Learning outcomes

Question 1

Define aetiology and pathogenesis

Answer 1

Aetiology = cause of disease
Pathogenesis = how it develops

Question 2

Define symptoms and signs

Answer 2

Symptom = what patient feels
Sign = our (doctors) observations

Question 3

Define diagnosis and prognosis

Answer 3

Diagnosis =  Defined abnormalities 
Prognosis = Predicted outcome

Question 4

Define natural history and classification of disease

Answer 4

Natural history = course of disease without treatment
Classification of disease:
1. Inflammation - Response of living tissue when injured
2. Circulatory disturbances - Abnormalities of blood components, vessels or flow.
3. Disorders of growth - Abnormal cell growth (types - maturation, differentiation, control, quantity)
4. Degenerative disease - Abnormalities of tissue and organs
5. Developmental - Abnormalities in the genetic information of gametes or embryos (gametogenesis and embryogenesis)
6. Unnatural - Traumatic (accident) and Iatrogenic (as a result of treatment)

Question 5

Understand the general organisation of the body systems

Answer 5

The body is made up of cells. A group of cells that share the same characteristics or specialisation and perform the same function are called tissues. A collection of tissues usually of different types that synchronise to perform a more complex function is called an organ. When multiple organs work in synchrony this is known as a organ system. Multiple organ systems working together creates an organism.

Organ systems are designed to support the production of energy. The study of how the systems function and work together is called physiology. Each system has a role in maintaining life. Therefore their role can be shown in relation to the equation of life. Nutrients + O2 = Energy (ATP) + waste (incl. CO2)

Question 6

Be able to outline the role of each major system in maintaining health and optimal
homeostasis

Answer 6

Cardiovascular System = Delivers O2 and nutrients to cells, removes waste from cells
Respiratory System = Acquires O2, disposes of CO2
Gastrointestinal System = Acquires nutrients, disposes of waste (faeces)
Renal System = Disposes of waste (urine)
Musculoskeletal System = Sources nutrients (allows you to find and eat food), removes us from danger, protects from threat (allowing us to continue living and eating).
Immune System = Protects us from infection (conserving energy? and allowing other systems to function)
Nervous System = Coordinates other systems
Endocrine System = Coordinates other systems, major role in allowing cellular access to nutrients that have been absorbed. (Takes nutrients from blood to cells)
Reproductive System = Ensures continuation of life

Question 7

Define the term homeostasis

Answer 7

The prevention of the disturbance in the system is known as homeostasis.

Question 8

Explain the importance of maintaining constancy of the internal environment

Answer 8

Our bodies are not very tolerant to change and therefore are constantly monitoring their internal state and responding to any threat to a change in there ‘similar internal conditions’.
Failure to adequately correct imbalances results in illness and disease, or pathology (Latin for suffering).
For example if you ate a sugary donut, glucose is absorbed across intestinal tract and the hormone insulin is released to remove glucose from the blood almost as fast as it enters to prevent blood glucose levels from rocketing.

Question 9

Describe the principles behind negative feedback control systems

Answer 9

This mechanism is called “Negative” feedback because the condition that triggered the homeostatic response becomes switched off/removed by that response.
The size of the response is proportional to the size of the disturbance.
When a condition that is homeostatically regulated (e.g. body temperature), is sensed to have shifted from the normal range, a signal (usually nervous or endocrine), is generated that produces a response (e.g. shivering or sweating), that corrects the original disturbance and brings the regulated condition back within the normal range
Characteristics: . There is oscillation around the set point. Restores the regulated condition after its initial disturbance, but cannot prevent it happening

Question 10

Explain what is meant by feed forward control

Answer 10

Feed forward systems are more sophisticated and can, to some extent, predict and prevent change. Feed forward systems contain additional receptors that permit system to anticipate change and therefore activate response earlier.
i.e. when you are thirsty the kidney detects the increased body fluid concentration and pre-empts a state of dehydration. It responds by producing smaller volumes of urine, and a more concentrated form of urine, thus conserving water.

Question 11

Illustrate the concept of homeostasis by outlining daily water balance in man

Answer 11

When a person is working outside on a hot dry day there body looses water through evaporation. This results in the body fluid becoming more concentration, Internal receptors sense change in this internal condition and simulate the thirst pathway. The person seeks out water and drinks. This process demonstrates both negative feedback and feedforward pathways. The water balance of a person is homeostatically controlled and therefore when the concentration changes the body responses by releasing signals which lead to the return to normal concentration.

Question 12

Identify the different body fluid compartments

Answer 12

Water is stored in 3 different compartments.

1. Intracellular fluid
2. Interstitial fluid (fluid between cells)
3. Plasma (fluid component of blood)

The plasma and interstitial fluid make up what is known as the extracellular fluid.

Question 13

Explain the importance of the nature of the barriers which separate the body
compartments

Answer 13

Natural barrier are important in maintaining concentration gradients within the body. The composition of plasma and interstitial fluid is very similar because the natural barrier that separates them is not very selective. However the composition of the extracellular fluid and the intercellular fluid is significantly different because the cell membrane is very selectively permeable. Life can only be maintained while the composition of these different fluid compartments is maintained therefore the natural barriers are extremely important.

Question 14

Define the dilution principle

Answer 14

The dilution principles states that v = m/c

Question 15

Describe the use of the dilution principle in the measurement of body fluid
compartments

Answer 15

Plasma is the only fluid compartment that we can access. Therefore:

Measuring the plasma volume: Add a dye or label that cannot cross the capillary wall. Let dye of label distribute then measure the concentration and calculate the volume using the dilution principle.

Measuring the extracellular volume: Add a molecule that can cross the capillary wall but not the cell wall. Let it distribute then measure the concentration and calculate the volume using the dilution principle.

measuring the total body fluid volume: Add a substance that can cross the capillary wall and cell wall i.e. heavy water . Let dye of label distribute then measure the concentration and calculate the volume using the dilution principle.

Measuring the interstitial fluid volume: Extracellular Fluid - Plasma Volume

Measuring the intracellular fluid: Total Body Water -Extracellular Fluid

Question 16

Define metabolism catabolism and anabolism, and describe, in outline, how they are
interdependent

Answer 16

Metabolism describes the chemical processes of a living organisms by which the energy stored in food is used for tissue growth and energy production.
Metabolism can be split into two pathways. Anabolic and catabolic.
In the catabolic pathways food molecules are broken down and oxidised to form more simple molecules. Some of energy released from this is lost in heat (2nd law of thermodynamics) however most of it is used to fed the anabolic pathways.
In the anabolic pathway small molecules are combined to form more complex molecules.

Question 17

Describe, in general terms, the structures and contributions to metabolic flow of ATP,
ADP, NADP, NAD, FAD

Answer 17

These are Intermediary Metabolites. These are used to store energy and therefore allow thermodynamically unfavourable reactions to proceed (anabolic pathways).

Question 18

Compare, in outline, the processes of substrate-level and oxidative phosphorylation

Answer 18

????

Phosphorylation and dephosphorylation is the process by which energy can be stored or released. ATP to ADP + Pi.

Question 19

Define the major elements used to construct human biomolecules

Answer 19

????

Question 20

State the importance of chemical functional groups and molecular configuration and
conformation in determining biomolecular function

Answer 20

Functional groups determine the function of a molecule. Molecules often contain functional groups which are groups of elements bonded to a carbon atoms. Example of function groups include, Hydroxyl group (-OH), aldehyde group (-CHO ) and the Keto group (R2C=O). Biochemical molecules can be defined by these functional groups.
The function of molecules is also determined by their conformation. Molecules can be cis or trans. The orientation of this can completely change there function.
The polarity of a molecule can also determine its function. Polarity is the distribution of electrons within a bond.

Question 21

List and give examples of the five kinds of chemical reaction occurring in living
organisms

Answer 21

1. Redox reactions. i.e. glucose to pyruvate
2. Making and breaking C-C bonds. i.e. Cleavage of glucose in glycolysis
3. Internal rearrangements. i.e. The rearrangement of the conformation of G6P occurs before the sugar is split in glycolysis
4. Group transfers. i.e. In an enzyme catalysed reaction, a phosphoryl group (PO32-) is transferred from ATP to F6P as part of glycolysis.
5. Condensation and hydrolysis reactions. i.e. construction of a carbohydrate, sucrose.

Question 22

Describe the general structures of proteins, nucleic acids, polysaccharides and lipids

Answer 22

Proteins are long chains of amino acids. Nucleic acids form the core structure of DNA and RNA. Nucleic acids are polymers composed of nucleotide monomers. A polysaccharides (complex carbohydrates) such as starch or glycogen are composed of many individual monosaccharide molecules e.g. glucose. Lipids consist of fatty acids. There are three classes of lipids: 1. Triacylglycerides 2. Phospholipids 3. Sterols

Question 23

Describe the structures present in all cell types

Answer 23

All cells have a cell membrane and cell organelles. Cell organelles are the “machinery” of the cell. All substances entering or leaving the cell must cross the cell membrane

Question 24

Define the roles of eukaryotic animal cell organelles: nucleus, nucleolus, endoplasmic
reticulum, ribosome, Golgi apparatus, lysosome, peroxisome, mitochondrion,
flagellum, cilium

Answer 24

Nucleus:
Contains DNA, nucleoprotein and some RNA
Nucleoli are sites of ribosomal RNA synthesis and ribosomal assembly. The nucleus is enclosed in the nuclear membrane which, like all biological membranes, is a phospholipid bilayer. It is closely associated with the Rough Endoplasmic Reticulum

Endoplasmic reticulum
Membrane bound organelles. Endoplasmic reticulum comes in rough (RER) and smooth (SER) varieties
RER has ribosomes attached giving it the “rough” appearance. RER modifies proteins. SER has no ribosomes attached and is mainly associated with lipid and steroid hormone production and metabolism of toxins

Ribosomes
Ribosomes synthesise proteins.

Golgi Apparatus
Golgi Apparatus packages up protein in preparation for transport out of the cell.

Lysosome
Enzymes are one form of protein packaged by the golgi apparatus. Enzymes catalyse reactions in cells but need to be stored until needed. Lysosomes are membrane bound vesicles containing enzymes – they separate enzymes from the rest of the cell. Used in autophagy (digestion of cells own materials) or digestion of engulfed particles (e.g. bacteria). Peroxisome are similar.

Mitochondria
Mitochondria are also organelles bound by a phospholipid bilayer. Outer membrane contains pores. Inner membrane has cristae (folds). Matrix contains most of the enzymes required for metabolising food molecules (e.g. Krebs cycle)

Some cells have surface projections supported by the cytoskeleton i.e. Cilia and eukaryotic flagella are made of microtubules. Cilia—short, usually many present, move with stiff power stroke and flexible recovery stroke. Flagella—longer, usually one or two present, movement is snakelike

Question 25

Correlate organelle structure with function

Answer 25

???

Question 26

Describe the structure and function of the eukaryotic plasma membrane.

Answer 26

The cell membrane (Sometimes called the plasma membrane or plasmalemma) comprises of a double layer of lipid with attached phosphate groups. This double layer of lipids is known as the phospholipid bilayer (See Forces Across Membranes for more detail). Embedded in the membrane are proteins which act as receptors to detect chemical messengers and signalling molecules in the fluid surrounding cells (extracellular fluid) The phospholipid bilayer forms a selective barrier, being choosy about what it allows to cross in or out of the cell

Question 27

Define the role of the cytoskeleton

Answer 27

Supports and maintains cell shape Holds organelles in position Helps move organelles around the cell It is compromised of one of three forms of protein: microfilaments, intermediate filaments, microtubules.

Question 28

Describe the interactions between water molecules and solutes that determine solubility.

Answer 28

``` When charged (polar) particles are dissolved in water the water forms a “screen” around them. i.e. When sodium chloride (common salt) is dissolved in water, the water forms ‘screens’ around each ion keeping the Na+ and Cl- ions in solution once dissolved. (Preventing them from reacting and forming sodium chloride) ```

Question 29

Define the term ‘pH’ and derive an expression that relates the degree of proton dissociation of a weak acid to its ionisation constant and the pH

Answer 29

-----

Question 30

Describe what is meant by the term ‘buffer’

Answer 30

-----

Question 31

Describe the basic structure of membranes

Answer 31

Membranes are composed of a phospholipid bilayer (with hydrophilic head and hydrophobic tails) and proteins and or carbohydrates. Proteins can be peripheral or integral. The cell membrane is selectively permeable. This permeability may vary over time. The membrane is dynamic, continually being formed and dismantled. Membranes are flexible and can expand though they will burst if they expand too much. Membranes are excellent insulators against electrical charge.

Question 32

Describe the functions of the cell membrane

Answer 32

Form a natural barrier between the intracellular and extracellular environments. The proteins embedded in the cell membrane are used as receptors, for transport (transporter and channel proteins), as enzymes, for maintenance of cell structure (anchorage) and for communication.

Question 33

Define what is meant by diffusion across membranes

Answer 33

Diffusion is the process by which a gas or substance in solution expands to fill all the available volume. Therefore molecules spread from regions of high concentration to regions of low concentration, until the concentration is uniform throughout the volume

Question 34

List the factors which favour diffusion through the lipid bilayer

Answer 34

Small, Uncharged and Lipophilic (hydrophobic)

Question 35

Describe the different general types of membrane proteins and their functions

Answer 35

Peripheral proteins – associated only with the phosphate head of the lipid bi-layer and do not penetrate the hydrophobic core Integral proteins – span the hydrophobic core of the lipid bi-layer

Question 36

Define electrochemical gradients

Answer 36

Electrochemical gradient is the net effect of the electrical and concentration gradient which ultimately drives the direction of passive movement.

Question 37

Explain what is meant by carrier mediated transport systems

Answer 37

Molecules too big to move through channel proteins use carrier-mediated transport proteins or “transporters”. These proteins have binding sites for the solutes they transport such as glucose. When they bind the solute, the transporter undergoes a change in shape which exposes the binding site on the other side of the membrane. The solute moves away from the transporter and the transporter returns to its original configuration.

Question 38

Explain the difference between osmolarity and tonicity

Answer 38

Osmolarity describes total number of particles in solution | Tonicity describes the number of non-penetrating particles in solution.

Question 39

Understand the physiological significance of osmolarity vs tonicity

Answer 39

``` Almost 20% hospital patients suffer complications due to inappropriate fluid administration. Some of these people die. Intravascular haemolysis (cells bursting) can kill. This is because Lysed (burst) cells introduce protein to ISF, increasing tonicity of ECF in an uncontrolled manner, making management very complicated. ```

Question 40

Explain the difference between an isosmotic solution and an isotonic solution

Answer 40

An isosmotic solution has the same total number of solute particles as normal ECF (plasma). An isotonic solution has the same number of non-penetrating solute particles as normal ECF (plasma).

Question 41

Describe the processes of endocytosis and exocytosis

Answer 41

These are mechanisms for moving macromolecules across membranes without disrupting them. In endocytosis, there is invagination of the cell membrane to form a vesicle which eventually disintegrates on the cytoplasmic (inside) surface of the membrane, releasing contents which then migrate within the cell to their destination. Endocytosis of membrane receptors is a common mechanism of terminating signals from extracellular ligands

Question 42

List the major cells involved in the innate and adaptive immune response systems.

Answer 42

Innate: Epithelial barriers, phagocytes, dendritic cells, complement, natural killer cells, Eosinophils, mast cells, Basophils, cytokines. Adaptive : B and T lymphocytes, Effector T cells

Question 43

Describe the main role of the innate immune system

Answer 43

Distinguishes between human cells and pathogens, but not between different types of pathogen Fast and immediate: first to come into play No memory: will produce the same response no matter what it is or whether this pathogen has invaded before.

Question 44

Describe the functions of natural killer cells

Answer 44

-

Question 45

Describe the process of phagocytosis and intracellular killing

Answer 45

Phagocytes: are the cells of the immune system that track down, engulf and destroy bacteria, other pathogens as well as own damaged or dead cells. Movement of the phagocyte toward the microbe Phagocytosis looks like this: Attachment of microbes to phagocyte surface Endocytosis of microbe and formation of phagosome Fusion of phagosome with lysosome Killing of microbe through digestion by enzymes Discharge of waste materials

Question 46

Define the primary and secondary lymphoid organs and their functions.

Answer 46

Primary: Bone Marrow and thymus. Places where blood cells are produced and receive their ‘early training’ (acquire ability to interact with antigens) Secondary: lymph nodes, tonsils, spleen. These are sites of Lymphocyte activation by antigens and the development of adaptive immune response to Antigens by T and B cells.

Question 47

Illustrate antibody the structure and function of antibody.

Answer 47

Antibodies: are proteins that are produced as an immune response against antigens Different antigens induce the production of different antibodies

Question 48

Describe how antigen processing cells and T-lymphocytes interact

Answer 48

-

Question 49

Describe the role of T-helper 1 and T helper 2 lymphocytes in controlling the immune response

Answer 49

- They cannot kill infected cells or pathogens | - They activate and direct other immune cells

Question 50

Briefly describe the complement system and its main function

Answer 50

Complement system consists of more than 30 proteins/factors that are found in the plasms, present in an inactive form They are activated in a cascade –like format activation of the complement in fact takes place on the surface of the target cells

Question 51

Describe the role of cytokines as chemical messengers within the immune system

Answer 51

Small proteins – secreted by both immune and some nonimmune cells in response to stimulus. They communicate with other cells bind to specific receptors on these cells producing a signalling molecules that lead to many biological effects in these cells.

Question 52

Know the average circulating volume in a typical adult male

Answer 52

5 litres

Question 53

List the functions of blood

Answer 53

1. Carriage of physiologically active compounds i.e. 2. hormones (carried in the plasma) 3. Clotting (platelets) 4. Defence (white blood cells) 5. Carriage of gas (red blood cells) 6. Thermoregulation 7. Maintenance of ECF pH

Question 54

Describe the composition of plasma

Answer 54

95% is water The composition of the plasma is normally kept within strict limits. (if test results showed that the levels of a hormone etc were at an unusual level that suggests that there is something going wrong with the organ or system associated with that hormone)

Question 55

Name the plasma proteins and describe their functions

Answer 55

Albumin – Creates oncotic pressure and circulates steroid hormones and fat soluble vitamins (lipophilic). These use albumin as a transporter because they don’t easily dissolve in water. Albumin makes up about 60% of the plasma proteins) 2) Globulin - Subdivided into , ß,  globulins. Globulins make up 38% of plasma proteins. Alpha and Beta globulins act in a very similar way to albumin (transporter proteins for steroid hormones and flat soluble vitamins). Gamma globulins act as antibodies (important role in immune system). 3) Fibrinogen and other clotting factors. Make up 2% of the plasma proteins

Question 56

Define the term oncotic pressure and describe the factors responsible for generation

Answer 56

Movement of water from a higher concentration in the interstitial fluid into the lower water concentration (due to the presence of proteins ) in the plasma.

Question 57

Know the normal lifespan of red blood cell and platelets in the circulation

Answer 57

Blood cells: 120 day lifespan | Platelets: Life span 10 days

Question 58

Describe the function of the red blood cell

Answer 58

Transport oxygen around the body.

Question 59

Describe the function of erythropoietin, where it is synthesised and the factors which may increase secretion

Answer 59

Erythropoietin is a hormone that controls and accelerates erythropoiesis (while in the bone marrow). 85% of erythropoietin is secretion in the kidney. The other 15% is secreted in the liver. Secretion of erythropoietin is enhanced when oxygen delivery to kidneys is reduced (hypoxia) i.e. when there is a low level of oxygen in the blood

Question 60

Name the five main types of white blood cells

Answer 60

Monocytes, Neutrophils, Basophils, Eosinophils and lymphocytes.

Question 61

Be able to classify the different types of blood cells

Answer 61

White blood cells: Monocytes, Neutrophils, Basophils, Eosinophils and lymphocytes Red blood cells: Erythrocytes Myeloid cells: Erythrocytes, Platelets, Monocytes, Neutrophils, Basophils and Eosinophils

Question 62

Appreciate the difference between a monocyte and a macrophage

Answer 62

5% circulating cells are monocytes. After 72 hours they migrate to connective tissue where they become macrophages and live for 3 months (important cells that carry out phagocytosis)

Question 63

Know the unique function of platelets

Answer 63

Membrane bound cell fragments. Adhere to damaged vessel walls and exposed connective tissue to mediate blood clotting. Forming the foundation of a blood clot. The platelets are not part of the clotting process, but they form the foundation that allows the clotting process to proceed.

Question 64

Outline the role of thrombopoietin in platelet formation

Answer 64

Formation of platelets is governed by Thrombopoietin

Question 65

Define what is meant by haematocrit

Answer 65

The haematocrit is a procedure used to determine the red blood cell volume. Normally red blood cells account for 40 – 50 % of the blood sample. Whether this is the case of not can be seen when a blood sample is put into a centrifuge.

Question 66

State the normal value for haematocrit and appreciate how this may change in certain circumstances

Answer 66

Normally 40 – 50 %. In dehydration that % will increase. The % will also increase if the patient has high levels of erythropoietin. Erythropoietin is an drug that can be taken illegally as a way of doping in sport. A hematocrit can show if this is the case.

Question 67

Define what is meant by blood viscosity

Answer 67

How thick/sticky blood is compared to water. The plasma - x 1.8 thicker than water.

Question 68

Describe how viscosity may change in certain circumstances

Answer 68

Viscosity is not an absolute value, depends on: Haematocrit - 50% increase in haematocrit increases viscosity approx. 100%. The more cells you have the thicker the blood becomes. Temperature - increase in temp decreases viscosity and vice versa. 1oC changes viscosity by around 2%. This is one of the complications of hyperthermia. The colder you are the thicker you blood and the harder it is to pump the blood around your body. Flow rate - decreased flow rate increases viscosity and vice versa.

Question 69

Describe the fundamental properties of an adaptive immune response.

Answer 69

Distinguishes between different pathogens based on shapes on the surface (these shapes are called antigens ) Slower: Can take few days to develop Immunological memory: memory cells remember

Question 70

Describe the role of B-Lymphocytes in immunity

Answer 70

B cells Involved in humoral immunity Main function is the production of Abs

Question 71

Define the various classes of naturally occurring amino acids.

Answer 71

``` Aliphatic = hydrocarbon in R group Aromatic = Hydrocarbon ring in R group Sulphur-Containing = Sulphur in R group Acidic = Basic = Polar = polar R group ```

Question 72

Describe the functions of proteins.

Answer 72

Proteins perform crucial roles in biological processes. Proteins may be structural (e.g. actin ‘scaffold’ within a cell or keratin in skin) or functional (e.g. catalytic function of enzymes or antibodies in immune defence)

Question 73

Define the terms ‘primary structure’, ‘secondary structure’, ‘tertiary structure’ and ‘quaternary structure’ as applied to proteins.

Answer 73

Primary structure = This is the sequence in which amino acid monomers are bonded together to form a polypeptide chain. Secondary structure = This is the 3D spatial arrangement of amino acids located near each other in the polypeptide chain. Secondary structure relies on hydrogen bonding between the amino hydrogen of one amino acid and the carboxyl oxygen of another amino acid in the same chain. Tertiary structure = Tertiary structure results when functional groups of ‘R’ chains of amino acids in the polypeptide chain interact with one another. Van der Waals, ionic, hydrogen, disulphide bridges and hydrophobic interactions can all be involved Quaternary structure = Sometimes several polypeptides interact with one another to form a quaternary structure (e.g. haemoglobin contains four highly-folded polypeptide chains and four iron-containing heme groups, with one group tucked within the interior of each folded polypeptide subunit)

Question 74

Discuss the particular properties that the possession of quaternary structure may confer on a protein.

Answer 74

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Question 75

Compare the structures and functions of fibrous proteins with those of globular proteins.

Answer 75

Globular proteins are used for: Storage as Enzymes, Hormones Transporters and for Structural. Fibrous proteins are sued for Muscle fibres Connective tissue

Question 76

Discuss the ways in which enzymes catalyse reactions.

Answer 76

Lower activation energy. 1. Entropy reduction Enzymes “force” the substrate(s) to be correctly orientated by binding them in the formation they need to be in for the reaction to proceed 2. Desolvation Weak bonds between the substrate and enzyme essentially replace most or all of the H-bonds between substrate and aqueous solution 3. Induced fit Conformational changes occur in the protein structure when the substrate binds

Question 77

Describe the ways in which the rate of an enzyme-catalysed reaction may vary with changes in the concentration of the enzyme and of the substrate.

Answer 77

-

Question 78

Define the term ‘Michaelis constant’, describe how it may be experimentally estimated and describe what a knowledge of the constant may allow to be deduced about the nature of the catalysed reaction.

Answer 78

- See slides -

Question 79

Describe the molecular nature of competitive and non-competitive inhibition of enzyme-catalysed reactions.

Answer 79

``` Competitive = Inhibitor binds to the active site. Non-competitive = Inhibitor binds to another site changing the shape of the active site. ```

Question 80

Understand why enzyme activity is measured in a clinical setting

Answer 80

diagnostic reasons?

Question 81

Understand what factors can influence enzyme activity in samples

Answer 81

-

Question 82

Discuss the use of enzyme assays in clinical diagnosis

Answer 82

-

Question 83

Define the major carbohydrates in the diet.

Answer 83

``` Monosaccharides Disaccharides Polysaccharides Glycoproteins Proteoglycans ```

Question 84

Describe, in outline, their digestion and absorption.

Answer 84

Enzymes help to break down the carbohydrates in the mouth and Duodenum. And then completely broken down in the small intestine. Glucose, fructose and galactose are then absorbed across the membrane.

Question 85

Describe and contrast the actions and functions of the enzymes hexokinase and glucokinase.

Answer 85

Glucokinase has a low affinity for the substrate while Hexokinase has high affinity for the substrate. This means that in blood of a normal glucose concentration the liver doesn’t “grab” all of the glucose, so other tissues can have it. However if the blood glucose concentration is high (i.e. after meal) the liver will “grabs” the Glucose. At a low blood glucose concentration Hexokinase will however be able to grab glucose effectively. The high Vmax of glucokinase means it can phosphorylate all the Glcose it traps quickly. This means that most of the absorbed glucose in our bodies is trapped in the liver. The low Vmax of Hexokinase means tissues are “easily satisfied”, so don’t keep “grabbing” Glc

Question 86

Describe the synthesis and degradation of glycogen.

Answer 86

Glycogen does not form directly from Glcose monomers. Glycogenin begins the process by covalently binding Glcose from uracil-diphosphate (UDP)-glucose to form chains of approx. 8 Glc residues Then glycogen synthase takes over and extends the Glc chains.

Question 87

Compare and contrast the functions of glycogen in skeletal muscle and liver.

Answer 87

In the liver If blood Glucose concentration falls the G6P can be converted back into glucose which can be released into the blood. However in skeletal muscle there is no glucose 6-phosphatase (not produced in skeletal muscle) so therefore glycogen is converted to ATP (energy).

Question 88

Describe the function and process of glycolysis.

Answer 88

Glycolysis sits in the middle of most metabolic pathways. Glycolysis is a catabolic pathway that saves some potential energy from glucose/G-6-P by forming ATP through substrate level phosphorylation It is essentially the only way that energy can be made from fuel molecules when cells lack O2 (exercising muscle) or mitochondria (RBCs) Gene sequencing has revealed that it is an ancient process, conserved through organism. It is though to have evolved before atmospheric O2 was plentiful. And it occurs in cytosol with no complex organelles required. It is therefore important to life and justifiably fills the central role in the metabolic pathways

Question 89

Describe the functions of the lactate dehydrogenase- and pyruvate dehydrogenase - catalysed reactions.

Answer 89

-

Question 90

Describe the fate of blood lactate.

Answer 90

a

Question 91

Describe the precursors for, functions of and process of gluconeogenesis.

Answer 91

a

Question 92

Describe, in brief, the fates of absorbed galactose and fructose

Answer 92

a

Question 93

Describe the functions and process of the citric acid cycle.

Answer 93

a

Question 94

Identify reactions that involve electron carriers

Answer 94

a

Question 95

Identify reactions that release CO2

Answer 95

a

Question 96

Describe links to other metabolic pathway

Answer 96

a

Question 97

Describe, in outline, the pathway of electron movement from reduced substrates to oxygen in the mitochondrion.

Answer 97

a

Question 98

Describe, in outline, the generation of a proton concentration gradient across the inner mitochondrial membrane, and how this is used to convert ADP to ATP.

Answer 98

a

Question 99

Define the major lipid classes and their role in health and disease

Answer 99

a

Question 100

Describe in outline the processes of lipid digestion and absorption.

Answer 100

a

Question 101

Describe how lipids are transported in the body and the role of lipoproteins in this process.

Answer 101

a

Question 102

Describe the synthesis of free fatty acids and define the term ‘essential fatty acid’.

Answer 102

a

Question 103

Describe the catabolism of fatty acids by beta-oxidation.

Answer 103

a

Question 104

Describe the structure and functions of cholesterol.

Answer 104

a

Question 105

Describe the structure and functions of eicosanoids and steroid lipids

Answer 105

a

Question 106

Describe the function, synthesis and metabolism of ketone bodies.

Answer 106

a