Genetic variation and control Flashcards
What is variation? Give examples.
Variation is the differences between individuals in the same species. examples include hair colour, eye colour, hand size and many other things.
Why is there genetic variation?
Most organisms inherit half of their genes from their mother and half from their father. This means that the combination of genes allows variation.
Describe some examples of variation caused by the environment.
Plants that have been grown in different light levels. Sunburn. Scars or cuts.
Define the following; -gene -chromosome
A gene is a short length of a chromosome. A chromosome can be found in the nucleus of a cell and contains the genetic information.
Explain how sexual reproduction produces variation.
Sexual reproduction is where genetic information from two organisms is combined to produce offspring which are genetically different. In humans, each gamete (sex cell) contains 23 chromosomes- half the number of chromosomes in a normal cell. The egg and the sperm cell then fuse together to form a cell with the full number of chromosomes. The offspring inherits features from both parents and this mixture of genetic material produces variation in the offspring.
How does Asexual reproduction work?
An ordinary cell can make a new cell by simply dividing in two. The new cell has exactly the same genetic information as the parent cell, this is known as asexual reproduction. There is no fusion of gametes, no mixing of chromosomes and no genetic variation between parent and offspring. The offspring are genetically identical to the parent- they’re clones. The cell divides in half and then the DNA reproduces itself.
How do you clone plants?
Cuttings. Gardens can take cuttings from good parent plants and then plant them to produce genetically identical copies of the parent plant. This is quick and cheap. Tissue culture. This is where a few plant cells are put in to a growth medium with hormones and they grow in to new plant clones of the parent plant.
What is adult cell cloning?
Adult cell cloning is another way to make a clone.
