Kolokium Biology

SMK METHODIST ACS SITIAWAN KOLOKIUM BIOLOGY

TEAM MEMBER • • • • •

NUR SYAWIQHA B. TAJUL AMER TOK YEN LING LEE WEI CHEE KERENE HENG LAI CHING LEE

QUESTION 2:

DESCRIBE A SPECIFIC EXAMPLE OF THE CORRELATION BETWEEN CELL STRUCTURE AND FUNCTION.

PLANT

CROSS SECTION OF A LEAF

EXTRA INFORMATION

CUTICLE

CON’T stoma

Guard cell Pea Leaf Stoma, Vicea sp

ANIMAL : Nerve

EPITHELIUM

Protection

•Protect the inner tissue from mechanical injury. •Protect body from pathogen infection. •Skin epidermis protects body from UV.

Exorine gland

•Duct(small tube) carry the secretion to specific areas.

Gas exchange

•Alveolus in the lung.

Food digestion

•Iluem epithelium absorbs digested food.

Stimuli receptor

•Sensory organ that receive stimuli such as pressure and heat.

Filter and entrance of molecule

•Filter and allow certain molecules to enter epithelium.

MUSCLE

Figure 1.4 Structure of muscle cells Muscles are composed of bundles of single large cells (called muscle fibers) that form by cell fusion and contain multiple nuclei. Each muscle fiber contains many myofibrils, which are bundles of actin and myosin filaments

STRUCTURE

FUNCTION

•Myofibrils are built from actin and myosin.

•Allow contraction and relaxation of muscle.

•Presence of synapes on striated muscle.

•Allow nerve impulses from nervous system to be transmitted to cause contraction.

•Presence of mitochondria in striated muscle fibre.

•Generate energy during muscle contraction.

•Sarcorplasmic reticulum store and releasing calcium ions into the sarcoplasm.

•To initiate muscle contraction.

QUESTION 11 WHAT ARE SOME ADVANTAGES OF MULTICELLULARITY?

Definition of multicellularity:  Multicellular organisms are [organism] s consisting of more than one [cell] , and

having [differentiated cell] s that perform specialized functions in the organism. Most life that can be seen with the naked eye is multicellular, as are all members of the [kingdom] s [ Plant] ae and [Animal] ia (except for specialized organisms such as [Myxozoa] in the case of the latter).

•Increased Volume of the Organism greatly increases the volume and total surface area of the cells and their membranes. •This enhances the ability to exchange chemicals with the environment, and provides local reservoirs for essential nutrients.

•It allows the separation of absorptive and non-absorptive regions of the organism. This leads to cell and tissue specialization. •The accumulated effect of the cellular exoskeleton (cell walls) and the turgor pressure of many cells combined, provides a greater degree of structural support. This protects the organism from physical forces like the movements of air and water.

•This also leads to larger organisms which can "out compete" other organisms for the resources available in the environment. •Parts of the plant may survive attack by an herbivore or pathogen and can regenerate complete organisms. •Larger organisms tend to have longer life spans. •Multicellularity also lends protection to reproductive structures.

Summary on advantages of multicellularity 

1. cellular specialization - structure and function 2. larger size a.) easier to maintain homeostasis - surface area/volume ratio - metabolic efficiency - greater range of habitats b.) able to occupy terrestrial habitats c.) greater range of food items d.) reduced number of predators

Questions??

THANKS