Notes

photoynthesis is a process where carbohydrates are produced by light energy and inorganic moecules.
chlorophyll and some other photosynthetic pigments in plants absorb light energy from the surrounding environment and thr light energy is used to drive the reaction.
during phototsynthesis, green plants trap sunlight with a green pigment called chlorophyll, take in carbon dioxide throuugh tiny openings called the stomata, take in water through the root hairs. Water is split into hydrogen and oxygen, the hydrogen combines with carbon dioxide to form carbohydrates. oxygen is given out a a waste product, carbohydrates are then convertedd to starch.
Carbom dioxide + water -^ sunlight and chlorophyll oxygen + glucose
Test fro starch 1. boil leaf in hot water to stop all enzymatic reactions as enzymes as denatured. then place ethanol n leaf into a tube and continue boiling, makes leaf brittle and will decolourise the leaf, ethanol s highly flammable. then soak leaf in hot water to soften it. put iodine.
Test for gas coolected during photosynthesis is oxygen.
Respiration is the oxidation of glucose in the presense of oxygen to release large amount of energy for living cells. Gas exchange is needed to take in oxygen n give out carbon dioxide. Gas exchange in humans take place in the alveoli between the lungs and the air sacs. It also occurs between the booldstream and body cells.
The differences betw cellular respiration and gas exchange : celllular respiraton is the chemical process y which energy is released from the breadown of food while gas ecxchange is the physical process by which o2, required for resp n co2 a waste product of resp is exchanged betw 2 regions w a conc gradient.
lungs - lie in thorax rib cage - protect lungs n heart , intercoastal muscles - help move the ribs, diaphragm - a sheet of muscle that lies below the luns, seperates thorax n abdomen. pharnx - throat , larynx -- voice box, trachea - wind pipe. Bronchi - branching off trachea, leading to the lungs. BRonchioles - branches 0f the bronchi , ALveoli - blind ending airr filled sacs, site of gas exchange. Gas exchange happens by diffusion ( higher conc of oxy ) our breathing constantly moves air in and out of the alveoli, this ensures the conc of oxyge n carb diox betw lungs and the blood stream remains high.
Adaptatios : millions of alveoli provide a large surface area for gaseous exchange
2. alveoli have a thin film of moisture to dissolve oxyen before it can diffuse in solution the blood.
3. The walls of the alveoli are thin for faster and easy diffusion of gases, as shorter diffusion dist leads to faster diffusionn
4. Alveoli are richly supplied with capilllaries for rapid transport of gases. Flow of blood maintains steep conc gradient.
Differences betw respiratin and breathing : resp is a chemical process as new subs as produced, while breathing is a physical process as no new subs produced, resp energy is released whie breathing no energy released, resp
taes place in cells while breathing takes place outside cells, resp requires enzymes while breathing does not require enzymes
uses of resp :
1 muscle contraction
2 for building of new protoplasm for the growth and repair of cells
3 for the synthesis of proteins by amino acids
4 for cell division
5 for active transport for absorption of digested food subs in the small intestine
6 conversion into heat energy to maintain body temp.
ptassium hydroxide solutio - to absorb all carb diox from the surrounding air
Differences betw photosynthesis and resp :
photosynthesis takes place in cells that contain chloroplasts while resp takes place in all living cells.
photosynthesis takes place only whn there is sunlight while resp takes places all the time
during photosynthesis, light energy is connverted to chemical energy, while during resp, chemical energy is converted to a form cells can use.
C.E is stored in food and o2 is produced from photosynthesis while in resp, C.E is released from food and o2 is used up.
they are opp reactions as the suns energy is trapped and converted to C.E while during resp energy in food is released so that it ca power cellular reactions.
Factors that affect both photosynthesis n resp : extreme temp n pH

heart

respiration is needed as it is an important life sustaining activities, cells undergo resp for release of energy stored in food.
transport system is needed to ensure that cells are provided with resources that are needed for carrying out their life processes and also ensure that waste produced by cells are removed
TRansport system is needed to supply trillions of cells with glucose and oxygen, remove waste products and transport molecules such as hormones to coordinate the functions of various organs.

DOUBLe CIRCULATION
pulomonary circuit : links hart to lungs, transports deoxygenated carbon dioxide rich blood to the luncgs for gaseous exchannge then oxygenated bloood back to heart.
systemic circuit : links heart to rest o the body, when heart pumps, the blood from lungs trans to all parts of body so that each cell will get oxygen, ensuring that co2 is also removed by diffusion into the blood stream.

ADVANTAGES :
when the heart pums, blood that flows to the lungs are at a lower pressure so that it will flow more slowly through the lungs so more o2 can diffuse into blood stream as there is sufficient timee.
blood is at a higher pressure to the rest of body so that oxygen can be quickl distributed to body tissues. this helps maintain high metabolism.
left side of heart - oxy, right side - deoxy
septu seperates the 2 side of the heart to prevent oxygenatedd blood from mmixing with deoxygenated blood.
ATRIAL VS VENTRICULAR WALLS
atrial walls are thinnner as they need to generate enough pressure to pump blood to the ventricles while the ventricular walls need to generate enough pressure to pump blood to the lungs or to the rest of the body thus they are thicker and more muscular.
R VS L VENTRICLE
the right ventricle is thinner only needs to generate eenough pressure to pump bloood to the pumoanry ciruit which is shorter and has fewer blood vessels, the left v is thicker n more muscular as it need to generate enogh pressure to pump blood to the systemic circuit which is a longer cicuit that has more blood vessels

VENTRICULAR SEPTaL DEFECt
ventricular septal defect is caused by the mixing of the deo2 n o2 blood in right n left ventricle
thus the conc of o2 in blood pumped to rest of body is lower as the conc gradient is less steep betw body cells n the blood, thus o2 will take more time to diffuse into the cells. cells receive less o23, lower resp rate, lesser energy released so patient cannot participate in vigorous exercise

right to left of heart diagram :
vena cava trans deo2 blood from rst or body back to heart (RA)
pulmonary arteries tran deo2 blood to the lungs from heart 9RV)
aorta the largest blood vessel in the body trans blood from heart (LV) to rest of body
pulmonary veins tran o2 blood from lungs back to heart
(LA)

right to left of <3 diagram
tricuspid valve in prevents the backflow of blood from the RV to the RA when the muscular walls of the RV conracts
ssemi-lunar valves prevent the bacflow of blood from the arteries back to the heart chambers ( found at entrance of pul art n aorta)
bicuspid valve sem

cardiac cycle
deo2 blood returning from the systemic circuit via the vena cava bolls into right atrium.
the muscles of the walls of the ra contract while the walls of rv ris relaxing t0 preparing to receivve the blood from ra, then the mmuscles of the walls of rv contracts, at this point the triccuspid valve closes ensuring the blood all pumped to pul art where blood will b sent t0 lungs for gaseous exchange.
BLOOD VESSELs
branches of arteries arre called arterioles that carry blood away from the <3
- branched of veins are called venules which carry blood towards the heart
- capillaries are the network of microscopic vessels that connect the venules and arterioles. they take the nutrients o2 and other useful subs to the cells and remove the waste products in these cells.

arteries : thick muscular and elastic wall, has a narrow lumen compared to the vein. Blood moves along the artery by strecthing and recoiling of the elastic tissue in the walls, blood flows at very high pressure, fast and in spurts , carries mostly o2 blood excep pulmonary arteries
veins : thick and less muscular , elastic walls. Has a wide lumen. it has valves to prevent the backflow of blood. blood moves by the stretching n recoiling of th elastic tissue n the walls, blood flows at the lowest pressure, slowly and smoothly. carries mostly deoxygentated blood except pulmonary vein
capilaries: one cell thick, blood flows smoothly, mostly at higher pressure at arteriole end than venule end. o2 at ateriole end and deo2 at venule end except for in lungs

blood is a fluid tissue that contains plasma, rbc n wbc and platelets. plasma is too transport dissolved subs such as waste products, plasma proteins, solubble food sub, hormones, proteins,blood cells and mineral salts.
rbc
o transport o2 to all parts of the body
it has a bi-concave, flattened disc shape : inc surf area to vol ratio for faster rate in and out of cells.
2. contains haemoglobin : to bind reversibly to o2, allowing rbc to carry it to the cells that need it
3. it is flexible n elasti to squeeze throgh narrow capillaries
4. reduce metabolism n o2 requirements. it increases the space so that it can pack more haemoglobin to so more o2 can b carried
- it has a life span of 4 months, worn out cells are destroyed in the spleen or liver. formed in bane marrow

wbc
they are bigger and less numreous than rbc, can change its shape and move abt. there are many kinds of wbc but the 2 main types are lymphocytes and phagocytes.
lymphocytes - produced in lymph glands and nodes. it produces antibodies that kill invading bacteria, it also causes bacteria to clump together in a process called agglutination of foreign bodies, which are easily ingestedd by the lymphocytes.
phagocytes - are producedd in the bone marrow. IT can easily ingest and engulf foreign particles like disease causing bacteria,which is called phagocytosis,
platelets- are cell fragants formed in the bone marrow that help clot blood, this seal stops further blood loss and stops foreign particles like disease causing bacteria to enter the body.

DIGESTION
- the process by which large, complex and insoluble food subs are broke down, physically or chemiclly into smaller, simpler and soluble forms which can be absorbed by the body.

why mst food be digested ?
1 food must pass through the walls or the alimentary canal and blood vessles before it can be used by all parts of the body
2 the walls of the alimentary canal and blood vessels has cells, cells have partially permeable walls, large molecules such as the food subs cannot pass through these walls
3 usually food is in the form of these large and insoluble molecules which cannot be passed through these membranes
4 so these large and complex food substances need to be chemically n physically broken dow into smaller simpler forms such as glucose and amino acids for them to pass through the walls of the villi and blood capillaires to be used by the body.
nutrition - the process of taking in food to use for growth and repair and to maintain health.
absorption - the diffusion of digested food across the walls of the small intestine and into the bloodstream
assimilaiom - the transportation and utilisation of absorbed nutrients to provide eneergy to the cells
egestion - the elimination of undsgested matter from the body through the anus

MOUTH
teeth : physically digests the food into smaller pieces, this is imp as it increases the surf area of food particles for enzyme action.
mouth :mixes food with saliva, rolls it into bolus and pushes it down the pharynx
salivary glands : contains salivary amylase to chemically digest starch into maltose [ only partial digestion ]
OESOPHAGUS
peristalsis : a series of altering muscle contraction and relaxation to help push bolus into stomach.

STOMACH
gastric juice that contains
: hydrochloric acid - it provides acidic medium for enzyme to work on , activates enzymes, kills bacteria and other disease causing baccteria, also provides an optimum pH for the fastest enzyme action
protease : to chemically digest proteins to polypeptides
peristalsis in the stomach, a churning actions helps to physically break down the food into smaller pieces and mash them, also helps to thoroughly mix the food and gastric juice ttogether forming a semi-liquid mass called chyme.

SMALL INTESTINE
contains :
pancreatic juice that is produced by the pancreas it ontains enzymes such as pancreatic lipase to chemically digest lipids to fatty acids n glycerol, pancreatic amylase to chemically digest starch into maltose and protease to chemically digest proteins to polypeptides.
intestinal juice that is secreeted by the intestinal glands that contains enzymes such as maltase to chemically digest maltose to glucose, protease to chemically digest polypeptides to amino acids, intestinal lipase to chemically digest lipids to fatty acids and glycerol.
- BIle tht is produced by the liver and stored to a higher conc in the gallbladder. It is needed to emulsify fats, physicaly digesting larger fat globules into smaller fat globules to inc surf area for faster rate of enzyme action of the lipase.
- all 3 digestive juices are alkaline to help neutralize the acidic chyme n provide optimum alkaline pH for enzyme to chemically digest food.

ABSORPTION
: glucose,amino acids,fatty acids and glycerol as well as mineral salts, vitamins and water are absorbed through the walls of the alimentary canal.
- glucose and amino acids are absorped by the villi of the capillaries
- fatty acids and glycerol are combined in the epitelium of the villi to form fats, the fats are absorbed by the lacteal.

ADAPTATIONS:
1 long and narrow to provide sufficient time for the absoprtion of nutrients from food
2. numerous folds of the inner walls of the small intestine to inc suf area thus increasing rate of absorption of nutrients from food
3. Presence of minute finger- like projections known as villi wich inc surf area of small int, increasing the rate of abs of nutrients from food
4 Presence of microvilli on vili which further inc surf area, increasing rate of absorpetion of nutrients from food.
5. Walls of the villi are one cell thick, allowing faster rate of diffusion of digested food through the walls and into blood capillaries
6. glucose and amino acids are transported by the blood capilaries while fats are transported away by the lacteal, this maintains the steep conc gradient for faster rate of absorption of digesred food

LA
: reabsorption of water, vitamins and mineral salts.
undigested food material is temporarily stored at anus as faeces.

FOOD TeSTS
benedicts test - for reducing sugar
1 prepare a boiling water bath
2 add 2cm3 of glucose to a test tube
3 add 2c3 of benedicts solution into test tube
4 place in boiling water bath for 5 mins
brick red precipitate - reeducing sugar found
remains blue - no reducing sugar

reducing sugars as monosaccarides (like glucose n fructose)
and dissacharides like maltose n lactose, except sucrose can be detected by benedicts test
green : lower conc , yello : moderate

BIURET TEST
test for proteins
1 add 2cm3 of albumin into testube
2 add 2 cm3 of sodium hydroxide into test tube n shake well
3 add 1 % copper || sulfate solution drop by drop,shaking aft each drop
violet colouration is observed

ETHANOL EMULSIon TSt
test for fats or lipids
liq : add 2cm3 of ethanol to a drop of liquid sample
2 shake well
3 add 2cm2 of water to mixture and shake well
white emulsion / colourless
solid:
1 cut the solid sample into small pieces and place them in a test tube
2 add 2cm3 of ethanol and shake well
3 alow solid particles to settle then decant the ethanol into another tubecontaining 2cm3 of water.
an emulsion is a mixture of 2 or more imiscible liquids, in thi case it is made of small droplets of oil in ater.

CARBOHYDRATEs
1 source of energy
2 form supportive structures
3 synthesise lunricants
4 builf=dinng up oher nutrienys
used in the formation of dna
[ milk, plant based]

PROTEINS
1 source of energy
2 muscle building
3 synthesise protoplasm
4 growth n repair of worn out cells
5b synthesis of enzymes and hormones

FATS
1 source 0f energy and storage
2 solvent for fat soluble vitamins
3 insulating material to prevent excessive heat loss

monosaccharide
glucose imp source of energy [ required for resp]
fructose
galactose

disaccharide
2 sugar units
maltose
lactose
sucrose

POLYSACCHARIDE
STARCH
CELLULOSE
GLYCOGEN
CHITIN