Cells and control

cell division

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

growth, repairing damaged tissues and for asexual reproduction

DNA replicates

chromosomes condense

Chromosomes line up in the middle of the cell

chromosomes and their copies move to either end of the cell

New membranes form around the chromosomes at each end of the cell.

cytoplasm divides

Changes (e.g. mutations) within a cell which lead to uncontrollable growth and division

cell division and cell differentiation

cell division, elongation and differentiation

The process where un-specialized cells become specialized.

So that cells can become specialised for a particular function and carry out this function in the most efficient way

A chart used to monitor growth, measurements can be compared to the expected values at a certain age

unspecialized cells from which differentiated cells develop

Undifferentiated cells from an embryo that can differentiate into any type of cell

parts of the plant where growth occurs, at the tip of the shoot and tip of the roots. cells of the meristem can differentiate

In early human embryos or the bone marrow of adults

They can replace cells that have been damaged or destroyed in diabetes, paralysis etc.

It's hard to find donors and it may not be successful, mutations can occur or contain a contamination and it can be seen as unethical with embryotic stem cells

A network of communications and control which allows us to use our senses

Brain and spinal cord receive stimuli from receptors; they then process this initiates impulses to effectors (muscles) to contract and move

neurons: they carry electrical impulses from one place to another

sensory, motor and relay

they're made of a long fibre called the axon insulated by the myelin sheath and tiny branches (dendrons) which branch further with dendrites. These pick up incoming impulses

They carry impulses from receptors to the CNS.

They carry impulses from the CNS to effectors.

Transmit electrical impulses between sensory neurones and motor neurones

gaps between neurons where two neurons meet, they transit the electrical impulses from one neuron to another

chemicals called neurotransmitters diffuse across the gap which are detected on the other side and trigger a new electrical signal

the nerve pathway that the electrical signal takes to produce the reflex

An automatic response in the body such as blinking

The reflex arc takes the impulse from the sensory neuron to the spinal cord to the motor neuron - no brain involved