Genes And Health Flashcards
What is the function of mucus?
- Traps foreign particles (dust, bacteria) and prevents them from entering the airways
- moisturises inhaled air (to aid diffusion)
What are the properties of gas exchange surfaces in living organisms?
- large sa/v ratio
- thin surface - short diffusion distance
- high concentration gradient
Ficks law - calculating rate of diffusion
The rate of diffusion is inversely proportional to the thickness of the gas exchange surface
rate of diffusion directly proportional to
SA x difference in conc
——————————
diffusion distance
How CF affects the respiratory system?
(breathing difficulties due to reduced gas exchange)
- less air can be breathed out - over inflation of the lungs causes elasticity of lungs decreases
- mucus blocks bronchioles: fewer alveoli available for gas exchange
- mucus fills alveolus: longer diffusion distance
- (Harder to breathe, exercise)
Gas exchange on outer surface of a land-living (terrestrial) organism?
- Outer surface for protection, not gas exchange
- high water content in mammal compared to the surrounding air, so would dry out
- outer layer is very thick, long diffusion distance ensures slow gas exchange
- have internet gas exchange surfaces to reduce evaporation losses
Multicellular aerobic respiration why?
Because they require a lot of energy and aerobic produces 19 times more ATP (adenosine triphosphate) per molecule of glucose
Gas exchange in other organisms:
Unicellular organisms: build up of CO2 - high conc gradient and thin surface membrane
Insects: hard exoskeleton unsuitable for gas exchange, lack of transport system - gas exchange through outer surface (short diff distance)
& tracheoles - large SA and they also contain fluid so glasses diffuse efficiently
How are alveoli adapted for efficient gas exchange?
- both endothelium and epithelium are 1 cell thick so short diffusion distance
- constant flow of blood and air flow from breathing so steep concentration gradient is maintained
- folded shape of alveoli, many alveoli and capillaries - large SA/v ratio
- pulmonary surfactant prevents the alveoli from collapsing
- moisture dissolves gases to allow diffusion + prevents lung tissue drying out
- close to capillaries - short distance
- smoking: destroys alveolar walls, decreased SA for gas exchange, decreased diffusion rate
Primary structure of proteins:
= The linear sequence of the amino acids in a protein
Secondary structure of proteins:
= Regular 3D structure formed due to hydrogen bonds between the H and O of PEPTIDE BONDS
Secondary structure - Alpha Helices
polypeptide chain wound round to form helix (many H bonds so have very strong, stable structure) - held together by hydrogen bonds running parallel with the long helical axis
Secondary structure - Beta pleated sheet
Polypeptide chain zig zags back and forward forming a sheet of anti parallel strands
Held together by H bonds between peptide bonds
Tertiary structure of proteins:
= 3D structure of the whole peptide chain, formed by hydrophobic interactions,
hydrogen bonds,
ionic bonds,
disulphide bonds between R GROUPS
Bonds involved in making up tertiary structure from weakest to strongest:
hydrophobic interactions between R groups
hydrogen bonds (between H and O)
ionic bonds between charged R groups
disulphide (covalent) bonds between cysteine R groups
Quaternary structure of proteins:
= The 3D structure of several polypeptide chains joined together
Conjugated proteins:
= proteins that are joined to other non-protein molecules (known as prosthetic groups e.g the Haem in Haemoglobin)
Globular proteins:
Proteins with a complex tertiary (sometimes quaternary) structure
- folded into spherical shapes (hydrophobic parts on the inside)
- soluble (hydrophilic parts on the outside)
• often small
E.g enzymes, antibodies, hormones
-insulin (51 aa)
Fibrous proteins:
= proteins that have little/no tertiary structure
- form long fibres made of several polypeptide chains
- insoluble
- often large
- strong
-structural role (e.g tendons)
-collagen (>1000 aa)
& Collagen has repeating sequences of amino acids
Why may the increase in temperature increase the length of the secondary structure of the polypeptide?
Increase in kinetic energy, more vibrations within the molecule that could break the hydrogen bonds - molecule unwinds
What surrounds the goblet cells and what are they attached to?
Ciliated columnar epithelial cells - attached to basal membrane that holds them in place
What is the fluid mosaic model?
1972 Singer and Nicholson’s membrane model:
Proteins are through the membrane, not holding phospholipids in place
• by increasing ionic strength of solutions or by adding protease-containing detergents, some proteins can be removed from membrane
What are the components of a phospholipid?
Hydrophilic phosphate heads face towards the solution (& polar)
Hydrophobic fatty acid tails face away from the solution (& non-polar)
What’s glycocalyx?
Protective role on membrane (carb part of glycolipid)
Why is it called the fluid mosaic model?
Fluid - because of the lateral movement of lipids and proteins through the bilateral
Mosaic - composed of many different macromolecules