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LIFE  PROCESSES  
 
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The  processes  that  get  together  to  maintain  functions  of  living  organisms  
are  called  life  processes
...
 
In  unicellular  organisms,  there  are  no  special  organs  for  special  functions  
because  the  entire  surface  is  in  contact  with  the  enviornment
...
 
FOOD-­‐  source  of  energy  and  the  material  that  helps  us  walk,  ride  a  bicycle,  
to  grow  or  develop
...
 Eg:  plants  and  bacteria
...
   
Organisms  use  enzymes  to  decompose
...
 
The  material  they  take  from  the  outside  in  the  form  of  carbon  dioxide  and  
water  is  converted  into  carbohydrates  in  the  presence  of  sunlight,  and  
chlorophyll
...
 
In  our  body  the  energy  is  stored  in  the  form  of  glycogen
...
 They  release  
water  and  oxygen  during  this  process
...
Absorbtion  of  light  energy  by  chlorophyll
...
Conversion  of  light  energy  to  chemical  energy  and  splitting  of  
water  molecules  into  hydrogen  and  oxygen
...
Reduction  of  carbon  dioxide  to  carbohydrates
...
 
− Stomata-­‐    
1
...
 
2
...
 
3
...
   

4
...
 
− Other  raw  materials  are  also  needed:  
1
...
Nitrogen,  phophorus,  iron  and  magnesium-­‐  taken  from  the  soil
...
 
                   -­‐Taken  in  the  form  of  nitrate  or  nitrite
...
 
− Some  organisms  break  down  the  food  outside  the  body  and  then  absorb  
it
...
 
− Other  organims  derive  nutrition  from  plants  without  killing  them
...
 
− Holozoic  nutrition  in  Amoeba:  
1
...
 They  fuse  over  the  food  particle  forming  a  food  vacuole
...
Inside  the  food  vacuole,  complex  substances  are  decomposed  into  simpler  
ones,  which  then  diffuse  in  the  cytoplasm
...
The  remaining  undigested  material  is  moved  to  the  surface  of  the  cell  and  
thrown  out
...
 Food  is  moved  to  this  spot  by  cilia
...
 
− The  alimentary  canal  is  a  long  tube  which  extends  from  the  mouth  to  the  
anus
...
 
− The  food  we  ingest  is  complex  and  has  to  be  made  simpler
...
 
− Saliva:  
1
...
 
2
...
   
3
...
 
− Peristaltic  movements:  
1
...
 
2
...
 
3
...
 

− Tongue:  
1
...
 
2
...
 
− Stomach:  
1
...
 
2
...
 
− Gastric  glands  are  present  in  the  stomach  and  release:  
1
...
 
2
...
 
3
...
   
− Small  intestine:  
1
...
 
2
...
 
3
...
 Herbivores  have  a  longer  small  
intestine  because  they  eat  grass  and  allow  the  cellulose  to  be  digested
...
 
4
...
 
− The  food  coming  from  the  stomach  is  acidic  and  has  to  be  made  alkaline
...
 
− Fats  are  present  in  the  intestine  as  large  gobules,  thus  it  is  difficult  for  the  
enzymes  to  act  on  them
...
 
− Pancreatic  Juice:  
1
...
 
2
...
 
− Intestinal  Juice:  
1
...
 
2
...
 
b) Complex  carboydrates  into  glucose  
c) Fats  into  fatty  acids  and  glycerol  
− Villi:  
1
...
 
2
...
 
3
...
 
4
...
   
− The  absorbed  food  is  then  used  for  obtaining  energy,  building  up  new  
tissues  and  the  repair  of  old  tissues
...
   
− The  villi  in  the  large  intestine  absorbs  water  after  which  the  rest  of  the  
material  is  thrown  out  through  the  anus
...
 
− In  all  cases  the  first  step  is  the  break  down  of  the  glucose,  a  6  carbon  
compound  into  a  3  carbon  molecule,  called  pyruvate
...
 
− CASE  1-­‐  In  yeast,  the  pyruvate  is  converted  into  ethanol  and  carbon  
dioxide
...
 
− CASE  2-­‐  The  break  down  of  pyruvate  with  oxygen  takes  place  in  the  
mitrochondria
...
 It  is  done  aerobically
...
   
When  this  happens  during  sudden  activity  it  causes  cramps
...
 
− ATP:  
1
...
 
2
...
 
3
...
When  terminal  phosphate  linkage  in  ATP  is  broken  using  water  
then  30
...
 
5
...
 

− Carbon  dioxide  and  oxygen  are  exchanged  by  diffusion  over  here  and  the  
direction  of  diffusion  depends  on  the  enviornmental  conditions  and  the  
requiremnet  of  the  plant
...
 During  the  day,  carbon  dioxide  generated  during  
respiration  is  used  up  for  photosynthesis,  therefore  there  is  no  carbon  
dioxide  release
...
 
− The  rate  of  breathing  of  aquatic  organisms  is  much  faster  than  terrestial  
organisms  because  the  amount  of  dissloved  oxygen  is  fairly  low  compared  
to  the  amount  of  oxygen  in  the  air
...
 
− Different  organs  absorb  oxygen  in  different  animals,  but  all  the  organs  
have  a  structure  that  increase  the  surface  area  which  is  in  contact  with  
the  oxygen  rich  atmosphere
...
 
− The  air  passing  the  nostrils  is  filtered  by  fine  hair  that  lines  the  passage,  
the  passage  is  also  lined  with  mucus
...
 
− Rings  of  cartilage  are  present  in  the  throat  to  ensure  that  the  passage  
does  not  collapse
...
 
− Aveoli:  
1
...
 
2
...
 
3
...
 
− Mechanism  of  breathing:  
o INSPIRATION:  
a) The  ribs  are  lifted  and  the  diaphragm  contracts
...
 
c) Air  is  sucked  into  the  lungs  and  fills  the  aveoli
...
 
e) The  oxygen  is  taken  up  by  the  blood  from  the  aveolar  air
...
 
b) The  lungs  recoil  and  the  volume  in  the  chest  cavity  decreases  so  
the  pressure  increases
...
 
− The  lungs  always  contain  a  residual  volume  of  air  so  that  there  is  enough  
time  for  oxygen  to  be  absorbed  and  carbon  dioxide  to  be  released
...
   
− Oxygen  is  transported  by  hemoglobin  as  it  has  a  high  affinity  for  oxygen
...
 
 
 
 
v TRANSPORTATION  IN  HUMANS:  
− BLOOD:    
1
...
 
2
...
 
3
...
 
4
...
 
b) White  blood  cells-­‐  provide  immunity
...
It  is  a  muscular  organ
...
Has  different  chambers  to  prevent  the  oxygen  rich  blood(oxygenated)  
mixing  with  the  blood  containing  carbon  dioxide
...
The  de-­‐oxygenated  blood  has  to  reach  the  lungs  for  the  carbon  dioxide  to  
be  removed  and  the  oxygenated  blood  has  to  be  bought  back  from  the  
heart  so  it  can  reach  the  rest  of  the  parts  of  the  body
...
Ventricles  have  thicker  muscular  walls  than  atria  because  they  have  to  
pump  blood  into  various  organs
...
The  following  are  the  events  of  the  cardiac  cycle:  
a) The  oxygen  rich  blood  from  the  lungs  comes  to  the  left  atrium  
through  the  pulmonary  veins
...
 
c) When  the  left  ventricle  contracts  the  oxygen  rich  blood  is  pumpec  
out  to  the  body  by  the  aorta
...
(large  vein)  
e) Then  the  right  atrium  contracts  and  transfers  the  de-­‐oxygenated  
blood  to  the  right  ventricle  which  expands
...
 
− The  separation  of  the  right  side  and  the  left  side  allows  an  efficient  supply  
of  oxygen  to  the  body
...
   
− The  animals  that  do  not  use  enrgy  to  maintain  body  temperature  their  
body  temperature  depends  on  the  temperature  in  the  enviornment
...
 
− Fish  have  only  a  two  chambered  heart
...
 

− DOUBLE  CIRCULATION-­‐  when  blood  goes  through  the  heart  twice  during  
each  cycle  of  passage  through  the  body
...
 
− In  fish,  it  goes  through  the  heart  only  once  in  each  cyle
...
 
organs  of  the  body
...
 
They  have  thick  elastic   They  have  valves
...
   
walls
...
 
arteries
...
 
− Valves  ensure  that  blood  does  not  flow  backwards
...
 
− Capillaries  join  together  to  make  veins
...
Present  in  the  blood
...
They  plug  leaks  by  helping  to  clot  the  blood  at  the  points  of  injury
...
They  prevent  leakage  that  could  lead  to  a  loss  of  pressure  which  would  
reduce  the  efficiency  of  the  pumping  system
...
Formed  when  some  amount  of  plasma,  proteins  and  blood  cells  escape  
into  inteercellular  spaces  in  tissues  from  pores  present  in  the  walls  of  
capillaries
...
Similar  to  plasma  but  colourless  and  conatins  less  proteins
...
Lymph  is  drained  into  lymphatic  capillaries  which  join  to  form  large  
lymph  vessels  that  open  into  larger  veins
...
It  carries  absorbed  and  digested  fat  from  the  intestine
...
It  drains  excess  fluid  from  extra  cellular  spaces  into  the  blood
...
 
− The  absorbtion  of  these  substances  will  occur  through  the  part  in  contact  
with  soil,  roots
...
 
− Plants  have  low  energy  needs  and  thus  can  use  slow  transport  systems
...
 
XYLEM  
PHLOEM  
Transports  water  and  minerals  
Transports  of  photosynthesis  from  

from  the  soil
...
 

 
• TRANSPORT  OF  WATER:  
− In  xylem  tissue,  vessels  and  tracheids  of  the  roots,  stems  and  leaves  are  
interconnected  to  form  a  continuous  system  of  water  conducting  
channels
...
 This  
creates  a  difference  between  the  root  and  the  soil
...
 
− This  movement  is  not  enough  to  push  the  water  upwards  to  the  leaves  as  
the  distance  is  long
...
 Evaporation  of  water  
molecules  from  the  cells  of  a  leaf  creates  a  suction  which  pulls  water  from  
the  xylem  roots
...
 
• TRANSPIRATION:  
1
...
 
2
...
 
3
...
 
− The  effect  of  root  pressure  in  transport  of  water  is  more  important  at  
night  because  during  the  day  when  the  stomata  are  open,  the  
transpiration  pull  becomes  the  major  driving  force  in  the  movement  of  
water  in  the  xylem
...
 
Occurs  in  phloem  and  is  achieved  by  using  energy
...
 
− The  phloem  transports:  amino  acids,  products  of  photosynthesis  and  
other  substances
...
 
− Steps  of  transportation  using  energy:  
a) Materials  like  sucrose  is  transferred  into  phloem  using  energy  
from  ATP
...
 
c) This  pressure  moves  the  material  into  the  phloem  to  tissues  which  
have  less  pressure
...

2
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d) This  allows  phloem  to  move  the  material  according  to  the  plants  
need
...
 
− Many  unicellular  organisms  remove  this  waste  by  simple  diffusion  from  
the  body  surface  into  the  surrounding  water
...
 
− Kidneys:  
1
...
 
2
...
 
3
...
 
− Urine  is  made  to  filter  out  waste  products  from  the  blood
...
 
− Nephrons:  
1
...
 
2
...
 
3
...
 
− Some  substances  in  the  intial  filterate  like  glucose,  amino  acids,  salts  and  
a  major  amount  of  water  are  selectively  re-­‐absorbed
...
 
− The  urine  formed  in  the  kidneys  enters  a  long  tube,  the  ureter,  which  
connects  the  kidneys  to  the  urinary  bladder
...
 
− The  bladder  is  muscular,  so  it  is  under  nervous  control  and  thus  we  cn  
control  the  urge
...
 
− They  can  get  rif  of  excess  water  by  transpiration
...
 
− Waste  products  may  be  stored  in  leaves  that  fall  off
...
 
− Some  waste  products  are  stored  as  resins  and  gums

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