B2 - Cell Division Flashcards
Why are new cells often needed
to grow and replace dead cells, to repair damaged tissue
Where are the genes in an animal (full flow chart)
genes -> DNA -> chromosomes -> nucleus
What do genes contain
all the instructions for making new cells, tissues and organs
What is a gene
a small packet of information that controls a characteristic
How many genes are in a chromosome
hundreds or thousands
How many chromosomes do body cells have
46
How many chromosomes do gametes have
23
What is the process through which asexual reproduction happens
mitosis
WHat are the three stages of the cell cycle
- What happens in each stage
growth - sub-cellular structures double in number
mitosis - nucleus divides
cytokinesis - cell divides in two
How many cells are produced from mitosis
- what are they called
2 daughter cells
how many cells approximately die each minute
around 300 million
What are stem cells
unspecialised cells that can become any type of cell
how to cells differentiate
some genes are switched on and off to do particular functions
what types of cell cannot divide
- what happens to them
- RBCs and WBCs get replaced by adult stem cells
- nerve cells usually do not grow back
What is the difference between animal and plant cells in regards to differentiating
animal cells only differentiate when they are a baby, it is quite rare for adult cells to
Plant cells can differentiate for most of their lives, and they can also re-differentiate
Where are adult stem cells produced and stored
bone marrow
Where are plant stem cells produced
meristem
What is the process of producing identical offspring called
cloning
why is it easier to clone a plant
the cells can differentiate to form the required tissue
what are the stages of life until an embryo
sperm and egg -> zygote -> embryo
What is a zygote
a signle cell formed from the fusion of a sperm and egg
What are some of the ways stem cells can be used
curing paralysis, insulin making cells, helping blindness, growing organs
WHy is it important to clone plants
to produce identical plants reliable, economically, safely and quickly
Where do most embryonic stem cells come from
aborted embryos
What are some issues with using embryonic stem cells
- unethical - killing life
- unreliable and unsafe
- violation of rights
- can cause cancer
What are some benefits to using embryonic stem cells
- divide and grow rapidly
- won’t be rejected
What are some negatives of using adult stem cells
- limited ability to differentiate
- trigger immune responses
What must be taken to prevent rejection of organs and cells
immunosuppressant drugs
Where can we get embryonic stem cells from to overcome some of the ethical problems
in the unbilical cord and fluid around the foetus
What does therapeutic cloning involve
- what is the benefit
using adult cells to produce a cloned embryo of themselves - it would have perfectly matched embryonic cells for medical treatments
