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Phase 1 M > IMMS > Flashcards

IMMS Flashcards

1
Q

Where in the cell is DNA located?

A

Nucleus and Mitochondria

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2
Q

Describe the structure of DNA

A

DNA is a filamentous, helical structure formed by two antiparallel polynucleotidic chains joined by pairing between their bases
Adenine –> Thymine (2 bonds)
Guanine –> Cytosine (3 Bonds)
DNA coils around histone proteins to form nucleosomes, then coils again into supercoils (solenoid) forms chromatin and then again into chromosomes

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3
Q

How many chromosomes do humans have?

A

46 - 22 autosome pairs and the sex chromosomes (XY)

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4
Q

Describe the structure of a chromosome

A

Long Q arm and a short P arm separated by a central centromere

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5
Q

What dyes can be used In chromosome identification?

A 
Giesma = G banding 
Quinacrine = Q banding
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6
Q

What is the purpose of mitosis?

A

Replace dead cells
Growth
Produce 2 daughter cells genetically identical to the parent cell

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7
Q

What happens in the S phase of the cell cycle?

A

DNA replication

Centrosome Replication

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8
Q

What happens in Prophase?

A

Chromatin condenses into chromosomes

Centrosomes nucleate microtubules and move to opposite poles of the cell

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9
Q

What happens in Prometaphase?

A

Nuclear membrane breaks down and the microtubules invade the nuclear space and attach to chromatids

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10
Q

What happens in metaphase?

A

Chromatids attached to microtubules line up along the equatorial plate (Metaphase plate)

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11
Q

What happens in Anaphase?

A

Sister chromatids separate and are pulled to opposite poles of the cell as microtubules shrink

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12
Q

What happens in telophase?

A

Nuclear membrane reforms and the chromosomes unfold into chromatid
Cytokinesis begins

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13
Q

What is the clinical relevance of mitosis histology

A

Is cancer malignant or benign
Grade malignant tumour
Detect chromosomal abnormalities
Drugs to slow mitosis

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14
Q

What drugs can be used to affect mitosis?

A

Stop spindle formation (Taxol and Vinca alkaloids (Vinblastine and Vincristine))
Stop spindle pole formation (Ispinesib)
Prevent Anaphase (Colchinine)

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15
Q

How does meiosis differ from mitosis (4 things)

A
  1. Only occurs in gametes
  2. Recombination of genetic material causing diversity
  3. 2 divisions
  4. produces 4 haploid daughter cells
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16
Q

Describe what happens in Meiosis

A

Start with parent cell that is 2M. DNA replicates and recombinates to produce a 4M cell which divides to produce to daughter 2M cells. These then divide further to produce 4 daughter cells that are M and are genetically different

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17
Q

What is crossing over and when does it occur?

A

Produces recombinant chromosomes which carry genes from different parents - this occurs in prophase I

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18
Q

Describe sperm production

A

Primordial cells are converted into spermatogonia via lots of mitoses in a process that takes 60-65 days
Cytoplasm divides equally

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19
Q

Describe the production of egg cells

A

Primordial cell –> 30 mitoses –> Oogonia
The meiotic process begins in utero but is suspended part way through Meiosis I. Meiosis I is completed at ovulation and Meiosis II is completed at fertilisation.
Cytoplasm divides unequally into one 1 egg with all the cytoplasm and 3 polar bodies with no cytoplasm that apoptose

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20
Q

What is non-dysjunction?

A

Failure of chromosomes pairs to separate in meiosis 1 and failure of sister chromatids to separate in meiosis 2

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21
Q

Describe what happens to cause downs syndrome

A

Abnormality of trisomy 21 - non dysjunction causes one cell to have no chromosome 21 and one cell to have 2 chromosome 21

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22
Q

What is gonadal mosaicism?

A

mutation arose in one of the stem cells which ultimately generates eggs or sperm then more that one egg or more than one sperm could contain the new mutation incidence
increases with increasing paternal age - most common in linked and autosomal dominant conditions

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23
Q

Define genotype

A

Genetic constitution of an individual

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24
Q

Define phenotype

A

Appearance of an individual (physical, biochemical and physiological) which results from interaction of environment and genotype
Characteristic that can be described or measured

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25
Q

Define allele

A

One of several alternative forms of a gene at a specific locus

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26
Q

Define polymorphism

A

Frequent hereditary variations at a specific locus

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27
Q

Define Homozygous

A

Both alleles at a locus are the same

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28
Q

Define Heterozygous

A

Alleles at a locus are different

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29
Q

Define Hemizygous

A

Only one allele refers to the locus on an x-chromosome in a male

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30
Q

Describe autosomal dominant inheritance and draw a diagram

A

Manifests in the heterozygous state with only one pathogenic variant required

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31
Q

Describe autosomal recessive and draw a diagram

A

Manifests in the homozygous state with the normal functioning gene compensating for the pathogenic variant - 1in4 chance of having disease and 2in4 chance of being carrier

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32
Q

Describe X-linked recessive and draw a diagram

A

Caused by pathogenic variants on the x-chromosome

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33
Q

What does tRNA do

A

Carries amino acids to ribosomes and ensures they are in the correct position - each tRNA only carries one AA at its 3’ end so there are 20 types

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34
Q

How is DNA made accessible to transcription factors to enable replication?

A

Heterochromatin inaccessible to transcription factors –> Recruit histone acetyltransferases –> Recruit chromatin remodelling complexes –> Recruit DNA demethylases –> Euchromatin = accessible to transcription factors

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35
Q

Define an out of frame deletion variant

A

Deletion of one or two bases causes reading frame to shift so Amino acids change and so does protein sequence

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36
Q

Define an in frame deletion variant

A

Loss of 3 bases resulting in loss of an amino acid and formation of a truncated protein ie. dystrophin truncation in milder Becker muscular dystrophy = less severe than out of frame

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37
Q

Define a splice site variant

A

Affects accuracy of intron removal - normal splice acceptor site is 4 base pairs ie. CCAT - however if A changed to C then enzyme doesn’t recognise so no cut made and abnormal protein is translated

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38
Q

Define a non-sense mutation

A

Out of frame deletion of a single base pair causes the codon to change to a stop codon at the deletion site or further along

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39
Q

Define a mis-sense mutation

A

Single base substitution changes amino acid in the protein sequence - may or may not be pathogenic

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40
Q

Give three examples of try-nucleotide repeat disorders

A

Huntington’s - CAG
Myotonic Dystrophy - CTG
Fragile X - CGG

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41
Q

Define allelic heterogeneity

A

Lots of different variants of one gene ie. cystic fibrosis

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42
Q

Define locus heterogeneity

A

Variants of different genes give the same clinical condition ie. hypertonic cardiomyopathy

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43
Q

Define autosome

A

Any chromosome other than the sex chromosomes that occurs in pairs in diploid cells

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44
Q

What are the characteristics of an autosomal recessive disorder

A 
Manifests in the homozygous state 
Males and females affected equally 
Affects individuals in only one generations 
If both parents are carriers 
1/4 has disease 
2/4 are carriers 
1/4 unaffected but if one parent affected...
all 4 children will be carriers
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45
Q

What is the carrier frequency of cystic fibrosis and where does the mutation occur?

A

1/25 with mutations occurring in the CFTR gene located on gene 7q31.2

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46
Q

Define Consanguinity

A

Reproductive union between two relatives

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47
Q

Define Autozygosity

A

Homozygosity by descent - inheritance of the same altered allele through two branches of the same family

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48
Q

What are the characteristics of autosomal dominant inheritance?

A

Manifest in heterozygous state
Male and female equally affected
Passed from both sexes to both sexes
Penetrance and variability

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49
Q

Define Penetrance

A

Percentage of individuals with. specific genotype showing the expected phenotype

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50
Q

What are the characteristics of X-linked inheritance

A

Gene carried on the x-chromosome
Usually transmitted through unaffected females
Usually only males affected
No male to male transmission

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51
Q

What are the 3 types of numerical chromosome abnormality?

A

Trisomy - gain of 1 chromosome
Monosomy - loss of 1 chromosome
Polyploidy - Gain of a whole chromosome set

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52
Q

What are the 4 types of structural chromosome abnormality?

A
  1. Translocation - exchange of material between chromosomes
  2. Inversion - part of a chromosome is chopped out, inverted and reinserted into itself or another chromosome
  3. Duplication - part of a chromosome is duplicated and reinserted
  4. Deletion
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53
Q

What is triploid karyotype?

A

3 of each chromosome = incompatible with life
if extra chromosome comes from mother = intrauterine malformation - if comes from paternal side = placenta becomes malignant

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54
Q

What disease is associated with deletion at the Q arm of chromosome 15?

A

If paternal = Prader Willi

if maternal = Angelman Syndrome

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55
Q

Define multifactorial disease

A

Disease that are the result of a combination of genetic and environmental factors

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56
Q

What studies can be used to determine if a disease has a genetic component?

A

Family
Twin
Adoption

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57
Q

Describe a family study

A

Compare the incidence of a disease amongst the relative of an affected individual with the general population

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58
Q

Describe twin study

A

Compare monozygotic (identical) and dizygotic (non identical twins - if disease has a genetic component the concordance rate should be higher in monozygous

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59
Q

Define heritability

A

Proportion of the aetiology that can be attributed to genetic factors as opposed to environmental factor

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60
Q

List environmental factors that may act on embryogenesis

A

Drugs and chemicals
Maternal infections
Physical agents (radiation)
Maternal illness (Diabetes)

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61
Q

List environmental factors that may act post natally

A

Obesity
Hormonal factors (pill)
Smoking
Recreational drugs

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62
Q

What are the 4 pathways of metabolism in the body

A

Storage - anabolic
Biosynthetic - anabolic
Oxidation - catabolic
Waste disposal - either

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63
Q

What are the dietary components?

A

Fuels, Essential Fatty Acids,

Essential amino acids, Vitamins, minerals, water, xenobiotics

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64
Q

What are the dietary fuels

A

Carbohydrates
Lipids
Proteins
Alcohol

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65
Q

Where are dietary fuels stored?

A
  1. Fat as triglycerides in adipose tissue (15kg)
  2. Carbohydrate as glycogen in the liver (200g) and the muscles (150g)
  3. Protein as muscle (6kg)
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66
Q

How much energy per gram is there from carbohydrates/protein/alcohol and lipids

A 
Carb = 4kcal/g
Protein = 4kcal/g
Alcohol = 7kcal/g
Lipid = 9kcal/g
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67
Q

What is the main source of ATP during rest and low intensity exercise

A

Oxidative system primarily using carbohydrates and Fats - during high intensity exercise almost 100% derived from carbohydrates

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68
Q

When is protein used as an energy source?

A

During prolonged exercise (>90mins) and during periods of starvation

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69
Q

Define basal metabolic rate

A

Every required to maintain non exercise bodily functions ie. respiration, heart muscle contraction, biosynthetic processes, repair and regeneration of tissues and ion gradients
BMR = approx 1kcal/kg body mass/ hour

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70
Q

What factors decrease basal metabolic rate?

A 
Age
Hypothyroidism 
Gender 
Diet and starvation 
Decreased muscle mass
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71
Q

What factors increase basal metabolic rate?

A 
Exercise 
Hyperthyroidism 
Low ambient temperature 
Caffeine/stimulant intake 
Body Weight 
Pregnancy and Lactation 
Fever/Chronic disease/Infection
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72
Q

What are the sources for gluconeogenesis?

A

Lactate
Amino Acids (Intestine, Muscle + Skin)
Glycerol (Fat breakdown)
Liver –> Ketone from fatty acids

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73
Q

Define malnutrition

A

State of nutrition with a deficiency, excess or imbalance of energy, protein or other nutrient that causes measurable adverse effects

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74
Q

What are the two essential fatty acids?

A

Omega-3

Omega-6

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75
Q

What are the essential amino acids and how much do we need?

A

Need 0.8g/kg/day

Lysine, isoleucine, leucine, threonine, valine, tryptophan, phenylalanine, methionine and histidine

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76
Q

What does vitamin B1 (Thiamine)?

A

Helps with energy production in the body

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77
Q

What does vitamin C do?

A

Helps to prevent cell damage and reduce certain cancers, heart disease and other diseases, collagen synthesis, protects from infections and increases the amount of iron the body absorbs

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78
Q

What does vitamin D do?

A

Increases the amount of calcium and phosphorus the body absorbs from foods and deposits calcium and phosphorus in bones, teeth making them stronger and healthier

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79
Q

What is the equation for the hydrolysis of ATP in ADP?

A

ATP + Water –> ADP + Pi + H+ +Heat

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80
Q

Where does glycolysis occur?

A

In the cytosol of the cell

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81
Q

What is the rate limiting factor in glycolysis?

A

Phosphofructokinase Enzyme

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82
Q

What enzyme catalyses the conversion of glucose to Glucose-6-phosphate? Where is it located?

A

Hexokinase (Form of glucokinase) found in the liver that acts when bloodstream glucose levels are high

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83
Q

What happens to the ADP produced in the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate?

A

ADP is converted to ATP and AMP by the action of Adenylate Kinase

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84
Q

What are the allosteric activators of phosphofructokinase?

A

AMP

Fructose-2,6-Bisphosphate

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85
Q

What are the allosteric inhibitors of phosphofructokinase?

A

ATP

Citrate

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86
Q

How does Fructose-2,6-bisphosphate allosterically activate PFK

A

Increase in glycolysis increases fructose-1,6-bisphosphate production which activates pyruvate kinase in the liver - increased insulin levels cause increased fructose-2,6-bisphophate levels and high glucagon levels reduce production

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87
Q

What is the fate of pyruvate in anaerobic and aerobic conditions?

A 
Aerobic = enters Krebs cycle 
Anaerobic = Lactate
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88
Q

Write an equation for the conversion of glucose to lactate in anaerobic conditions

A

Glucose + 2ADP + 2Pi –> 2 Lactate + 2ATP + 2H2O + 2H+

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89
Q

How many molecules of pyruvate are produced from one molecule of glucose-6-phosphate?

A

2

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90
Q

Aerobic oxidation of glucose to CO2 produces how many molecules of ATP?

A

30-32 mol of ATP per mol of glucose

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91
Q

What happens in anaerobic glycolysis and what is the ATP yield?

A

Lactate dehydrogenase oxidises NADH from glycolysis by converting pyruvate into lactate - produces 2 mol ATP per mole of glucose

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92
Q

What inhibits hexokinase?

A

Glucose-6P inhibits glucokinase action so glucose is not taken up and phosphorylated by cells unless glucose-6P enters a metabolic pathway

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93
Q

What is the function of glycolysis?

A

ATP production
Generates pyruvate as precursor for fatty acid biosynthesis
Provides precursors for synthesis of Amino acids and five carbon sugar phosphates

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94
Q

What can glucose-6P be used for?

A

Glycolysis
Other pathways
Pentose Phosphate Pathway
Glycogen Synthesis

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95
Q

Fructose-1,6-bisphosphate is cleaved into dihydroxyactone phosphate and glyceraldehyde phosphate by which enzyme

A

Aldolase

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96
Q

Which enzyme is responsible for the oxidation of glyceraldehyde 3-phosphate into 1,3-bisphosphate and what else is produced

A

glyceraldehyde-3-phosphate dehydrogenase and NADH

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97
Q

Which enzyme is responsible for the conversion of 1,3-bisphosphoglycerate into 3-phosphoglycerate

A

phosphoglycerate kinase

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98
Q

Which enzyme is responsible for the conversion of glucose 6P into fructose 6P

A

Phosphoglucose isomerase

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99
Q

Which enzyme is responsible for the conversion of 3-phosphoglycerate into 2-phosphoglycerate

A

Phosphoglycerol mutase

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100
Q

Which enzyme is responsible for the conversion of 2-phosphoglycerate into phosphenolpyruvate and what biproduct is produced?

A

Enolase and water

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101
Q

Which enzyme is responsible for the conversion of Phosphenolpyruvate to pyruvate

A

Pyruvate kinase

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102
Q

Write an overall equation for glycolysis

A

Glucose + 2ADP + 2Pi + 2NAD+ –> 2 Pyruvate + 2NADH + 2ATP + 2H20 + 4H+

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103
Q

How does AMP allosterically activate PFK-1?

A

Binding of AMP increases the affinity of PFK for fructose 6P

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104
Q

Write an overall equation for the TCA cycle

A

Acetyl CoA + GDP + 3NAD+ + 2H2O +FAD + Pi –> CoASH + GTP + 3NADH + 3H+ + GTP + FAD (2H)

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105
Q

Which enzyme catalyses the conversion of oxaloacetate to citrate

A

Citrate dehydrogenase

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106
Q

Which enzyme catalyses the conversion of citrate to isocitrate

A

Aconitase

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107
Q

Which enzyme catalyses the conversion of isocitrate to alpha-ketoglutarate

A

Isocitrate dehydrogenase

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108
Q

Which enzyme catalyses the conversion of alpha-ketoglutarate into succinyl CoA

A

Alpha-ketoglutarate dehydrogenase

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109
Q

Which enzyme catalyses the conversion of succinyl CoA into succinate?

A

Succinate thiokinase

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110
Q

Which enzyme catalyses the conversion of succinate into fumarate

A

Succinate dehydrogenase

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111
Q

Which enzyme catalyses the conversion of fumarate into malate

A

Fumarase

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112
Q

Which enzyme catalyses the conversion of malate into oxaloacetate?

A

Malate dehydrogenase

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113
Q

What is the is rate limiting step in the TCA cycle

A

Isocitrate dehydrogenase

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114
Q

What are the allosteric activators of isocitrate dehydrogenase

A

ADP

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115
Q

What are the allosteric inhibitors of isocitrate dehydrogenase

A

NADH

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116
Q

Describe the process of fat absorption

A
  1. Bile salts emulsify fats forming micelles
  2. Intestinal lipase break down TG’s
  3. FA’s are taken up by intestine and converted to TG’s
  4. TG’s combine with apolipoproteins and cholesterol to form chylomicrons
  5. Chylomicrons enter bloodstream through lymphatic system
  6. Lipoprotein lipase in capillary releases FA’s and glycerol
  7. FA enters cell and Is oxidised for use as fuel or esterified for storage
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117
Q

What are four reaction stages of B-oxidation

A
  1. Oxidation
  2. Hydration
  3. Oxidation
  4. Thiolysis
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118
Q

What enzyme catalyses the first oxidation stage of B-oxidation and what are the byproducts

A

Acyl CoA dehydrogenase

FAD+ converted to FAD (2H)

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119
Q

What enzyme catalyses the hydration stage of B-Oxidation and what is required for this to occur?

A

Enolase Hydrate

H2O

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120
Q

What enzymes catalyses the second oxidation step of B-oxidation and what are the byproducts

A

Hydroxyacyl CoA dehydrogenase

NAD+ converted to NADH

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121
Q

What enzyme catalyses the thiolysis stage of B oxidation and what are the byproducts?

A

Thiolase

CoA-SH converted to Acetyl CoA and Acyl CoA is produced

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122
Q

What factors affect the rate of ketogenesis?

A

Release of FA as more FA saturate TCA cycle so more Ketones produced
Glycerol-3-phosphate increases TG production so less ketones but decreased glycerol 3-P will increase TG production
Depends on levels of insulin and glucagon

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123
Q

What symptoms will diabetic patients with ketoacidosis present with?

A

Hyperventilation

Vomiting

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124
Q

What are three effects of an insulin deficiency

A
  1. Inhibition of glycolysis and stimulation of gluconeogenesis
  2. Glycogen breakdown and inhibition of glycogen synthase
  3. Increased lipolysis and FA production
    These effects lead to hyperglycaemia and increased ketones production = diabetic ketoacidosis
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125
Q

Describe what happens in alcoholic acidosis?

A

Increased blood ethanol and depleted carbo and protein stores leads to impaired gluconeogenesis, increased glucagon and decreased insulin which increases lipolysis and FA production and increases ketone production

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126
Q

What are the physiological consequences of ketoacidosis

A

High O2
Low CO2
Low HCO3
Low Blood pH

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127
Q

Describe the properties of a channel membrane protein

A

Narrow aqueous pore
Selectivity based on size and charge
Passive process
Can be gated based on ligand or voltage

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128
Q

Describe the properties of a carrier membrane protein and describe the three different types

A 
Have a specific binding site that will cause a conformational change
Can be active or passive  
1. Uniport 
2. Symport 
3. Antiport
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129
Q

What are the types of membrane transport

A

Passive (Simple or facilitated)

Active (Primary or secondary)

130
Q

Describe primary active transport giving an example and a further example of when it goes wrong

A

Directly uses an ATP source ie. Na+/K+ATPase
ATP7B is a Cu2+ ATPase in the liver that transports copper into the bile - Wilsons disease causes copper deposits in the liver, brain and eyes

131
Q

Describe secondary active transport giving an example and a further example of when it might go weong

A

Transport against a concentration gradient coupled to the movement of another ion downs its conc gradient ie. Na+/glucose cotransporter (SGLT1)
Less functional SGLT1 causes the glucose-galactose malabsorption

132
Q

Where do steroid hormones bind?

A

Intracellular

133
Q

Where do peptide hormones bind?

A

Cell-surface

134
Q

Describe positive eugenics

A

Encouraging a group of individuals to reproduce

135
Q

Describe negative eugenics

A

Discouraging a group of individuals to reproduce

136
Q

Define homeostasis and the parameters that are controlled

A 
Maintenance of a constant environment 
Temp
pH
O2 Conc 
Blood Pressure 
Glucose 
Energy production and demand
137
Q

What are the three major cell communication systems

A

Endocrine
Nervous
Immune

138
Q

What is autocrine signalling

A

Cell communicates with itself

139
Q

What is paracrine signalling and give an example

A

Signal diffuses across gap between neighbouring cells and doesn’t enter bloodstream
ie. AcH and Neuromuscular junctions

140
Q

What is endocrine signalling

A

Cells talking to other cells elsewhere in the body

ie. hormones entering the bloodstream

141
Q

Describe the organisation of the endocrine system

A

Hypothalamus releases hormones which act on the anterior pituitary to release stimulating hormones which act on a target tissue directly or through an endocrine gland to affect a target tissue

142
Q

What are the 6 hypothalamic hormones

A 
Gonadotrophin releasing hormone 
Growth hormone releasing hormone 
Somatostatin 
Thyrotropin releasing hormone 
Corticotropin releasing hormone 
Dopamine
143
Q

What are the 6 main anterior pituitary stimulating hormones

A 
Follicle stimulating hormone 
Luteinising hormone 
Growth hormone 
Thyroid stimulating hormone 
Prolactin 
Adrenocorticotrophic hormone
144
Q

What are the two main posterior pituitary hormones

A

Oxytocin

Anti-diuretic hormone (Vasopressin)

145
Q

Define what a hormone is and what the three main times are

A

A molecule that acts as a chemical messenger
Peptide
Steroid (from cholesterol)
Amino Acid (from tyrosine/tryptophan)

146
Q

Give an example of a peptide hormone, amino acid hormone and steroid hormone

A

Peptide = insulin/growth hormone
Amino Acid = Adrenaline and thyroxine
Steroid = testosterone

147
Q

What is the function of the smooth endoplasmic reticulum?

A

Site of lipid synthesis and some drug metabolism

148
Q

What is the function of the golgi body?

A

Mediates protein sorting to specific sites

149
Q

What is the function of the rough endoplasmic reticulum?

A

Protein synthesis

150
Q

What is the function of ribosomes?

A

Translate mRNA into protein

151
Q

Describe the structure of a phospholipid

A

Fatty acid tail are non polar and hydrophobic (either saturated or non sat)
Phospholipid head is polar and hydrophilic (either serine, choline or inositol

152
Q

What is the plasma membrane permeable to?

A

Water, Gases (CO2, N2, O2) and small uncharged polar molecules (urea and ethanol)

153
Q

What is the plasma membrane impermeable to?

A

ions (Na+/K+/Cl- and Ca2+
Charged polar molecule molecules (ATP, Glucose-6-phosphate)
Large uncharged polar molecules (Glucose)

154
Q

What is an integral cell membrane protein

A

A protein that is embedded within the bilayer

155
Q

What Is a peripheral cell membrane protein

A

A protein that is associated with the membrane

156
Q

What are the constituents of the plasma membrane

A 
Receptors 
ATP driven transporters 
Ion channels 
Transporters 
Adhesion molecules 
Self: Non-self
157
Q

What happens when pH and temperature of plasma membrane change?

A

Both extremes of pH will damage protein and inhibit cell function
Too cold and the proteins slow down and membrane becomes less fluid
Too hot and the proteins denature and membrane fluidity increases

158
Q

Describe the distribution of water in the body

A 
Total body water is 42L
28L Intracellular 
14L Extracellular 
 Of this 14 L
3L is intravascular 
11L is interstitial
159
Q

What ion is the main contributor to ECF osmolality and volume?

A

Sodium

160
Q

What Is the predominant ion in the ICF?

A

Potassium

161
Q

Describe the pathways and volumes of water gain in the body

A

Food and drink = 2.2L/day

Metabolic Production = 0.3L/day

162
Q

Describe the pathways and volumes of water loss in the body

A 
Insensible loss (Skin and lungs) = 0.9L/day
Urine = 1.5L/day
Faeces = 0.1L/day
163
Q

What is normal plasma osmolality

A

275-295

164
Q

Describe what happens during water deprivation/dehydration

(Increase in ECF Osmolality) = rapid change

A

Water moves from the ICF to the ECF
ECF osmolality increases
ADH released from posterior pituitary = renal water retention
Stimulation of thirst centre in hypothalamus = increased water intake

165
Q

What happens when ECF volume decreases?

A

Decreased renal perfusion detected by juxta glom causes renin release from kidneys. Renin converts Angiotensinogen from the liver to angiotensin 1 which is converted to angiotensin II by ACE from lungs

166
Q

What are the effects of Angiotensin II

A

increased sympathetic activity
Tubular Na+, Cl- reabsorption and K+ excretion = water retention
Aldosterone secretion from adrenal gland
Arteriolar vasoconstriction to increase blood pressure
ADH secretion causing increased h2 absorption at collecting duct

167
Q

What are the causes of water depletion?

A 
Vomiting 
Diarrhoea 
Diuresis/Diuretics 
Burns 
Sweating 
Reduced intake
168
Q

What are the symptoms of dehydration?

A 
Thirst 
Dry mouth 
inelastic skin
Sunken eyes 
Raised haematocrit 
Weight loss 
Confusion 
Hypotension
169
Q

What happens when there is water excess in the body

A

Water moves from ECF to the ICF
ECF osmolality decreases so no stimulation of thirst centre
ADH secretion is inhibited leading to increased urine volume
Results in risk of cerebral over hydration

170
Q

What are the consequence of water excess in the body?

A

Hyponatraemia

Cerebral over hydration which causes headaches, confusion and convulsions

171
Q

Define Oedema

A

Excess accumulation of fluid in the interstitial space

172
Q

Define hydrostatic pressure

A

Pressure difference between the plasma and the interstitial fluid

173
Q

Define oncotic pressure

A

Pressure difference between the plasma and the interstitial fluid caused by protein concentration

174
Q

Define serous effusion

A

Excess water in a body cavity

175
Q

What is the two main pathogenesis of oedema and serous effusion?

A

Impaired fluid reabsorption

Increased fluid leakage into interstitial spaces

176
Q

What are the 4 types of oedema?

A

Inflammatory
Venous
Lymphatic
Hypoalbuminaemic

177
Q

Define transudate?

A

Fluid pushed through the capillary due to high pressure within the capillary

178
Q

Define Exudate

A

fluid that leaks around the cells of the capillaries caused by inflammation and increased permeability of pleural capillaries to proteins

179
Q

What are the causes of hypernatraemia?

A

Water deficit due to poor intake, osmotic diuresis or diabetes insipidus
Sodium excess due to mineralocorticoid excess

180
Q

What are the causes of hyponatraemia?

A

Artefactual
Sodium loss due to diuretics and Addison’s disease
Excess water due to Iv fluids or SIADH

181
Q

What is the general formula for carbohydrates?

A

Cn(H2O)n

182
Q

What is the difference between the structure of alpha and beta glucose?

A

In alpha glucose the OH group is below and in beta glucose the OH group is above

183
Q

Describe a glycosidic bond

A

When a hydroxyl group of a monosaccharide reacts with the OH or NH group of another monosaccharide to form a glycoside

184
Q

What are the constituents of Maltose

A

2 alpha glucose molecules

185
Q

What are the constituents of sucrose

A

Alpha glucose and fructose

186
Q

What are the constituents of lactose

A

Galactose B and alpha glucose molecule

187
Q

Give three examples of polysaccharides

A

Starch (Amylose (Glu 1-4) and amylopectin (Glu 1-6)
Proteoglycans
Glycogen

188
Q

How are phosphoacylglycerols formed?

A

Derived from phosphatidic acid

FA are esterified to glycerol and phosphorylated at C3

189
Q

What are sphingolipids formed from?

A

Ceramide

190
Q

What molecule are steroids derived from?

A

Cholesterol

191
Q

What are ecosanoids derived from and give examples

A

Synthesised for Eicosanoic acid and include prostaglandins

192
Q

What are the constituents of a Nucleotide

A

Nitrogenous Base
Sugar
Phosphate

193
Q

Which amino acid has a cyclic structure?

A

Proline

194
Q

Which amino acids contain sulphur in their side chains?

A

Methionine

Cysteine

195
Q

What are the noncharged polar Amino acids

A

Methionine, cysteine, glutamine, serine and threonine

196
Q

Which amino acids are negatively charged?

A

Glutamate

Aspartate

197
Q

Which amino acids are positively charged?

A

Arginine
Lysine
Histidine

198
Q

What are the aromatic amino acids

A

Tyrosine
Tryptophan
Phenylalanine

199
Q

Describe Van Der Waal Forces

A

Weak attractive interactions between atoms due to fluctuating electrical charges - important when macromolecular surfaces fit closely in shape

200
Q

Describe hydrogen bonds

A

Interaction between oppositely charged dipoles due to partial charges on oxygen, nitrogen and fluorine molecules

201
Q

Describe ionic bonds

A

Occur between fully or partially charged groups

202
Q

Describe disulphide bonds

A

Covalent bonding between cysteine residues

203
Q

Define the primary sequence of an amino acid

A

Linear sequence of amino acids linked by peptide bonds

204
Q

Give 4 examples of super secondary structures

A

Helix turn helix
Beta alpha beta unit
Leucine zipper
Zinc finger

205
Q

What factors influence the rate of a chemical reaction

A 
Temperature 
Concentrations of reactants 
Catalysts 
Surface area of the solid reactant 
Pressure of gaseous reactants or products
206
Q

Describe the structure of a chromosome

A

Two strands of sister chromatids joined by a central centromere

207
Q

Describe the stages of the cells cycle?

A 
G1 = growth and metabolism 
S = DNA replication 
G2 = Preparation for cell division
M = mitosis
208
Q

Which enzyme opens up the DNA double helix

A

Helicase

209
Q

What is the function of topoisomerase?

A

Unwinds supercoiled DNA t form uncoiled DNA

210
Q

What are the functions of the plasma membrane?

A

Act as a semipermeable membrane
Host cell membrane receptors
Regulates what goes in and out of the cell
Separates the intracellular and extracellular contents

211
Q

What are the differences between DNA are RNA?

A

DNA in nucleus, RNA in cyto
DNA double strand, RNA single
DNA deoxyribose, RNA ribose sugar
RNA bases exchange thymine for uracil

212
Q

Define osmolality

A

Concentration of solutes in plasma per kilogram solvent

213
Q

Define osmolarity

A

Concentration of solutes in plasma per litre of solution

214
Q

Define the secondary structure of proteins

A

Local folding of polypeptide chain into helices or sheets

215
Q

Define the tertiary protein structure

A

Three dimensional folding pattern of a protein due to side chain interactions

216
Q

Define quaternary protein structure

A

Protein consisting of more than one amino acid side chain

217
Q

What does H and E stain in the cell?

A

Haematoxylin stains nuclei blue
Eosin stains cytoplasm pink
Extracellular fibres stain pink
GAG do not stain

218
Q

What does PAS stain for?

A

Sugars - stains magenta

useful for GAG’s in intestinal border

219
Q

What does van giesons stain for and what colour?

A

Elastic
Stains brown for elastic stains
Collagen stains pinkish red
Muscle stains yellow

220
Q

What does alcian blue stain for?

A

Mucins secreted by epithelial cells

221
Q

Give an example of a small cell and its size

A

Lymphocytes 10micrometers in diameter

222
Q

Give an example of a large cell and its size

A

Motor neurones 100 micrometers in size

223
Q

What are the 6 types of cell

A 
Rounded
Polygonal 
Cuboidal
Columnar 
Squamous (flattened) 
Fusiform
224
Q

What are the differences between metabolically active and dormant cells

A

Dormant cells are smaller and have less cytoplasm and smaller nuclei whereas active cells are larger and have a nucleoi

225
Q

Which cells have life span of days, months, years, nearly whole life and lifetime?

A

Days - cells lining gut
Months - Skin, blood and connective tissue
Years - bones and tendons
Near WL - Skeletal muscle
WL - nerves, brain, cardiac muscle and germ cells

226
Q

What are the membrane organelles

A

Nucleus, mitochondria, lysosomes, peroxisomes, ER and golgi

227
Q

What are the non membrane organelles

A

Ribosomes, centrosomes, centrioles and basal bodies

228
Q

Describe the structure of the nucleus

A

Contains cellular DNA and nucleolus
Measures 5-10um diameter
Double membrane that contains pores

229
Q

Describe the structure of the double membrane of the nucleus

A

Inner membrane contains nuclear lamins which are network of protein filaments that maintain spherical shape
Outermembrane binds perinuclear space which is continuous with lumen of ER

230
Q

What os the size and function of the nucleolus?

A

1-3 microns in diameter and functions as the site of ribosomal RNA formation

231
Q

What are the three areas of the nucleolus?

A 
Pars Amorpha (Pale areas)
Pars Fibrosa (Dense stain areas)
Pars Granulosa (Granular regions)
232
Q

Which forms of chromatin is light stained and is actively transcribed?

A

Euchromatin

233
Q

Which form of chromatin is dense stained and highly condensed so transcriptionally inactive?

A

Heterochromatin

234
Q

What processes occur in the outer mitochondrial membrane?

A

Lipid synthesis

Fatty acid metabolism

235
Q

What processes occur in the inner mitochondrial membrane?

A

Respiratory chain ATP production

236
Q

What process occurs in the mitochondrial matrix?

A

TCA cycle

237
Q

What process occurs in the mitochondrial inter membranous space?

A

Nucleotide phosphorylation (ADP –> ATP)

238
Q

What is the function of the RER?

A

Site of protein synthesis

Produces phospholipids and proteins of the plasma membrane

239
Q

What is the function of SER?

A

Site of membrane lipid synthesis and processes synthesised proteins

240
Q

What is the function of the Golgi apparatus?

A

Synthesises steroids and other lipids
Detoxifies alcohol and drugs
Processes macromolecules synthesised in the ER and stores them

241
Q

Describe the location and function of the cis face of the Golgi apparatus

A

Nuclear facing

Receives the transport vesicles from the smooth ER and phosphorylates some proteins

242
Q

Describe the location and function of the medial golgi

A

central part of golgi

Forms oligosaccharides by adding sugar to lipids and peptides

243
Q

Describe the location and function of the trans golgi apparatus

A

Outer face
Proteolysis
Sorts molecules into vesicles that become lysosomes, migrate to plasma mem and fuse or become secretory vesicles that store protein for later

244
Q

What are the 5 types of vesicles

A 
Cell surface derived pinocytic and phagocytic vesicles 
Golgi derived transport vesicles 
ER derived vesicles 
Lysosomes 
Peroxisomes
245
Q

What is the function of lysosomes?

A

Intracellular digestion

H+ ATPase on membrane creates low internal pH

246
Q

What are the function of peroxisomes?

A

Small (0.5-1 microns)

Produced by ER and use molecular oxygen to oxidise organic molecules

247
Q

What is the function of the cytoskeleton?

A

Determines the cell shape, structure, organises cell contents, directs movement of materials within the cell and contributes to cell movements as a whole

248
Q

What are the properties of microfilaments?

A

Smallest (5nm)
Made of actin
Forms branching mesh on inner surface of cell membrane to maintain shape

249
Q

What are the properties of microfilaments?

A

25nm diameter
Made from tubulin
Scaffold for mitosis and meiosis radiating from centrosome

250
Q

What are the properties of intermediate filaments?

A

10nm diameter
6 different types of proteins
Anchored to transmembrane proteins and spread tensile forces throughout proteins

251
Q

What are the 6 types of intermediate filament and where are they localised?

A 
Cytokeratins = epithelial cells 
Desmin = Myocytes 
Glial Fibrially acid protein = astrocytic glial cells 
Neurofilament protein = neurones 
Nuclear laminin = Nuclei of all cells 
Vimentin = mesodermal cells
252
Q

What is lipofuscin?

A

membrane bound orange-brown pigment
Peroxidation o lipids in ider cells
Common in heart and liver

253
Q

What are the constituents of the extracellular matrix?

A

Fibrillar proteins (Tendons - collagen and elastin)
Glycosaminoglycans
Inorganic salts as solids

254
Q

What does a pink stained (Acidophilic) cytoplasm indicate?

A

accumulations of organelles usually mitochondria

255
Q

What does a blue cytoplasm indicate?

A

Presence of cytoplasmic RNA in ribosomes and active protein production

256
Q

What are the three functions of epithelia?

A

Protection - skin
Absorption - gut
Secretion - pancreas, liver and GIT

257
Q

Describe the organisation of simple squamous epithelia and its function

A

Single layer of cells on basement membrane, parallel oval nuclei - absorption and secretion

258
Q

Describe the organisation of stratified (compound) epithelia and where it is found?

A

Two or more layers of cells on basement membrane - protection
Areas of body that experience frictional and abrasive forces ie. skin, mouth, throat, oesophagus and vagina

259
Q

Where are simple squamous epithelium found?

A 
Lining of blood vessels (Endothelium) 
Outside lungs (Mesothelium)
Abdominal Organs (Peritoneum)
Alveoli - form barrier between air and blood
260
Q

Describe the organisation of simple cuboidal epithelium and where it is found?

A

Single layer of cells with same heigh and width
Central spherical nuclei
Found in ducts and glands including sweat, salivary and pancreas
ducts in exocrine glands

261
Q

Describe the organisation of simple columnar epithelium and where it is found?

A

Single layer, taller than are wide, spheroidal nucleus - can be ciliated or microvilli
Lines the stomach, intestines and uterus

262
Q

What lies at the boundary of blue/purple living cells and dead pink keratinising layers

A

Layer of blue keratohyaline granules

263
Q

Describe pseuostratified epithelium and where it is found

A

Single layer of cells of variable height with all cells in contact with basement membrane
Lines conducting airways

264
Q

Describe urothelium and its location

A

Looks stratified but there is a surface layer of umbrella cells not in contact with the basement membrane
Lines bladder, ureter and renal pelvis

265
Q

What proteins is the basement membrane composed of?

A

Fibronectin and collagen IV

266
Q

What are the three types of epithelial junction?

A

Occluding (tight)
Desmosomes
Gap

267
Q

Describe an occluding junction

A

Band like fusions that prevent diffusion between cells

268
Q

Describe a desmosome and its function

A

Plaques that form physical junctions between cells by connecting adjacent cytoskeletons
Spread mechanical forces across cells

269
Q

What is the function of a hemidesmosome?

A

Connect intermediate filament network of cells to extracellular matrix

270
Q

Describe gap junctions

A

Electrical junctions that permit transfer of small molecules and electrically couple adjacent cells

271
Q

Describe the properties you would see in a protein secreting epithelial cell

A

Large nuclei and abundant RER - blue colouration with H and E stain

272
Q

Describe the properties you would see in a mucin secreting epithelial cell

A

Expanded golgi system

273
Q

Describe the properties you would see in a steroid producing epithelial cell

A

Extensive smooth ER

274
Q

Define holocrine

A

Secrete by releasing cells

275
Q

Define apocrine

A

Secrete by budding

276
Q

What are the properties of amorphous material?

A

High molecular weight
Strongly hydrophilic
Negatively charged
Enables retention of water

277
Q

What secretes GAGs?

A

Mainly fibroblasts but also epithelial cells, muscle, cartilage and bone

278
Q

Describe fibrous connective tissue

A

Contains large numbers of fibres including collagen, elastin and reticulin

279
Q

Describe loose irregular fibrous connective tissue

A

Contains few randomly orientated fibres

280
Q

Describe dense irregular fibrous connective tissue

A

Contains large number of fibres with little amorphous material

281
Q

Describe fatty connective tissue

A

Contains mainly fat cells with intervening blood vessels particularly capillaries

282
Q

What is the origin of connective tissue cells

A

Mainly undifferentiated mesenchymal cells forming fibroblasts, adipose, chondroblasts and osteoblasts and from haemopoietic stem cells (monocytes, macrophages, lymphocytes and mast cells

283
Q

What are the constituents of connective tissue

A 
Cells (fibroblasts/cytes, adipose
Visible fibres (Collagen, elastin, reticulin)
Ground substance (Proteoglycans, glycosaminoglycans, laminin, fibronectin
284
Q

Where would you find type 1 collagen?

A

Skin, teeth, bone and organ capsules

285
Q

Where would you find type 2 collagen?

A

Cartilage

286
Q

Where would you find type 3 collagen?

A

Liver, bone marrow and spleen (known as asreticulin)

287
Q

Where would you find type 4 collagen?

A

Basement membrane

288
Q

Where would you find type 5 collagen?

A

Placenta

289
Q

Describe the formation of collagen fibres

A

Fibroblasts secrete tropocollagen subunits with are assembled extracellularly to give rise to individual fibres

290
Q

Where is brown fat most likely to be found?

A

across back and shoulders of Neonates

291
Q

Describe the structure of cartilage

A

Chondroblasts derived from mesenchymal stem cells become embedded in GAG matriculates contain glycosaminoglycans (Hyaluronic acid) and proteoglycans (Condroitin sulphate and keratin glycan) and mature into chondrocytes. Cartilage is surrounded by fibrous perichondrium capsule which contains undifferentiated progenitor cells

292
Q

What are the three types of cartilage?

A

Hyaline
Elastic
Fibrocartilage

293
Q

Describe hyaline cartilage and where it is found

A

GAG rich matrix containing collagen and elastin fibrils

Found in synovial joints, lone bones and rings of trachea and larynx

294
Q

Describe elastic cartilage and where it is found

A

Found in the pinna of the ear and the epiglottis - visible on H and E stain but more visible with Van Geisons

295
Q

Describe fibrocartilage

A

Contains large amounts of collagen and organised into sheets or laminae - found in the annulus fibrosus (intervertebral discs) and pubic symphysis

296
Q

Name three groups of cells with contractile properties

A

Pericytes - lie alongside small blood vessels
Myofibroblasts - involved in scar formation
Myoepithelial cells - assist in expression of milk during lactation

297
Q

Draw the structure of an artery

A

See diagrams notes

298
Q

Describe the structure of elastic arteries and give examples

A

Aorta and pulmonary artery

Media contains abundant concentric sheets of elastin arranged in circumferential sheets

299
Q

Describe the structure of muscular arteries and give examples

A

radial and splenic artery

media comprises of layers of concentric sheets of Smooth muscle 7

300
Q

Define what an arteriole is and describe their structure

A

Resistance vessel of the circulatory system
Has 3 or fewer muscle layers in media or up to 100um or less in diameter
Lack an external elastic laminae

301
Q

Draw the structure of a capillary

A

See diagrams sheet

302
Q

What lines capillaries?

A

Lined by pericytes which form discontinuous layer which becomes continuous as they get larger - where endothelium is incomplete = fenestrate capillaries

303
Q

Draw the structure of a vein

A

See diagrams sheet

304
Q

Describe the structure of a venule

A

Wall consists of endothelium surrounded by connective tissue - contractile pericytes wrap around endothelial cells as venules get larger - replaced by smooth muscle as change to veins

305
Q

What are the two parts of the Nervous System?

A 
CNS = brain and spinal cord 
PNS = Axon processes passing to target organs and tissues
306
Q

What type of neurium lies between myelinated axons

A

Endoneurium

307
Q

What type of neurium surrounds groups of axons to form fascicles

A

Perineurium

308
Q

What type of neurium binds fascicles together to form nerves

A

Epineurium

309
Q

Where do motor neurones have their cell bodies

A

In the grey matter of the spinal cord

310
Q

Where do neurones have their cell bodies

A

In dorsal root ganglia

311
Q

Where do sympathetic neurones have their cell bodies?

A

Cell bodies in grey matter of cord and in adjacent sympathetic ganglia

312
Q

Where do parasympathetic neurones have their cell bodies

A

In the brain and local ganglia

313
Q

Which cell types produce antibodies

A

Plasma cells and B-lymphocytes

314
Q

Why is glycolysis inhibited by acidosis?

A

Because PFK-1 is pH dependent and is inhibited by acidotic conditions

315
Q

What stimulates the activity of hexokinase

A

Stimulated by glucose and insulin

316
Q

What inhibits the activity of hexokinase

A

Glucose 6 phosphate and glucagon

317
Q

What stimulates the activity of glucokinase

A

Glucose and insulin

318
Q

What inhibits the activity of glucokinase

A

Fructose 6 phosphate and glucagon

319
Q

What stimulates the activity of PFK-1

A

ADP
Fructose 2,6 bisphosphate
Insulin

320
Q

What inhibits the activity of PFK-1

A

ATP
Citrate
Glucagon

321
Q

Why does fructose 2,6 bisphosphate stimulate PFK-1

A

Because some fructose 6 phosphate enters the binuclear enzyme complex containing PFK-2 and Fructose 2,6 bisphosphatase. Here the F6P is converted by PFK-2 to F2,6 bisphosphate and is then converted back to F6P by fructose 2,6 bisphosphatase

322
Q

Why does insulin stimulate PFK-1 activity

A

Because insulin stimulates PFK-2 which increases the conversion of F6P to F2,6bisphophate which is a stimulator of PFK-1 and also inhibits fructose 2,6 bisphosphatase which slows the conversion of fructose 2,6 bisphospho back into fructose 6P

Phase 1 M (11 decks)

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