2.3

• Epithelium cell


  • Thin cells; arranged closely
• Epithelium cell function


  • Provide protection
  • Aid in gaseous exchange
  • Helps in nutrients absorption, secretes mucus
• Muscle cell


  • Contains many fibres; aid in movement
  • Have many mitochondria; provide energy for muscle contraction
• Muscle cell function


  Contracts to produce movement
• Nerve cell


  • Have long dendrites and axon
  • Axons covered with myelin sheath; faster transmission
• Nerve cell function


  Transmits nerve impulse from one part to another part of the body
• Red blood cell


  • Contains haemoglobin; transport oxygen
  • Elastic and flexible; allow the blood to squeeze through thin blood capillaries
  • Has a biconcave disc shape; increases the ratio of surface area per volume; increase the diffusion of respiratory gases
• Red blood cell function

  Transports respiratory gases
• White blood cell


  • Can change shape; easily squeeze through the tiny blood vessels to the interstitial space to hunt the pathogens
• White blood cell function

  Protects the body from pathogens
• Sperm cell


  • Has a long tail; helps the sperm to move
  • Contains mitochondrion; provide energy for the sperm to swim
  • Contains enzymes; helps the sperm to penetrate the ovum
• Sperm cell function


  Fertilises the ovum
• Spongy palisade mesophyll cell

  • Packed loosely; efficient gaseous exchange
• Spongy palisade mesophyll cell function

  Facilitate gas permeation
• Xylem


  • Consists of porous long tubes; to transport substances efficiently
  • Strengthen by lignin; to prevent the xylem from collapse
• Xylem function


  Transport water and mineral salts from the roots to a whole plant
• Sieve tubes


  • Matured sieve tubes have no nucleus; provide more space for transportation
  • Have sieve plates
  • No lignin
• Sieve tubes function


  Transport organic substances; sucrose, amino acids and hormones from the shoots to other parts of the plant
• Root hair cell


  • Have many mitochondria; provide energy to absorb more mineral salts through active transport
  • The root hairs increase the surface area; maximising the absorption
• Root hair cell function

  Absorb water and dissolved mineral salts in the ground
• Guard cell


  • Have chloroplasts; produce glucose
  • Have a large vacuole; control the osmotic pressure of the cell; aid in controlling the opening and closing of the stoma
• Guard cell function


  Control the opening and closing of the stoma
• Types of cell organisation in animals

  • Epithelium
  • Muscles
  • Nerve
  • Connective
• Epithelium


  • Consists of one or more layers of cells
  • Some epithelium tissues form glands (exocrine and endocrine glands)
  • Epithelial tissues carry out functions associated with protection, secretion and absorption
• Muscles


  • Musculoskeletal: involves involuntary movements; contracts and relaxes to move the bones
  • Smooth: contracts and relaxes that allows involuntary movements; peristalsis in intestines
  • Cardiac: found in the heart walls; contracts and relaxes that allows pumping the blood
• Nerve


  • Consists of neurons or nerve cells
  • Functions to transmit nerve impulses, control and coordinates the activities in the body
• Connective


  Consists of several types of cells and fibres that are distributed across the body that has many functions
• Types of connective tissue

  • Loose connective tissues
  • Fibrous connective tissues
  • Cartilage
  • Bone
  • Blood tissues
  • Adipose tissues
• Loose connective tissues


  • Places between the organs
  • Functions to anchor the epithelium tissues to other tissues and places the organs in one place
• Fibrous connective tissues


  • Consists of fibrous collagens that are arranged close to one another
  • Found in tendon and ligament
• Cartilage


  • Strong and flexible
  • Supports the nose, ears and covers the end of the bones, which functions to absorb pressure and shock
• Bone


  • Consists of cells in one matrix of mineral salts and fibrous collagen
  • Collagen matrix is hardened by the deposition of minerals such as calcium phosphate
  • Functions to protect the organs and provides support to the body
• Blood tissues


  • Consists of blood cells; red blood cells, white blood cells and platelets
  • Blood functions to protect, transport and regulate
• Adipose tissues


  • Functions to store fats, protects the organs and insulates heat
  • Found in the skin dermis and at the surroundings of the organs
• Types of plant tissues

  • Meristematic tissue
  • Parenchyma tissue
  • Collenchyma tissue
  • Sclerenchyma tissue
  • Epidermis
  • Xylem
  • Phloem
• Meristematic tissue


  • A group of undifferentiated cells; active in cell division
  • Two types; apical and lateral meristems
  • Apical meristem: primary growth; vertical growth
  • Lateral meristem: secondary growth; horizontal growth
• Parenchyma tissue


  • Thin-walled cells; loosely arranged with spaces between them
  • Provides support and shapes
  • Stores food
  • Conducts photosynthesis
• Collenchyma tissue

  • Elongated, polygonal cells with unevenly thickened cell walls
  • The cell walls are thickened by cellulose and pectin
  • Provides support to: Herbaceous plants, Young stems, Leaf stalks, Petioles
• Sclerenchyma tissue


  • The cells are rigid
  • Have cell walls; thickened by lignin
  • Most of the cells are dead at maturity
  • Provide support and protection to the plant
• Epidermis


  • The outermost layer that covers the whole plants
  • The wall of epidermal cells is normally covered by cuticle
  • The cuticle on the epidermal tissue helps to: Prevent water loss, Protects the plants from mechanical injury, Prevent the invasion by disease-causing microorganisms
  • In roots, some of the epidermal cells have long projections called root hairs; increase the surface area for absorption of water and minerals
  • In leaves, the lower epidermis contains specialised cells, called guard cells; controls the opening and closing of stomata