Reproduction Flashcards
what does progesterone do
stimulates the growth of blood vessels in the lining of the uterus as its getting ready for pregnancy
if a fertilized egg arrives, progesterone helps keep the pregnancy going
what is the placenta and what does it do
special organ that passes food and oxygen from the mother to the fetus
takes urea and CO2 from the fetus and into the mother’s blood
secretes progress trine which maintains the pregnancy
how does amniotic fluid protect the fetus
cushions and protects the fetus as it develops
what does oestrogen do
stimulates the lining of the uterus to build up
reduces levels of FSH, increased levels of LH
explain mutations
change in the DNA of a cell;
mutations take place when the DNA is replicating as the cell divides;
because sequence change, gene might code for a different sequence of amino acids;
protein might not be able to carry out usual function
why are mutations harmful
cancer is a result of mutation in cells as they grow and divide;
if mutation is in sec cells, might be passed on to next generation;
whole chromosome mutation can result in death of cell
describe mitosis
results in two genetically identical DIPLOID daughter cells;
a copy of each chromosome is made before cell divides;
during division each daughter cell receives copy of each chromosome;
describe meiosis
two cell divisions and FOUR HAPLOID CELLS that are NOT genetically identical;
chromosomes replicate to form two strands, followed by two cell divisions;
chromosomes divided randomly between daughter cells, so not identical;
what happens during the first division of meiosis
one chromosome from each homologous pair goes into each daughter cell
what happens during the second division of meiosis
chromosome splits into TWO STRANDS, each going into each daughter cell. gives variety.
what do two sex cells form when combined, and in what process
zygote; fertilization
what does FSH do
stimulates ova in ovary to develop; stimulates production of oestrogen
what does LH do
stimulates release of mature egg from ovary; stimulates production of progesterone
what does oestrogen do
stimulates lining of uterus to build up; reduces levels of FSH and increases levels of LH
what does progesterone do
stimulates growth of blood vessels in lining of uterus getting ready for a pregnancy; if a fertilized ovum arrives in the uterus, it keeps the pregnancy going
