Biology

Producing New Cells

Learning Intentions

1. Why do cells need to make new copies of themselves?

2. What is found inside the nucleus?3. What are the stages in the

process of cell division?

1. Why do cells divide?

Cells have to divide soorganisms can:-

1. Grow

2. Repair cells(e.g.broken bones, wounds)

2. Cells Dividing

1. Parent Cell2. Nucleus (containing genetic information) divides into 23. Cytoplasm divides into 24. Two new cells (identical to the parent cell) are formed

Why do you think it is so important that the nucleus divides properly?

3. What is inside the nucleus?

The nucleus contains thread-like structures called chromosomes

Chromosomes are made up of 2 chromatids joined together.

Chromosomes contain important genetic information.

4. Chromosome Complement

The characteristic number of chromosomes that certain organisms

should have is called the “Chromosome Complement”

Human Dog

5. Diploid and Haploid Cells

Human body cells have 46 chromosomes (2 sets of chromosomes)

and are called Diploid Cells

Human gametes (sperm/eggs) have 23 chromsomes (1 set of

chromosomes) and are called Haploid Cells

Human Body Cells Human Gametes (sex cells)

46 chromosomes 23 chromosomes2 sets of chromosomes in each cell 1 set of chromosomes

Diploid (2 sets) Haploid (1 set)

6. Mitosis

Mitosis is the process of Cell Division

The stages in Mitosis are:-Stage 1 Parent Cell chromosomes are copiedStage 2 Chromosomes become visibleStage 3 Chromosomes line up at equatorStage 4 Chromatids are pulled apart to either pole by spindle fibresStage 5 Parent cell divides to produce 2 new cells identical to

parent cell

Mitosis ensures that the new cells contain the same number and type of chromosomes

(the chromosome complement) so the new cells can develop and function properlymitosis glow video You Tube Mitosis animationBitesize animation Its Playdoh Time!!

7. Uncontrolled Cell DivisionNormal cell division (mitosis)

is carefully controlled so new

cellsdevelop properly.

Abnormal uncontrolled cell division (mitosis) can lead to different types of cancerswhat is cancer -glow video

Stem Cells Learning Intentions

4. State the role of stem cells

5. State the role of meristems

8a) Stem Cells

Stem cells are cells that have the potential to develop into any type of cell

Video Clip - “A Stem Cell Story” at www.eurostemcell.org/films

8 b) Stem Cells have 2 roles

Stem cells are different from other cells of the body because stem cells can:

1.SELF-RENEW (Make copies of themselves) AND 2.Differentiate (Make other types of cells)

2c) Stem Cell Facts

1. Stem cells are found in all plants and animals

2. Stem cells are produced by cell division

3. Stem cells have the potential to develop into any type of cell

4. Stem Cells are involved in growth and repair and can be used to grow many different types of cells, tissues, organs

5. In animals cell division occurs all over the body

6. In plants cell division only occurs in structures called meristemsStem Cell video clip (3:13)

8d) Stem Cells & Medical Treatments

Activity Cards - EuroStem

8e) Different Types of Stem Cells

There are 2 different types of STEM CELLS:-1.Tissue Stem Cells (also called Adult Stem Cells)2.Embryonic Stem Cells

8f) Where do we find Embryonic Stem Cells?

8g) Where do we find Tissue Stem Cells?

8h) Stem Cells: A controversial topicA controversial topic, is a topic that people will disagree about.

Embryonic Stem Cells cause the most arguments and disagreements.Arguments FOR the use of Embryonic Stem Cells• Embryonic Stem Cells can develop into ANY type of cell so they are the most

useful type of stem cell• Stem cells can be used to make cells you need, test drugs, understand

diseases, develop new medicines,• Embryonic Stem Cells can be used to save the lives• The embryos used for Stem Cell Research are from embryos that are no longer

needed for IVF Treatments for couples trying to have babies. Once fertilisation is successful, there are spare embryos, and the couple have 3 choices:-1) Destroy the embryos2) Donate embryos to another couple3) Donate embryos to scientific research on STEM CELLS

Arguments AGAINST the use of Embryonic Stem Cells• Embryos could eventually become babies, so some people believe that

scientists are destroying a human life when they use these embryos for research.

• Needs much more research before we understand full implications of this procedure.

Therapeutic Cells Clip 3:26

9a) Mitosis & BiotechnologyCell Production by Cell CulturesIn Biotechnology, humans can artificially producenew cells by creating cell cultures.

Cell cultures are when cells are taken out of a living organism and grown in a Lab using aseptic techniques.

The cells can be used for research, Drugs and Tissue therapy to help patients (e.g. Growing new skin cells for burns sufferers or growing new strains of carrots that can survive in areas of drought)

Cells that can develop into other types of cells are called STEM CELLS

CELL CULTURES

9b) Mitosis & Biotechnology

Aseptic TechniquesAseptic techniquesare techniques used to help avoidcontamination

CELL CULTURES

9c) Mitosis & Biotechnology

Cell Production by Cell Cultures

In order to produce new cells by cell culture, there must be:-

- Aseptic techniques used- An appropriate growth medium- Control of factors e.g. temperature, pH

Cell cultures are used for many applications e.g. skin grafts, medical research, disease resistant plants

Practical – Cauliflower Cloning

CELL CULTURES

10. Meristems1. Cell division in plants only occurs in meristems

2. Stem cells found in the meristems have the potential to develop into any type of plant cell e.g. xylem, phloem, palisade mesophyll cells

3. Apical meristems are found at the root and shoot tips.

Apical meristems increase the length of a plant.

4. Lateral meristems are made of cambium which is found in the vascular bundles between the xylem and phloem

Lateral meristems increase in the girth (thickness) of the plant; this process leads to the formation of annual rings.