11

BIOLOGY FORM 5BIOLOGY FORM 5

22

• The Importance of Having a Transport The Importance of Having a Transport System in Some Multicellular OrganismsSystem in Some Multicellular Organisms

• The Circulatory SystemThe Circulatory System

• The Mechanism of Blood ClottingThe Mechanism of Blood Clotting

• The Lymphatic SystemThe Lymphatic System

• The Role of the Circulatory System in the The Role of the Circulatory System in the Body’s Defence MechanismBody’s Defence Mechanism

• Appreciating a Healthy Cardiovascular Appreciating a Healthy Cardiovascular SystemSystem

• The Transport of Substances in PlantsThe Transport of Substances in Plants

• The Transport of Organic Substances & The Transport of Organic Substances & Water in PlantsWater in Plants

SUBTOPICS

33

44

•LEARNING OUTCOMESLEARNING OUTCOMES : :•To identify To identify the problem that could the problem that could be faced by multicellular organismsbe faced by multicellular organisms in obtaining their cellular in obtaining their cellular requirements & getting rid of their requirements & getting rid of their waste productswaste products

•To suggest To suggest how the problem is how the problem is overcomeovercome in multicellular organisms in multicellular organisms

1.1 - The Importance of 1.1 - The Importance of Having a Transport System Having a Transport System

in Some Multicellular in Some Multicellular OrganismsOrganisms

55

1.1 - The Importance of Having a 1.1 - The Importance of Having a Transport System in Some Transport System in Some

Multicellular OrganismsMulticellular Organisms

• All living organisms All living organisms need to constantly need to constantly exchange substances exchange substances between cells & their between cells & their external environment external environment (food, waste & gases).(food, waste & gases).

• All this process is All this process is performed by a performed by a transport system.transport system.

66

• Small organisms have a Small organisms have a large total surface large total surface area to volume (TSA/V) ratioarea to volume (TSA/V) ratio. So, diffusion of . So, diffusion of substances occurs rapidly (substances occurs rapidly (short distance onlyshort distance only).).

• Some simple organisms such as flatworms have Some simple organisms such as flatworms have thin flatten bodies thin flatten bodies provide a large surface provide a large surface areaarea

• In In HydraHydra, water enters through the mouth into , water enters through the mouth into the body cavity. As the body wall is only two the body cavity. As the body wall is only two cell layers thick, substances can move rapidly cell layers thick, substances can move rapidly into or out of the body cells.into or out of the body cells.

• Do not requireDo not require a specialised internal transport a specialised internal transport systemsystem

77

• Larger organisms, Larger organisms, increased need for increased need for more more nutrientsnutrients & & oxygenoxygen to be to be suppliedsupplied to the larger number of cells. to the larger number of cells. Need to Need to excrete more excrete more wastewaste products. products.

• The size increases, TSA/V ratio The size increases, TSA/V ratio decreases.decreases.

• Many of the Many of the body cells are too body cells are too far far awayaway from the external surface or from the external surface or between different parts of the body.between different parts of the body.

• Simple diffusion occurs at Simple diffusion occurs at too slowtoo slow a a rate to sustain cellular activities.rate to sustain cellular activities.

88

• Larger multicellular organisms have Larger multicellular organisms have adapted by developing adapted by developing specialised specialised structuresstructures to increase the surface area to increase the surface area for exchange of substances.for exchange of substances.

• Have developed an Have developed an internal transport internal transport systemsystem of vessels or tubes. of vessels or tubes.

• In human & more complex animals, there In human & more complex animals, there is development of a is development of a blood circulation blood circulation systemsystem to carry the substances. to carry the substances.

• In plants, transport of substances is In plants, transport of substances is carried out by the carried out by the vascular systemvascular system (xylem & phloem).(xylem & phloem).

99

EXPERIMENT 1.1 : EXPERIMENT 1.1 : Determining the relationship Determining the relationship between total surface area to between total surface area to

volume ratio & its effect on the volume ratio & its effect on the rate of diffusionrate of diffusion

• AIM :AIM : To determine the relationship To determine the relationship between TSA/V ratio & its effect on the rate between TSA/V ratio & its effect on the rate of diffusionof diffusion

• PROBLEM STATEMENTPROBLEM STATEMENT : What is the effect : What is the effect of TSA/V ratio on the rate of diffusion of of TSA/V ratio on the rate of diffusion of substances?substances?

• HYPOTHESISHYPOTHESIS : the larger the size of the : the larger the size of the object, the smaller the total surface area to object, the smaller the total surface area to volume ratio & the lower the rate of diffusionvolume ratio & the lower the rate of diffusion

1010

• VARIABLES VARIABLES : Manipulated – size of potato : Manipulated – size of potato cubes, Responding – Area stained relative cubes, Responding – Area stained relative to total surface area of cut surface, Fixed – to total surface area of cut surface, Fixed – red ink solution, potatored ink solution, potato

• MATERIALMATERIAL : potatoes, coloured solution : potatoes, coloured solution

• APPARATUS : 400 ml beaker, white tile, APPARATUS : 400 ml beaker, white tile, knife, ruler & forcep.knife, ruler & forcep.

• PROCEDUREPROCEDURE : :– A knife is used to cut 3 potato cubes with the A knife is used to cut 3 potato cubes with the

dimensions 1cm x 1cm x 1cm, 2cm x 2cm x dimensions 1cm x 1cm x 1cm, 2cm x 2cm x 2cm, 4cm x 4cm x4cm2cm, 4cm x 4cm x4cm

– The 3 potato cubes are immersed in coloured The 3 potato cubes are immersed in coloured solution for 30 minutessolution for 30 minutes

1111

• PROCEDURE (cont…)PROCEDURE (cont…)– The potato cubes are removed from the The potato cubes are removed from the

beaker. Each potato is cut in half. The beaker. Each potato is cut in half. The region stained by the colour solution are region stained by the colour solution are observed.observed.

1212

•RESULT :RESULT :AA BB CC

Original length (cm)Original length (cm) 11 22 44

Original width (cm)Original width (cm) 11 22 44

Original height (cm)Original height (cm) 11 22 44

Total surface area Total surface area (cm2)(cm2)

Volume (cm3)Volume (cm3)

TSA/V ratioTSA/V ratio

Relative rate of Relative rate of diffusiondiffusion

1313

• DISCUSSION :DISCUSSION :– Answer the questions inside the Answer the questions inside the

practical book page 3practical book page 3

• CONCLUSION :CONCLUSION :– Make your own conclusionMake your own conclusion

1414

END END OFOF

SUBTOPIC 1.1SUBTOPIC 1.1

OPPS…DON’T FORGET TO COPY OPPS…DON’T FORGET TO COPY EXERCISE ON THE NEXT PAGE!!EXERCISE ON THE NEXT PAGE!!

1515

EXERCISE 1.1EXERCISE 1.11.1. State State twotwo problems faced by problems faced by

multicellular organisms in obtaining multicellular organisms in obtaining their cellular requirements & their cellular requirements & removing waste product.removing waste product.

2.2. State how these problems are State how these problems are overcome in multicellular organisms.overcome in multicellular organisms.

3.3. Explain why unicellular organisms do Explain why unicellular organisms do not face the problems listed in (Q1).not face the problems listed in (Q1).

1616

Iyah..iyah..Iyah….