Cell division + differentiation Flashcards
What is cell division called?
mitosis
Why do cells divide?
-Growth
-Repair
-Replacement
What is inside the nucleus?
Chromosomes
What do chromosomes do?
Carry genetic information with instructions on how to make new cells.
What is a gene?
A section of DNA which controls a characteristic of your body
How many chromosomes are in a nucleus?
46 (23 pairs)
Where do chromosomes come from in pairs?
One from the mother and one from the father
What is the series of stages when a cell divides known as?
The cell cycle
What happens after a cell divides?
2 identical daughter cells are made
What happens because 2 identical cells are made?
All the chromosomes and genetic information in your body cells are the same.
What happens in asexual reproduction?
The cells of the offspring are produced by mitosis from the cells of the parent. This is why they contain the exact same genes as their parent.
What happens to the speed of the cell cycle?
-It can vary from <24hrs to >1yr
What happens to the speed of the cell cycle with age?
As an animal ages, the speed of the cell cycle slows as new cells are not needed as often when an animal stops growing.
What are examples of regions that continue to quickly grow, even in adulthood?
-Hair follicles
-Skin
-Blood
-Digestive system lining
How many stages are in the cell cycle?
3
What is stage 1 of the cell cycle?
-The cell grows bigger and replicates DNA to form 2 copies of each chromosome
-More sub-cellular structures are made such as mitochondria, ribosomes and chloroplasts
-The cell continues its normal activities during this process
What is stage 2 of the cell cycle?
mitosis - one set of chromosomes is pulled to each end of the dividing cell and the nucleus divides.
What is stage 3 of the cell cycle?
This is the stage during which the cytoplasm and the cell membranes also divide to form two identical daughter cells.
Why do children gain cells?
Mitotic divisions produce cells faster than old cells die
Why do adults not gain or lose cells?
Cell death and mitosis stay in balance
Why do old people show signs of ageing?
Mitosis slows down
What is a stem cell?
A cell that can differentiate into any cell type that is needed
What is a specialised cell?
A cell with different sub-cellular structures to carry out specific functions
Whats an example of a type of cell that is grown/replaced by mitosis?
Muscle
Whats are examples of types of cells that are grown/replaced by stem cells?why?
-Red blood
-Skin
-This is because they cannot divide
What is a type of cell that doesn’t divide or get replaced by stem cells?
What is the impact of this on this type of cell?
-Nerve cells
-When they are damaged, they are not usually replaced.
How long do plant cells differentiate for?
All their lives
Where are undifferentiated cells formed in plants?
Formed at active (growing) regions of the stems and roots, known as meristems
What happens if you move a plant cell to a different part of a plant?
It redifferentiates and becomes a different type of cell
What is the word for producing identical offspring?
Cloning
What type of organism is easy to clone?
Plants
What type of organism is hard to clone?
Animals
How are plant clones made?
Take a piece of tissue from the plant and, under the right conditions, the cells will become unspecialised and multiply by mitosis, these will then differentiate and form new plant organs, eventually becoming a whole plant that is identical to the parent.
