Reproduction Flashcards
Diploid and haploid number of chromosomes in human cells
Diploid - 46 (chromosomes)
Haploid - 23 (pairs)
Fertilisation
The fusion of a male and female gametes to form a zygote that undergoes cell division and develops into an embryo.
Division of a cell by mitosis produces…
Two cells which contain identical sets of chromosomes
When does mitosis occur?
During - Growth Repair Cloning Asexual reproduction
Pregnancy sequence
Zygote formed Developing embryo moves into uterus Implanted in lining of uterus Placenta forms Placenta secretes progesterone Fetus connected to placenta by umbilical cord Fetus is surrounded by amniotic fluid
Average length of pregnancy
40 weeks
Meiosis
Meiosis is the special form of cell division that results in the sex cells or gametes.
Involves 2 cell division and produces 4 haploid cells that are not identical.
Mitosis
Results in 2 genetically identical, diploid, daughter cells.
The growth of a pollen tube followed by fertilization leads to…
Seed and fruit formation
Germination
The process by which the embryo plant in the seed starts to grow to the point where it's photosynthesizing independently. Conditions needed: Warmth Water Oxygen
Germinating seeds utilise…
Food reserves until the seedling can carry out photosynthesis.
How is the developing embryo protected?
A membrane called the amnion enclosed the embryo and it secretes a fluid called amniotic fluid, which protects the developing embryo against jolts and bumps.
The role of the placenta
The embryo develops a placenta, which will allow the embryo to obtain materials such as oxygen nutrients from the mother’s blood. It also allows the embryo to get rid of waste products such as urea and carbon dioxide, as well as anchoring the embryo in the uterus. The placenta secretes female hormones, like progesterone, that maintain the pregnancy and prevent the embryo from aborting.
