stem cells

stem cell

undifferentiated cells that can differenitate into different cell types

what can stem cells do? (2)

-can replicate themselves to produce more stem cells [self-renewal]

-differentiate into different cell types

types of stem cells and what they can differentiate into and examples

Totipotent stem cells - can differentiate into any cell type and form whole organisms [e.g. fertilised egg]

Pluripotent stem cells - can differentiate into almost any cell types but cannot form whole organisms [e.g. embryonic stem cells (only present in embryo)]

Multipotent stem cells - can only differentiate into a few different cell types [e.g. bone marrow stem cells→can produce any type of blood cell]

Unipotent stem cells - can only differentiate into one cell type

embryonic stem cell

source?

what type of stem cell is it?

adult stem cell

source?(5)

what type of stem cell is it?

plant stem cell

source?

what type of stem cell is it?

embryonic stem cell

-blastocyst [early embryo]

-pluripotent

adult stem cell

-bone marrow, skin, muscle, brain, intestine etc

-multipotent

plant stem cell

-meristem

-pluripotent

why can adult stem cells replace damaged tissue?

they are multipotent so can differentiate into specific cell types needed for tissue repair

Where do erythrocytes and neutrophils derive from?

stem cells in the bone marrow

Where do xylem and phloem derive from?

stem cell in meristems

where are meristem found in plant?

tips of roots and shoots

whats the name of the meristematic tissue that’s found between phloem and xylem?

vascular cambium→ produces xylem and phloem cells

uses of stem cells (4)

-repair damaged tissues

-treat neurological diseases (e.g. Parkinson's and Alzheimer's)→it regenerates nerve cells

-scientists use it to research developmental biology→help understand how organs develop

-test new drugs for toxicity and side effects

benefits of stem cell therapy (2)

-treats disease→ by replacing damaged cells

-using stem cells from the patient’s bone marrow reduces the risk of immune rejection, as they are genetically identical

disadvantages of stem cell therapy (2)

-The body may reject foreign stem cells so the treatment may not work

-may need immunosuppressive drugs

ethical issues of stem cell therapy

-against

-for

-The use of embryonic stem cells involves the destruction of embryos→some people view this as morally wrong because they believe that an embryo is a potential human life and that life begins at conception.

-Others argue that using these embryos for research is acceptable if it leads to medical advancements and treatments for serious diseases.