Genetic Variation and Control Flashcards
What is variation?
The differences between members of the same species.
What are the two types of variation?
Genetic and environmental variation.
What are genes?
Codes in our cells that control how you’re made.
How are genes passed on from parents to their offspring?
They are passed on through gametes.
What is environmental variation?
How environmental factors around an organism change it.
Give three examples of environmental variation.
- Losing toes to a piranha
- Getting a suntan
- Plants having yellow leaves
Give three characteristics that are informed by both genetic and environmental factors.
- Height
- Health
- Intelligence
Where is genetic material kept in most cells?
In the nucleus.
How many chromosome pairs do humans have?
23
What are chromosomes?
Long lengths of DNA
What are genes?
Individual bits of DNA that give different characteristics to an organism.
What are alleles?
Different versions of the same gene.
What is sexual reproduction?
When genetic information from two organisms are combined to produce genetically different offspring.
What are gametes?
Sex cells - sperm and ova.
How many chromosomes do human gametes have?
23
What is fertilisation?
When sperm and ova fuse to form a cell with a full amount of chromosomes.
What is asexual reproduction?
When a cell splits itself in half to create two genetically identical offspring.
How do cells achieve asexual reproduction?
Each chromosome in the cell splits into two “half chromosomes.” A membrane forms around each sell and then the DNA replicate themselves to give each cell a full set of chromosomes.
What is cloning?
Making a genetically identical copy of an organism.
How are plant cuttings used for cloning?
Th cuttings are taken from good parent plants and are planted to produce genetically identical offspring.
What are two advantages of planting plant cuttings?
It is quick and cheap.
Describe using a tissue culture.
A few plant cells are put in a growth medium with added hormones which grow into genetically identical plants.
What are three advantages of using tissue cultures?
It is quick, space efficient and not affected by seasons.
Describe the process of embryo transplantation.
1) Sperm cells are taken from the father with desirable traits and is fused with an ovum from a mother with desirable traits.
2) The embryo is split many times before any specialisation happens.
3) The cloned embryos are implanted in surrogate organisms.
4) The offspring are genetically identical to each other but not to the parents.
