B2 Flashcards
Chromosomes
Contained in nucleus your genetic material in the form of chrmosomes. They are coiled up lengths of DNA molecules. Carry a large number of genes. Different genes mean different characteristics
Chrmosomes in body
23 pairs. Humans have teo copies of each chromosomes
Cell cycle
Body cells in multicellular organism divide to produce new cells. Results in two new cells identical to orginal cell, with same number of chromosomes
Motiosis
The stage in cell cycle when cell divides. Multicellular organisms use mitosis to grow or replace cells that have been damaged
DNA replication
Cell has to grow and increase amount of subcellular structures so theres one copy for each new cell. Once cell copied now ready for mitosis
Process of mitosis
Chromosomes line up at the centre of the cell and cell fubres pull them apart. The two arms of each chromosome go to opposite ends of the cell. Membranes from around each of the sets of chromosomes becoming the nuclei of two new cells. Lastly cytoplasm and membrane divide. The cell now produced two new daughter cells containing exactly the same DNA
Differation
Cell changes to become spcialised for job
Animal cells differentiation
In early life
Plant cell differentiation
Dont lose ability to be specialised
How are differentiated cells used
Repairing and replacing cells
Stem cells
Undifferentiated cells that can divide to produce lots more undifferentiated cells. They can differentiate into different types of cell depending on instruction given
Where can stem cells be found
Early human embryos or adult bone marrow
What do we do with stem cells
Can be grown in lab to produce clones and made to differentiate into specialised cells to use in medicine or research
Stem cells in medicine
Stems cells from bone marrow of healthy person can replace faulty cells in patient who recieves them
Embryonic stem cells
Also be used to replace faulty cells in sick people
Risk of stem cells
Could be contaminated with a virus which could be passed on to the patient
Why are some against stem cell research
Believe human embryos shouldnt be used for experiments since each one is a potentisl human life. Some argue the life of an existing patient is more important and argue that a lot of these embryos are unwanted and would be destroyed anyway
Stem cells in plants
Found in meristems(parts of plant whee growth occurs) cam differentiate into any plant cell
How can plant stem cells be used
Produce clones of plants quickly and cheaply, used to grow rare species,used to grow crops of identical plants
