How did this happen?

Cell division and growth B2 5.1 P.186

Homework To show the stages in mitosis:- EITHER Make a mitosis flick book (animate) OR mitosis poster This link may help Link to a short movie made for homework

Objectives Copy and fill the gaps … results in the production of additional cells for growth, repair and replacement. Before each cell division, the genetic information on the … is … so that the new cells have the same genes as the parent cells. Most animal cells differentiate at an early stage but most … cells have the ability to differentiate throughout life. copied / Mitosis / chromosomes / plant

Card sort (recap of B1) DNA –The chemical from which chromosomes are made. Cell –The basic building block of a living organism. Gene –A small packet of information controlling a characteristic. Chromosome –Thread-like structures holding genes. Nucleus –The part of a cell that contains genetic information. Fastest?

What’s the order? (use p.202 Fig 1 to help)

My toes (non-sexy) Cell division to produce normal cells is called MITOSIS

Time lapse pictures of a cell undergoing mitosis.

What is Mitosis? (Don’t copy yet) Mitosis begins with a single cell. How many chromosomes does this cell contain? original cell cell division 2 new cells 4.Each new cell has a full set of chromosomes and is identical to the original cell. 1.First the cell makes a copy of each chromosome…. 2.The copies remain joined at the middle for a bit… 3.then it divides.

Mitosis animation Mitosis video in amphibian lung cellJohn Kyrk mitosis animation

What is Mitosis? (Copy down) Mitosis begins with a single cell. This cell contains 46 chromosomes. original cell cell division 2 new cells 4.Each new cell has a full set of chromosomes and is identical to the original cell. 1.First the cell makes a copy of each chromosome to make 92 in total…. 2.The copies remain joined at the middle for a bit… 3.then it divides. Q 1,2,3 p. 187 Early-finishers can do the activities On the next two slides

Mitosis activity

Stages of mitosis activity

Answers text p Growth, replace, genetic information, nucleus, genes, chromosomes, mitosis 2.a) cells die and need replacing, cells are damaged, cells needed for asexual reproduction in some organisms b) cells need to be identical to do the same job 3. a) differentiation is the process by which cells become specialised b) in animals it occurs in the embryo and in bone marrow, and in some other tissues and organs. It is permanent, in plants it occurs throughout life in stem tips, buds and root tips. c) plants can be cloned more easily, differentiation can be reversed, mitosis induced, cells re-differentiate into new tissues. In animals differentiation cannot be reversed so to make clones embryos have to be made

DNA and cell division What happens to the chromosomes when a cell divides during mitosis? cell division chromosomes are copied What must happen to DNA during this same process? Why must chromosomes be copied before a cell divides? Centrioles make ‘spindle fibres’

What is mitosis? Each new cell can keep on dividing by mitosis. Mitosis makes new cells for growth and repair in all living things. That’s how you get from one cell to 50 billion! Mitosis is also called copying division. What does this mean?

Observing the stages in mitosis Use the prepared slides and complete the worksheets These are cells in a plant root tip

Differentiation also covered in stem cell lesson Non-specialised cells are called stem cells These stem cells, in animals, differentiate to become specialised cells – e.g. liver/hair Some genes have been switched on and others switched off Liver cells can only produce liver cells by mitosis. Hair cells can only produce hair, etc… At certain growth points, undifferentiated plant cells are always being produced. In this way, plants can produce stem cells all through their lives. Once an animal cell has differentiated it stays that way.

Cloning a cauliflower (recap from B1)

Syllabus In body cells the chromosomes are normally found in pairs. Body cells divide by mitosis. The chromosomes contain the genetic information. When a body cell divides by mitosis: ■ copies of the genetic material are made ■ then the cell divides once to form two genetically identical body cells. The cells of the offspring produced by asexual reproduction are produced by mitosis from the parental cells. They contain the same alleles as the parents.