A micro-organism that causes disease.
Micro Organism into body & Defences
Gas exchange system
Pathogens cause disease
Damage host cells
CHD lifestyle factorsa nd redusing the risks
smoking, high blood pressure, blood cholesterol levels, obesity, diet, physical activity
giving up smokeing not starting, avoid obesity, reduce salt intake, reduse cholesterol, more sat. fats in diet, regular aerobic exercise, alcohol intake low, increase dietery fibre & anti oxidents
Major parts of the digestive system
Oesopagus- transport, thick muscular wall
Stomach- muscular sac, produces enzymes and mucous
small intestine- long muscular tube, S.A increased (micro)villi
large intestine- absorbs water, faeces, egestion
salivary gland- amylase, starch into maltose
pancreas- large gland, protease-proteins, lipase-lipids, amylase-starch
2 types of digestion
Physical- large molecules to small molecules, by means of structures like teetha nd stomach muscles, increases surface area for chemical digestion,
Chemical- large insoluable molecules into smaller soluable ones, carried out by enzymes functioning by hydrolysis, (adding water to break up bonds molecules)
Carbohydrase- carbohydrates into monosaccharides
Lipase- lipids into glycerol and fatty acids
Protease- proteins into amino acids
readily form bonds with other carbon atoms, organic compounds formed,
Monosaccharides & Reducing sugars
sweet tasting, soluble, general formular (CH2)0 n, 3<n<7
Glucose is a monosacchride, 6 carbons,
benedicts reagent is an alkaline solutions of copper (II) sulphate, when redusing sugars are heated you get red precipitate, copper oxide
blue-none, green-very low, yellow- low, orange- medium, red- high
Non- reducing sugars you have to boil then it will go orange-brown
Disaccharides and Polysaccharides
Glucose + Glucose -> Maltose
Glucose + Fructose -> Sucrose
Glucose + Galactose -> Lactose
When monosaccharides are are formed through condensation a water molecule is given out, forming a gylcosidic bond
breaking them is called hydrolysis, addition of a water molecule.
-OH HO- --------> -O- +H2O
food into mouth chewed, smaller pieces, larger surface area
salvia, mixed with food, salviary amylase startd hydrolysing any starch, to maltose, neutral pH
into stomach, amylase denatured by pH, bacteria killed
small intestine, mixes with pacreatic juices containing pancreatic amylase, starch into maltose, pH neutral again
then maltase is produced breaking maltose into alpha-glucose
Amino Acids (primary, secondary, tertiary, quatern
amino group (-NH2)
r group- (-variety of different chemical groups)
hydrogen atoms- (-H)
carboxyl group- (-COOH)
Primary- monomers joined together through polymerisation, produces polypeptide, determines ultimate shape and function
secondary- (-NH) has +tive charge (-O) had -tive charge, alpha helix or beta pleated sheet, made by H bonds, 3D shape
tertiary- twisted on itself, disulphide bonds -> strong, ionic bonds -> carboxyl groups and amino groups weaker effectd by pH, H bonds -> numerous easily broken.
Quaternary structure- groups or tertiary structure linked together, haemoglobin (haem group)
Fibrous and Globular
Fibrous- structural functions
unbranched polypeptide chain
polypeptide chain tightly wounded, compact
twisted second helix
3 polypeptide chains wound like rope
Globular- metabolic functions, haemoglobin, enzymes.
Lock and Key, Induced Fit Model
Lock and Key-
Advs- specific shape (active site), substrate complementary.
Disadvs- rigid structure, applying pressure to substrate.
Advs- slightly flexible, moulds to substate like glove to hand, applying pressure to break substrate, molecules affect enzyme activity, activation is lowered.
Diadvs- not so complementary to substrate.
Effect on enzyme activity
Temp- more kinetic energy, move more rapidily, more collision more often, more enzyme-substrate complexes.
pH- alters charges on amino acid and carboxyl groups that make up active site, not complementary, less enzyme-substrate complexes, breaks bonds creating the tertiary structure,
Substrate Conc.- rate of reaction increases as conc. increases, more substrates to bind with and break, will plateau because enzyme becomes a limiting factor.
Competitive- in active site, substrate cannto bond with enzyme, compete for active sites, if enzyme conc. increases the effect of the inhibitor is reduced.
Non-Competitive- they attached at other site not active site, affects the shape of active site, enyme not complementary, less enzyme-substrate complexes, an increase in substrate conc. does not effect the effect of the inhibitor.
magnefication=size of image/size of object
size of object= size of image/magnefication
resolution- min. dstance apart 2 things must be to be seen as seperate objects, clarity, light mocroscope, 0.2 micrometres, electron microscope 0.1 nanometres
electron microscope-2 types TEM, SEM
advs- electron beam is very short wavelength good resolution, beam can be focused ( -tively charged)
TEM- in vacuum, dead specimins, complex staining process, black white image, specimin extremely thin, can contain artefacts
SEM- all of TEM except specimins can be thicker, build up 3D image.
cold- to reduce enzyme activity
isotonic- to stop osmosis
buffered- control pH
cells broken up, relaease organelles from cell, filtered to remove any complete cells or large debris.
placed in centrifuge and spung low speed
heavy organelle at bottom form sediment/pellet
fluid at top removed spun faster
supernatant is removed leaving sediment
nucleus, mitochrondira, endoplasmic reticulum
Structure of an Epithelial Cell (Nucleus)
Nucleus-control cell, retain genetic materials, manufacture RNA & ribosomes
nuclear envelope- double membraned, had ribosomes on it, controls entry and exit, contains reactions
nuclear pores- allows passage of large molecules
nucleoplasm- granular, jelly like, material makes up most of nuclus
Chromatin- DNA within nucleus this is diffuse form that chromosomes make up when cell is not dividing
Nucleolus- small spheric body withing nucleoplasm, manufactures RNA
Structure of an Epithelial Cell (Mitochondria)
Mitochondria- rod shaped RESPIRATION
double membrane- outer controls what goes in/out, inner folded to form extension known as cristae
Cristae- shelf like extensions, large S.A,
Matrix- semi rigid, contains proteins, lipids, traces of DNA
responsible for making the energy-carrier molecule, ATP from carbohydrates
epithelial cells use lost of energy, active transport, need lots of ATP
Structure of an Epithelial Cell (Endoplasmic retic
Endoplasmic reticulum- elaborate, 3D system
rough RER- ribosomes present on surface membrane
large surface area, pathway for transport of materials espec. proteins
smooth SER- lack of ribosomes on surface, more tubular,
synthesis, store and transport lipids and carbohydrates.
Structure of an Epithelial Cell (Golgi Apparatus)
Golgi apparatus- similar structure to SER, more compact, modifies proteins, adds non protein components, 'labels' them, send to correct destinations, transported in vesicles
add carbs to proteins to make gylcoproteins
transport, modify, and store lipids
Structure of an Epithelial Cell (Lysosomes)
Lysosomes- contain potentially harmful enzymes, suicide cells, gets rid of enzymes outside of cells or in phagocytic cells,
break down materials ingested by phagocytic cells such as white blood cells
release enzymes to outside cell to destroy outside cells
digest worn out organelles
completely break down cells after they have died
Structure of an Epithelial Cell (Ribosomes/Microvi
Ribosomes- PROTEIN SYNTHESIS small cytoplasmic granules, associated with RER or cytoplasm, 2 types
80s- eukaryotic cells, bigger
70s- prokaryotic cells, smaller
2 sub units, one big, one small, each contain RNA and protein,
Microvilli- finger-like projections, increase S.A, allow efficient absorption,
contain carbon, hydrogen, oxygen
proportions are smaller then in carbs
insoluble in H2O
soluble in organic solvents such as alcohol
solid room temp
Main group- triglycerides (condensation reaction (+H2O), phospholipids, waxes
energy source double bond- unsaturated
waterproofing single bonds- saturated
Phospholipids- Polar, test for them by the emulsion test (ethanol)
hydrophilic 'head'- interacts with water not fat
hydrophobic 'tail'- moves away from water but mixes with fats.