69

Non Steroidal Anti Inflammatory Drugs

Front 70

Cholesterol is synthesised from what basic precursor molecule?

Back 70

Acetyl-coa

Front 71

List the basic steps of cholesterol synthesis

Back 71

Acetate -> mevalonate -> activated isoprene -> squalene -> lanolesterol -> cholesterol

Front 72

Cholesterol lowering compounds, statins, target which enzyme?

Back 72

HMG-coa reductase

Front 73

Cholesterol is more commonly transported in blood as?

Back 73

Cholesteryl esters

Front 74

Bile salts and steroid hormones are derived from which lipid?

Back 74

Cholesterol

Front 75

What steroid hormone is an intermediate of other steroid hormones?

Back 75

Pregnenolone

Front 76

List water and lipid soluble vitamins:

Back 76

Water: B C

Lipid: A D E K

Front 77

Energy carriers are derived from what vitamins?

Back 77

Vitamin B family

FADH = B2

NAD(P)H = B3

CoA = B5

Front 78

What vitamin is derived from cholesterol?

Back 78

Vitamin D

Front 79

What vitamins are derived from activated isoprene?

Back 79

Vitamins A E K

Front 80

Vitamin D3 is derived from cholesterol but needs additional steps to become biologically active. True or False?

Back 80

True. UV light to skin -> liver -> kidney

Front 81

Name the biologically active form of vitamin D

Back 81

1a,25-Dihydroxyvitamin D

Front 82

Vitamin D deficiency results in what to health conditions?

Back 82

Rickets

Osteomalacia

Front 83

Name the process which converts solar energy to biochemical energy

Back 83

Photosynthesis

Front 84

Write the basic equation for photosynthesis

Back 84

2H2O + photons + CO2 -> (CH2O)n + O2

Water + photons + carbon dioxide -> Carbohydrates + oxygen

Front 85

Name the 2 main reactions of photosynthesis

Back 85

Light

Dark (carbon assimilation)

Front 86

Name the 3 main products of light reactions

Back 86

ATP, NADPH and O2

Front 87

Name the organelles which capture light and convert it to chemical energy

Back 87

Chloroplasts

Front 88

Name the structure where light reactions take place

Back 88

Thylakoid membrane

Front 89

Name the structure where dark reactions take place

Back 89

Stroma

Front 90

What is the main photorecptor in chloroplasts?

Back 90

Chlorophyll

Front 91

Chlorophyll mainly absorbs what 2 regions of visible light?

Back 91

Blue and Red regions

i.e. leaving green to be reflected

Front 92

Secondary light absorbing pigments are also known as what?

Back 92

Carotenoids (Beta-carotene and lutein)

Front 93

Why are secondary light absorbing pigments important?

Back 93

Expand the range of wavelengths absorbed

Front 94

Name the arrays containing arranged light-absorbing pigments

Back 94

Photosystems

Front 95

Outline the basic organisation of photosystems

Back 95

Chlorophylls and other pigments surround the reaction centre. Chlorophylls and pigments with proteins form LHCs

Front 96

A nucleotide is made up of a...?

Back 96

Phosphate - Pentose - Purine/Pyrimidine base

Front 97

Name the two pathways by which purine bases can be assembled

Back 97

De novo purine synthesis

purine salvage pathway

Front 98

Complete the following sentence. _____ is an important branch point in purine biosynthesis.

Back 98

IMP (Inosinate monophosphate)

Front 99

Name the amino acids required to form AMP and GMP from IMP.

Back 99

AMP - Aspartate - Enzyme: Adenylosuccinate synthetase

GMP - Glutamine - Enzyme: IMP dehydrogenase

Front 100

The first committed step in purine biosynthesis involves which enzyme?

Back 100

Glutamine-PRPP amidotransferase

Front 101

The enzyme responsible for the breakdown of hypoxanthine -> xanthine -> uric acid is what?

Back 101

Xanthine oxidase

Front 102

What medication, an isomer of hypoxanthine, inhibits xanthine oxidase and is a treatment for gout?

Back 102

Allopurinol

Front 103

Gout is caused by an accumulation of what?

Back 103

Sodium Urate deposits in the joints

Front 104

The enzymes that remove ammonium ions NH4+ during purine nucleotide catabolism (salvage pathway) are known as what?

Back 104

Deaminases

Front 105

What is the main source of amino acids? (Food)

Back 105

Dietary proteins

Front 106

What are zymogens?

Back 106

Proenzymes which need to be cleaved to be activated such as trypsinogen or pepsinogen.

Front 107

Which amino acid is transported to the liver from working muscle?

Back 107

Alanine (amino side chain, like glutamine)

Front 108

Which amino acid is transported to the liver from extrahepatic tissues (not working muscle)?

Back 108

Glutamine (amino side chain makes it a viable transporter)

Front 109

How do these excrete nitrogenous wastes: Bony fish

Birds

Terrestrial animals and sharks

Back 109

Fish - ammonia

Bird - uric acid

Human - urea

Front 110

The enzyme which catalyses the first step in the urea cycle is ___________

Back 110

The enzyme which catalyses the first step in the urea cycle is carbamoyl phosphate synthase I

Front 111

Hyperammonemia is what?

Besides a waste of a flash card

Back 111

Excessive ammonia in the blood

Front 112

Can most amino acids directly enter the TCA cycle?

Back 112

Most AAs cannot enter the TCA cycle directly and must be converted to other AAs. E.g. Phe -> Tyr via phenylalanine hydroxylase

Front 113

Which enzyme is defective in phenylketonuria and what effect does this have?

Back 113

Phenylalanine hydroxylase. fails to convert phe to tyr, buildup of phe -> retardation

Front 114

What is the main storage site of amino acids in our body?

Back 114

Muscle

Front 115

What is the key problem of starvation diets?

Back 115

Glycogen depletion and shift to muscle catabolism for AAs/gluconeogenesis

Front 116

4 problems with 'high protein' (ketogenic not high protein really junk question) are:

Back 116

Risks of ketogenic diets:

Hypoglycemia

Ketoacidosis

Hyperlipidemia

Hyperammonia

*suspicious question

Front 117

The process by which bacteria and archaea convert N2 to NH3 is ________

Back 117

The process by which bacteria and archaea convert N2 to NH3 is nitrogen fixation

Step 1: Fixation

Front 118

The four chemical transformations that maintain a balance between N2 and biologically useful nitrogen are...

Back 118

1. Fixation. N2 -> NH3

2. Nitrification. NH3 -> NO2-

3. Assimilation. NO2- -> NH3

4. Denitrification. NO3- -> N2

Front 119

The key role of glutamate in biosynthesis is _____ and _______

Back 119

A key entry point for nitrogen into biomolecules.

Along with glutamine it is one of the 2 major sources of N for biosynthesis reactions.

Front 120

Glutamine synthetase converts _______ into glutamine through ________ of _________ and then replacement of __ with ____.

Back 120

Glutamine synthetase converts glutamate into glutamine through phosphorylation of carboxylic acid side chain and then replacement of Pi with NH3.

Front 121

Is glutamine synthetase a major regulatory point in biosynthesis?

Back 121

Yes it is a key control point

Front 122

Two mechanisms by which glutamine synthetase is regulated are:

Back 122

Adenylation (stimulated by glutamine and Pi)

Allosteric inhibition by products such as a-ketoglutarate.

Front 123

Name the three pathways which yield carbon skeletons for AA synthesis.

Back 123

Glycolysis

Krebs

Pentose Phosphate Pathway

Front 124

Essential amino acids must be supplied by diet T/F

Back 124

True

Front 125

Name the reactions used to transfer an amine group, usually from glu or gln, to a carbon skeleton for amino acid synthesis

Back 125

Transamination reactions catalysed by aminotransferases

Front 126

In addition to biosynthesis, amino acids are involved in energy production. List 3 main energy pathways they are involved in.

Back 126

Gluconeogenesis

TCA cycle

Ketogenesis

Front 127

Name the enzyme which converts arginine to nitric oxide

Back 127

Nitric oxide synthase

Front 128

Which enzyme makes PRPP from ribose-5-phosphate?

Back 128

PRPP synthetase

Front 129

Which enzyme uses glutamine to add nitrogen to PRPP?

Back 129

Glutamine-PRPP amidotransferase

Front 130

Cytidylate is an example of nucleoside, nucleotide or nucleic acid?

Back 130

Nucleotide

Phosphate - Ribose - Cytosine

Front 131

The carbon and nitrogen atoms in the pyrimidine ring come from which two molecules?

Back 131

Carbamoyl phosphate and Aspartate

Front 132

Where is carbamoyl phosphate 1 located, what process does it make carbamoyl phosphate for?

Back 132

Hepatic mitochondria, urea cycle

Front 133

Where is carbamoyl phosphate 2 located, what process does it make carbamoyl phosphate for?

Back 133

Cytosol. Pyrimidine de novo synthesis

Front 134

Why are dTTP synthesis enzymes valid targets for chemotherapeutic agents?

Back 134

Inhibit DNA synthesis as dTTP is unique to DNA and needed for its synthesis.

Example drug: 5-fluorouracil -> 5-fluorodeoxyuridylate (5-dUMP) irreversibly inhibits enzyme that produces dTMP.

Front 135

Name two the photosystems in chloroplasts

Back 135

PS II and PS I

Front 136

Name the complex which links PS II to PS I

Back 136

Cytochrome B6F

Front 137

Give the main function of Cb6f

Back 137

Pump protons into the thylakoid lumen

Front 138

Increased protons in the thylakoid membrane lead to the generation of what?

Back 138

ATP via ATP synthase

Front 139

Name the protein that carries electrons from C b6f to PS I

Back 139

Plastocyanin

Front 140

Distinguish between non cyclic and cyclic electron transfer from ferredoxin

Back 140

Non cyclic drives NADPH production

Cyclic drives proton gradient and subsequent ATP production

Front 141

Which two products of light reactions feed directly into the calvin cycle?

Back 141

NADPH and ATP

Front 142

What are the 3 stages of the calvin cycle?

Back 142

1. CO2 -> 3-phosphoglycerate

2. 3-phosphoglycerate -> Glyceraldehyde-3-phosphate

3. Triose phosphate -> ribulose-1,5-bisphosphate

Front 143

What enzyme catalyses the first step in the calvin cycle? What is its limitation?

Back 143

Rubisco aka ribulose-1,5-bisphosphate carboxylase oxygenase

It has very low activity

Front 144

How many of the triose phosphates generated in the calvin cycle must be recycled to ribulose-1,5-bisphosphate?

Back 144

80%

Front 145

Besides low activity what is another limitation of rubisco?

Back 145

Fixes O2 as well as CO2

Front 146

What waste product can rubisco form?

Back 146

2-phosphoglycerate

Front 147

Name 3 organelles involved in salvage of 2-phosphoglycerate

Back 147

Mitochondrion, peroxisome, chloroplast

Front 148

What is the first step in c4 carbon assimilation

Back 148

CO2 -> HCO3- -> Oxaloacetate

Front 149

Name the enzyme which catalyses the first step of C4 carbon assimilation

Back 149

Phosphoenolpyruvate carboxylase

Front 150

What two cell types are required for C4 pathway in plant leaves?

Back 150

Mesophyll and bundle-sheath cells

Front 151

Chemical energy in the form of ATP and NADH is used in what kind of reaction in the body?

Back 151

Endergonic, unfavourable reactions

Front 152

Define enthalpy

Back 152

Total potential energy of a system

Front 153

Define entropy

Back 153

a measure of increasing disorder due to energy lost during transformations

Front 154

How do enzymes lower the activation energy of reactions?

Back 154

Orientation of reactants at active site

Front 155

Oxidation is ____ of electrons, reduction is ____

Back 155

Oxidation is loss of E- Reduction is gain of E-

Front 156

What is the primary antioxidant in animals and which enzyme replenishes it when oxidised?

Back 156

Glutathione

Glutathione reductase and also NADPH

Front 157

Humans may lose consciousness below what blood glucose concentration?

Back 157

3.5mmol/L

Front 158

Which organ is primary storage reserve of glucose?

Back 158

Liver as glycogen

Front 159

What energy sources are used by brain?

Back 159

Glucose, Ketone bodies

Front 160

Which organ is able to use phosphocreatine as an energy source?

Back 160

Muscle

Front 161

What is the effect of insulin on blood glucose?

Back 161

Insulin decreases blood glucose and begins storage processes

Front 162

What is the effect of glucagon on blood glucose?

Back 162

It increases blood glucose by lipolysis, gluconeogenesis

Front 163

What are the effects of ghrelin and leptin on appetite?

Back 163

Ghrelin = hunger, remember GH increased growth hormone when fasting

Leptin = satiety, released when full. Obese may be leptin resistant

Front 164

List 4 metabolic effects of cortisol. What is one health condition that can arise from prolonged cortisol release and why?

Back 164

Increased lipolysis

Increased gluconeogenesis

Muscle catabolism

Increased glycogenolysis.

Type 2 diabetes, long term increase in blood glucose and insulin resistance.

Front 165

What are the two main cellular locations of receptors?

Back 165

Membrane and Intracellular: cytosol/nucleus

Front 166

What are the 3 main types of receptors important in metabolism?

Back 166

Growth factor receptors e.g. insulin

G-protein coupled receptors e.g. glucagon epinephrine

Steroid receptors e.g. glucocorticoids, sex hormones

Front 167

How is the insulin signal controlled?

Back 167

Binds to receptor to form dimer, activating tyrosine kinase, kinase cascade occurs, activating response proteins and enzymes.

Receptor signal is controlled by internalisation of insulin receptor - endocytosis.

Front 168

What are the function of STATs in leptin signalling?

Back 168

STATs enter the nucleus in hypothalamic cells and regulate transcription

Front 169

Name one enzyme activated by the second messenger cAMP

Back 169

cAMP activates Protein Kinase A