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Pasteurisation reduction of pathogenic bacteria by heating at 72 degrees for 15 seconds
Sterilization destruction of pathogenic bacteria by heating between 110 and 130 degrees
for 10-30 minutes
Bactericidal antibiotics that kill bacteria directly
Bacteriostatic antibiotics that inhibit the assembly of peptide links in peptidoglycan wall,
causing the cell wall to weaken and causing osmotic lysis if water enters the cytoplasm by
Four phases of growth are lag phase, log/exponential phase, stationary phase and decline
Lag phase cells adapt to new environment e.g synthesising new enzymes to deal with new
food source
Log phase nothing limiting reproduction of bacteria
Stationary phase death balances cell division, caused by intraspecific competition
Cells counted by haemocytometer or viable count using serial dilution
Coccus spherical
Vibrio comma shape
Bacillus rod shaped
Spirillum spiral shape
Gram stain technique shows whether bacteria are gram positive or gram negative
Gram positive stain violet no lipopolysaccharide layer so crystal violet dye is taken up by
peptidoglycan wall
Gram negative stain red lipopolysaccharide layer that prevents crystal violet being
trapped in the peptidoglycan wall is made more permeable by the crystal violet dye, so that
the counter stain saffronin can be taken up by the peptidoglycan wall
Batch fermenter
Paddle stirrers ensure microorganisms in contact with nutrients, ensures even
Nutrient input energy source e.g carbohydrate and growth materials e.g amino acids
Constant temp water jacket keep temp constant
Sterile conditions aseptic technique
Gas outlet allows gas to leave fermenter to avoid pressure damage
Probes monitor conditions, sends info to computer control systems, correct changes by
negative feedback
Vessel walls made of stainless steel doesn't corrode, easily cleaned and sterilised using
steam jets
Penicillin is a secondary metabolite of fungus Penicillium

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Niche where organism lives and how it feeds
Abiotic factors water, oxygen, light, toxins, pollutants, climate
Biotic factors food availability, predators, parasites, disease, territorial interactions
Density-dependent factors always biotic
Density-independent factors biotic or abiotic
Biotic potential maximum reproductive capacity given no environmental resistance
Carrying capacity maximum number of organisms of a species that can be accommodated
by the environment
Carbon cycle
Atmospheric carbon dioxide 0.…read more

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Nervous system
Reflex actions rapid involuntary responses to stimuli that prevent the body becoming
Relay neurone transmits sensory impulse across spinal chord, not myelinated so speed of
transmission relatively slow, significant for modifying reflex response
Central canal contains cerebrospinal fluid, nourishes and maintains electrolyte balance in
Grey matter cell bodies, unmyelinated axons, absence of myelin gives grey colour
White matter motor and sensory neurones, well myelinated gives light colour
Dorsal root ganglion swelling in dorsal root…read more

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Phototropism growth response which allows shots to grow towards light, giving optimum
Large surface area of leaves held perpendicular to light source allow optimum illumination
Thin leaves light only absorbed by a few cell layers before it is received by photosynthetic
Leaf mosaic arrangement of leaves minimises overlapping/shading; maximises exposure
to light
Shoot system holds leaves in optimum position for carbon dioxide uptake/illumination
Cuticle waxy compound called cutin secreted by upper epidermis, reduces water loss by
Upper epidermis one/two cells thick,…read more

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Photosynthometers have a fixed light source, of light intensity 1/d2, constant temperature,
hydrogen carbonate solution of known concentration to provide carbon dioxide, aquatic
plant of fixed length, capillary tube to transport gas, syringe to collect gas produced
Chromatography separates components of mixture according to their relative affinities
by passing solvent (mobile phase) over paper (stationary phase)
= distance
retardation factor distance travelled by compound
travelled by solvent front
Flucoxanthin brown pigment of seaweeds which absorbs blue/green light; these
wavelengths penetrate water better than red light…read more

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Light dependent stage of photosynthesis (non-cyclic)
PS2 absorbs photons of light energy and passes it onto primary pigment at reaction centre
causes high energy electrons to be emitted
Electrons reduce electron acceptor, and are then passed down electron transport chain,
finally being accepted by PS1 enough energy released to actively pump H+ ions from the
thylakoid exterior to the thylakoid interior, creating an electrochemical gradient
When H+ ions diffuse across thylakoid membrane, the electrical potential energy allows ATP
to be synthesised from ADP and Pi…read more


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