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Medicine > IMMS > Flashcards

IMMS Flashcards

1
Q

2 haploid gametes fuse forming…

A

Diploid Zygote

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2
Q

3 phases of interphase

A

G1- Cells get bigger in prep for division
S- Each chromosome is copied (still 46 chromosomes but each chromosome contains 2 sister chromatids joined at centromere)
G2- Cell does more growing in prep for mitosis

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3
Q

Anaphase (Mitosis)

A
  • Starts when a microtubule from each
    centrosome has attached to the
    kinetochore of each chromosome
  • Centrosomes pull on spindle fibre pulling
    sister chromatids to opposite poles of cell
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4
Q

Anaphase I

A

Tetrads split up by spindle fibres (1 chromosome to each pole of cell)

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5
Q

Cytokinesis

A

Throughout mitosis, cell pinches tighter and tighter until it separates into 2 daughter cells post telophase

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6
Q

G0 phase

A

Only some cell like neurons which carry on growing but don’t divide have a G0 phase

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7
Q

The difference in the interphase process that occurs between MI and MII

A

During S phase, chromosomes aren’t replicated

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8
Q

Meiosis produces…

A

4 genetically different haploid daughter cells

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9
Q

Metaphase (Mitosis)

A

Prometaphase - Nuclear membrane and nucleolus disintegrate
Actual Metaphase - Chromosomes align along metaphase plate (midline of cell)
Spindle fibres connect to kinetochore of centromere

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10
Q

Metaphase I

A

Tetrads go to metaphase plate

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11
Q

Non-disjunction

A

Failure of chromosome pairs to separate during Meiosis I or sister chromatids to separate during Meiosis II (Trisomy 21)

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12
Q

What % of meiosis is prophase I?

A

90%

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13
Q

What occurs in Prophase I

A

46 chromosomes of 2 chromatids condense and nuclear membrane disintegrates
Each chromosome finds its homologue (forming a tetrad)
Crossing over occurs between homologues at chiasmata

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14
Q

Prophase (Mitosis)

A

Chromatin fibres condense (untangle into individual chromosomes)
2 centrosomes at opposite poles of cell each have 2 centrioles (protein structures at right angles to each other)
Each centriole sends spindle fibres made of microtubule protein connecting centriole to centromere

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15
Q

Telophase (Mitosis)

A

New nuclear envelope forms around centrosome and chromosomes

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16
Q

What does Telophase I and Cytokinesis I produce?

A

2 haploid daughter cells (containing bivalent chromosomes)

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17
Q

Genotype

A

Genetic constitution of an orgnaism

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18
Q

Phenotype

A

Appearance of an individual resulting from interaction of environment and genotype

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19
Q

Allele

A

1 of several alternate forms of a gene at a specific locus

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20
Q

Haplo-insufficiency

A

1 gene is inactivated or deleted and the remaining functional copy isn’t sufficient to produce needed gene product for normal function

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21
Q

Polymorphism

A

Frequent hereditary variations at a locus

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22
Q

Define Genomics

A

Study of entirety of DNA, the genome, together with technologies that allow sequencing, interpretation and analysis

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23
Q

Pathogenic Variant

A

Alteration in genetic sequence increasing an individual’s susceptibility to a certain disorder

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24
Q

Name for an alteration in genetic sequence which isn’t disease causing

A

Benign Variant

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25
Q

Name for an alteration in genetic sequence whose association with disease risk is unknown

A

Variant of unknown significance

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26
Q

What is penetrance?

A

Proportion of individual’s with a particular genotype who express the associated phenotype (develop the condition)

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27
Q

When would you carry out a predictive test for a genetic disease?

A

Testing an unaffected individual for a pathogenic variant known to be present in a family

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28
Q

Name for an individual who has only 1 member of a chromosome pair/segment rather than the usual 2

A

Hemizygous (males only have 1 X chromosome)

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29
Q

What is the ACMG criteria?

A

Formal scoring system to decide if a gene variant is pathogenic

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30
Q

Name for something you’re born with

A

Congenital

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31
Q

A Karyotype shows…

A

Complete set of an individuals chromosomes in metaphase (so they’re clear to see) from largest to smallest

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32
Q

Centromeres divide chromosomes into…

A

Long arm (q)
Short arm (p)
Bands are then numbered from centromere outwards to give an idea of where an abnormality is

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33
Q

How would an individual with Down’s Syndrome be written?

A

47, XX, +21

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34
Q

How would a polyploidy individual be written?

A

69, XXY

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35
Q

How would an individual with one X chromosome be written?

A

45, X

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36
Q

What type of mutation is this?
t(1;2)(q24;p12)

A

Translocation (swap between sections of chromosome 1 and 2)

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37
Q

What type of mutation is this?
inv(7)(q11q21)

A

Inversion (chromosome folds over at q21 sticking back in at q11)

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38
Q

What type of mutation is this?
dup(11)(p14p15)

A

Duplication (p14-p15 of chromosome 11 duplicated)

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39
Q

What type of mutation is this?
del(22)(q11q12)

A

Deletion (p11-p12 of chromosome 22 deleted)

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40
Q

Reciprocal Translocation

A

Bit of one chromosome snaps off and attaches to another

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41
Q

Acrocentric Chromosome

A

Non-central centromere (located near end of chromosome)

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42
Q

Robertsonian Translocation

A

Occurs between Robertsonian/acrocentric chromosomes (one arm present) and one arm attaches to another chromosome (resulting in 1 less chromosome)

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43
Q

What is genomic imprinting?

A

Term for 1 copy of a gene in an individual being expressed (mother or father) and the other is suppressed

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44
Q

What is FISH testing?

A

Fluorescence in situ Hybridisation (Tests for several deletions) - DNA probes labelled with fluorophores which bind to regions of DNA you’re interested in
If target DNA region is missing - No/half signal
If target region is duplicated - signal is duplicated (trisomy on a microscope slide)

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45
Q

Multifactorial Inheritance

A

Diseases due to a combination of genetic and environmental factors

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46
Q

For diseases with high genetic loading, will MZ or DZ twins have a greater concordance rate?

A

MZ but DZ still have a higher rate than rest of population

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47
Q

Define hereditability

A

Proportion of aetiology that can be ascribed to genetic factors as opposed to environmental factors (out of 1 / a %)

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48
Q

Microarrays:
What does it test for?
How does it work?

A

Test for deletions/duplications across the whole genome

-DNA added to test card, if DNA
doesn’t bind, signal shines
through (deletion)

-Binds twice as much reducing signal for duplications

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49
Q

Explain liability threshold model

A

Liability combines genetic and environmental factors
Normal distribution curve
Curve shifts right with genetic factors meaning less environmental exposure required to result in more severe disease

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50
Q

Name for a germline substitution of a single nucleotide

A

Short Nucleotide Polymorphism (SNP)

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51
Q

What is SNPs role in GWAS?

A

Tagged to sections of the chromosome that could be causing phenotype (compares healthy vs patient pools looking for SNPs notably more common in patients)

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52
Q

Mendel’s 3 Laws

A
  • Dominance (in heterozygotes,
    1 allele shows)
  • Segregation (alleles separate
    randomly during meiosis)
  • Independent Assortment (traits transmitted to offspring independent of one another)
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53
Q

Name for receiving 2 copies of a chromosome from 1 parent and 0 from the other

A

Uniparental disomy

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54
Q

2 types of mitochondrial inheritance

A
  • Homoplasmy - Cell whose
    copies of mitochondrial DNA
    are identical (normal or
    mutated)
  • Heteroplasmy - Multiple copies
    of mtDNA in each cell with
    mutations affecting only a
    proportion of molecules in the
    cell
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55
Q

Pedigree drawing:
What does a triangle mean?

A

Miscarriage

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56
Q

Pedigree drawing:
What does a diamond mean?

A

Unknown gender

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57
Q

Pedigree drawing:
What does a double line between parents mean?

A

Related parents

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58
Q

Pedigree drawing:
What do diagonal lines mean?
If horizontal line across the diagonals is present…

A

Twins
Twins are MZ (identical)

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59
Q

What is Allelic Heterogeneity?

A

Different mutations within the same gene result in the same clinical condition

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60
Q

What is Locus Heterogeneity?

A

Variants in different genes give rise to same clinical condition

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61
Q

What is a compound heterozygous?

A

Presence of 2 different mutated alleles at a particular gene locus

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62
Q

In what instance(s) does autosomal recessive manifest?

A

In homozygous and compound heterozygous state

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63
Q

What is consanguinity?

A

Reproductive union between 2 blood relatives

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64
Q

What is autozygosity?

A

Homozygosity by descent (inheritance of same altered allele through 2 branches of the same family) (cousins)

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65
Q

In what instance does autosomal dominant inheritance manifest?

A

Only in heterozygous state

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66
Q

What is expressivity?

A

Refers to the range of phenotypes expressed by a specific genotype

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67
Q

What is a De novo mutation?

A

Mutation in genome that wasn’t present/transmitted by parents (mutation occurs spontaneously during DNA replication)

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68
Q

What is anticipation in genetics?

A

Where genetic disorders affect successive generations earlier or more severely due to expansion of unstable triplet repeat sequences (the trinucleotide repeats get larger like in myotrophic dystrophy)

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69
Q

What is somatic mosaicism?

A

Genetic fault present only in some body tissues (1 cell line normal, other cell line has mutated allele)

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70
Q

What is gonadal mosaicism? (causes our offspring problems)

A

Genetic fault in gonadal tissue

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71
Q

What is a late-onset condition?

A

Condition not manifested at birth (adult-onset)

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72
Q

What are sex-limited genes?

A

Present in both sexes of sexually reproducing species but are expressed in only one sex and have no penetrance, or are simply ‘turned off’ in the other

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73
Q

What is the only pattern of inheritance with male-to-male transmission?

A

ADI

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74
Q

What is Lyonization?

A

The normal phenomenon in which one of the two X chromosomes in female cells is inactivated during embryonic development (can be skewed but typically 50/50) which explains why some individuals in a family get a disease and some don’t

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75
Q

With X-linked inheritance, an affected male can have affected daughters but not affected sons. Why?

A

No male-to-male transmission in X-linked inheritance

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76
Q

What is a VUS?

A

In genetic testing, a variant of uncertain significance

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77
Q

What is a splice-site variant?

A

Alteration occurring at boundary between exon and intron resulting in loss of exons or inclusion of introns (affects accurate removal of introns)

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78
Q

What is nonsense-mediated decay?

A

Surveillance pathway which reduces errors in gene expression by eliminating mRNA transcripts containing premature stop codons (caused by a nonsense mutation)

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79
Q

What is a missense variant?

A

Single base pair change (changing type of amino acid in protein)

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80
Q

What is a synonymous variant?

A

Codon substitution that doesn’t change the encoded amino acid

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81
Q

At what point is a mutation considered benign/polymorphism?

A

When it’s present in +5% of the healthy population

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82
Q

What are secondary findings in genetic testing?

A

Incidental findings (finding a non-target DNA mutation)

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83
Q

Explain Sangar Sequencing

A

Using PCR to amplify regions of interest followed by sequencing PCR products
Useful for single gene testing (very accurate but slow and expensive)
Uses a single start primer and only a single DNA fragment is sequenced (easier to read)

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84
Q

Explain NGS

A

Quick, lower cost
Can sequence human genome in 1 day using parallel analysis. Harder to interpret, less accurate than Sangar
Must sift through “noise” of NGS due to rare missense variants found in healthy people to find the mutation responsible for disease

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85
Q

What % of total DNA do the following sequence?
-Whole Genome
Sequencing
-Whole Exome
Sequencing
-Targeted Sequencing

A

95%
1.5%
0.005-0.01%

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86
Q

What are targeted panels?

A

Selecting specific genes to sequence producing less “noise” and fewer VUS

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87
Q

What is eugenics?

A

Racial improvement and planned breeding to perfect human beings (but 2 people with high intelligence likely have child of average intelligence due to deviation to the mean)

88
Q

What is genetic counselling?

A

Advising patients at risk of a disease its consequences, probability of it developing / you passing it on and ways it can be prevented/ameliorated (non-directive as in your choice)

89
Q

What is an NIPT?
Why is it done?

A

Non-invasive pre-natal test - sample of maternal blood and take DNA from embryo that’s leaked across placenta (helps identify a trisomy)
Invasive tests can cause the foetus harm (increases likelihood of miscarriage)

90
Q

Example of a disease caused by an expansion of a trinucleotide repeat

A

Huntington’s Disease (CAG repeated more)

91
Q

What is PGD?

A

Preimplantation genetic diagnosis - Sperm + egg to make embryo, 8 cell stage embryo biopsied, genetic material extracted and tested for genetic condition. Only embryos without genetic change placed into woman’s womb

92
Q

When might a child be considered to have 3 parents?

A

When they’ve had mitochondrial replacement therapy using donor mtDNA

93
Q

Side chain (R) of an amino acid determines…

A

Polarity (hydrophilicity) / Non-polarity (hydrophobicity)

94
Q

How many amino acids are there?

A

20

95
Q

What effect does increased pH have on an amino acid?

A

Dissociation of H+ from carboxyl and dissociation of H+ from NH3+ changing charge of amino acid

96
Q

Nucleotides bond to form a nucleotide polymer by…

A

Phosphodiester bonds

97
Q

Water is liquid over the range…
Max density of water achieved at what temperature?

A

0-100 degrees celsius
4 degrees celsius

98
Q

What is an aldose?

A

A monosaccharide with an aldehyde group

99
Q

What is a ketose?

A

A monosaccharide with a ketone group

100
Q

Proteoglycans

A

Long, unbranched polysaccharides radiating from a core protein

101
Q

Nucleotide with no phosphate group attached is called…
With 1 attached is called…
With 2 attached is called…
With 3 attached is called…

A

Nucleoside (not nucleotide)
Nucleoside monophosphate (NMP) (nucleotide)
Nucleoside diphosphate (NDP) (nucleotide)
Nucleoside triphosphate (NTP) (nucleotide)

102
Q

What type of glycosidic bond is found in nucleotides?

A

N-glycosidic bonds between a nucleotide base and pentose sugar (N-C)

103
Q

What type of bond binds 2 monosaccharides?

A

O-glycosidic bond

104
Q

How many monosaccharides in an oligosaccharide?

A

3-12

105
Q

4 sugar derivatives

A

Aminosugars (NH2 group present)
Alcohol-sugars
Phosphorylated sugars
Sulphated sugars

106
Q

How do melting points change in fatty acids?

A

Relative degree of unsaturation (less saturated = lower melting point)

107
Q

5 forces holding proteins together

A

Van der Waals forces (IDDI)
Hydrogen Bonds (H + O/N binded to H)
Hydrophobic Forces
Ionic Bonds (weakened in aq solution by shielding water molecules and other ions present)
Disulphide Bonds (covalent bonding between side chains)

108
Q

Formation of a-helix protein

A

H-bonds between each carbonyl group and the H attached to the N which is 4 aa along the chain

109
Q

How do we determine protein structure?

A

X-ray diffraction of protein crystals (Keratin produces X shape due to presence of helices)

110
Q

Define metabolism

A

The sum of the chemical reactions that take place within each cell of a living organism

111
Q

Ligand- vs voltage-gated protein channels

A

Voltage-gated allow passage of 1 type of ion ligand-gated allow passage of 2+ types of ion

112
Q

Difference between uniport, symport and antiport membrane carrier proteins

A

Uniport - Single substance
Symport - 2 substances in same direction
Antiport - 2 substances in the opposite direction

113
Q

Driving forces moving substances across a membrane

A

Chemical
Electrical
Electrochemical (net direction equal to the sum of electrical and chemical forces)

114
Q

GLUT4 carrier protein

A

Expressed in skeletal muscle and adipose tissue
Glucose uptake (facilitated diffusion)
Expression upregulated by insulin

115
Q

Common active transport example

A

Na+/K+-ATPase
Pumps 3 Na+ out and 2 K+ in using hydrolysis of ATP -> ADP + Pi

116
Q

How does the Na+/K+-ATPase pump allow secondary active transport of glucose?

A

Creates a concentration gradient of Na to enter the cell allowing co-transport of glucose with Na

117
Q

Why is glucose intake much more important for a foetus?

A

Low arterial PO2 in uterus and placenta (prevents activation of gluconeogenic enzymes)

118
Q

Receptor-mediated endocytosis

A

Metabolites/proteins/hormones bind to receptors on cell surface triggering invagination of membrane producing a vesicle inside the cell

119
Q

Exocytosis: Constitutive vs Regulated Secretion

A

Constitutive (always going on, eg antibody secretion)
Regulated (synaptic transfer)

120
Q

Where and under what conditions does glycolysis take place?

A

Cytosol under anaerobic conditions (with or without O2)

121
Q

3 precursors produced in glycolysis

A

G-6-P (used to produce nucleotides)
Pyruvate (substrate for fatty acid synthesis)
Glycerol-3-P (backbone of triglycerides)

122
Q

Glycolysis summary equation

A

Glucose + 2NAD+ + 2Pi + 2ADP -> 2Pyruvate + 2NADH + 2H+ + 2ATP + 2H2O

123
Q

Phosphofructokinase (PFK1) allosteric regulation

A

Converts F-6-P into F-1,6-BP)
Inhibited by: ATP, citrate
Activated by: AMP (when ATP is used up, ADP accumulates and is converted to AMP) (2ADP -> ATP + AMP catalysed by adenylate kinase). Also activated by F-2,6-BP

124
Q

Fate of pyruvate in anaerobic conditions (reversible reaction)

A

Pyruvate -> Lactate
Catalysed by lactate dehydrogenase (and NADH and H+ to regen NAD+ for glycolysis)

125
Q

Fate of pyruvate in aerobic conditions (irreversible reaction)

A

Enters mitochondria and converted to Acetyl CoA and CO2 by pyruvate dehydrogenase (process inactivated by high concs of Acetyl CoA and NADH)

126
Q

Where does Kreb’s cycle occur? Under what conditions?

A

Mitochondrial matrix
Aerobic conditions

127
Q

Kreb’s cycle overall reaction

A

Acteyl-CoA + 3NAD+ + FAD + GDP + Pi + 2H2O -> 2CO2 + 3NADH + FADH2 + GTP + 3H+ + CoA

128
Q

Mnemonic for remembering kreb’s cycle intermediates

A

Citrate
Is - Isocitrate
Kreb’s - a-ketoglutarate
Starting - Succinyl-CoA
Substrate - Succinate
For -Fumarate
Making - Malate
Oxaloacetate

129
Q

Net energy gain of Kreb’s cycle per glucose molecule (2 pyruvate per glucose)

A

6 NADH
2 FADH2
2 GTP

130
Q

Summarise Oxidative Phosphorylation

A

NADH and FADH2 oxidised giving off H+ and e
Electrons transferred to electron acceptor and passed along chain of electron carriers releasing free energy which fuels them to pump electrons into the intermembrane space
Creates electrochemical gradient so protons flow through ATP synthase providing energy to produce ATP

131
Q

Final electron acceptor in oxidative phosphorylation

A

Oxygen
0.5O2 + 2H+ + 2e- -> H2O

132
Q

Fatty acid structure

A

Carboxylic head with aliphatic tail (saturated or unsaturated)
Derivatives of triglycerides and phospholipids

133
Q

Bile salts role

A

Emulsify lipids forming mixed micelles so fats are soluble in the gut
Intestinal lipase can then break down triglycerides into free fatty acids

134
Q

What transports triglycerides around the body?

A

Triglycerides incorporated with cholesterol and apoproteins into chylomicrons which transport triglycerides around the body

135
Q

Role of lipoprotein lipase?

A

Recognises the apoprotein present in a chylomicron triggering lipoprotein lipase to break down triglycerides again into free fatty acids to absorb them into tissues

136
Q

Fatty acid activation (occurs in cytoplasm of cells)

A

Fatty acid -> Acyl Adenylate (requires a molecule of ATP)

Acyl Adenylate -> Acyl-CoA (acyl-CoA synthetase required

Acyl-CoA is then transported through mitochondrial membrane for fatty acid oxidation

137
Q

How does Acyl-CoA get from the cytoplasm through the mitochondrial membrane?

A

Acyl-CoA <12 carbons (can diffuse straight through membrane)
Acyl-CoA >14 carbons (taken through mitochondrial membrane using the carnitine shuttle) (active process)

138
Q

Start and end point of fatty acid oxidation

A

Starts with Acyl-CoA
Ends with an Acetyl-CoA (which enter TCA) and an Acyl-CoA with 2 less carbons (each thiolysis stage chops off 2 carbons)

139
Q

4 stages of fatty acid oxidation

A

Oxidation
Hydration
Oxidation
Thiolysis

140
Q

How is Acetyl-CoA used?

A

Most is used in TCA cycle
Small amount converted to ketones (when large amounts of acetyl-CoA are produced exceeding TCA cycle capacity) (ketones produced in liver)

141
Q

Ketogenesis example pathway

A

2 Acetyl-CoA -> Acetoacetyl-CoA -> HMG-CoA -> Acetoacetate -> Acetone (spontaneously) or B-Hydroxybutyrate (requires enzymes)

142
Q

How are ketone bodies utilised by extrahepatic tissues?

A

Conversion of beta-hydroybutyrate and acetoacetate to acetoacetyl-CoA using enzyme succinyl-CoA transferase

143
Q

Where in the body is succinyl-CoA transferase not found?

A

Only hepatic tissues (as that’s where ketones are made)

144
Q

Factors affecting rate of ketogenesis

A

ATP demand high = acetyl-CoA oxidised by TCA cycle

Greater release of free fatty acids from adipose tissue (from low carbohydrate levels)

High glycerol-3-phosphate conc in liver = greater triglyceride production (less free fatty acids)

Insulin downregulates ketone production (suggests high glucose levels), glucagon upregulates

145
Q

Phospholipid structure

A

2 fatty acid tails attached to glycerol attached to a phosphate group attached to either
Serine (phosphatidyl-serine)
Choline (phosphatidyl-choline)
Inositol (phosphatidyl-inositol)

146
Q

Membrane is permeable to…

A

Water, gases, small uncharged polar molecules (urea)

147
Q

Membrane is impermeable to…

A

Ions, Charged polar molecules, Large uncharged polar molecules

148
Q

Desmosomes

A

Join the intermediate filaments in 1 cell to another (make sure contents of a hollow organ either enter cells or stay in the lumen)

149
Q

Gap Junctions

A

Allow passage of small water soluble ions and molecules

150
Q

Hemi-desmosomes

A

Anchor intermediate filaments in a cell to the basal lamina

151
Q

Tight junctions

A

Seals neighbouring cells together to prevent leakage

152
Q

Nuclear Steroid Receptors

A

Sit inactive in cytosol
Specific hormone (e.g-oestrogen) binds to receptor resulting in structures change to the NSR so it can enter the nucleus
Then binds to certain sequence of DNA to modulate gene expression

153
Q

Membrane-bound Steroid Receptors speed of action

A

Quicker than NSRs in altering gene expression

154
Q

Growth factor receptors

A

Stimulate cell growth when a growth hormone binds to them

155
Q

G-Protein Coupled Receptors made up of…

A

The receptor (primary specificity))
3 G-proteins (alpha, beta, gamma) (peripheral so can move around freely and provide further specificity)
Adenylyl Cyclase (converts ATP -> cAMP which is a second messenger)
Phosphodiesterase (enzyme converting cAMP -> AMP once cAMP function has been carried out)

156
Q

Different G alpha subunit’s determine secondary messenger in GPCRs

A

Can promote (turn on) cAMP pathway
Can turn off cAMP pathway when alpha i (inhibitory) is activated
Gaq makes a different secondary messenger (IP3 and DAG)

157
Q

pH effect on Ca2+ conc in serum

A

Acidosis - Less Ca2+ bound to plasma proteins (H+ ions buffered by albumin)

Alkalosis - More Ca2+ bound to plasma proteins (fewer H+ ions on protein)

These 2 change the ratio of Ca2+:Ca in blood (this can effect membrane permeability to Na+ in excitable tissues)

158
Q

Heat exhaustion temp
Heat stroke temp

A

37<x<40 (can still sweat)
x>40 (no longer sweat)

159
Q

How do steroids pass over membrane?

A

Hydrophobic and fat soluble

160
Q

How do enzymes increase RoR?

A

Stabilise intermediates

161
Q

2 DNA functions

A

Transcription / Protein Synthesis
Genetic material (for heredity)

162
Q

How to determine protein structure?

A

Crystallise protein
Pass a slice through x-ray diffraction which will reflect off electrons giving you an idea of the structure

163
Q

What connects the phosphate group of 1 nucleotide to the pentose sugar of another?

A

A phosphodiester (covalent) bond

164
Q

How many H bonds between:
C and G?
A and T?

A

3
2

165
Q

How do proteins alter DNA gene expression?

A

Slide in major and minor grooves of the helix

166
Q

DNA wraps around histone protein forming a…
Which as a chain wrap up to form a…

A

Nucleosome
Solenoid

167
Q

Condensed form of chromatin called…
More open form called?

A

Heterochromatin (darker bands when photographed)
Euchromatin (lighter bands)

168
Q

Proto-oncogene vs oncogene

A

Proto-oncogene controls normal cell growth (if mutated can become an oncogene resulting in uncontrolled cell growth)

169
Q

DNA Polymerase path of action
How fast does it act?

A

Prints 5’ -> 3’
700-1000 bp per second

170
Q

DNA Polymerase error proofing function

A

Editing Function
Deletes incorrect insertion of base and will excise and repeat

171
Q

PCR

A

-Design 2 primers which will anneal to DNA at right place (1 on each strand)

-Heat up mixture to 96degreesC so DNA separates

-Cool it and primer anneals to sequence

-Add polymerase + nucleotides to extend from each primer to make a copy of the DNA sequence (Then repeat process)

172
Q

How has the issue of enzymes dying in PCR been overcome?

A

Use thermostable enzymes

173
Q

DNA Repair

A

Proteins detect changes/mismatches in DNA causing enzymes to excise the damaged section of DNA

174
Q

p53 gene

A

Tumour Suppressor Gene
Detects DNA damage and stops cell replication
If cell isn’t repaired, p53 commands it to apoptose

175
Q

The genetic code is…(3)

A

Degenerate but unambiguous (each codon codes only 1 aa)
Almost universal
Non-overlapping

176
Q

Transcription factors

A

Protein factors which control if a gene is turned on

177
Q

TATA-Binding-Protein (TBP)

A

Recognises the common TATA base sequence in DNA and binds in the minor groove bending the strand 80degrees (imposed strain lowers required energy for separation)

178
Q

4 pathways of dietary components

A

-Biosynthetic Pathways (forming proteins etc.)
-Fuel storage
-Fuel oxidative pathways (respiration)
-Detoxification and waste disposal pathways

179
Q

Cofactors

A

Often vitamins which help enzymes catalyse reactions

180
Q

Breakdown of lactate in the liver

A

Lactate -> Pyruvate -> Glucose (Gluconeogenesis example)

181
Q

How much protein do you need a day?

A

0.8g/kg/day

182
Q

Stores of:
Fat
Carbohydrates
Proteins

A

Adipose Tissue (as triglycerides) (only 15% water as fat is hydrophobic)
As glycogen in liver and muscle cells
Muscles (cells 80% water as proteins are hydrophilic)

183
Q

How much energy released per gram?
Carbohydrate
Protein
Alcohol
Lipid

A

4kcal/g
4kcal/g
7kcal/g
9kcal/g

184
Q

Basal Metabolic Rate (BMR)

A

Energy needed to stay alive at rest (non-exercise body functions like respiration, contraction of heart muscle)

185
Q

Factors decreasing BMR

A

Older age
Female gender
Dieting/starvation
Hypothyroidism
Decreased muscle mass

186
Q

Factors increasing BMR

A

Higher BMI
Hyperthyroidism
Fever

187
Q

Define Malnutrition

A

Deficiency, excess or imbalance of energy, protein or other nutrients, causing measurable adverse effects

188
Q

Vitamin C

A

Fruit and Veg
Collagen synthesis
Improves iron absorption
Antioxidant

189
Q

Vitamin B12

A

Eggs, meat, milk
Protein and DNA synthesis
Energy production

190
Q

Folate (Folic acid)

A

Produce and maintain DNA
Helps make RBCs and prevent anaemia

191
Q

Vitamin D

A

Increases amount of Ca and P your body absorbs
Deposits Ca and P in bones and teeth (makes them stronger)

192
Q

Oocyte is…
Sperm is…

A

Female Germ Cell
Male Germ Cell

193
Q

Zygote is…

A

Cell resulting from union of sperm and oocyte at fertilisation

194
Q

Blastomeres are…

A

Early embryonic cells

195
Q

Morula

A

Solid mass of 12-32 blastomeres

196
Q

Blastocyst

A

Stage where morula has entered uterine cavity and blastocystic cavity develops from within

197
Q

Gastrula

A

Stage after trilaminar embryonic disc formation

198
Q

Neurula

A

Stage after where neural tube opens

199
Q

Embryo

A

Developing human during embryonic stage (to end of 8th week)

200
Q

Fetus

A

Period from week 9 to birth

201
Q

Autocrine vs Paracrine vs Endocrine secretion

A

Autocrine - Cells talking to themselves
Paracrine - Cells talking to neighbouring cells (signal diffuses across gap between cells)
Endocrine - Cells talking to other cells elsewhere in the body

202
Q

Steroid hormones

A

All made from cholesterol
Different enzymes modify cholesterol to make different hormones
Can’t dissolve in water (so binds to protein in blood), can in lipids

203
Q

Water composition of body

A

Total body water is 60% of body weight (42L)
Intracellular is 40% of body weight (28L)
Extracellular is 20% of body weight (14L) (11 interstitial, 3 plasma)

204
Q

Predominant cation in ECF and ICF

A

ECF - Sodium
ICF - Potassium

205
Q

Plasma Osmolality

A

Conc of solution expressed as mmol/kg (normal is 275-295mmol/kg)

206
Q

3 responses to increased ECF osmolality from dehydration

A

1) Movement of water from ICF to ECF
2) Stimulation of thirst centre in hypothalamus making you want to drink
3) ADH release from posterior pituitary resulting in renal water retention

207
Q

Body response to change in ECF volume (Renin-angiotensin-aldosterone system)

A

1) Decrease in renal perfusion acts on the juxtaglomerular apparatus and causes release of renin form the kidney

2) Renin then acts on angiotensinogen (released from liver) converting it to angiotensin I

3) Angiotensin I converted to angiotensin II by ACE (released from pulmonary and renal endothelium)

4a) Adrenal gland detects angiotensin II and secretes aldosterone which acts on distal kidney tubules to increase water retention (reabsorbing Na+ and Cl- whilst excreting K+)

4b) Angiotensin II also stimulates ADH release from pituitary glands

4c) Angiotensin II also causes arterial vasoconstriction

5) These all increase perfusion of juxtaglomerular apparatus switching the system off

208
Q

Oncotic pressure

A

Pressure caused by difference in protein concentration between plasma and interstitial fluid
Water moves interstitial fluid -> plasma

209
Q

Normal sodium concentration in blood

A

135-145mmol/L

210
Q

When does implantation occur?

A

Day 21 of menstrual cycle
7 days after fertilisation

211
Q

Upon implantation, how does the zygote gain fuel for growth?

A

Endometrial cells provide metabolic fuel for growth

212
Q

Maternal recognition of embryo

A

By secretion of IL-2 prevents rejection

213
Q

What attaches embryo to endometrium?

A

Integrins

214
Q

What is the decidual reaction?

A

Differentiation of endometrial stromal cells adjacent to the blastocyst

215
Q

Differentiation in pregnancy

A

Splitting of the trophoblast into 2 cell layers (synctiotrophoblast and cytotrophoblast)

216
Q

Invasion in implantation

A

Synctiotrophoblast erodes blood vessels by using enzymes to digest basal lamina

Medicine (14 decks)

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