B5

Specialised Cell; a specialised cell is adapted for a particular job

Phloem; a plant tissue that transports sugar throughout a plant

Zygote; the cell made when a sperm cell fertilizes an egg in sexual reproduction

Meristem Cells; unspecialised cells in plants that can develop into any kind of specialised cell

Auxins; a plant hormone that affects plant growth and development

Organelles; the specialised parts of a cell, such as the nucleus and mitochondria

Replicated; a clone of another cell or DNA

Mitosis; cell division that makes 2 new cells identical to each other and to the parent cell

Meiosis; cell division that halves the number of chromosomes to produce gametes

Gametes; the sex cells that fuse to form a zygote. Gametes in males is sperm and gametes in females is the egg

Cells; these are the basic building blocks, they become specialised, e.g, Red blood cell, Nerve cell, Sperm or Egg cell

Cells -> Tissues

Tissues; a collection of all the same specialised cells, e.g, Heart cells, Muscle cells

Tissues -> Organs

Organ; a collection of different tissues, e.g, Heart, Lungs

Organ -> Organ System

Organ System; a collection of different organs, e.g, Circulation System (Heart, Blood, Lungs, Blood Vessels)

Organ System -> Organism

Organism; the complete living organism, e.g, Mam, Tulip. Hamster

A specialised cell is one which carries out a particular job, e.g, muscle cells contract to cause movement, nerve cells are specially shaped to carry impulses and red blood cells lack nuclei, giving extra room to carry oxygen. Plants also have specialised cells, e.g, xylem, which is tissue for transport of water and minerals and phloem, which is tissue for sugar transport.

Meristem cells are plant cells which can develop into any type of cell, this means the plant can continue to grow throughout its life.

Human Stem Cells can develop into some types of cells. They can not develop into any types of cells, some animals have stem cells which can develop into any type of cell, e.g, frogs, crabs, lobsters, starfish, can all grow new limbs.

Unspecialised cells in plants are called meristems. These cells use cell division to produce new cells. Some cells specialise to become plant organs - leaves, roots, stems.Plants continue to grow throughout their life. An identical copy (or clone) can be grown using tissue culture. A lump of unspecialised cells. An identical copy (or clone) can be grown using tissue culture. A lump of unspecialised cells form, they are made to specialise, using plant hormones.

Phototropism is a plant response to light. Plants grow towards the light, this is because;

• The plant will get more light
• So they can photosynthesis more
• So they can make more glucose
• They have more glucose for respiration
• So they have more energy for growth. Phototropism is controlled by the hormone auxin