Block 1 - Foundations of Medicine - Weeks 1-3 Flashcards
1
Q
What type of cell looses normal function?
A
A cancer cell
2
Q
How are cancer cells arranged?
A
They’re disorganised
3
Q
6 characteristics of cancer
A
- Loss of normal controls of cell division
- Can’t keep the cell inside tissue boundaries
- Evades bodily defence mechanisms
- Recruits blood vessels to the tumour
- Migrates into the blood/lymphatics
- Establishes tumours in the ‘wrong’ tissue
4
Q
How thick is a specimen for a light microscope?
A
1cm
5
Q
What is the difference between bright field and fluorescence light microscopy?
A
Bright field: Dense stains and dead specimins
Fluorescence: Increased sensitivity and precise localisation to see organelles
6
Q
How many membranes does mitochondria have?
A
2
7
Q
How does the mitochondria divide and why?
A
Independently as they have their own DNA
8
Q
2 reactions that occur in the mitochondrial matrix?
A
Citric cycle reactions
Fatty acid metabolism
9
Q
How abundant are peroxisomes compared to mitochondria?
3 reactions
A
Less abundant than mitochondria
Metabolism, detoxification and oxidative reactions
10
Q
What do oxidative reactions generate in peroxisomes?
What enzyme is involved?
A
Hydrogen peroxide –> Water and Oxygen
By catalase
11
Q
What happens to molecules at the golgi apparatus?
Example
A
They are modified
e.g. Glycosylation (adding a polysaccharide chain)
12
Q
What stores molecules ready for a signal?
A
Secretory granules
13
Q
What will a vesicle transfer the molecule to when it is taken up by the plasma membrane?
A
Endosome
14
Q
What are the 3 types of filaments in the cytoskeleton of the cell?
A
Intermediate
Actin
Microtubules
15
Q
What are intermediate filaments and where are they found?
A
Structual components
Throughout the cell
16
Q
Where are actin filaments found?
A
Near the cell surface
17
Q
Where are microtubules found?
A
Throughout the cell
Extends from a centrosome in the cell centre
18
Q
What 2 things do viruses hijack in the cell other than the cytoskeleton network?
A
Synthesis pathways and the endocytotic pathway
19
Q
8 roles of the cytoskeleton
A
Basis of cilia and microvilli, Cell division, Cell shape, Contractility, Internal organisation, Mechanical strength, Movement, Vesicle transport
20
Q
What does a low carb diet mean?
A
Low sucrose
21
Q
4 main minerals absorbed in the diet?
A
Calcium, Sodium, Iodine and Iron
22
Q
How much more energy dense is fat compared to glucose?
A
2x as energy dense
23
Q
What are the two differences between the glycogen and fat store?
A
Glycogen: Finite (ST)
Fat: Infinite (LT)
24
Q
4 places in the body where anaerobic respiration is needed?
A
Red blood cells, kidney medulla, eye lens and tumour cells
25
What happens to lactate?
It is converted back to pyruvate, glucose or glycogen in the liver by gluconeogenesis in the CORI CYCLE
26
How many carbon atoms does glucose phosphate have?
6 carbon atoms
27
What is each molecule made by/ what does each molecule produce in glycoslysis?
GP made by 2 ATP
| Pyruvate made by 4 ADP and NAD --> 4 ATP and 1 NADH
28
Which stage of the link reaction produces the reduced coenzymes?
Pyruvate --> Acetate (1st stage)
29
What theory is oxidative phosphorylation?
Chemiosmotic theory
30
How much ATP is produced from NAD and FAD?
```
10 NAD (3 ATP each)
2 FAD (2 ATP each)
```
31
Where does gluconeogenesis occur?
Liver and kidney
32
How is acetyl CoA converted to ketones?
By ketogenesis
33
What are the three waste products from ketogenesis?
Acetoacetate, acetone and beta-hydroxybutyrate
34
What is the purpose of the pentose phosphate pathway?
- Pentoses for DNA/RNA synthesis
| - NADPH for fat synthesis
35
2 methods to produce acetyl CoA from fat?
Beta oxidation: Fat - Acetyl CoA in the mitochondria
| Pentose-phosphate pathway: Fatty acid - Fatty acetyl CoA - Acetyl CoA
36
What is the barrier in the plasma membrane called?
Permeability barrier
37
5 things that receptors recognise
Extracellular matrix, growth factors, hormones, neurotransmitters, proteins
38
4 roles of complex lipids in the bilayer
- Create a fluid and dynamic environment
- Permeability barrier
- Matrix for protein localisation
- Signal transduction
39
7 roles of proteins, glycoproteins and glycolipids in the plasma membrane
- Receptor, enzyme and carrier
- Junctions
- Signal transduction
- Links to cytoskeleton and extracellular matrix
40
What is signal transduction
Causes foreign DNA to be introduced into the cell
41
2 reasons why the bilayer is asymmetric
2 halves of the bilayer are different
| 2 halves of the protein inserted are different
42
How do water soluble substances produce intracellular effects without entering the cell?
They bind to a receptor which then carries out the intracellular signalling cascade
43
Which isomer decreases the melting point?
The cis isomer
44
What is the structure of most phospholipids in regards to melting point?
Saturated fatty acid in chain 1
| Cis unsaturated fatty acid in chain 2
45
How can the shape of the protein influence the fluidity of the membrane?
The protein can change shape
46
5 factors which influence the fluidity of the phospholipid bilayer?
Chain length, charge, cholesterol presence, headgroup size, hydration
47
What is another word for 'dual affinity'?
Amphiphatic
48
What structure do proteins which associate with the membrane have?
Name them
Secondary
| Alpha helix or Beta pleated sheet
49
Second messenger cascade for adrenaline and noradrenaline in muscle cells
Adenylate cyclase - cAMP - Protein kinase A - Phosphorylate kinase - Glucose phosphorylase - Gluconeogenesis
50
Second messenger cascade for adrenaline and noradrenaline in fat cells
Adenylate cyclase - cAMP - Protein kinase A - Lipase - Lipolysis - Fatty acid release
51
What is the diffusion rate proportional to in passive diffusion? (aside from concentration gradient)
Hydrophobicity of molecule
| Increased hydrophobicity = faster diffusion
52
What is the rate limiting step of simple diffusion?
Getting the molecule through the hydrophobic part of the bilayer
53
What water souble molecules can and cannot pass by simple diffusion?
5 e.g.
Uncharged polar molecules (e.g. water, urea, glycerol, glucose and sucrose)
NO IONS
54
Difference between the direction of transport between carrier and channel proteins
Carrier: Both ways
Channel: One way
55
How do transporters work?
One substrate binds at a time --> conformational change
56
Difference between an antiporter and a symptorter?
Antiporter: 2 molecules in opposite directions
Symporter: 2 molecules in the same direction (one down and one against)
57
What direction will a uniporter move its molecule?
Down its concentration gradient
58
3 roles of nucleotides
Energy carriers (ATP)
Signalling (cAMP)
Enzyme co-factors (CoA)
59
What are the different names of nucleotides depending on the number of phosphate groups?
Nucleotide monophosphate, diphosphate, triphosphate
60
What is the backbone of DNA called?
The sugar-phosphate backbone
61
What direction do nucleotides read in?
FIVE --> THREE
62
How many genes does mitochondrial DNA have?
37
63
Define chromatin
DNA and associated proteins
64
Percentage of nuclear mass made from chromatin?
80%
65
Define euchromatin
Single strand of nucleotides
66
Define heterochromatin
Densely packed chromatin fibre
67
What is the chromosome scaffold made from?
Super-coiled chromatin fibres associated with non-histone proteins
68
Define centromere
Point of attachment to the mitotic spindle
69
Which arm is the long and short part of the chromosome?
Q: LONG
P: SHORT
70
Define homologous
Same
71
Define Karyotype
Stereospecific number and shape of chromosomes as seen during metaphase
72
How do the chromosomes condense?
They condense around the protein scaffold
73
Define cell cycle
An ordered series of events that leads to the division of a cell into 2 identical daughter cells
74
What are the 5 stages of the cell cycle and their timings
```
G0: hours to years
G1: 18-30 hours
S: 2-10 hours
G2: 2-10 hours
M: 30-60 minutes
```
75
What happens during the G0 stage of the cell cycle?
| When does the cell move from G0 to G1?
Resting phase
| Moves to G1 when it gets a signal to divide
76
What 2 things happen during the stage G1?
Proteins made
| 2nd growth phase
77
What 4 things happen during prophase?
Chromosomes condense
Nucleoli disperse
Centrosomes separate
Mitotic spindle forms
78
What 3 things happen during protemetaphase?
Nuclear envelope fragments
Spindle attaches to the centromere
Chromosomes move to the cell centre
79
What is the equator of the cell called?
Metaphase plate
80
What 4 things happen during telophase?
Chromosomes uncoil
Nucleoli redevelop and fuse
Spindle is disassembled
Nuclear envelope is reformed
81
What is the mitotic spindle made from?
2 centrosomes made from microtubules
82
Define centrosomes
Areas where the spindle forms
83
Define kinetochore
A complex structure made from proteins which binds to specific DNA sequences
They also help microtubules to attach to the chromosome
84
2 ways of preventing genetic conditions from occuring
Surgery
| Designer baby
85
2 characteristics of genetic information
Seen/hidden
| Significant/non-significant
86
Define polymorphic
2 or more variants of an allele
| Found introns and exons
87
What are the three types of polymorphism
Single nucleotide polymorphisms
Restriction fragment length polymorphisms
Short tandem repeats
88
Where in the genome do SNP's occur?
Introns and exons
89
What is the section of DNA which is amplified called in STR's
Where in the genome are they most common
Motif
| Increased in introns than exons
90
What are restriction fragment length polymorphisms?
A single nucleotide/ row of nucleotides are different
91
6 uses of polymorphisms
Disease analysis, genetic fingerprinting, gene localisation and identification, genetic markers, linkage analysis, tissue typing
92
How can RFLP's be used to screen for sickle cell?
The nucleotide is A instead of T so the restriction fragment will not cut the DNA
93
What units are chromosome markers distanced in?
| What is this distance based upon?
CentiMorgans
| A distance based on the probability that STR's will combine
94
What is linkage analysis?
The genetic fingerprints of a family are analysed
95
Define evolution
Change of frequencies of allels in the gene pool of a population
96
What 7 things does Hardy Weinberg state that evolution needs?
Fixed population size, genetic drift, gene flow, migration, mutation, natural selection, non-random mating
97
What is genetic drift?
Random change in allele frequency due to random choices in mating which randomly increase the proportion of certain alleles
98
What is Confer Survival?
| Example
People who are carriers of a disease may have a selective advantage
E.g. sickle cell
99
Define gene flow
Migration between populations
100
What does gene expression change in regards to disease?
How genes are identified and treated
101
What percentage of DNA is made from introns and exons?
Introns: 2%
Exons: 98%
102
How is DNA removed in splicing?
In loops
103
Define gene
An ordered nucleotide sequence which is part of a chromosome and determines the order of monomers in a polypeptide/ nucleic acid
104
What determines when and where a gene is transcribed?
Promoter and regulatory sequences
105
What are the two strands of DNA called?
Which one does polymerase bind to?
Which strand does it make a copy of?
Sense and antisense
| Binds to antisense to make a copy of sense
106
What direction does polymerase move down the DNA?
Which end of the growing chain does it add nucleotides to?
Which direction does the ribosome read mRNA?
From 3' to 5'
Adds nucleotides to the 3' end
Reads from the 5' end
107
What end of the RNA chain is capping and a poly-A tail added?
Capping: 5'
| Poly-A tail: 3'
108
How many adenine bases is a poly-A tail made from?
| How are they added?
100-300 bases
| Added by the enzyme poly-A polymerase
109
What is the stop codon recognised by?
| What does it cause to happen?
A releasing factor
| Causes the two parts of the ribosome to fall apart
110
What does AUG code for?
The amino acid METHIONINE
111
What is ubiquitination?
Degradation of misfolded proteins by adding small chemical groups called ubiquitin
112
What is the function and localisation of a protein determined by?
Structure, sequence and post-translational modifications
113
What signal do proteins in the nucleus have?
Nuclear localisation signal
114
What signal do proteins in the plasma membrane have?
| Where are they transported to?
Endoplasmic reticulum sequence
| Golgi apparatus for more modification
115
What proportion of fluid in the body is intracellular and extracellular?
2/3 intracellular
| 1/3 extracellular
116
What percentage of the extracellular fluid is interstitial and what percentage is blood?
Interstitial: 80%
Blood: 20%
117
Which holds more water: fat or muscle?
Muscle
118
What happens to water content if you are a:
Female?
Infant?
Elderly?
Female: Decreased as more fat than muscle
Infant: Increased as more muscle than fat
Elderly: Decreases with age
119
What is trans-cellular fluid?
| 4 places where it's found?
A type of extacellular fluid
| Cerebro-spinal, Eyes, Synovial and Serous
120
Define homeostasis
Maintaining the EXTRACELLULAR FLUID at a constant space
121
Where is the highest level of: Na, K and Non-carbohydrate?
| Where is the lowest level of protein?
Na: Highest in blood and interstitial fluid
K: Increased in intracellular
Non-carbohydrate: Increased in blood
Protein: None in the interstitial fluid
122
What 6 factors in the extracellular fluid NEED to be kept constant?
Carbon dioxide, glucose, ion concentration, osmotic pressure, oxygen, temperature
123
Define hydrostatic pressure
Pressure exerted by the blood onto the capillary walls
124
Define osmotic pressure
| What is another name for it
Negative pressure created by proteins in the plasma
Proteins cannot leak out so a vacuum is created which sucks fluid in from the intracellular fluid
Colloid pressure
125
Where are the leakiest lymphatic capillaries found?
Kidneys, intestines and liver
126
What happens to vessels as they move away form the heart?
| Why?
They get more permeable so diffusion can increase
127
Does a leaky endothelial require energy?
No - there is free movement
128
2 examples of molecules which pass the membrane by free diffusion
Oxygen and carbon dioxide
129
Which molecule cannot pass through the membrane?
Vitamins
130
Define primary active transport
What pump is used?
Example
Against the concentration gradient using ATP
Antiport
Na/K pump
131
Define secondary active transport
What pump is used?
Example
One molecule moves down whilst one molecule moves against
Symport
Na and glucose
132
Explain why osmosis is needed in the body
If 2 cells have different solute concentrations and a permeable membrane then they will diffuse to reach equilibrium
If the membrane is not permeable then water will diffuse
133
Define molarity
Number of moles per litre
134
Define osmolarity
Number of molecules per litre
135
Define tonicity
Number of non-penetrating molecules per litre
136
What two things does drinking too much cause?
| How?
Confusion and vomiting
| Cell is hypotonic
137
Where is ADH released form?
Pituitary gland
138
Why is the kidney system slow?
Salt takes a few days to be excreted
139
What can RBC do to maintain pH?
Mop up hydrogen ions
140
What do proteins do in a low and high pH?
Low pH: Cellular proteins release H+
| High pH: Cellular proteins release NH4+
141
What is protoza?
A class of pathogen
142
Define commensalism
One organism benefits and the other is unaffected
| majority
143
Define mutualism
BOTH organisms benefit
144
Define parasitism
One organism benefits at the expense of an other
145
What is the envelope surrounding a virus made from?
Lipids
146
How many chromosomes do prokaryotes have?
1
147
What is pili?
Used for attachment in bacterial cells
148
What is the gram + cell wall made from?
Lipopolysaccharide
149
What is the gram - cell wall made from?
Peptidoglycan
150
3 ways can bacteria be classified?
Cell wall (+/-)
Shape
Size
151
What are myobacteria?
Gram + bacteria with a waxy and acidic coat
152
Explain the three stages of bacterial replication
Genome replication: Begins at the origin of replication and regulated by DNA polymerase
Septum formation: Folding of plasma membrane and in-growth of cell wall
Cell division: Gives the bacteria its shape
153
What type of viruses are bacteriophages?
Lytic viruses
154
What are the two pathways by which lytic viruses can kill bacteria?
Virulent pathway: Kill the host immediately
| Lysogenic pathway: Reside for long periods
155
What is the life-cycle of a parasite like?
Dual life cycles with extensive replication
156
What are the three classes of helminth parasites?
Cestodes, Nematodes, Trematodes
157
Give an example of a parasite
Malaria
158
What are the two ways of classifying fungi?
Type of infection: Superficial or deep
| Appearance: Filamentous (branching) or yeasts (spherical)
159
Which class of bacteria do lysosomes treat?
Gram +
160
How does the innate immune system recognise pathogens?
| What do they specifically recognise and what do they then do?
By germ-line receptors which are already on the surface of the phagocyte
Broad classes of antigens --> phagocytosis
161
What do the receptors in the adaptive immune system require?
Sophisticated rearrangement of receptor genes
162
2 examples of primary immune tissue
Bone marrow and thymus
163
3 examples of secondary immune tissue
Spleen, Lymph nodes and Peyer's patches
164
Where do immune cells also arise from in chronic inflammatory conditions?
Spleen and lymph nodes
165
What is the complement system?
A multi-catalytic system which involves blood proteins with enzyme activity
166
Give an example of a protein which has enzyme activity
| What can genetic disorders do?
Proteases
| Genetic disorders can activate these incorrectly
167
What is the complement system activated by?
Pathogens
168
What are the roles of the complement system?
- Coat pathogens to allow them to be recognised by phagocytes in opinisation
- Kill pathogens directly by membrane lysis
- Regulate acute inflammation by working with acute phase proteins (e.g. CRP)
169
Where do macrophages reside?
Peripheral tissues
170
What is the relationship between PRR and PAMP
Phagocyte has a PRR (pattern recognition receptor) that is a receptor for the PAMP (pathogen associated molcular pattern) on the phagocyte
171
What is another role of PAMP?
Discriminates between bacteria
172
3 components of a lysosome
Antimicrobial peptides, decreased pH and high levels of reactive oxygen species
173
What is the most common white blood cell?
Neutrophils
174
What are the two main immune system phagocytes?
Polymorphonuclear neutrophil
| Mononuclear phagocyte
175
4 characteristics of polymorphonuclear neutrophils
Kill ingested pathogens
Short lived
Rapidly recruited
Release toxic granules
176
3 characteristics of mononuclear phagocytes
Activate acquired response
Kill pathogens by playing host
Long lived
177
Give 3 types of mononuclear phagocytes
Blood monocytes
Tissue and blood dendritic cells
Tissue macrophages
178
How big are natural killer cells?
Larger than B and T cells
179
3 roles of natural killer cells
Release toxic granules and interfering gamma
| Causes local inflammation
180
Stages of differentiation for B and T cells
Recombination + rearrangement --> maturation --> clonal expansion
181
4 roles of helper T cells
Activate macrophages
Help B cells make antibodies
Help cytotoxic T cells
Regulate the response
182
4 roles of dendritic cells
Chops peptides and presents them to T cells
Fills gap between innate and adaptive
Phagocytosis
Surveillance
183
What are the 4 classes of somatic cells?
Connective
Epithelial
Muscle
Nervous
184
What is the nucleus called in the zygote?
| How is it formed?
Nucleus is a PRONUCLEI
| Formed by a process called SINGONY
185
What happens when the zygote is 4 and 8 cells big
4 cells: Genome activated
| 8 cells: Cell-cell junctions form
186
When does specialisation begin to occur?
64 cells
187
What do cells outside the embryo become when specialisation begins to occur?
2 things they form
1 characteristic
Become TROPHECTADUM cells
Terminally specialised
Form the placenta and trophoblast
188
What do cells inside the embryo become when specialisation begins to occur?
How?
Express transcription factors and made a FATE DECISION to become INNER MASS CELLS (IMC)
189
What 3 things happen between 5 and 7 days?
The blastocyst begins to expand by osmosis
Menstruation stops
The embryo moves into the uterus from the fallopian tubes
190
Another name for the inner mass cells
Pluriblast
191
What are the two layers which from the bilaminar disc?
What are the cavities in these structures called?
What is the epithelium like?
Epiblast: Proamniotic cavity
Hypoblast: Blastocel cavity
STRUCTURED epithelium
192
What are the three layers which form the trilaminar disc
What are they made from?
What is the epithelium like?
Ectoderm: Made from the epiblast
Mesoderm: Made from the epiblast
Endoderm: Made from the hypoblast
Mesoderm DISRUPTS the epithelium
193
What 2 things from the primitive streak?
Made from the primitive node and mesoderm cells pushing through the ecotderm
194
What epithelium does the ectoderm become?
The epithelium which lines the inner body
195
What is the amnion, chorion and yolk sac made from?
Amnion: Ectoderm and mesoderm
Chorion: Trophoblast and mesoderm
Yolk sac: Endoderm and mesoderm
196
What does the ectoderm form?
Brain, nervous system and skin
| teeth and eyes
197
What does the endoderm form?
Inner lining of systems (e.g. digestive) and organs e.g. liver, lungs and pancreas
198
What does the mesoderm form?
Circulatory, muscular, respiratory, reproductive and skeletal systems
199
Which parts of the trilaminar disc form epithelium and which form esenchyme?
What is esenchyme?
Epithelium: Ectoderm and endoderm
Esenchyme: Mesoderm (looser structure)
200
9 functions of epithelium
Barrier, communication, lubrication, maintenance, movement, protection, secretion, stimuli transduction, transport
201
What is the structure of stratified epithelium?
Many layers of cells
202
What are the 8 types of ducts?
Simple tubular - Simple branched tubular - Simple coiled tubular - Compound tubular
Simple acinar - Simple branched acinar - Compound acinar
Compound tubuloacinar
203
2 other names for the basement membrane
Basalaminar
| Extracellular matrix
204
What 2 things is the basement membrane made from?
Ground substance and collagen
205
3 examples of basement membranes?
Bone, cartilage and connective tissue
206
What is the main component of cartilage?
Proteoglycans
207
What cells maintain cartilage?
Chondrocytes
208
What are the two main structural proteins?
Elastin and collagen
209
What is collagen secreted by?
What strength does it have - why?
What is the main amino acid?
Secreted by fibroblasts
High tensile strength due to a triple helix
Glycine
210
What are the two main amino acids in elastin?
Is it hydroxylated?
What is its structure when it is relaxed?
Glycine and proline
No hydroxylation
Coiled
211
What is the ground substance made from?
Protein and polysaccharide complexes
| e.g. proteoglycans and glycoproteins
212
What is a proteoglycan mesh?
A hydrated gel made from collagen and elastin which bind to proteins
213
What is the role of adhesive glycoproteins?
Stick the epithelium to the basement membrane at the basal lamina
214
What is the role of the basal lamina?
Support and organise tissue
| Permeable so allows movement
215
2 examples of adhesive glycoproteins
Fibronectins and Laminins
216
What are integrins?
Protein dimers which stick to the extracellular matrix through the RGD domain
Cluster at the bottom of cells --> hemidesmosomes
217
What forces do collagen, elastin and glycoaminoglycans resist?
How?
Glycoaminoglycans: Resist compressive forces as they are VISCOUS
Collagen and elastin: resist tensile forces as they are FIBROUS
218
What is the difference between dense and loose connective tissue?
Dense: More collagen
Loose: More fibroblasts
219
What is the membrane ABOVE the junction called?
Apical
220
What is the membrane BELOW the junction called?
Basolateral
