Genetics and inheritance Flashcards
Revise it! (14 cards)
What is the structure of DNA?
DNA is a double helix
The double helix structure was first described by James Watson and Francis Crick.
What forms weak bonds in DNA?
Base pairs form weak bonds
These weak hydrogen bonds allow the DNA strands to separate during replication.
What are the four bases of DNA?
Adenine, Guanine, Cytosine, and Thymine
These bases pair specifically: Adenine with Thymine, and Guanine with Cytosine.
What is the pair for Adenine in DNA?
Thymine
This is known as the A-T pair.
What is the total number of chromosomes in body cells?
46 total
Body cells contain 23 pairs of chromosomes.
What is the specific name for half the number of chromosomes?
Haploid
Haploid cells contain 23 chromosomes, which is half of the diploid number.
What determines gender in chromosomes?
23rd pair of Chromosomes
XX is female and XY is male.
When are chromosomes visible?
During cell division (mitosis)
Chromosomes condense and become visible under a microscope during mitosis.
What is Trisomy?
An extra chromosome
Trisomy can lead to genetic disorders.
What is Trisomy 21 also known as?
Down Syndrome
Down Syndrome is characterized by an extra 21st chromosome.
What does phenotype refer to?
Physical characteristics (e.g height, gender)
Phenotype is influenced by genotype and environmental factors.
What does genotype refer to?
What the genes are saying, their code (e.g XX, XY)
Genotype is the genetic makeup of an organism.
What is a karyotype?
When the chromosomes are arranged from the largest to the smallest
Karyotyping is used to detect chromosomal abnormalities.
What is a pedigree?
A visual way to show the inheritance of a trait like a family tree
Pedigrees help track genetic traits across generations.
