So tiny & yet filled with the Secrets of the Universe

Candidates should be able to:

»identify cell structures & organelles of plant & animal cells from diagrams, photomicrographs and under light microscope using slides & fresh material treated with an appropriate temporary staining technique:

• chloroplasts • cell membrane • cell wall • cytoplasm • cell vacuoles (large sap-filled in plant cells, small temporary in animal cells) • nucleus

(b) identify membrane systems & organelles from diagrams & electron micrographs:

• endoplasmic reticulum • mitochondria • Golgi body • ribosomes

(c) state functions of the membrane systems and organelles identified above.(d) compare the structure of animal & plant cells.(e) state the relationship between cell function and cell structure for the following:

• absorption – root hair cells• conduction and support – xylem vessels• transport of oxygen – red blood cells

(f) differentiate cell, tissue, organ and organ system.

» Cell membrane» Nucleus» Mitochondria» Endoplasmic Reticulum» Vacuole» Cytoplasm» Ribosomes» Golgi Body

» Cell membrane˃ Partially permeable (only some substances pass through)˃ Double phospholipid layer membrane˃ Controls movement of substances in & out of cell

» Nucleus˃ Controls cellular activities (repair, growth, division)˃ Chromatin threads contain hereditary DNA (Deoxyribonucleic acid)

» Vacuole˃ Contains water & food substances

» Cytoplasm˃ Jelly-like fluid contain enzymes & organelles (specialised structures)˃ Site where most reactions occur

» Cytoplasm contains organelles such as mitochondria, ribosomes, endoplasmic reticulum & Golgi body.˃ Mitochondria (Power station)

+ Releases energy for cell activities during aerobic respiration ( Glucose + O2 CO2 + H2O + energy)

˃ Ribosomes+ Synthesis of proteins within the cell

˃ Endoplasmic Reticulum+ Smooth & Rough ER (lined with ribosomes)+ Synthesis of proteins, lipids and other cellular

substances˃ Golgi body

+ Secretion of protein + Processes & packages proteins

» It is an organelle that functions to release energy within the human body.

» It is a POWER STATION for all living organsims!» The formula that you need to know.

» Similar to an animal cell» Differences

˃ Cell Wall+ Non-living+ Fully permeable+ Made of cellulose+ Gives a fixed shape + Protects from injury

˃ Larger vacuole sap filled+ Contains cell sap rich in sugar,

mineral salts & amino acids.˃ Chloroplast

+ Contains chlorophyll that traps light energy

+ Site of photosynthesis (CO2 + H2O Glucose + O2 )

» Draw with pencil (easily to be erased)» Draw big and clearly» No shading» No double lines» No fine lines» Label parts of the diagram» Label with straight lines

» Chloroplast» Cell wall» Vacuole

» Sometimes the cell is not enough to carry out more specific functions. ˃ Transport of oxygen˃ Absorption of water & mineral salts

» Thus, the average cell does develops into a more complexed structure to enable them to carry out specific functions.

» Process whereby a cell becomes specialised for a specific function. ˃ Red Blood Cell˃ Root Hair Cell˃ Xylem

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» Red Blood Cells (Erythrocytes)˃ Transport oxygen from lungs

to all cells in the body (HBO)˃ Circular, flattened biconcave

disc (increases cell’s surface area to volume ratio)

˃ NO NUCLEUS (more space to carry oxygen)

˃ Contains haemoglobin (carries oxygen)

˃ Elastic – able to squeeze through small blood vessels

˃ Formed by bone marrow˃ Lasts 3-4 months

» Cell has a long and narrow elongation

» Increases surface area to volume ratio

» More water and mineral salts can be absorbed from the soil

» Long hollow tubes» Transports water and mineral

salts from roots to leaves» No protoplasm or nucleus

˃ Hollow lumen˃ Allow more substances to be easily

transported

» Contains lignin (dead)˃ Strengthens the walls˃ Prevents xylem vessels from collapsing˃ Provides mechanical support

» Cells Tissues Organ Organ System

» Tissues ˃ Group of similar cells

performing the same function (muscle, RBC’s)

˃ Simple – one type of cells˃ Complex – more than one type

of cell

» Organs˃ Several tissues work together

for a specialised function. (lung)

» Organ System˃ Several organs working together

+ Circulatory System – Lungs, Heart

+ Digestive System