Chapter 2: Cell division

How many pairs of chromosome does human have?

23 pairs of chromosome

How many chromosome does human have?

46 chromosomes

How does human body call?

diploid

Put the following in order size from biggest to smallest: nucleus, DNA, chromosomes, gene, cell

cell, nucleus, chromosomes ,DNA, gene

What are chromosomes made from?

DNA molecules

What is cell division by mitosis?

body cells divide to form two identical daughter cells

What is the purpose of mitosis?

growth and repair of cells, asexual reproduction

What is the name of the first stage of the cell cycle?

growth and DNA replication

What happens during the first stage of the cell cycle?

1) cell grows bigger

2) DNA replicates(chromosomes are duplicated)

3) increase in number of sub-cellular structures, such as ribosomes and mitochondria

What is the name of the second stage of the cell cycle?

mitosis or nucleus divides

What happens during the second stage of the cell cycle?

1) a complete set of chromosomes is pulled to each end of the cell

2) the nucleus divides to form two nuclei

What is the name of the third stage of the cell cycle?

cell divides

What happens during the third stage of the cell cycle?

cytoplasm and cell membrane divide to from two identical daughter cells

what is the name of cell division in term of bacteria cells?

binary fission

What are aseptic techniques?

aseptic techniques are techniques to avoid unwanted microorganisms happening

Sate 3 aseptic techniques

1) sterilise all equipment

2) work near a flame

3) secure the lid onto the agar plate with tape( not fully sealed)

What is stem cell?

a stem cell is an undifferentiated cell that can differentiate into one or more types of specialised cell

What are 2 types of stem cells in mammals?

adult stem cell and embryonic stem cell

Where are adult stem cells can be found?

adult stem cells can be found in specific parts of the body in adult and children

What can adult stem cells differentiate into?

adult stem cells can only differentiate to form certain types of cells

What are advantages of adult stem cells?

1) fewer ethical issues-adults can consent to have their stem cells removed and used

2) an already established technique for treating diseases such as leukaemia

What are disadvantages of adult stem cells?

1) can take a long time for a suitable donor to be found

2) can only differentiate into some specialised cells, so can be used to treat fewer diseases

Where are embryonic stem cells can be found?

embryonic stem cells can be found in early human embryos(often taken from spare embryos from fertility clinics)

What can embryonic stem cells differentiate into?

embryonic stem cells can differentiate into any type of specialised cell in the body

What are advantages of embryonic stem cells?

1 )embryonic stem cells can differentiate into any specialised cell in the body, so can be used to treat many diseases

2) no donor needed as they are obtained from spare embryos from fertility clinics

What are disadvantages of embryonic stem cells?

1) ethical issues surrounding their use and each embryo is a potential human life

2) risk of transferring viral infections to the patient

What are plant meristems?

an area where rapid cell division occurs in the tips of roots and shoots of plants

Where are plant meristems can be found?

meristem regions in the end of the roots and shoots of plants

What can plant meristems differentiate into?

plant meristem can differentiate into all cell types

What are advantages of plant meristem?

1) rare species of plants can be cloned to prevent extinction

2) plants with special features can be cloned to produce many copies

What is disadvantages of plant meristem?

a whole crop could be destroyed by a single disease or genetic defect

What are 3 topics about therapeutic cloning?

1) cells from a patient’s own body are used to create a cloned early embryo of themselves

2) stem cells from this embryos can be used for medical treatments and growing new organs

3) these stem cells have the same genes as the patient, so are less likely to be rejected when transplanted