Biology B1 OCR (Higher)

Biology revision cards for B1 of the OCR Higher syllabus. Information taken from the CGP GCSE Biology 21st Century Science Revision Guide (Higher Level). Topics include:  Ethical Dilemmas, Stem Cells.

HideShow resource information
  • Created by: cg97
  • Created on: 22-03-12 16:27

Ethical Dilemmas

There are two approaches to erthical dilemmas. They are:

You may think that certain actions are always unnatural or wrong. This means that, whatever the possible benefits, you feel that these actions are unacceptable. Some people would say that research on human embryos comes into this activity.

You may also say that the right decision is the one that brings the greatest benefit to the greatest number of people. Some people would argue that embryo research does more good than harm so it is acceptable.

The law is sometimes involved too.

1 of 4

Stem Cells

Definition: An undifferentiated cell of a multicellular organism that is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation

...Basically most cells in your body are specialised for a particular job. Some cells are undifferentiated (they can develop into different typres of cell depending on what instruction they're given). These cells are called stem cells.

Stem cells may be able to cure many diseases

However, the use of stem cells is controversial.

2 of 4

Genetic Disorders

Genetic disorders are caused by faulty alleles.

  • Some genetic disorders are caused by recessive alleles i.e. Cystic Fibrosis

Defective alleles are responsible for genetic disorders. Most of these defective alleles are recessive.

  • Others are caused by dominant alleles i.e. Huntington's Disorder

A dominant allele means that there's a 50% chance of each child inheriting the disorder if just one parent is the carrier. The 'carrier' parent will, of course, be a sufferer.

3 of 4


Clones are genetically indentical organisms. Nature makes clones:

By asexual reproduction

Some organisms reproduce asexually (without sexual reproduction). This means that there is only one parent, and the offspring are genetically the same as each other and the parent. This often occurs in plants.

When cells of an embryo split

A single egg is fertilised by a sperm and an embryo begins to develop as normal. Occasionally, the embryo splits into two, and two separate embryos begin to develop. The two embryos are genetically identical. This occurs within humans; this is how identical twins are born.

4 of 4


No comments have yet been made

Similar Biology resources:

See all Biology resources »