Genes Flashcards
Genes
A stretch of DNA that carries a set of instructions on protein should be made
How many genes are there
Approximately 23,000
What are chromosomes
The thing that makes organisms what they are
What do chromosomes do
They carry all the information used to help a cell grow, thrive and reproduce
Who discovered DNA
Rosalind Franklin, James Watson and Francis Crick
What are allele
Different versions of the same gene. E.g. alleles for aye colour are blue and brown eyes
What is a genotype
An allele pair
What is a phenotype
The physical expression of an allele pair
What is selective breeding
When people breed 2 types of a certain organism together in order to make offspring with similar features
What are the main steps in selective breeding
- Decide which characteristics are important enough to select
- Choose parents that show these characteristics
- Choose the best offspring to produce the next generation
- Repeat the process
What are some disadvantages of selective breeding
Increase in inherited disorders
Breathing and birthing difficulties
What is a clone
An organism that is genetically identical to it’s parent
Advantages of cloning
Cheap
All plants are genetically identical
Produced quickly
What are some disadvantages of cloning
Reduces the variety of genes available which increases the risk of disease
How does cloning happen
- Remove the egg cell from the donor sheep
- Take a cell from the udder of the cell donor
- Put the nucleus of the cell donor sheep into the egg of the first sheep
- Give the embryo an electric shock so it divides
- Implant the embryo into a surrogate mother sheep
