6.1.2 Patterns of Inheritance Flashcards
What is the phenotype?
The appearance of the organism (the way the characteristic is displayed)
What influances the phenotype?
The genotype and environment
What genetic factors cause variation?
Mutation
What are mutagens?
Things that cause mutations
What are examples of mutagens?
x-rays, Gamma Rays, UV light.
Toxic Gases.
Viruses.
What mutations can you have?
Specific genes.
Chromosomes.
Are phenotypes caused by changed genetics passed on?
Yes - the offspring could have the same phenotype
Are phenotypes caused by environmental factors passed on?
No - they don’t change the genes so don’t get passed onto offspring
What are examples of phenotypes caused by enviromental factors?
Speakign with a certain dialect.
Loosing a limb.
Having Scars.
Beaks - as a result of diet.
What is etiolation?
Plants growing in a partial or complete lack of light.
What happens to a plant during etiolation?
Leaves do not develop and the lack of chlorophyll means that the plant is yellow or yellow-white.
The plant is described as chlorotic or suffering from chlorosis.
How is chlorosis an example of environment changing the phenotype?
Chloric plants have the genes to produce chlorophyll but due to the environmental factors, it isn’t turned on.
When do you use a monohybrid cross?
For simple tests involving only one characteristic with one pair of contrasting traits.
What gametes are produced from homozygous parents?
The allele for the individual. Either Dominant or recessive.
e.g.
TT -> T X2
tt -> t X2
What gametes are produced from heterozygous parents?
One of each type of allele that they have.
e.g.
Tt -> T and t
What is the ratio for a monohybrid cross of heterozygous parents?
3:1
Dominant : Recessive
How do you set up a punnet square?
All possible gametes are arranged in rows. Females vertically and males horizontally.
The predicted genotypes of the next generation are produced by combining the male and female gametes
What does it mean to have multiple alleles?
The gene has more than two alleles. However, an individual can only possess two alleles at a time - one on each gene locus in a pair of homologous chromosomes.
What are the Human blood groups?
A, B, O, AB
What are the alleles for human blood groups?
Ia, Ib, Io
What alleles are dominant and recessive in the human blood groups?
Ia and Ib are dominant.
Io is recessive.
What happens if you get both Ia and Ib appearing on the gene for blood group?
You have the blood group AB. They share dominance - an example of co-dominance.
What colour is an agouti rabbit?
Grey base, Yellow band and a black tip.
What colour is an albino rabbit?
White - no pigment develops.
What colour is a chinchilla rabbit?
Silvery grey - lack the yellow band of agouti.
What colour are Himalayan rabbits?
White with black feet, nose ears and tails.
What effects the colour of rabbits?
A single gene that has 4 alleles.
C - Agouti
Cch - Chinchilla
Ch - Himalayan
c - Albino
What is the dominant higharqy of for rabbit fur colour?
C - Agouti is most dominant
Cch - Chinchilla is more dominant than Ch - Himalayan. c - Albino is recessive to all others.