Questions and Answers
Discuss how variation in the genotypes of offspring, including gender, arise as a result of the processes of meiosis and fertilisation.
Random assortment of chromosomes (1) - when the maternal and paternal chromosomes line up by chance on either side of the equator at metaphase
Crossing over (1) – Homologous chromosomes exchange material at metaphase which occurs randomly (1)
Non-disjunction (1) – pairs of homologous chromosomes fail to separate at metaphase (I or II) which alters the chromosome number in each gamete being formed (1)- one will have one extra and one will lack one, which can result in birth defects.
Describe the changes involved in the development of the zygote from conception to its implantation in the endometrium wall.
Zygote is the fertilised egg
Undergoes mitosis / cleavage
Forms a morula
Which is a solid ball of cells
Becomes a blastocyst
Which is a hollow ball of cells
Develops an inner cell mass
Thickened at one end
Surrounded by a cavity that contains fluid
Infertility occurs in approximately 10% of couples. Describe two different treatments that couples may try in order to overcome MALE infertility.
Artificial insemination by donor (or from your partner): the male partner does not produce enough viable sperm sperm are collected from a donor and inserted thru the female's vagina into the uterus close to the fallopian tubes
Intracytoplasmic sperm injection (ICSI) sperm count is very low single sperm is injected into a single egg resulting EMBRYO is IMPLANTED INTO UTERUS
Discuss how combined and mini pill prevent pregnancy from occurring. Include in your discussion what type of person would utilise these techniques, as well as any limitations of the named techniques.
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