Inheritance and Genetic Diseases Flashcards Preview

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Flashcards in Inheritance and Genetic Diseases Deck (9)
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1
Q

Why is sexual reproduction (meiosis) important? (3)

A

Results in greater genetic variation which allows:

  1. Beneficial combinations of genes
  2. Non-beneficial genes to be removed
  3. Important for evolution for fight against microbes (red queen hypothesis)
2
Q

Describe Meoisis (7)

A
  1. Starts with diploid germline cell with paternal and maternal homologs
  2. Prophase: The chromosomes of each homolog duplicates.
  3. The dupilcated homologs pair up and recombine
  4. Metaphase - line up ready to be pulled apart by spindles
  5. Anaphase (pulled apart) and Telophase (Cytoplasm + cell membrane separation). This forms 2 new cells
  6. The 2 new cells undergo
    PMAT again, ending with seperation the two sister chromatids.
  7. Four new unidentical haploid gametes formed.
3
Q

What is the kinetochore and chiasma? (2)

A
  1. Kinetochore (in centromere) is the point where microtubules attach on chromatids.
  2. Chiasma is point where the two duplicated chromosomes cross over during recombination.
4
Q

What happens when meiosis gametes are improperly formed during meiosis (Non-disjunction)? (4)

A

Could lead to:

  1. Trisomy (1 additional chromosome)
  2. Monosomy (1 less chromosome)
5
Q

What are examples of Trisomy which are not fatal? (3)

A
  1. Down’s syndrome (3 copies of chromosome 21)
  2. Patau’s Syndrome (Trisomy 13)
  3. Edward’s Syndrome (Trisomy 18)
6
Q

In what situation is Monosomy non-fatal? What is an example of Monosomy? (2)

A

Monosomy is normally fatal unless on X chromosome, only shows in females.
1. Turner Syndrome

7
Q

Example of XXY chromosome disorder? (1)

A
  1. Klinefelter Syndrome (Male, reduced fertility, lower IQ).
8
Q

Who was Gregor Joahnn Mendel, why was he important? (2)

A
  1. An Austrain Frair who used on pea plants to study inheritance of monogenetic genetic diseases. Published work in 1866.
  2. This is the basis of genetic counselling.
9
Q

What type of inheritace pattern are the following Conditions:

  1. Cystic Fibrosis
  2. Sickle Cell
  3. Huntingtons
  4. Harmophilia A
A
  1. Cystic Fibrosis - Autosomal Recessive
  2. Sickle Cell - Autosomal ‘incomplete’ recessive - retained due to increased protection to malaria
  3. Huntingtons - Autosomal Dominant
  4. Haemophilia A - X-linked recessive trait. Therefore more dominant in Males. Deletion/inversion to F8 Gene causing loss of function to blood clotting factor.