Chapter B2- Cell Division Flashcards
What is cell division called?
Mitosis
Why does cell division exist?
New cells are needed for an organism or part of an organism to grow. They also need to replace cells that become worn out and to repair damaged tissue. These new cells must have the same genetic material and information as the originals so they can do the same job.
How many chromosomes are in the nucleus of your body cells?
46
Or
23 pairs
Who gives you yours chromosomes?
Half from your mum and half from your dad
What does mitosis do?
Produces two identical “sister” cells
Give a real life example of new cells being needed on an duly body?
Hair follicles
Skin
Blood
Lining of digestive system
What are the stages of mitosis?
Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
What happens during interphase?
The cell spends most of its time in this phase. The DNA in chromosomes copies itself ready for mitosis.
What happens during prophase?
The DNA in chromosomes condenses and becomes more visible. The membrane around the nucleus disappears.
What happens during metaphase?
Chromosomes and their copies line up in the middle of the cell
What happens during anaphase?
Chromosomes and their copies are pulled to different ends of the cell.
What happens during telophase?
New membranes form around the chromosomes at the end of each cell.
What happens during cytokinesis?
The cell membrane punches in two and eventually divides into two daughter cells.
What does differentiate mean?
The process where cells become specialised for a specific process
What is an unspecialised cell known as?
A stem cell
What is the difference between stem cells in plants and animals?
Animal stem cells cannot change back once they have differentiated, whilst plant stem cells can alternate between roles
What is cloning?
Producing identical offspring
What are the two kinds of stem cells?
Embryonic stem cells and adult stem cells
Where can adult stem cells be found?
The bone marrow
Why is cloning plans important?
Rare plants can be saved from extinction
Plants can be mass produced for sale- example banaanas
Name problems with embryonic stem cells
Potential death to embryo/possible harm Progress has been slow, expensive and difficult to control Concern that they may cause cancer. Long term effects unknown Untested and unrealiable
name problems with adult stem cells
They may be infected with viruses and so may transfer infection.
Stem cells from another human may cause an immune response, resulting in immunosuppressant drugs needing to be taken.
Is a painful process
Operation hazards
Can not differentiate into all cells
Name advantages to adult stem cells
No ethical issues as consent is gained
Quick recovery
Safe- does not kill doner/ low risk
Tested
Name advantages to embryonic stem cells
Can treat a wide variety of diseases and problems (they are pluripotent)
Many available/ plentiful
Using them is better than wasting them
Painless
Describe the structure of a chromosomes
Double helix strand holds dna
Legs of the X shape are called chromatids
Middle is called the centromere
Contain genes
What are the bases of your dna?
A- adenine
T-thiamine
C- cytosine
G- guanine
What are the paired bases?
A-T
C-G
What is a gene?
A piece of dna that is responsible for a characteristic
What happens if an embryo has three chromosomes in the 21st pairing?
The child will have Down syndrome
