Chromosomes And Genes Flashcards
(15 cards)
Ethical issues with genetic screening
Genetic screening can show if a baby might have serious health problems, leaving parents with a hard decision: to end the pregnancy or have a child who may need lifelong care. However, some people are against abortion for moral reasons, and it is illegal in some countries.
What is a recessive allele?
An allele that will only show in the phenotype if both alleles are present (e.g., b).
What is a genotype?
The genetic makeup of an individual represented by two symbols like BB, Bb, or bb.
What is a phenotype?
The physical trait you see, like blue eyes or brown eyes.
What does homozygous mean?
Both alleles of a particular gene are the same (e.g., BB or bb).
What does heterozygous mean?
Two alleles of a particular gene that are different (e.g., Bb).
What is a Punnett square?
A diagram that shows how traits might be inherited from parents and predicts possible genotypes and phenotypes for offspring.
What is an allele?
One of 2 possible versions of a particular gene.
What are dominant alleles?
In a heterozygous condition, the dominant allele overrides the recessive allele (e.g., B).
What’s mutation and examples?
• A random change in the structure of a gene or number of chromosomes
• Down’s syndrome
• Cystic fibrosis
Describe the structure of DNA
• Double helix
• Sugar phosphate backbone
• Base pairing
What are chromosomes?
Genetic structures occurring in functional pairs in the nucleus of cells.
What are genes ?
Sections of chromosomes made up of short lengths of DNA that control characteristics
What are the 2 types of variation?
• Continuous: a gradual change in a feature with no distinct groups (height, hand span, shoe size) in histogram.
• Discontinuous: individuals that can be divided into a small number of distinct groups with no overlap (eye colour, tongue rolling, blood group) bar chart.
What is variation?
Variation is the difference between organisms or individuals, of the same species
Variation can be:
• Genetic (caused by our genes)
• Environmental (due to environment or lifestyle)
• A combination of both
