Essential BioFacts from Year 8

FOOD GROUPS

• CARBOHYDRATESshort-term energy storage

• PROTEIN growth and repair of cells

• VITAMINSchemical reactions

FOOD TESTSSTARCH GLUCOSE PROTEIN

iodine

brown

blue/black

starch

Benedict’s reagent

blue

brick red

glucose

heat

Biuret reagent

purple

light blue

protein

starch

glucose (simple sugar)

amino acidchains

DIGESTIVE SYSTEM

large intestine(water absorption)

small intestine – ileum(nutrient absorption)

pancreas(digestive juice production)

stomach(digestion)

oesophagus(food transport to stomach)

small intestine – duodenum

(digestion)

gall bladder(bile storage)

liver(bile production)

mouth(mechanical digestion)

DIGESTIVE ENZYMES

• MOUTH + DUODENUM

starch glucose

amylase

• STOMACH + DUODENUM

• DUODENUM

protein amino acids

protease

lipids glycerol + fatty acidslipase

VILLI IN ILEUM

capillaries(absorb glucose+ amino acids)

lacteals(absorb lipids)

villuscells with microvilli

glycerol + 3 fatty acids

• FATlong-term energy storage

• FIBREprevents constipation

• WATERrehydration, transport of molecules around body

• MINERALShealthy blood and bones

DIFFUSION solute H2O

= the movement of molecules from high to low concentration

time

time

EFFICIENCY:• large SA

large SA/V ratio• short diffusion

distance• large concentra-

tion gradient• high temperature

SA/V ratio

SA:

1 cm

2 cm

3 cm

6x1= 6

6x4= 24

6x9= 54

V: 1x1x1= 1

2x2x2= 8

3x3x3= 27

SA/V:

6/1= 6

24/8= 3

54/27= 2

= the smaller the organism the larger its SA/V ratio

• large SA • short diffusion distance• large concentration

gradient

FOOD CHAINS

PYRAMID OF NUMBERS AND BIOMASS

PHOTOSYNTHESIS

RESPIRATION

producer primaryconsumer

secondaryconsumer

tertiaryconsumer

herbivore carnivore top carnivore

prey predator/prey predator

trophic level 1 trophic level 2 trophic level 3 trophic level 4

PYRAMID OF NUMBERS

• shows number ofall organisms in each trophic level

PYRAMID OF BIOMASS

• shows dry mass ofall organisms in each trophic level

oak tree

caterpillars

voles

owl

= show energy flow in feeding relationships

• not all eaten• not all digested• respiration• movement• reproduction

ENERGY TRANSFER• growth

• not all eaten• not all digested• respiration• movement• reproduction• body heat

• not all eaten• not all digested• respiration• movement• reproduction• body heat

100%

90% 90% 90%

10%

• growth• growth

food foodfood

10% 10%

= energygained

= energylost/used

• BACTERIA- single-celled- no nucleus + other organelles- circular chromosome- plasmids- cell wall - flagellum

• VIRUSES- not alive, not made of cells- no organelles!- need host cell to reproduce- genetic material (DNA or RNA)- protein coat

Essential BioFacts from Year 8

DEFENCE AGAINST DISEASEMICROBES

PATHOGENS

• FUNGI- single- or multi-celled- cell wall (chitin)- saprophytic nutrition(secrete enzymes to digest foodoutside cells)

• PROTOCTISTA- most single-celled- nucleus + other organelles- some do photosynthesis

yeast mould

amoebaalgae

• PLATELETS

• WHITE BLOOD CELLS(A) PHAGOCYTES

(B) LYMPHOCYTES

bacteria vacuolephagocyte

lobed nucleus

digestive enzymes

ENGULFMENT DIGESTION

woundplatelet

redblood cell

blood clot

lymphocyte

nucleus antibody

bacteria

destructionof bacteria

memory cell

(1)

(2)

antibody release + binding to antigens on bacteria

rapid antibody production(= IMMUNITY)

IMMUNITYplasma cell

reinfection

ANTIBIOTICS

anti

bo

dy

pro

du

ctio

n

time

infection re-infection

antibodies made slowly

illness

recovery

immunity

memory cells made

ANTIGENS + ANTIBODIES

YOGHURT

BREAD BEER /WINE

antibodies made quickly

anti

bo

dy

pro

du

ctio

n

time

injection with pathogen’s antigens infection

immunity

memory cells made

antibodies made quickly

VACCINATION

• inhibit bacterial cell wall synthesis

ORbacteria destroyed

• inhibit bacterial protein synthesis

• BUT don’t inhibit virusesbacteria can’t growand multiply

x

• lactobacillus• anaerobic respiration

• yeast• aerobic respiration

• yeast• anaerobic respiration

glucose O2 CO2 water glucose CO2 ethanol(alcohol)

+ + +

lactose(milk sugar)

lactic acid

air in bread

kneadingof dough

flour fizz

wine: grapesbeer: barley

yoghurt

• milk is pasteurised at 85°C to kill pathogens• milk is cooled to 40°C to allow lactobacillus to be added• mixture is incubated for several hours while lactobacillus respires• pH falls as lactic acid is produced causing milk to curdle

x

• different antibodies recognise different antigens on the surface of pathogens x

antigen

antibodies

bacteria

• BACTERIA- produce toxins- e.g. pneumococcus

= microbes that cause disease

• VIRUSES- take over host cell and destroy it- e.g. flu virus , HIV

E. coli