2. Cells and Control: Cell Division and Growth Flashcards
What are the 3 things involved in GROWTH?
Cell Division
Cell Differentiation
Cell Elongation
What is GROWTH?
An increase in size and mass
Plants and animals grow and develop due to these processes
What is Cell Division?
Happens in mitosis
What is Cell Differentiation?
Process by which a cell changes - becomes specialised for its job
Specialised cells - allows multicellular organisms to work more efficiently
What is Cell Elongation?
Plant cell expands - cell gets bigger - makes the plant grow
How does growth occur in Animals?
Cell division - animals tend to grow when they are young - when reach full growth they stop growing - when young cells divide at a fast rate - once an adult, most cell division used for repair - cell divides to replace old or damaged cells
In most animals cell differentiation lost at an early stage
How does growth occur in Plants?
Growth in height - cell elongation - cell division usually happens in the tips of roots and shoots (areas called meristems) - plants grow continuously - plants continue to develop new parts
What is Cancer?
Case of uncontrolled cells
Rate at which cells divide by mitosis controlled by genes (chemical instructions) in an organisms DNA
If change in one of genes that controls cell division - cell may start dividing uncontrollably - mass of abnormal cells called a tumour - if tumour invades or destroys surrounding tissue it is called cancer
What are percentile charts?
Used to monitor growth
Growth charts - assess a child’s growth over time - overall pattern in development can be seen and any problems highlighted e.g. obesity, malnutrition, dwarfism
3 lengths taken - length, mass and head circumference
Chart shows a number of ‘percentiles’
Doctors likely to investigate a baby if it’s size is above top percentile or below bottom percentile or if there is an inconsistent pattern or if there size increases or decreases by 2 or more percentiles over time
