IMMS Flashcards
1
Q
what are the structures and functions of mitochondria?
A
Cytosol - site of glycolysis
Matrix - site of Krebs cycle
Cristae - Site of electron transport chain and CHEMIOSMOSIS
Inner membrane - Has ATP synthase allows flow of H+ from ETC to produce ATP
2
Q
What is chemiosmosis?
A
Movement of ions across semipermeable membrane down their electrochemical gradient. E.g ATP gen via movement of H+
3
Q
Function of Ribosomes
A
Protein synthesis
4
Q
Function of Rough ER
A
Synthesis and processing of proteins - network of branching sacs with ribosomes attached.
5
Q
Function of Smooth ER
A
Contains enzymes for synthesis of lipids
6
Q
Function of Golgi apparatus
A
Processing and packaging of proteins
7
Q
Function of cytoskeleton
A
Structural support, movement of materials (i.e vesicles)
8
Q
Function of nucleus
A
Contains genetic information, assembles ribosome subunits (RNA)
9
Q
Function of lysosomes
A
Contains acid hydrolases for digestion and recycling.
10
Q
Function of peroxisomes
A
Fatty acid and ethanol oxidation, contains catalase (converts hydrogen peroxide —-> water + oxygen.
11
Q
What is lipofuscin?
A
yellow-brown pigment granules made from lipid-containing residues of lysosomal digestion. (perioxidation of lipids)
12
Q
Where are lipids stored in the body?
A
stored in adipocytes (as tryglycerides) in cell membranes in lipoproteins (HDL&LDL)
13
Q
Where is glycogen stored?
A
Stored in liver and muscle
how excess glucose is stored-converted by glucagon from pancreas
14
Q
Describe the structure of the cell membrane
A
Phospholipid bilayer-fluid mosaic model.
15
Q
What does a cell membrane contained?
A
Cholesterol - binds together phospholipids
Proteins - Channel and carrier - for transport
Glycolipids/proteins - cell signalling
16
Q
Functions of a cell membrane
A
Partially permeable membrane
site of membrane receptors
regulates what goes in and out of the cell
Acts a barrier separates IC (intracellular) from EC
17
Q
Describe simple diffusion
A
the passive movement of particles from a region of high conc to low conc through partially permeable membrane.
SMALL NON POLAR molecules
18
Q
Describe facilitated diffusion
A
Transport of particles through pp membrane using a carrier molecule.
LARGE AND POLAR
19
Q
Describe active transport
A
movement of particles from a low to a high concentration using ATP - usually requires carrier molecule.
20
Q
Cell junctions
A
Tight junction Adherens Junction Desmosome hemidesmosome Gap junction
21
Q
Describe a tight junction
A
Seals neighbouring cells together in epithelial sheet
prevents leakage of molecules.
22
Q
Describe an adherens junction
A
Joins an actin bundle in one cell to a similar bundle in another cell.
23
Q
Describe a desmosome.
A
Joins the intermediate filaments in one cell to those in a neighbouring cell.
24
Q
Describe a hemidesmosome
A
anchors intermediate filaments in a cell to a basal lamina
25
Describe the purpose of a Gap junction
Allows the passage of small water-soluble ions and molecules.
26
Define homeostasis.
the maintenance of a constant internal equilibrium - despite external changes.
27
Describe the major communication systems involved in homeostasis.
Endocrine (hormones)
nervous (neurotransmitters)
immune (antibodies, and immune chemical messengers i.e cytokines).
28
Describe positive feedback.
amplification of a signal e.g oxytocin release during childbirth - clotting cascade.
29
Describe negative feedback.
bearing towards an equilibrium i.e thermoregulation , blood glucose regulation
30
Define Autocrine cell communication
Chemical released from cell into ECF and acts upon itself
31
Define paracrine
Local cellular communication; travels short distances i.e ACh at NMJ. These travel in ECF
32
Define endocrine.
Secretion into blood NOT via duct. Long distance communication i.e. HPA axis
33
Define exocrine.
Secretion via ducts into organ i.e (salivary and sweat glands.
34
What are the three modes of secretion?
Merocrine
Apocrine
Holocrine
35
Merocrine secretion is when?
No part of the cell is lost with secretion
36
Apocrine secretion is when?
The top part of the cell is lost with secretion.
37
Holocrine secretion is when?
The entire cell is lost with secretion.
38
Based on an average 70kg male what is the total water content?
42L (~60%)
39
Describe the water distribution in a 70 kg male.
42L Total -->28L ICF
| 14L ECF ---> Interstitial fluid 11L and Plasma (intravascular) 3L
40
Define Osmosis
The net diffusion of water across a PP membrane from a region of high water potential to a region of low water potential.
41
Define osmolality
Total solute conc of a solution: number of solute particles per 1kg of solvent (HIGHER osmolality = LOWER water potential)
42
Define osmolarity
Total solute conc of a solution: number of solute particles per 1L of solvent (HIGHER osmolality = LOWER water potential)
43
Define osmotic pressure
The pressure that must be applied to one side of a membrane to prevent osmotic flow of water across the membrane from a compartment of pure water.
44
Define Oncotic Pressure
A form of osmotic pressure exerted by proteins (albumin)
45
Study the RAAS diagram
understand what acts on what
46
Normal water levels are when
excess water in the intracellular tissue space
47
What is inflammatory Oedema
Increased vascular permeability causes proteins to leak out;water follows proteins.
Fibrinogen polymerizes to form fibrin mesh - antibodies collect.
48
Venous oedema
Due to increased venous pressure/ obstruction i.e. thrombus.
49
Lymphatic Oedema
Caused by blockage of lymphatic system from tumour / parasite
50
What are 3 causes of Hypernatremia
renal failure, mineralcorticoid excess, diabetes insipidus
51
What is a consequence of hypernatremia
Cerebral intracellular dehydration
52
what are causes of Hyponatremia
diuresis, oedema, excess IV fluids
53
what are consequences of hyponatremia
intracellular overhydration,hypotension
54
What are 3 causes of hyperkalaemia
renal failure, diuretics, ACE inhibitors
| ACE produces aldosterone - aldosterone controls na/k pump
55
what are 3 consequences of hyperkalaemia
risk of MI- high K+ levels interfere with resting potential for heart contraction
56
what are 3 causes of Hypokalaemia
D&V, alkalosis, hypomanesaemia
57
consequences of Hypokalaemia consequences?
weakness, cardiac dysrhythmia
58
Causes of Hypercalcemia
10 hyperparathyroidism (Calcium ions leached from bone, increasing blood calcium), vit D toxicity, TB, skeletal metastases
59
consequences of hypercalcemia
metastatic calcification (calcium deposition; forming stones)
60
causes of hypocalcemia
vit D deficiency, Mg deficiency, renal disease, parathyroidectomy
61
Consequences of Hypocalcemia
tetany (spasms of hands, feet, voice box)
62
General formula for carbohydrate
CnH2nOn
63
What is a tryglyceride
3 fatty acids + glycerol
| melting point decreases with degree of unsaturation
64
What is a phospholipid
Glycerol, 2 fatty acids, phosphate group
| Hydrophilic phosphate head, hydrophobic fatty acid tail.
65
Define Lipoproteins
```
HDL = GOOD = transports cholesterol to the liver to be metabolized
LDL = BAD = transports cholesterol to the cells
```
66
Define primary protein
A sequence of amino acids
67
Secondary protein
Local folding - alpha helix or beta pleated sheets
68
Supersecondary protein
Intermediate be secondary and tertiary
| Zinc finger, helix-turn-helix, beta-alpha-beta, beta-hairpin. Just know an example!
69
Tertiary protein
3D folding pattern due to chain interactions
70
Quaternary protein
Protein consisting of more than one amino acid chain.
71
Enzymes
Biological catalysts – reduce the activation energy of a reaction
Large, globular proteins
Do not change their structure during the reaction
Lock and Key model
Induced fit model
Very specific to the reaction they are catalysing
72
Coenzymes
Non-protein compound necessary for the normal functioning of an enzyme
Small, organic molecules
Bind to the active site of an enzyme, activating it
Change in structure during the reaction; bind to functional groups released from the reaction
Less specific
73
Three characteristics of human DNA replication
Semi-conservative, non-continuous, universal
74
What is the role of Topoisomerase in DNA replication
Relieves supercoils, unwinding the double helix
75
What is the role of DNA Helicase in DNA replication
Breaks hydrogen bonds between the two strands, exposing nucleotides
76
What is the role of DNA polymerase in DNA replication
Reads 3’ to 5’. Prints 5’ to 3’. Works in pairs to make 2 strands of new DNA. Semi-conservative as one strand is preserved. Starts at primer
77
What is a primer (DNA replication)
short strand of DNA – acts as a starting point for DNA synthesis as DNA polymerase can only add nucleotides to an existing strand
78
What is a Single strand binding protein (SSB)
– keeps the two DNA strands apart during the synthesis of new DNA – prevents annealing
79
First stage of transcription
Topoisomerase unwinds the DNA double helix (relieves supercoils)
SSBs coat the DNA strand to prevent annealing
80
Second stage of transcription
Free mRNA nucleotides line up against their complementary bases on the template - begins at promoter region
81
Third stage of transcription
Antiparallel mRNA strand formed - from 5' to 3'
| mRNA leaves nucleus and attaches to 80S ribosome in cytoplasm
82
First stage of translation
mRNA attached to 80S ribosome
| tRNA molecules have anticodons complementary to the codons on the mRNA strand on one end and an amino acid on the other
83
Second stage of translation
Once two tRNA molecules are adjacent a peptide bond forms between the amino acids
84
Third stage of translation
Process of peptide bonds forming stops once stop codon is reached
At stop codon no tRNA binds, so then the polypeptide is released into the cytoplasm
85
What is a missense mutation
When a DNA nucleotide is switched out for another resulting in a different amino acid being coded for.
86
What is a nonsense mutation
When the switch in nucleotides results in a stop codon being coded for
87
What is a silent mutation
When a nucleotide is switched out but the same amino acid is coded for
88
First 4 stages of mitosis in order
```
Interphase
Prophase
Prometaphase
Metaphase
(LEARN WHAT THE STAGES LOOK LIKE)
```
89
Last 3 stages of mitosis in order
Anaphase
Telophase
Cytokinesis
90
Describe what happens in prophase
nuclear envelope breaks down, chromosome condenses and become visible - CROSSING OVER OCCURS
91
Describe what happens in prometaphase and metaphase
Prometaphase - spindle fibres begin to form
Metaphase - chromosomes line up along the metaphase plate, each sister chromatid attached to spindle fibres from opposite poles.
92
Describe what happens in Anaphase
Centromeres split in two. sister chromatids pulled towards opposite poles
93
Describe what happens in Telophase
nuclear envelope begins to reform, cleavage begins to form, spindle breaks down
Then cytokinesis and two new cells form
94
Describe meiosis
Production of sex cells by reducing their chromosome number in half
2n -> 4n -> 2n -> n
Creates genetic variability in the gametes
95
Name 3 genetic abnormalities
Non-disjunction
Numerical
Structural
96
What is Non-disjunction
When homologous chromosomes fail to separate properly during cell division
97
What is a numerical genetic abnormality
A type of chromosomal defect; different number of chromosomes i.e 47XXY (Klinefelter Syndrome)
98
What is a structural genetic abnormality
When parts of an individual chromosome is missing, duplicated, transferred to another chromosome, or turned upside down. (Insertion, translocation)
99
What is mosaicism
Mosaicism is when a person has 2 or more genetically different sets of cells in his or her body.
100
What is gonadal mosaicisim
More than one set of genetic information is present-specifically in gamete cells
All or part of a parental germline is affected by disease mutation, but the parental somatic cells aren't affected
May or may not affect offspring
101
Example of gonadal mosaicism
Osteogenesis imperfecta
102
What is a phenotype
The observable characteristics of an individual derived from the genotype and it's interaction with the environment
103
What is a genotype
The genetic constitution of an organism
104
What is a Karyotype
The number and visual appearance of the chromosomes in the nuclei of an organism
105
What is Mendelian inheritance
pattern of inheritance following the laws of segregation and independent assortment
106
What is multifactorial inheritance
where both genetic and environmental factors produce a trait or condition
107
What is Mendel's 2nd Law
Independent assortment
Each pair of genes separate independently of each other in the production of sex cells - gene pairs on separate chromosomes assort independently at meiosis
108
what are the patterns of inheritance
Autosomal dominant/recessive
Sex linked
Pedigrees
Lyonization (X inactivation)
109
What is sex (x) linked inheritance
Gene causing the trait is located on the X chromosome
| Men only have one so will definitely inherit the trait.
110
What is lyonization?
Process by which one of the X chromosomes can be inactivated in females
111
What is Knudson's 2-hit hypothesis
Sporadic cancers - require 2 acquired mutations to become malignant
Inherited cancers - only require 1
112
Name 3 Genetic diseases
```
Down syndrome (trisomy 21)
Edwards syndrome (trisomy 18)
Patau syndrome (trisomy 13)
```
113
Name 3 Multifactorial diseases
Cleft lip/palate
Diabetes
Schizophrenia
114
Name 3 Environmental diseases
Poor diet - Kwashiorkor
Infection
Drug related illness
115
What is penetrance ( in relation to genes)
The proportion of individuals carrying a particular gene (genotype) that also express an associated trait
116
What is variable expression
When one genotype can produce a range of different of phenotypes i.e one individual may be more severely affected than the other.
117
What is sex limitation
Genes present in both sexes but only expressed in one, and remains turned off in the other.
118
Define metabolism
Chemical processes that occur in the body to maintain life
119
Define Basal Metabolic Rate
the amount of energy needed to keep the body alive in the resting state
120
What is the BMR in humans
1kcal/kg body mass / hr
121
Name 3 factors that increase BMR
High BMI
Hyperthyroidism
Pregnancy
122
Name 3 factors that decrease BMR
Age
Females compared to males
Starvation
123
What is the equation for the ADP - ATP cycle
ADP + phospate --> ATP
124
What is glycolysis
The formation of pyruvate from glucose
| OCCURS IN CYTOPLASM
125
What are the first 4 steps of glycolysis
```
Glucose + ATP (used)
Glucose-6-phosphate
Fructose-6-phosphate + ATP (used)
Fructose-1,6-bisphosphate
Glyceraldehyde-3-phosphate
Dihydroxyacetone phosphate
```
126
What are the last steps of glycolysis
```
Glyceraldehyde-3-phosphate
1,3-bisphosphoglycerate + NADH (produced)
3-phosphoglycerate + ATP (produced)
2-phosphoglycerate
Phosphoenolpyruvate + H2O (produced)
PYRUVATE
```
127
What are the enzymes used in the first 4 steps of glycolysis
Hexokinase
Phosphohexose isomerase
Phosphofructokinase-1
Fructose Bisphosphate Aldolase
128
What are the enzymes used in the last steps of glycolysis
```
Triose phosphate isomerase (Side step)
Glyceryaldehyde-3-phosphate dehydrogenase
Phospoglycerate kinase
Phosphoglucerate mutase
Enolase
Pyruvate kinase
```
129
How is pyruvate converted into Acetyl CoA
Pyruvate + CoA + NAD+ -----> Acetyl CoA + NADH + H+
130
What is the pneumonic for Krebs' Cycle
Can I Keep Selling Socks For Money Officer
131
What are the First 4 Steps in Krebs
```
Oxaloacetate + acetyl coA
Citrate (H2O and CoA produced biproduct)
Isocitrate
α- ketoglutarate (NADH + H+ and CO2 biproduct)
Succinyl Co-A ( NADH + H+ biproduct)
```
132
What are the last 4 steps in Krebs
Succinate (GDP -> GTP) and ( ATP to ADP) biproducts
Fumarate (FADH2 biproduct)
Malate (H20 biproduct)
Oxaloacetate (NADH + H+ biproduct)
133
Pneumonic for the enzymes in Krebs'
Amy Is Keeping Some Socks For My Cat
134
First 4 enzymes in krebs
Aconitase
Isocitrate Dehydrogenase
α-Ketoglutarate dehydrogenase
Succinyl Coenzyme A synthetase
135
Last 4 enzymes in krebs
Succinate dehydrogenase
Fumurate Hydratase
Malate dehydrogenase
Citrate synthase
136
Oxidative phosporylation first steps
Electrons are passed down the ETC through a series of redox reaction - they release energy as they go
Energy used to pump H+ into intermembrane space
137
Oxidative phosporylation later steps
H+ move through ATP synthase into matrix down a conc gradient ADP converted to ATP
O2 is terminal electron acceptor - it splits into two separate atoms that bind to H+ to form water
138
What is fatty acid beta-oxidation
The production of ATP from fat sources e.g diet or storage using beta- oxidation
139
What are the first steps of fatty acid beta oxidation
Acetyl CoA
Acyl CoA loses CoA
Carnitine and Acyl Carnitine
Carnitine excess formed into Acyl Carnitine via Carnitine acyltransferase 1
140
What are the final steps of fatty acid beta oxidation
Acyl Carnitine gains CoA and forms Acyl CoA
| Acyl CoA goes on to be oxidised
141
Overall equation of fatty acid beta oxidation
Acyl CoA - 2 Carbons(At beta position) = 1 mol (NADH + FADH2 + Acetyl CoA)
142
What is Ketogenesis
Production of ketones to provide an alternative source of energy for the body
143
When does Ketogenesis occur
During starvation
excessive exercise
in some diabetic patients.
144
What is an acid
Proton Donor
145
What is a base
Proton acceptor
146
What is a strong acid
An acid that completely dissociates in solution to form h+ ions and a base
147
What are weak acids or baces
Only partially ionise in solution
148
What are buffers
Weak acids or bases with the conjugate base or acid respectively
149
What is unique about buffers
They resist change in pH when small quantities of strong acids or bases are added; limits change in [H+]
150
What is the Henderson Hasselbach equation
pH = pKa + log( [A-] / [HA] )
151
What is the ideal body pH
7.40
| Normal range between 7.35 - 7.45
152
What are the main body buffer systems
Bicarbonate - MOST IMPORTANT
proteins - mainly ALBUMIN
Haemoglobin
CO2 elimination - Respiratory system
153
How does bicarbonate contribute to the buffer system
H2CO3 ---> HCO3- + H+
154
How do proteins contribute to the buffer system
Most contain weak acidic and basic groups
155
How does haemoglobin contribute to the buffer system
Binds both CO2 and H+ so a powerful buffer
Deoxygenated Hb has strongest affinity for CO2 & H+
so most effective buffer in the tissues.
156
In what two ways is Oxygen toxic
ROS = Reactive oxygen species
| Hydroxyl radical - most potent (OH-) lipid soluble can damage
157
How are free oxygen radicals toxic
Free radicals contribute to ageing homeostasis and some cancers.
158
How are hydroxyl radicals formed
Fenton reaction
| Haber-weiss reaction
