BIOLOGICAL DIVERSITY-3 Flashcards
What does DNA stand for?
Deoxyriboneucleic Acid
What is DNA responsible for?
The inherited material responsible for genetic variation.
When was DNA first identified
1869
What are the chemicals in a DNA ladder?
guanine (G)
cytosine (C)
adenine (A)
and thymine (T).
Which chemicals always pair up together?
C and G
A and T
What is a chromosome?
All the DNA of a cell compacted into packages.
Where are chromosomes stored?
In the nucleus.
How many chromosomes does a human cell contain?
46 pairs. 23 from the mother, 23 from the father.
What makes the 23rd pair significant?
It is the sex chromosome.
It determines if you are male or female.
If it is XX, you are a female, if it’s XY, you’re male.
What is a gene?
It is an uninterrupted segment of DNA containing instructions for a specific trait.
Offspring inherit genes from both parents
What are different forms of a gene called?
Alleles
What is Mitosis
A cell divides into two daughter cells, each containing the same number of chromosomes
What is meiosis
There are 4 daughter cells, each with only half the chromosomes as the original cell.
What are the two types of cell division
Mitosis and Meiosis
Define artificial selection
Only allowing the two organisms with the most desirable traits reproduce
What is a dominant traits
The gene that expresses itself more strongly (uppercase letter)
What is a recessive gene
Appears in offspring only if the two recessive traits combine (lowercase letter)
Define Incomplete dominance
When neither the dominant or recessive trait are expressed, both alleles are combined and expressed as a mixture of both.
Define Co-dominace
When both are equally dominant
True or False: Environment can also effect DNA
True
