Organisation of Cells (Cambridge (CIE) O Level Biology) : Revision Note

Ciliated cell

Movement of mucus in the trachea and bronchi of the chest cavity

• Hair-like structures form on the surface of the cell called cilia

• These beat to move mucus and trapped particles up and out of the trachea

Nerve cell

Conduction of impules

• Long so that nerves can run to and from different parts of the body to the central nervous system

• The cell has extensions and branches for communication. The axon is insulated for speed of transmission of the nerve impulse

Red blood cell

Transport of oxygen

• Biconcave disc shape increases surface area for more efficient diffusion of oxygen

• Contains haemoglobin for to carry oxygen

• No nucleus to increase space for carrying oxygen

Sperm cell

Reproduction

• The head contains the genetic material for fertilisation in a haploid nucleus (containing half the normal number of chromosomes)

• The acrosome in the head contains digestive enzymes so the sperm cell can penetrate the egg cell

• The mid-piece has many mitochondria to provide energy for tail movement

Egg cell

Reproduction

• Contains a lot of cytoplasm which has nutrients for the growth of the early embryo

• Haploid nucleus contains genetic material for fertilisation

• Cell membrane changes after fertilisation by a single sperm cell so no more sperm can enter

Root hair cell

Absorption of water and minerals from soil

• Root hair increases the surface area to ensure maximum absorption of water and minerals

• Walls are thin to ensure water moves through quickly

• No chloroplast present as no light underground 

Xylem vessel

Conduction of water through the plant; provides support for the plant

• No top or bottom cell walls for continuous flow of water

• Cells are dead so no organelles to ensure a smooth stream of water can flow

• Thickened cell walls with lignin to provide structural support

Palisade mesophyll cell 

Photosynthesis 

• Column shaped to maximise absorption of sunlight

• Contains many chloroplasts for maximum photosynthesis

Cells

Basic functional and structural units in a living organism

Tissues

GRoups of cells of similar structure working together to perform the same function

Organs

Made from different tissues working together to perform a specific function

Organ systems

Groups of organs with related functions working together to perform body functions

Shoot system

Leaf, stem, flower, fruit

• Epidermis mesophyll

• Xylem

• Phloem

Root system

Root, tuber

• Xylem

• Phloem

• Ground tissue

Digestive system

Oesophagus, stomach, small and large intestines

• Muscle

• Connective

• Nerve

• Epithelial

Circulatory system

Heart, arteries, veins

• Muscle

• Connective

• Nerve

• Epithelial

Immune system

Thymus, spleen

• Bone marrow

Respiratory system

Trachea, bronchi, lungs

• Muscle

• Connective

• Nerve

• Epithelial

Excretory system

Liver, kidney, skin, lungs

• Muscle

• Connective

• Nerve

• Epithelial

Nervous system

Brain , spinal cord

• Nerve

Reproductive system

Ovary, uterus, vagina, penis, testes

• Muscle

• Connective

• Nerve

• Epithelial