Science for Medicine summary Flashcards
(225 cards)
1
Q
What is metabolism?
A
The chemical processes in a living organism that allow food to be used for tissue growth
2
Q
What two major reaction types does metabolism consist of?
A
Summative/Anabolic
Degradative/Catabolic
3
Q
What reactions occur with a positive ∆G value and are not spontaneous?
A
Anabolic
4
Q
What reactions occur with a negative ∆G value and are spontaneous?
A
Catabolic
5
Q
What is ∆G?
A
Change in free energy
6
Q
What is a metabolic intermediate?
A
A molecule which is the precursor or metabolite of a biologically significant molecule
7
Q
Name a functional group that is polar and soluble?
A
Hydroxyl Carboxyl Carbonyl Amine Phosphate
8
Q
Name a biomolecule in which the carboxyl functional group is found
A
Amino acids
Proteins
Fatty acids
Acetic acids
9
Q
What is meant by Hydrophobic?
A
Non-polar molecules that do not interact with water
10
Q
What is meant by Hydrophilic
A
Polar molecules that interact with water
11
Q
What is an amphipathic molecule?
A
A molecule which contains both hydrophobic and hydrophilic parts
12
Q
Give an example of an amphipathic molecule
A
Phospholipids
Hydrophobic fatty acid tails, hydrophilic phosphate head
13
Q
What is the major difference between eukaryotes and prokaryotes?
A
Eukaryotes contain a nucleus and membrane bound organelles whereas prokaryotes contain no membrane bound nucleus or organelles
14
Q
What does the nucleus contain?
A
DNA, nucleoprotein and some RNA
15
Q
Where is the site of ribosomal RNA synthesis and ribosomal assembly?
A
Nucleoli
16
Q
What are the two types of Endoplasmic Reticulum?
A
Rough
Smooth
17
Q
Which type of Endoplasmic Reticulum is responsible for lipid biosynthesis and membrane synthesis and repair?
A
Smooth
18
Q
What type of Endoplasmic Reticulum synthesises, packages and secretes proteins?
A
Rough
19
Q
What organelles are known as the “protein factories” of the cell?
A
Ribosome
20
Q
What shape are mitochondria?
A
Cigar shaped
21
Q
What is the folded inner membrane of a mitochondrion known as?
A
Cristae
22
Q
What are Lysosomes?
A
Cellular stomachs
They contain amorphous granular materials which help break down bacteria and debris
23
Q
The packaging and processing of secretory proteins, as well as the synthesis of complex polysaccharides, occurs in what organelle?
A
Golgi apparatus
24
Q
Peroxisomes contain catalases and oxidases, what function do these have?
A
Catalases regulate hydrogen peroxide concentration
Oxidases are involved in the ß-oxidation of long chain fatty acids
25
What is the name given to the irregular structure formed by a single circular chromosome in prokaryotes?
Nucleoid
26
What is the main function of fimbriae?
Adherance
27
What is the main function of flagella?
Movement
28
What does the nuclear membrane/envelope consist of?
A double lipid bilayer - inner nuclear membrane and outer nuclear membrane
29
What molecules are peptide bonds usually formed between?
Amino acids
30
A peptide bond is formed in a reaction between what two functional groups?
Carboxyl and amino
31
The formation of a peptide bond is what kind of reaction?
Condensation / dehydration synthesis
32
What is released in the formation of a peptide bond?
A water molecule
33
Disulphide bridges are formed between cysteine residues (thiol group) by what process?
Oxidative folding
34
The formation of disulphide bridges is involved in the formation of what protein structure?
Tertiary
35
Sickle cell anaemia is caused by a change in how many nucleotides?
One
36
What kind of mutation occurs in sickle cell anaemia?
Nucleotide Substitution - A is substituted with T, changing codon sequence for amino acid 6 from GAG to GTG
37
Haemoglobin in a person with sickle cell anaemia is referred to as what?
HbS
38
What is covalent bonding?
Sharing of electron pairs between two non-metal atoms
| Stable balance of attractive and repulsive forces
39
What is glucose converted to in the liver?
Glycogen
40
Is glycogen formed directly from glucose?
No
41
What does Glycogenin do in the conversion of glucose to glycogen?
Covalently binds glucose from UDP-glucose to form chains of approximately 8 sub units
42
What extends chains until they are broken by glycogen branching enzyme?
Glycogen synthase
43
What is the net gain of ATP per glycolysis cycle?
2 ATP
44
What phases does glycolysis consist of?
Preparatory Phase
| Payoff Phase
45
Do the reversible reactions in glycolysis have a positive or negative ∆G value?
Positive
46
In the preparatory phase: from 1 molecule of glucose, 2 molecules of what are produced to enter the payoff phase?
G-3-P
47
There are 2 irreversible reactions in the preparatory phase, what kind of reactions are they?
Phosphorylation
| phosphorylation of glucose, phosphorylation of F-6-P to F-1,6-bisP
48
What catalyst is involved in the conversion of triose sugars in reaction 5 of the preparatory phase?
Triose phosphate isomerase
49
How many molecules of ATP are used in the preparatory phase per glycolysis cycle?
2 ATP
50
What steps of the payoff phase are energy coupled reactions?
Steps 6 and 7
| oxidation of G-3-P to 1,3-bisPG and phosphate transfer from 1,3-bisPG to ADP
51
How many molecules of NADH are produced in the oxidation of G-3-P to 1,3-bisPG?
(if you take into account that reactants are doubled from this step of glycolysis)
2 NADH
52
What molecule is produced in the dehydration of 2-PG to PEP?
H2O
53
During what reactions of the payoff phase are ATP molecules produced?
Step 7 - phosphate transfer from 1,3-bisP to ADP, 2 ATPs produced
Step 10 - Transfer of phosphate from PEP to ADP, 2 ATPs produced
54
What reactions in the payoff phase are highly exergonic so spontaneous?
Step 7 - phosphate transfer from 1,3-bisP to ADP, 2 ATPs produced
Step 10 - Transfer of phosphate from PEP to ADP, 2 ATPs produced
55
Reactants are doubled from what step in glycolysis?
Step 6 - oxidation of G-3-P to 1,3-bisP
56
What molecule needs to be regenerated in order for glycolysis to occur?
NAD+
57
In what step of glycolysis is pyruvate produced?
Step 10 - transfer of phosphate from PEP to ADP
58
What kind of reaction is the process of NAD+ being reduced and NADH being oxidised?
Redox balance
59
What is the fate of pyruvate produced in glycolysis under aerobic conditions in animal cells?
Converted into Acetyl CoA which enters the citric acid cycle
60
What kind of cells do not rely solely on glucose as an energy source (under normal conditions i.e. not during starvation) and what do they use instead?
Muscle cells
Fatty acids
(specifically oxidative type 1 muscle fibre)
61
For every citric acid cycle how many CO2 molecules are produced?
2
62
What 3 other molecules are produced in the citric acid cycle (not CO2)?
3 NADH
1 FADH2
1 GTP
63
Where in a cell does glycolysis occur?
Cytoplasm
64
What is oxidative phosphorylation and where does it occur?
Mechanism for ATP synthesis
| Occurs in mitochondria
65
Where in a cell does fatty acid synthesis occur?
Cytosol
66
The Krebs cycle and citric acid cycle occur where?
Mitochondrial matrix
67
Where in a cell does the pentose-phosphate pathway occur?
Cytosol
68
The electron transport chain is the final stage in what?
Respiration
69
Where does the electron transport chain take place and how many proteins in the membrane does it involve?
Mitochondrial matrix and intramembrous space
| 4 proteins
70
What two proteins in the electron transport chain reduce a molecule and pass the electrons to Ubiquinone to form Ubiquinol?
NADH-Q Oxidoreductase - reduces NADH
| Succinate Q Reductase - reduces FADH2
71
Where does Q Cytochrome C Oxidoreductase pump H+ ions?
Into the intramembrous space
72
What does Cytochrome C Oxidase do?
Takes electrons from cytochrome C and passes them to oxygen
| Pumps protons into intramembrous space
73
What does the pumping of protons in the electron transport chain set up?
A proton gradient across the inner membrane of the mitochondrion
74
Proton motive force does what?
Allows proton gradient to work
75
What does ATP-synthase do with the energy released as the protons pass through the membrane protein and what is this system known as?
Use it to add ADP + Pi to form ATP
| Binding change mechanism
76
What are the purposes of lipids?
```
Stored form of energy
Structural component of cell membranes
Needed as enzyme cofactors
Used in hormones
Used for the synthesis of vitamins A, D, E and K
Used as a signalling molecule
```
77
What are the 3 major lipid classes?
Fatty acids
Triglycerides
Phospholipids
78
What are Linoleic acid and A-Linoleic acid examples of?
Essential fatty acids
79
How must essential fatty be obtained by humans?
From plants in our diet
80
Give an example of a good fat
Plant oils e.g. sunflower oil
81
What are bad fats high in?
Saturated fatty acids
82
Trans fatty acids are found in what?
(Really) bad fats
83
What class of lipids coalesce into droplets in water?
Triglycerides
84
What are phospholipids composed of?
Glycerol + 2 fatty acids + phosphate
85
What class of lipids are amphipathic?
Phospholipids
86
What class of lipids are a major component of adipose tissue?
Triglycerides
87
What are the main dietary lipids?
Triglycerols
88
Triglycerols are digested in the small intestine through the use of what?
Pancreatic enzymes
Emulsification by bile salts
Peristalsis
89
Why is homeostasis important?
The body needs the internal environment (extracellular fluid) to be maintained in a state compatible with cell survival
90
What proportion of the extracellular fluid is interstitial fluid?
80%
91
What proportion of the extracellular fluid is plasma?
20%
92
What is negative feedback control?
Detection of change in an internal factor by receptors
Change fed to integrating centre and compared to reference level
If there is a difference, signal is sent to an effector and the change is negated
93
The magnitude of an error signal is proportional to what?
Size of the response and the deviation
94
The skin detecting minor changes in temperature before core temperature is affected is an example of what kind of control?
Feed-forward control
| changes anticipated before significant changes occur
95
What proportion of total body water is intracellular fluid?
2/3
96
What is tonicity?
The relative concentration of two solutions separated by a semi-permeable membrane that determine the direction and extent of diffusion
97
What is osmolarity?
The measure of solute concentration i.e. number of osmoles of solute per litre of solution
98
What is osmolality?
The measure of osmoles of solute per kilogram of solvent
99
If the ECF has a higher osmolarity than the ICF, will the solution be hypertonic or hypotonic?
Hypertonic
100
What would happen to cells in a hypertonic solution?
The cells will shrink as water leaves via osmosis
101
If the ECF has a lower osmolarity than the ICF, will the solution be hypertonic or hypotonic?
Hypotonic
102
What would happen to cells in a hypotonic solution?
They would swell (and burst)
103
What kind of solution has an equal number of penetrating and non-penetrating solutes on either side of the membrane?
Isosmotic
104
What kind of solution has an equal number of non-penetrating solutes on either side of the membrane?
Isotonic
105
What is endocytosis?
Invagination of membrane to form a vesicle around a target substance
106
What process involves the fusion of a vesicle membrane with the plasma membrane followed by the expulsion of the vesicle contents?
Exocytosis
107
The sodium-potassium pump does what?
Pumps 2 K+ into the cell, pumps 3 Na+ out of the cell
108
What is the resting membrane potential and why is it this value rather than the theoretical value?
-70mV
| Due to the permeability of the membrane to other ions and leaky ion channels
109
What is the axon hillock?
Specialised part of the soma that connects to axon
| Last site in soma where the membrane potentials propagated from synaptic inputs are summated before transmission to axon
110
What are the main cells responsible for the functions of the nervous system?
Neurones
111
Why are dendrites important?
They are an important route for information from other neurones
112
The information for making an action potential is collected where?
Initial segment
113
Where is the neurotransmitter released from?
Axon Terminal
114
Are action potentials graded or all or nothing?
All or nothing
115
What kind of potentials are self-propagating?
Action potentials
116
When the threshold for firing an action potential is reached, voltage gated Na+ channels open and Na+ rushes in causing what?
Huge depolarisation of the neuron
117
Graded potentials transmit over what distances?
Short
118
Are inhibitory graded potentials hyperpolarising or depolarising?
Hyperpolarising
119
Voltage gated channels change their conformation when
Changes in electrical potential act on charged regions of the channel proteins
120
Acetylcholine receptors are an example of what kind of gated channel?
Ligand gated
121
What are the 3 types of neurones?
Afferent (sensory)
Interneurones
Efferent (motor)
122
What neurones carry a signal to effector cells/tissue?
Efferent (motor)
123
Larger axons allow
Faster transmission
124
The normal effect of a receptor is mimicked by
Agonists
125
The normal action of a receptor is blocked by
Antagonists
126
As agonist concentration increases, it's effect
Increases
127
What are the largest family of membrane receptors?
G protein coupled receptors
128
G protein coupled receptors coupled to Adenylyl Cyclase can increase/decrease the concentration of cAMP and do what to PKA?
Activate/inhibit
129
What is albumin?
The main protein of human blood plasma
130
What is the main function of albumin?
To regulate colloidal osmotic pressure of blood
131
What does epithelial tissue cover and separate?
Covers surfaces and separates body compartments
132
Does epithelial tissue have contact inhibition?
No
133
Cell-cell junctions contain desmosomes to provide
Firm anchorage
134
What do gap junctions allow?
Cell-cell communication
135
Hemidesmosomes are found in what junctions?
Cell-ECM
136
Give an example of simple squamous epithelium
Alveoli
| Capillaries
137
Give an example of simple cuboidal epithelium
Lining of nephrons
138
Give an example of simple columnar epithelium
Lining of the digestive tract
139
Give an example of stratified squamous epithelium
Epidermis
140
Give an example of stratified cuboidal epithelium
Ducts of sweat glands
141
Give an example of stratified columnar epithelium
Pharynx
142
What simple epithelium type is thin to allow easy diffusion?
Squamous
143
What epithelium type moves mucus when ciliated?
Simple columnar
144
What type(s) of squamous epithelium provide protection
Cuboidal
| Columnar (also secretion)
145
Epithelial cells in the kidneys are arranged into what?
Nephrons
146
What are glands?
Collections of multi or single cellular secretory epithelial cells
147
What do endocrine glands do
Secrete into blood
148
What do exocrine glands do
Secrete to surface
149
Sweat glands are an example of what type of gland?
Exocrine
150
What system produces a "fight or flight" response when activated?
Sympathetic
151
Which system causes an increase in gut motility when activated?
Parasympathetic
152
Stored energy is released at the activation of what system?
Sympathetic
153
Ganglia are usually paravertebral in what system?
Sympathetic
154
What is divergence?
When one preganglionic fibre activates lots of post ganglionic fibres
155
Noradrenaline acts in what system on what receptors?
Sympathetic system
| Alpha or Beta
156
Acetylcholine acts on what receptors in the parasympathetic system?
Muscarinic
157
The skull, vertebral column and ribs are parts of what skeleton?
Axial
158
The shoulder girdle and pelvis are parts of what skeleton?
Appendicular
159
What is the function of Osteoclasts?
Bone resorbing cells - absorb any area of damaged bone
160
What is the function of Osteoblasts?
Laying down new bone
161
What is the function of Osteocytes?
To act as sensors of mechanical pressure and damage
162
What movement does the anterior compartment of the upper arm allow?
Flexion of elbow joint
163
What compartment of the arm allows the extension of the elbow joint?
Posterior
164
What is the major blood supply to the arm?
Brachial artery
165
What plexus innervates the arm?
Brachial plexus
166
The anterior compartment of the forearm is responsible for what movement(s)?
Flexion
| Pronation
167
The compartment allowing extension and supination of the arm is what?
Posterior compartment of forearm
168
What nerve supplies all extensor muscles in the upper limb?
Radial nerve
169
What compartment of the thigh are the hamstrings?
Posterior
170
What movement are the hamstrings responsible for?
Flexion of knee
171
What nerve supplies the anterior compartment of the thigh?
Femoral nerve
172
The sciatic nerve supplies what thigh compartment?
Posterior
173
Obturator nerve supplies what thigh compartment?
Medial
174
What thigh compartment is responsible for adduction?
Medial
175
What lower leg compartment everts the foot?
Lateral
176
The deep fibular nerve supplies what lower leg compartment?
Anterior
177
Ankle is flexed and foot is inverted by what compartment?
Posterior compartment of lower leg
178
What movements occur at the subtalar and transverse talar joints?
Inversion and eversion of foot
179
What kind of joints are present at the elbows and knees?
Synovial hinge
180
What kind of joints are present at the hips and shoulders?
Synovial ball and socket
181
What plexus is composed of fibres from vertebral levels L1-S5?
Lumbosacral
182
If a ventral rami is damaged, what function will be lost?
Sensory and motor, as it is a mixed nerve
183
If a nerve is cut at the motor ventral root, what function will be lost?
Motor
184
Where is the T4 dermatome?
Skin over nipples
185
Where is the T10 dermatome?
Skin over umbilicus
186
What are the functions of the vertebral column?
Weight bearing
Protection
Permits movement
Site of muscle attachments
187
What kind of joints are between vertebrae and intervertebral discs?
Secondary cartilaginous
188
What is the C2 vertebra commonly known as?
Axis
189
The vertebra prominens is at what vertebral level?
C7
190
T7 vertebra is the
Inferior tip of scapula
191
Superior aspect of iliac crest is at what vertebral level?
L4
192
The posterior superior iliac spine is at what vertebral level?
S2
193
How many cervical, thoracic, lumbar, sacral and coccygeal vertebrae are there?
```
C - 7
T - 12
L - 5
S - 5
Cc - 3-5
```
194
The head of the rib articulates with what?
Facet on the vertebral body
195
The tubercle of the rib articulates with what?
The transverse process facet of vertebrae
196
What kind of joint is found at the atlantoaxial joint?
Synovial pivot
197
What kind of joint is found at the antlanto-occipital joint?
Synovial ellipsoid
198
What movement occurs at the atlanto-occipital joint?
Flexion
Extension
Lateral flexion
199
What are the main functions of the lymph system?
Tissue drainage
| Return of plasma proteins
200
Lymph fluid consists mainly of
Fluid and plasma proteins (but it gains lymphocytes as it flows through lymphatic capillaries)
201
What type of lymphatic drainage follows arteries?
Deep
202
Inguinal lymph nodes in and around the femoral triangle at the base of the lower limb are an example of what kind of lymph nodes?
Superficial
203
What two ducts does lymph fluid drain to?
Right lymphatic duct
| Thoracic duct
204
The lymphatic ducts empty into the venous system at
The jugular/subclavian junction
205
What is aetiology?
Cause of disease
206
What is pathogenesis?
How a disease develops
207
What is prognosis?
Prediction of probable outcome
208
What are the functions of the cytoskeleton?
Strength
Support
Allows cell motility
209
Abnormal bone marrow/blood can lead to
Leukaemia
210
What layers does the skin consist of?
Epidermis (epithelia)
Dermis (connective tissue)
Hypodermis (fat)
211
In what molecules in the body is nitrogen mainly found?
Amino acids
Ammonia
Urea
212
What is the only amino acid that can obtain nitrogen from ammonia?
Glutamate
213
Other amino acids obtain nitrogen from pre-existing amino acids through what reactions?
Transaminase
214
Nitrogen is transferred using
Glutamine and alanine
215
Nitrogen transferred from catabolised protein in muscle cells is transported back to the liver as alanine where it is converted back to glucose, what enzymes does this process involve?
Transferase enzymes
216
Why is nitrogen transferred as glutamine and alanine rather than glutamate?
Glutamate has a negative charge so
- would require a cation
- won't pass readily through cell membranes
Glutamine and alanine have no charge
217
What is urea formed from?
Ammonia
218
Ammonia is formed through?
Oxidative deamination (where glutamate loses nitrogen in the form of ammonia
219
Ammonia is fed into what cycle?
The urea cycle, where it is converted to urea and excreted
220
What is the most common urea cycle disorder?
Ornithine transcarbamylase (OTC) deficiency
221
What kind of inheritance is involved in the most common urea cycle disorder?
X-linked
222
What is Phenylketonuria?
An absence or deficiency of phenylalanine hydroxylase (PAH)
223
What kind of disease is PKU?
Autosomal recessive
224
If untreated, what will PKU lead to by 6 months of age?
Delayed mental development and neurological features
225
How is PKU diagnosed?
Neonatal screening offered in UK, if screening test is positive, quantitative amino acid analysis is carried out to confirm diagnosis
