Chromosomes and variation Flashcards
How is genetic material inherited?
Egg and sperm cells are the only cells to contain 23 chromosomes and only one copy of each chromosome (xx for female or xy for male.) During fertilisation, the egg and sperm cells join together and their chromosomes pair up producing an embryo with 46 chromosomes.
What are chromosomes?
46 long strands of DNA; half from your father and half from your mother.
What is DNA?
Contains all the information to make an organism.
What are genes?
Hold the information to produce a characteristic.
useful trick to help remember the definition of chromosome, DNA and gene —>
A chromosome is like a library
DNA are like books
And genes are like sentences.
What does continuous variation mean?
Characteristics that can take on any value within a range. Example: height.
What does discontinuous variation mean?
Characteristics that can only result in certain values. Example: hair colour.
What graph should be used to plot discontinuous data?
A bar chart.
What graph should be used to plot continuous data?
A histogram.
What is meant by environmental variation?
Variation caused by your surroundings or what happens to you.
What is meant by inherited variation?
Variation inherited from your parents.
What is the definition for variation?
Differences in characteristics.
What is the definition for species?
Organisms that have lots of characteristics in common.
