B2 Cell Division And Stem Cells Flashcards
How many chromosomes does human body cells and ganetes have
Human body - 46 chromsomes
Gametes - 23 chromosomes
Why chromosomes in body cells are normally found in pairs
Each pair contains two chromosomes, one coming from each parent
Why genetic material must be doubled during mitosis
So all important genetic information ends up in each of the new cells
Situations where mitosis is occurring
Development and growth
Mitosis
The part of the cell cycle when a eukaryotic cell divides to produce two daughter cells
Chromosomes
Thin strands of DNA
DNA
The chemical that makes up the genetic material of humans
What does DNA stand for
Deoxyribonucleic acid
Gene
A section of DNA which controls part of a cell
Gamete
A sex cell
Why mitosis is an important process in living things and how characteristics are inherited
Plays an important part in the development of embryos
Growth
A permanent increase in size or mass
Differentiation
The process a cell becomes specialised
Importance of cell differentiation in multicellular organisms
They are able to perform a specialised function in the body
Compare and contrast differentiation in plants and animals
Plant cells retain their ability to differentiate throughout their whole life
Animal cells are mainly restricted to repair and replacement in later life
Why plant clones are genetically identical to each other
Clones contain identical sets of genetic material in the nucleus
How using tissue culture creates a clone of a plant
Small groups of cells extracted from a plant and placed in a petri dish
Division of cells eventually result in formation of a clone of parent plant
Why it is easier to clone a plant compared to an animal
Plant cells have a cell wall, which makes it easier to isolate and grow individual cells
How to clone a plant
A branch from parent plant cut off
Leaves removed
Stem planted in damp compost
Stem cell
A cell that is not differentiated
Why embryonic stem cells are more useful for helping medical conditions
Embryonic stem cells can be used to regenerate or repair diseased tissue and organs
What can plant stem cells be used for
To create clones
Why plant clones are produced in the agriculture industry
Allows a variety of a plant with desirable characteristics to be produced cheaply, quickly and on a large scale
How can stem cells be used to help medical conditions
A stem cell transplant replaces damaged blood cells with healthy ones
Can be used to treat conditions affecting the blood cells such as leukaemia and lymphoma
Arguments for the use of stem cells
Can treat medical diseases
They could be used to replace cells that have been damaged or destroyed
Arguments against the use of stem cells
Some people believe life begins at contraception which means the embryo is alive
They view the use of stem cells as killing an embryo
What therapeutic cloning can be used for
Understanding disease and developing new treatments for disease
Therapeutic cloning
A process that produces an embryo with genes that are identical to the patient’s
Evaluate use of stem cells
They could be used to replace cells that have been damaged or destroyed
