Extra IMMS Flashcards

1
Q

What are the net products of Glycolysis?

A

2 PYRUVATE, 2ATP AND 2NADH

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2
Q

What does a kinase enzyme do?

A
  • enzyme that adds/removes phosphate group to things from/to an ATP
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3
Q

What are the basic steps of Glycolysis?

A
Gross  - Glucose 
Guys  - Glucose 6 phosphate 
Favour - Fructose 6 phosphate 
Big Butts - Fructose 1-6 Biphosphate 
Good - Glyceraldehyde 3 Phosphate (G3P)
Boys - 1-3 Bisphosphate 
Prefer - 3 Phosphoglycerate
PrettyGirlsIn - 2 Phosphoglycerate
Pink -  Phosphoenolpyruvate
Pyjammas - Pyruvate
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4
Q

What is the enzyme to catalyse the first reaction of glycolysis?

A

Hexose Kinase in the rest of the body, but Glucose Kinase in the Liver!

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5
Q

What are the two energy consuming steps of Glycolysis

A

The first step:
Glucose ==> Glucose 6 Phosphate (Hexose Kinase in the rest of the body, but Glucose Kinase in the Liver!) ATP => ADP +Pi

And the third step:
Fructose 6 phosphate ==> Fructose 1,6 Bisphosphate (Phosphofructokinase 1 /PFK1) ATP => ADP +Pi

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6
Q

What is the 3rd step of glycolysis? What is the significance of it?

A
  1. Fructose 6 phosphate ==> Fructose 1,6 Bisphosphate (Phosphofructokinase 1 /PFK1) ATP => ADP +Pi

This also irreversible = it is the rate limiting step - the rate at which this happens determines the rate of Glycolysis

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7
Q

What are the regulators of glycolysis?

A

Insulin
Glucagon
Glucose 6 phosphate (the first product)
Phosphofructoskinase-1

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8
Q

Define Allosteric

A

modifies the active site of the enzyme, changing its affinity for the substrate

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9
Q

What are to two energy generating steps of glycolysis?

A

The 6th step:
1-3 Biphosphoglycerate ==> 3 Phosphoglycerate (Phosphoglycerate Kinase) THIS STEP GENERATES 2 ATP

The last (9th) step:
Phosphoenolpyruvate ==> Pyruvate (Pyruvate Kinase) THIS STEP GENERATES 2 ATP
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10
Q

How does Insulin effect Glycolysis?

A

increases the rate of Glycolysis, by increasing PFK 1

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11
Q

How does Glucagon effect Glycolysis?

A

Decreases levels of PFK 1

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12
Q

How does Glucose 6 Phosphate affect Hexose Kinase enzyme (the enzyme in the 1st step) effect Glycolysis?

A
  • The Higher the concentration of Glucose 6 Phosphate (its product), the lesser the activity of the enzyme Hexokinase to make more of it!
  • so more glucose (makes sense)
  • –> this is the minor regulator
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13
Q

How can phosphofructokinase be affected, and how does this affect glycolysis? (enzyme in the 3rd step)

Energy/phospate

A

a. Allosterically effected (stimulated) by AMP ==> More AMP = More PFK action
b. Allosterically Inhibited by ATP, and Citrate==> More ATP and citrate = Less PFK action

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14
Q

How does AMP effect PFK-1?

A

It Allosterically effects/stimulates PFK-1, so more AMP = More PFK action

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15
Q

How does ATP effect PFK-1?

A

It allosterically inhibits PFK-1, so more ATP = Less PFK action

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16
Q

What is the irreversible step of Glycolysis?

A

Step 1, 3, 9
hexokinase; phosphofructokinase;
pyruvate kinase.

(New enzymes are needed to catalyze new reactions in the opposite direction for gluconeogenesis.)

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17
Q

How does Citrate effect PFK-1?

A

It allosterically inhibits PFK-1, so more citrate = Less PFK action

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18
Q

If in anaerobic conditions, and the NADH and pyruvate can’t enter the Krebs cycle, what will happen to them?

A

They will form Lactate and NAD+, as well as little more ATP. This needs to happen so Glycolysis can continue, so NAD+ can go back to accepting H+

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19
Q

In Glycolysis, What step generates NADH?

A

Glyceraldehyde 3 Phosphate (G3P) => 1,3 Bisphoglycerate,

By enzyme G3P Dehydrogenase

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20
Q

In order to undergo beta oxidation, what do Fatty acids get converted to in the cytoplasm?

A
Fatty acids ==> Acyl Adenylate ==>
 Acyl CoA (by acyl CoA synthase)
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21
Q

In order to cross the outer membrane of the mitochondria to get into the intermembrane space, what happens to Acyl coA? What enzyme catalyses this?

A

becomes acyl carnitine (by carnitine acyltransferase 1 –CAT1), as part of the CARTNITINE SHUTTLE

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22
Q

what happens once acyl carnitine has crossed into the intermembrane space?

A
  • Acyl carnitine is reformed to acyl coA (by carnitine acyltransferase 2 – CAT2)
  • On the interior side of the membrane, in the matrix

the carnitine is recycled

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23
Q

What happens to Acyl coA once it is now in the intermembrane space?

A

Once acyl coA has crossed the membrane it can now be oxidised
This involves the sequential removal of 2 carbon units by oxidation – the second (hence beta) carbon is cleaved

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24
Q

What does one round of beta oxidation produce?

A

Each round of beta oxidation produces 1NADH, 1FADH2 and 1 acetyl coA

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25
Q

Define Nucleotide

What is an Nucleoside?

A

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

A nucleoside is a Pentose Sugar and a BASE

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26
Q

Define a single nucleotide polymorphism

A

SNP= DNA sequence variation that occurs at a single nucleotide

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27
Q

What cells produce elastin?

A

Fibroblasts

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28
Q

Where is renin produced?

A

Juxtaglomerular (grannular cells) cells in the kidney

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29
Q

Where is ADH produced?

Where is it secreted?

A

The Hypothalamus

The Posterior Pituitary gland

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30
Q

What does Renin do?

A

Renin converts angiotensinogen into angiotensin I

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31
Q

Which 2 proteins are involved in the generation of ciliary movement

A

Tubulin and dynein are involved in the generation of ciliary movement

Tubulin is a microtubule (25nm)

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32
Q

What is a gene sequence coded in?

A

A gene sequence is coded in single strand DNA

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33
Q

What is a promoter sequence? What is it coded in?

A

This area of DNA indicates the starting point of transcription, and there may be multiple promoter sequences within a DNA molecule. It is what mRNA recognises and where it starts.
It is coded in single strand DNA

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34
Q

What is the transcriptome composed of?

A

The transcriptome is composed of all the RNA present in the cell

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35
Q

During transcription, what do specific amino acids bind to?

A

Amino acids bind to tRNA

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36
Q

What is the structure of Haemoglobin?

A

2 alpha and 2 beta polypeptide chains

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37
Q

What type of inheritance pattern is seen with sickle cell disease?

A

Autosomal recessive.

38
Q

A mutation in what gene results in HbS production?

what chain is involved?

A

HBB gene.

The beta globin chain

39
Q

What does the Sickle cell disease single nucleotide polymorphism result in?

A

an amino acid replacement at position 6 in the beta-globin chain from glutamic acid to valine. This results in sickled haemoglobin (HbS).

40
Q

Under physiological stress, what happens to sickled haemoglobin?

eg hypoxia, cold temperature, dehydration, acidosis

A
sickled haemoglobin (HbSS) polymerises and causes erythrocytes to deform into a sickled shape, 
and crystallises
41
Q

Define non disjunction

A

occurs when homologous chromosomes fail to separate in M1 OR

sister chromatids fail to separate in M2.

42
Q

Define gondal mosaicism

A

occurs when precursor
germline cells to ova or spermatozoa involve a mixture of 2 or more genetically
different cell lines- this may occur due to random mutation in the germline cells that
undergo mitosis leading to mutated gametes, or due to errors in mitosis during
gametogenesis; the result is such that one cell line is normal and the other is
mutated.

43
Q

By which process is ATP formed during glycolysis?

A

In glycolysis, ATP is formed by substrate level phosphorylation

44
Q

what are the 3 types of Cytoskeletons? What are their respective sizes?

A

Microtubules - 25nm
Intermediate Filaments - 10nm
Microfilaments - 5-7nm

45
Q

Give an example of each of the 3 types of cytoskeletons

A

Microtubules - eg Tubulin, used in Mitosis, found in cilia along with Dynein

Intermediate Filaments - help remain Cell integrity and cell to cell contact - seen in Desmosomes eg Nuclear laminin - in nuclei of all cells

Microfilament - eg Actin seen in Adheren junctions,
ACTIN forms a bracing mesh (cell cortex) on the inner
surface of the cell membrane

46
Q

Where does the Krebs cycle occur?

A

The Mitochondrial matrix

47
Q

Why is glycolysis inhibited in acidic conditions?

A

Because PFK-1 enzyme is inhibited by acidic conditions

48
Q

Why can the krebs cycle only take place in aerobic conditions?

A

since oxidative
phosphorylation is required to covert NADH & FADH2 back to NAD+ and FAD to be used in the conversion of isocitrate to a-ketoglutarate

49
Q

Outline the link reaction

A

Pyruvate ==> Acetyl CoA + CO2, and NADH

50
Q

Briefly outline the Krebs cycle

A
Acetly CoA enters, becomes
Citrate
Isocitrate
A-ketoglutarate
Succinyl CoA
Succinate 
Fumarate
Malate 
Oxaloacetate
Citrate again
51
Q

What are the rate limiting substances in the krebs cycle?

A

Citrate Synthase
Citrate
a-ketoglutarate dehydrogenase
Calcium

52
Q

How can citrate synthase be inhibited?

A

○ can be Allosterically inhibited By ATP and NADH
Can be competitively inhibited by Succinyl CoA

Slows Down

53
Q

What affect does Citrate have on the krebs cycle?

A

Inhibits PFK1 , a key enzyme in Glycolysis, which would therefore reduce production of Pyruvate

Slows Down

54
Q

What affect does a-ketoglutarate dehydrogenase have on the krebs cycle?

A

Its products - (Succinyl CoA and NADH) will inhibit this enzyme

55
Q

What affect does Calcium have on the Krebs cycle?

A

Stimulates the Link reaction, so accelerates the TCA

Speeds up

56
Q

What effects will high levels of ATP, NADH and FADH2 have on the Krebs cycle?

What about ADP?

A

High levels inhibit the Krebs Cycle

Conversely, it is activated by high ADP levels

57
Q

What happens if the krebs cycle is inhibited?

A

there is a build up of acetyl coA and this undergoes fatty acid synthesis

58
Q

Where does CO2 and NADH first get produced during a turn of the krebs cycle?

A

When isocitrate becomes a-ketoglutarate

Under action of isocitrate dehydrogenase enzyme

59
Q

Explain DENA, DENA , A, FA, WA NA

A

CO2 and NADH (off Isocitrate)

CO2 and NADH (off a-ketoglutarate)

ATP(/GTP) off Succinyl CoA

FADH2 (off Succinate)

Water IN (to convert Fumarate to malate)

NADH (off Malate) when going to Oxaloacetate

60
Q

What are the products of one turn of the Krebs cycle

A
3 NADH (3ATP each)
1 FADH2 (2ATP)
1 GTP (1ATP)

= 12 ATP

61
Q

Where does Oxidative phosphorylation take place?

A

the inner membrane of the mitochondria

62
Q

How many complexes are there?

Which one removes electrons from NADH and Which from FADH2

A

4 complexes

Complex I – removes electron from NADH
Complex II – removes electrons from FADH2 in the presence of co enzyme Q (ubiquinone)

63
Q

What is needed in order to remove electrons from FADH2?

A

co enzyme Q (ubiquinone), at complex 2

64
Q

What are the electrons finally transferred to? What does this form?

A
electrons are finally transferred to molecular oxygen, which then combines with
hydrogen ions (protons) to form water.
65
Q

What does the energy generated from ETC do?

A

cytochromes to pump hydrogen ions
from the matrix into the intermembranal space - the compartment between the inner
and outer mitochondrial membranes

• This creates a source of potential energy in the form of a hydrogen-ion-
concentration gradient across the membrane.

hydrogen ion to flow back
into the matrix via chemiosmosis, generating energy for ATP to be formed from ATP and ADP and Pi

66
Q

Pedigree interpreting:
How do you show
a Healthy Male
b Healthy Female

A

Male is an empty Square

Female is an empty circle

67
Q

Pedigree interpreting:
How do you show
a Affected Male
b Affected Female

A

Male is an coloured in Square

Female is an coloured in circle

68
Q

Pedigree interpreting: How do you show an an unborn, or sex unknown

How would you show a still birth?

A

empty diamond

Put an SB by the diamond if they are a still birth

69
Q

Pedigree interpreting:
How would you show
a) a pregnancy
b) a termination

A

a) an empty triangle

b) an empty triangle with a cross over it

70
Q

How do you show consanguinity?

A

A double line between the couple in question

71
Q

Name some charateristics of X linked conditions

A

Caused by mutations carried on the X - chromone
(NO MALE-TO-MALE
TRANSMISSION
All daughters from an affected male are CARRIERS all sons are UNAFFECTED
Males can NEVER be carriers
• Usually only males are affected

Can either be dominant - Alports Syndrome or recessive -DMD

72
Q

Define Lyonization

A

The process of X chromosome inactivation = One of the two X chromosomes in every cell in a female is randomly inactivated early in embryonic development -prevents two sets of X chromosomes being expressed (only need one)

73
Q

What is the rate limiting step of the Krebs cycle?

A

Isocitrate ==> A ketoglutarate,

As the enzyme involved, isocitrate dehydrogenase is an allosterically controlled enzyme.

74
Q

What does the nucleus contain dna in the form in?

What is it wrapped around?

A

Chromatin. It is wound around histone proteins

75
Q

Euchromatin vs Heterochromatin: What is what?

A
Euchromatin = Loose coils, Expressed
Heterochromatin = tight coils repressed
76
Q

Mitosis - Outline what happens in the prophase.

A
  • Nuclear Membrane begins to break down
    • Chromatin condenses into Chromosomes
      Centrioles (tubules) move to polar ends - forms spindle
77
Q

Mitosis - Outline what happens in the prometaphase.

A
  • Nuclear membrane breaks down

Spindles form
Cell no longer has a nucleus
Chromosomes attach to spindle via a centromere

Tubulin, a microfilament, (25um) forms the centrioles

78
Q

Mitosis - Outline what happens in the metaphase.

A

Chromosomes line up at the equator

79
Q

Mitosis - Outline what happens in the anaphase.

A

Sister chromatids separate, pushed to opposite poles of the cell, as spindle fibres contract < > shaped

80
Q

Mitosis - Outline what happens in the telophase.

A
  • Chromosomes unfold into chromatin

- Nuclear membrane reforms

81
Q

Mitosis - Outline what happens in the cytokinesis

A
  • Division of the Cytoplasm, and organelles ==> 2 genetically identical daughter cells form
82
Q

What happens in Prophase 1 of Meiosis?

A

CROSSOVER Homologous chromosomes exchange small parts of themselves, ==> so 1 chromosomes contains both maternal and paternal DNA ==> to increase genetic diversity (known as crossover)

83
Q

What happens in Metaphase 1 of Meiosis?

A

Independent Assortment
Maternal and Paternal chromosomes line up randomly on either side of the equator = So each gamete will either Mum or Dads genetic material - leads to more genetic diversity amongst offspring.

84
Q

DNA replication enzymes: What does Topoisomerase do?

A

Unwinds the Supercoils (double helix, makes it unconvoluted)

85
Q

DNA replication enzymes: What does Helicase do?

What do SSBs do?

A

Breaks the H bonds

Single strand bases SSBs from the Nucleus keeps the base pairs away from each other to stop repairing
So now, free DNA nucleotides can bind

86
Q

DNA replication enzymes: What does DNA polymerase do?

A

Catalyses the phosphodiester bonds between the Free nucleotides - (reads in the 3’5 direction, and synthesising in the 5’3’

87
Q

DNA replication enzymes: what does DNA Ligase do?

A

joins Ozaki Fragments (Short DNA Pieces) together in one continuous strand - SEMI CONSERVATIVE REPLICATION - ONE ORIGINAL AND ONE NEW STRAND

88
Q

What factors INCREASE BMR

A

Being Overweight, Caffeine, Temperature, Hyperthyroidism, Exercise, Pregnancy, Being Tall, Stress

89
Q

What factors DECREASE BMR

A

Increasing Age, Being Female, Starvation, Hypothyroidism

90
Q

Define BMR, and give its standard value

A

Basal Metabolic Rate - The rate of metabolism needed to sustain life at rest (24kcal/kg/day)