Genetics semester 1 Flashcards
What are Mendels three laws?
- Segregation
- Independent assortment
- Dominance
Is a amoebe unicellular or multicellular?
Unicellular.
When mating types 1 and 2 meet what happens?
They form a plasmodium.
What do plasmodium eat?
Amoebe.
Does the plasmodium show the genotype or the phenotype?
Genotype.
Do the plasmodium have a type?
No.
What are aspergillus nidulans?
Asexual spores with one nuclei and a coloured pigment.
What colour is mycelium?
They are colourless.
Do conidia or mycleium have thread like hyphae?
Mycleium.
Where do the conidia get their colour from?
Through the colourless mycelium.
What two processes make up nuclear cell division?
Karykinesis and cytokinesis.
What is the definition of variance?
Tendency for offspring to differ from parents.
What is the definition of heredity?
Tendency of offspring to resemble parents.
What did Jennifer Dees experiment with mating type show?
That there is more than one allele per gene.
What is chimera?
When there is more than one genotype per zygote. This is naturally rare in humans.
What is the definition of totipotency?
Ability of a cell to give rise to a whole new organism.
What is cytogenetics?
The connection between the behaviour of chromosomes and the behaviour of genes.
What is a centromere?
The constriction on each chromosome.
How many identical cells does there need to be for it to be considered a clone.
More than 2.
There are 10^14 clone cells in the body with how many different morphogens?
200.
What are two consequences of mutations?
Apoptosis or cancer.
Do haploid or diploid organisms go through mutations?
Both.
Is AB/ ab described as cis or trans?
Cis.
Is Ab/Ba described as cis or trans?
Trans.
What are the ends of chromosomes called?
Telomeres.
What arm is (P)?
The short arm.
What arm is (Q)?
The long arm.
What is chromatin a mix of?
Protein and DNA.
What protolytic enzyme allows G banding?
Tripsin.
What is the stain called that G banding is involved in?
Giasma stain.
Which sex chromosome is smaller?
Y.
What type of proteins allow sister chromatid cohesion?
Glue proteins.
What happens at the end of the spindle fibres allowing them to shorten?
Depolymerisation.
What is euchrochromatin?
Loose DNA which is transcribed.
What is heterochromatin?
Tight DNA that is not transcribed.
What can prophase be separated into?
Prophase and prometaphase.
What is nordisjuction?
Failure of normal segregation.
What does the chiasma do?
Helps hold the bivalents together.
What disorder does XO show?
Turner syndrome.
What disorder does XXY show?
Sex klinefelter.
What is the genetic notation for a Down’s syndrome female?
47 XX +21
What is the notation for Cri Du Chat?
46 XX 5P-
What is the definition of heredity?
Transmission of characteristics from parents to offspring by the means of genes.
What does aneuploidy mean?
An incomplete set of genes. Either too many or not enough.
What type of aneuploidy is trisomic?
2n+1.
What type of aneuploidy is monosomic?
2n-1.
What type of aneuploidy is nuclisomic?
2n-2.
What type of aneuploidy is disomic?
n+1.
Duplication can be tandem or ______.
Insertional.
What happens in an inversion of DNA?
The segment is cut out, flipped and reversed.
In a paracentric inversion is the centromere inside or outside?
Paracentric- outside
Pericentric- inside.
How many chromosomes are there before and after mitosis?
46
There are 92 chromatids before and no chromatids after.
Is meiosis 1 or 2 a reduction division?
1.
Is meiosis 1 or 2 an equational division?
2.
When do bivalents form in meiosis?
Prophase 1.
What type of segregation happens in tetrads.
2:2 segregation.
Is Mendels law of independent assortment always true?
No.
What holds together tetrads?
Membrane sacs called ascus.
What type off cross over do you need to make a tetrad with a non parental diatype?
A double cross over.
What needs to be restrained to get ordered tetrads?
Meiosis.
For a tetrad to be all recombinant what needs to happen?
A four strand double cross over.
When there are no cross overs what type of segregation has occurred?
First division segregation.
When one cross over has occurred when type of segregation has happened?
Second degree segregation.
The probability of a cross over between two genes is roughly proportional too?
The distance between them.
What holds chromosomes together until anaphase 1?
Cross overs.
If a cross over is unlikely are there more parentals or recombinants in the progeny?
Parentals.
In tetrads if there is less NPD then P what can it show?
Linkage.
What does Mendels second law not apply too?
Linked genes.
What does the recombination frequency equal?
Recombinants/ total meiotic products x 100.
Why is the maximum combination frequency 50%?
Because if the genes lie far enough apart is it equally likely that they will be P or R.
What does a polymorphic population mean?
Two or more alleles are present at a significant frequency of more than one.
How do you calculate allele frequency?
)No. of allele A)/ 2N.
What 3 assumptions do you have to make for Hardy Weinburg to be true?
No mutation, no migration, random genetic drift.
What is the founders effect?
When a breeding female moves out of a population to make a new one, for example on the Galápagos Islands.
What does positive assortative mating involve?
Choosing a mate if they have the same phenotype as you.
What does positive assortative mating occurs what to do you end up with more off?
More homozygous in the population.
Allele frequency is not changed.
What does negative assortative mating ( avoiding choosing a mate with similar characteristics as yourself) increase?
The frequency of heterozygous in a population.
When will natural selection not act against an allele?
When it has no effect on the phenotype.
What can transient polymorphism be followed by?
Fixation of an old or new allele.
What is pleiotropy?
When one gene affects more than one phenotype.
What are the three types of dominance?
Simple, incomplete and over dominance.