Cells- ABS notes

Question 1

what constitutes a cell?

Answer 1

Definition of a cell- the basic unit from which living organisms are made, consisting of an aqueous solution of organic molecules enclosed by a membrane. All cells arise from existing cells, usually by a process of division.

Question 2

Describes the cells ability to form tissues (3)

Answer 2

 particular genes are switched on, triggered by signals from their immediate
environment (developmental biology), which cause production of mRNA, travels out of cells to manufacture
a particular protein. There are about 200 different types of cells in the body
 These genes produce enzymes which induce the formation of specialised cytoskeleton, organelles, cell-cell contacts, secretion and absorption
 The distribution of organelles within a cell is unsymmetrical, i.e. one end of the cell faces the lumen and the other the basal membrane, hence polarity is established

Question 3

Definition of polarity

Answer 3

refers to a structure such as an actin filament or a fertilised egg that has an inherent asymmetry so that one end can be distinguished from the other.

Question 4

Scales: Size of cells

Answer 4

10-20 micrometres in diameter

Question 5

Volume of a cell is measured in…

Answer 5

nanolitres

Question 6

Mass of a cell

Answer 6

1 nanogram.

Question 7

Size of a virus

Answer 7

10 nanometres

Question 8

A small protein:

Answer 8

40 nanometres

Question 9

Size of molecules:

Answer 9

0.2 nanometres in diameter

Question 10

Definition of organelles

Answer 10

separate, recognizable sub-cellular structures that perform specialized functions within the cell

Question 11

Organelles

Nucleus:

Answer 11

Enclosed within two concentric membranes and

contains DNA organized into chromosomes.

Question 12

Nucleolus:

Answer 12

large structure in the nucleus where ribosomal RNA is transcribed and ribosomal subunits are
assembled

Question 13

Nuclear pores:

Answer 13

specialised protein complexes which carefully control and filter the molecules moving between the nucleus and the cytoplasm.
Note: adenoviruses have a an advantage as they can travel through/block nuclear pores.

Question 14

Mitochondria:

Answer 14

membrane-enclosed organelle, about the size of a bacterium, that carries out oxidative
phosphorylation and produces most of the ATP in eukaryotic cells.

Question 15

Vesicles:

Answer 15

small, membrane-enclosed, spherical organelles in the cytoplasm of a eukaryotic cell

Question 16

Secretory granules:

Answer 16

membrane-enclosed organelle in which molecules destined for secretion are stored
prior to release. Visible as small solid object due to darkly staining contents.

Question 17

Golgi Apparatus:

Answer 17

membrane-enclosed organelle in eukaryotic cells where the proteins and lipids made in the
endoplasmic reticulum are modified and sorted for transport to other sites around the cell

Question 18

Centriole:

Answer 18

short cylindrical array of microtubules, usually found in pairs at the centre of a centrosome in
animal cells. Also found at the base of cilia and flagella (called basal bodies).

Question 19

Ribosome:

Answer 19

particle composed of ribosomal RNAs and ribosomal proteins that associate with mRNA and
catalyses the synthesis of protein (translation)

Question 20

Cytoskeleton:

Answer 20

system of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell shape and
the capacity for directed movement. Its most abundant components are actin filaments, microtubules, and
intermediate filaments.

Question 21

Lysosome:

Answer 21

intracellular membrane-enclosed organelle containing digestive enzymes, typically those most
active at the acid pH found in these organelles.

Question 22

Liposomes:

Answer 22

artificially prepared vesicles made from the lipid bilayer.

Question 23

Plasma membrane:

Answer 23

the membrane that surrounds a living cell.

Question 24

Cilia:

Answer 24

hairlike extension on the surface of a cell with a core bundle of microtubules and capable of
performing repeated beating movements. Cilia, in large numbers, drive the movement of fluid over epithelial
sheets, as in the lungs.

Question 25

Endoplasmic reticulum:

Answer 25

membrane-enclosed component in the cytoplasm of eukaryotic cells, where lipids
and secreted and membrane-bound proteins are made

Question 26

Smooth endoplasmic reticulum:

Answer 26

region of ER not associate with ribosomes, but involved in the synthesis of
lipids.

Question 27

Rough endoplasmic reticulum:

Answer 27

region of the ER associated with ribosomes and involved in the synthesis of
secreted and membrane-bound proteins.

Question 28

Sarcoplasmic reticulum:

Answer 28

specialist form of SER found in smooth and striated muscle.

Question 29

Define cytosol

Answer 29

Definition of cytosol- contents of the main compartment of the cytoplasm, excluding membrane-enclosed organelles
and cytoskeletal components.
 Intracellular fluid
 Site of many chemical reactions including the manufacture of proteins and Glycolysis
 Constituents: soluble proteins, sugars, ions (K+, Na+, Mg2+, Ca2+, PO4 2-, Cl-), nucleotides (ATP, cAMP: cyclic
adenosine monophosphate, GTP: guanosine triphosphate), amino acids, mRNA, t-RNA, lipids and peptides

Question 30

Define the basement membrane

Answer 30

 Thin sheet of fibres that underties the epithelium
 Selective barrier for macromolecules, type VI collagen network, laminas, type XV collagen
 Type XV collagen- is manufactured within cell, then transported to form membrane. Provides strength

Question 31

Define extracellular fluid

Answer 31

Definition of extracellular fluid: complex network of polysaccharides (e.g. glycosaminoglycans, cellulose) and proteins (e.g. collagen) secreted by cells.
A structural component of tissues that also influences their development and physiology
 Ions (Na+, Cl-, PO4 2-, CO3 2-, Mg2+, Ca2+)
 Soluble proteins, carbohydrates and sugars
 Vitamins, amino acids, hormones, nucleotides (ATP), lipids, cholesterol
 Lymph, plasma, saliva, urine, bile, sweat, milk etc

Question 32

Similarities of prokaryotic and eukaryotic cells (8)

Answer 32

 All have a cell membrane that separates the outside from the organised interior
 contain DNA as the genetic material (exceptions e.g. RNA virus)
 Contain several varieties of RNA molecules and proteins (mostly enzymes).
 Are composed of the same basic chemicals: carbohydrates, proteins, nucleic acids, minerals, fats and
vitamins.
 Regulate the flow of nutrients and wastes that enter and leave the cell.
 Reproduce and are the result of reproduction.
 Require a supply of energy.
 are affected and respond to the reactions that are occurring within them and many of the environmental
conditions around them; this information is continually processed to make metabolic decisions

Question 33

Define a prokaryote

Answer 33

major category of living cells distinguished by the absence of a nucleus or other
membrane-bound organelles. Single-celled organisms comprising the kingdoms archaea and bacteria.

Question 34

Define a eukaryote

Answer 34

living organism composed of one or more cells with a distinct nucleus and cytoplasm.
Include all forms of life except archaea, bacteria, and viruses.
 Evolved from aggregates of prokaryotic cells that became interdependent and eventually fused to form a
single larger cell
 Have a higher degree of organisation than prokaryotes, in that they contain many organelles or structures
separated from the other cytoplasm components by a membrane

Question 35

Differences between pro and euk (5)

Answer 35

No organelles VS Membrane-bound organelles
No nucleus VS Nucleus
Have external whip-like flagella for locomotion
or hair-like pili for adhesion VS May have cilia or microvilli on surface of cell
membrane

Simpler, smaller, haploid VS Cytoskeleton
Cell walls contain PEPTIDO-GLYCAN VS No cell wall- only cell membrane

Question 36

Define Cancer

Answer 36

disease caused by abnormal and uncontrolled cell division resulting in localised growths, or
tumours, which may spread throughout the body.

Question 37

Mutations that can lead to cancer (10)

Answer 37

Switch on “divide” signals.
 Switch off “don’t divide” signals.
 Loss of correction mechanism on DNA copying
 Loss of escape mechanism from cell division
 Loss of limit on number of times a cell can divide
 Loss of control keeping cell within tissue boundaries
 Ability to evade body defence mechanisms
 Ability to recruit blood vessels to growing tumour
 Ability to migrate into blood stream of lymph vessels
 Ability to establish tumours in the “wrong” tissue.

Note: Not all mutations cause cancer because most mistakes which occur during the copying of the genetic code
are removed/destroyed

Question 38

List the main types of infectious agents causing disease and name their distinguishing features (5)

Answer 38

Viruses: obligate intracellular parasite consisting of nucleic acid (RNA or DNA) enclosed in a protein coat that make use of a host cell to undergo intracellular replication, and then divide and bud out of the host cell.
Viruses show host specifity but have the ability to infect almost all other life forms including bacteria.
 Bacteria: prokaryotes that replicate by binary fission, and contain a chromosome of DNA but no nucleus. The DNA is condensed into nucleoids.
Bacteria are widely distributed in nature, but some are pathogenic
 Fungi: single-celled eukaryotes that exist as yeasts or filaments or both which cause cutaneous, mucosal and systemic mycoses. Yeasts bud or divide, whereas filaments (hyphae) have cross walls or septa. Systemic
infections with fungi often affect immuno-comprimised people.
 Protozoa: unicellular, free-living, non-photosynthetic, motile eukaryotic organisms which include intestinal,
blood and tissue parasites which acquired by ingestion or through a vector. They replicate in the host by
binary fission or by formation of trophosoites inside a cell, and often have complex life cycles involving two
hosts.
 Helminth parasites: Multicellular eukaryotes of the Kingdom of Metazoa, which are visible to the naked eye and have life cycles outside of the human host.

Question 39

Examples of Viruses

Answer 39

SARS, Influenza and HIV (use of reverse transcriptase breaks DNA makes RNA makes protein rule)

Question 40

Examples of Bacteria

Answer 40

Neisseria meningitis, mycobacterium tuberculosis, shigellosis (shigella spp. Is an invasive pathogenresponsible
for 50% of deaths from diarrhoeal disease) and septicaemia (characterised by rapid progression,
septic shock, severe inflammatory response)

Question 41

examples of Protozoa

Answer 41

malaria (plasmodium spp.- vector is female anophelese mosquito which targets red blood cells)
and leishmania spp. (vector is sand fly- targets white blood cells)

Question 42

Properties of the membrane

Answer 42

 Selectively permeable
 Impermeable to macromolecules, biochemical intermediates.
 Permeable to water molecules and a few other small, uncharged molecules like oxygen and carbon dioxide,
nutrients, waste products.
 Transfer of information (signal transduction).

Question 43

Lipid bilayers are permeable to… (2)

Answer 43

 Water

 Some small uncharged molecules like oxygen and carbon dioxide

Question 44

Simple Diffusion

Answer 44

the movement of molecules and small particles across the semi-permeable membrane driven by a
difference in the concentration of molecules on either side.

Question 45

Osmosis

Answer 45

the net movement of water molecules across a semi-permeable membrane driven by a difference in
concentration of solute on either side. The membrane must be permeable to water but not to the solute molecules

Question 46

Active Transport

Answer 46

the movement of a molecule across a membrane against its concentration gradient driven by ATP
hydrolysis or another form of metabolic energy

Question 47

Facilitated diffusion

Answer 47

the movement of hydrophilic (charged) molecules down their concentration gradient through
protein pores that hide the ionic charges from the hydrophobic core of the lipid bilayer. Proteins offer a water-filled channel. The channel can be ‘gated’- specific, i.e. a particular molecule may modify its
structure, opening the channel allowing the substance to pass through the membrane e.g. drugs

Question 48

Lipid bilayers are impermeable to… (4)

Answer 48

Cations (K+, Na+, Ca2+) but some do leak through, down the concetration gradient.
 Anions (Cl-, HCO3-)
 Small hydrophilic molecules like glucose
 Macromolecules like proteins and RNA

Question 49

Definition of a membrane protein

Answer 49

a protein associated with a lipid bilayer; can either be integral (transmembrane, monolayer-associated, or lipid-linked) or peripheral.

Question 50

Definition of a membrane transport protein

Answer 50

any protein embedded in a membrane that serves as a carrier of ions or small molecules from one side to the other

Question 51

Functions of the Proteins (7)

Answer 51

Transport (Sodium-Glucose transport)
 Transmission of signals
 Anchors to link intracellular actin filaments to extracellular matrix proteins (anchors the membrane to
macromolecules on either side)
 Receptors for hormones and growth factors- detect chemical signals in the cell’s environment, and relay
them to the cells interior
 Cell recognition and adhesion
 Electron carriers in cellular respiration and photosynthesis in mitochondria and chloroplasts
 Enzymes

Question 52

Define Membrane potential

Answer 52

voltage difference across a membrane due to a slight excess of positive charge on one side and
of negative ions on the other. A typical membrane potential for an animal cell plasma membrane is -80mV (inside negative), measured relative to the surrounding fluid.

Question 53

Describe the Sodium-Potassium Pump

Answer 53

Electrostatic force due to the charge separation across the membrane tends to move ions in a direction determined by its particular charge
 The high concentration of fixed anions inside cells (the protiens) and their accompanying cations (e.g. chloride ions) means that water is drawn into the
cells by the resulting osmotic gradient.
 The high concentration of Na+ in the extracellular space means that Na+ will tend to move down its concentration gradient into the cell.
 The sodium-potassium pump (Na+ -K + ATPase) maintains the osmotic balance and stabilises the cell volume by transporting 2K+ into the cell in exchange for 3Na+. This is electrogenic (unequal transfer of charge) therefore requires energy.
 It also provides a diffusion gradient for chloride ions. The chloride ions tend to move inward down their concentration gradient, but excess negative charge inside the cell (from nondiffusible proteins, lipids, and the unequal distribution of positive charge of K+ and Na+) tend to push Cl- ions back out of the cell.

 The sodium-potassium pump consists of two polypeptide chains, alpha and beta, with 1000 and 300 amino acids respectively. The alpha-chain spans the membrane 10 times, forming a hydrophilic pore.
 The K+ Na+ exchange is mediated by a series of conformational transitions of the pump molecule, which is driven by phosphorylation of an aspartyl residue followed by hydrolysis of aspartylphosphate.
 There are two consequences: Ionic gradients are created: less Na+ and more K+ inside the cell than outside. A charge gradient is also created, which results in the inside of the cell being at a more negative potential than the outside.
 The potassium channel consists of four subunits and is highly specific for K+, as it mimics the environment
potassium is usually surrounded by.
 The high concentration of potassium inside the cell means there is a tendency to move out of the cell, but
this would accentuate the voltage difference across the cell (making it more negative), therefore an
equilibrium is reached when the rate of inward movement = rate of outward movement.
 This equilibrium does not fully compensate for the electrogenic sodium-potassium pump, therefore the
membrane potential of a nerve or muscle cell at rest is about -80mV.
 The Nernst equation describes how the distribution of ions leads to a membrane potential
 Action potentials occur in elongated cells (nerves, muscle) when the membrane potential is disrupted by a
brief pulse of current which cause a massive influx of Na+ in the cell (depolarisation), which must then use
metabolic energy to reinstate the membrane potential.
 Na+ channels become inactivated locally, preventing further Na+
entry.
 Voltage-gated K+ channels open, to restore the resting membrane potential.
 The process propagates down the nerve/muscle

Question 54

Describe Glucose transport

Answer 54

Glucose is membrane-impermeant.
 Glucose moves down the concentration gradient into the cell
 Glucose binds to a specific glucose transporter which functions by a flip-flop mechanism
 The transport is ‘facilitated’.
 Several different proteins. Some are insulin-sensitive

Question 55

Describe amino acids transport

Answer 55

 Uses coupled transporters- symporters and antiporters

 Move in the opposite direction to Na+ using ATP hydrolysis

Question 56

Explain how external chemical signals can be sensed at the interior of a cell.

Answer 56

 exocytosis, e.g. hormones.
 lipid-soluble molecules that cross membranes.
 trans-membrane receptors.

Question 57

What happens at the nueromuscular junction

Answer 57

1. When a nerve impulse is received at the neuromuscular junction, the synaptic vesicles fuse with the presynaptic
   membrane and release acetylcholine
2. The acetylcholine diffuses to the post-synaptic membrane, altering its permeability to sodium ions,
   depolarising the membrane
3. The acetylcholine is broken down by acetylcholinesterase to ensure that the muscle is not over-stimulated
4. The resulting choline and ethanoic acid diffuse back into the neurone, where they are recombined to form
   acetylcholine using energy

Question 58

Describe muscle stimulation

Answer 58

 An action potential reaches many neuromuscular junctions simultaneously, causing calcium ion channels to
open and calcium ions to move into the synaptic knob
 Calcium ions cause the synaptic vesicles to fuse with the pre-synaptic membrane and release their
acetylcholine
 Acetylcholine diffuses across the synaptic cleft and binds with receptors on the post-synaptic membrane,
causing it to depolarise.

Question 59

Muscle contraction (8)

Answer 59

 The action potential travels deep into the fibre through T-tubules that branch throughout the sarcoplasm
 The action potential opens the calcium ion channels on the sarcoplasmic reticulum, flooding into the
sarcoplasm down a diffusion gradient
 The calcium ions cause Troponin molecules to change shape, which causes the Tropomyosin molecules to pull away from the actin binding sites
 The ADP molecule attached to the myosin heads bind to the actin filament and form a cross-bridge
 The myosin heads then change their angle, pulling the actin filament along and releasing a molecule of ADP
 An ATP molecule attaches to each myosin head, causing it to become detached
 The calcium ions then activate the enzyme ATPase, which hydrolyses ATP to ADP, providing the energy
needed for the myosin head to return to its original position
 The myosin head with ADP then re-attaches itself further along the actin filament

Question 60

List the main functions of the blood (8)

Answer 60

 Connective tissue
 Transport (connects every part of body)
 Heat distribution
 Immunity
 Haemostasis (process whereby bleeding stops)
 Support (e.g. external genitalia - VIAGRA)
 MAINTAIN HOMEOSTASIS (constant internal environment)
 Blood volume (5l male; 3.5l female

Question 61

List the major components of blood

Answer 61

 Erythrocytes- red blood cells
 Leukocytes- white blood cells
 Platelets- derived from megakaryocytes in bone marrow; involved in coagulation and clot formation
 Plasma- fluid component of blood which acts as the carrier for all blood cells

Question 62

Describe the essential features of the erythrocyte and list its major functions (6)

Answer 62

 Primary function: respiratory transport. Binds with oxygen to form oxyhaemoglobin for transport to cells.
Binds with carbon dioxide to form bicarbonate from carbonic anhydrase for removal from cells.
 Biconcave disc maximises surface area for diffusion of oxygen
 No nuclei or organelles
 Packed with haemoglobin
 7.5micrometres and flexible, important as able to penetrate through to smallest vessels
 Molecules on the surface confer blood group

Question 63

Describe regulation of erythrocytes (6)

Answer 63

 Erythrocytes are regulated by the kidney in a negative feedback loop.

1. Low oxygen
2. kidney (+testosterone- hence higher levels of erythrocytes in men) produces erythropoietin (hormone)
3. bone marrow stem cells differentiate to form erythrocytes (erythropoiesis) blood
4. haemoglobin increases
5. blood oxygen increases
6. negative feedback- back to the beginning

Question 64

Describe the life Cycle of erythrocytes

Answer 64

 Produced in bone marrow from precursors which produce haemoglobin then lose organelles
 Immature erythrocytes contain ribosomes: reticulocytes.
 High levels of circulating reticulocytes are useful in diagnostics e.g. anaemia, chemotherapy
MCD Cells Alexandra Burke-Smith
14
 Removed through reticulo-endothelial system (phagocytic macrophages in spleen)
 Lifespan = 120 days (short, no nuclei; 1% or 250 billion cells per day)
 Dependent on dietary iron (meat, egg yolk, nuts), iron deficiency causes anaemia

Question 65

Explain the importance, basic structure and role of haemoglobin

Answer 65

Globular protein consitisting of 4 subunits (polypeptide chains),
each with a prosthetic haem group.
 Haem contains a ferrous iron (FE2+), each of which binds with one
molecule of oxygen
 Hb = deoxyghaemoglobin. Hb02 = oxyhaemoglobin
 100ml blood: 15.8g (male)
13.7g (female)
 Due to the compact conformational shape of globin molecules,
haemoglobin has a low affinity for oxygen
 However, oxygen binding breaks the conformation and opens up the structure, allowing the second oxygen
molecule to bind more easily
 This means in a high oxygen environment (e.g. the lungs), cooperative binding can take place which allows
more oxygen to be carried
 Different form in foetus with higher O2 affinity, as foetus must obtain oxygen from mother’s blood
 Carbon monoxide combines with haem at a 200X greater affinity to form carboxyhaemoglobin, reducing
oxygen binding, which can deprive cells of oxygen resulting in cell death.

Question 66

Key red cell Parameters

Answer 66

 Concentrations of haemoglobin (g/dl)- men: 13.5-16.5, women: 11.5-14.5
 Red cell count- men 5.4x1012/l, women 4.8x1012/l
 Haematocrit (packed cell volume PCV): men 0.40-0.54/1.00, women 0.35-0.47/1.00
 PCV is the proportion of blood which are erythrocytes
 Normal MCV (mean cell volume) 82-99fl
 Normal MCH (mean cell haemoglobin) 27-33pg
 Normal MCHC (mean cell haemoglobin concentration) 32-34 g/dl

Question 67

Definition of anaemia:

Answer 67

low blood haemoglobin concentration

Question 68

Define the 3 types of anaemia

Answer 68

Microcytic (small MCV): Failure of haemoglobin synthesis (and hence smaller erythrocytes) caused by an
iron deficiency as a result of gradual blood loss e.g. menstruation, GIT lesions or cancers and parasitic
infection
 Normocytic: red blood cell production is normal, but is a result of acute blood loss
 Macrocytic (large MCV): During erythropoeisis, DNA synthesis and cell division fail and reduced division of
progenitor cells so fewer but larger erythrocytes. Folic acid and vitamin B12 are essential for division. Caused
by pregnancy (lack of folic acid), autoimmune disease, pernicious anaemia (destroys uptake of B12 in gut),
and in vegetarians and vegans- all caused by lack of vitamin B12.

Question 69

Describe polymorphic granulocytes

Answer 69

Segmented nucleus, full of cytoplasmic granules. First on scene - adhere to blood
vessels in infected area and migrate into tissue. Engulf, kill and digest microorganisms. Main types are
neutrophils (phagocytic), eosinophils (allergic + asthma responses), basophils (histamine-producing). Release
inflammatory mediators: toxic oxygen products, digestive enzymes, vasodilators, chemotaxins.

Question 70

Describe B- Lymphocytes

Answer 70

Mature in bone marrow- involved in Humoral (antibody-mediated) immunity. Foreign
antigen → RNA synthesis → immunoglobulin (antibody) production. Immunoglobulins: IgM; IgG; IgA; IgD;
IgE. Antibody-antigen reactions: assist phagocytosis by precipitation; agglutination (clumping) or coating in
antibody (opsonisation) or prevent attachment of micro-organism to tissues (neutralisation). In the primary
immune response, it is the first exposure, so antibodies appear after latent period, peak then fall. The
Secondary response will be greater, quicker, longer response due to memory cells (long lived Blymphocytes).
Passive immunity: inject immunoglobulins (vaccine) or cross placenta (colostrum in some
species)

Question 71

T- Lymphocytes:

Answer 71

Derived in bone marrow, but migrate to thymus where they aquire surface antigenic
molecules and become immunologically competent. Involved in cellular immunity: Circulate → foreign
antigen → blast transformation (rapid cloning) → with receptors for antigen. Activated T-lymphocytes
release chemotaxins (attract macrophages); lymphotoxin (kills cells); interferon (kills viruses).
Subgroups: Cytotoxic T-cells, helper T-cells, Supressor T-cells (no info required)

Question 72

Monocytes

Answer 72

Large, single horse-shoe nucleus. Appear after granulocytes and in tissue become macrophages
(“big eaters”), engulfing micro-organisms, tissue debris and dead polymorphs. Secrete inflammatory
mediators and stimulate angiogenesis (vessel growth = repair). Ingest and store antigens, present modifies
antigen to lymphocytes

Question 73

Explain simply the major functions of platelets

Answer 73

 Derived from megakaryocytes
 2 - 3 µm diameter (small)
 Normal platelet count 25 x 104
/ml
 Life span 8 - 10 days
 Granules
 Many organelles, no nucleus

Question 74

Describe Haemostasis

Answer 74

Express surface receptors for platelet activators in the presence of collagen in vessels or thrombin from
coagulation cascade
 They adhere to exposed collagen (in wound or atherosclerosis), and release granules which promotes
platelet aggregation
 Coagulation cascade- Produce thromboxane A2 from cycloxygenase enzyme, which is involved in
clot/thrombus formation
 Aspirin inhibits cycloxygenase and is therefore anti-clotting. The vascular endothelium also produces
prostacyclin and nitric oxide which inhibit platelet activation.

Question 75

. List the major functions of plasma (5)

Answer 75

 Fluid component of blood, acts as transport carrier
 “Organic and inorganic substances dissolved in water”
 Water and proteins
 Plasma proteins: exert osmotic pressure to maintain blood volume. Albumins + globulins are carrier
molecules e.g. hormones, bile salts, water insoluble drugs. Fibrinogen is present for clotting. If the balance of
proteins is changed, can lead to blood pressure and kidney function problems
 Serum: plasma with proteins removed due to clotting

Question 76

Key components of plasma

Answer 76

Nutrients -Glucose, Lipids, Amino acids
Hormones- Thyroxine, Cortisol,
Erythropoietin
Proteins- Clotting factors, Albumin,
Globulins
Inorganic ions -Na, K, Ca, PO4, HCO3
Products of metabolism- Urea, Lactic acid