Reproduction and Growth Flashcards
(32 cards)
what is a species?
a group of organisms that can interbreed and produce fertile offspring
why does variation occur?
because all offspring are different
why is variation important?
for the survival of the species
how many chromosomes does each body cell contain?
46 chromosomes
how many sets of chromosomesdoes each body cell have?
2 sets
what process is new body cells made by?
mitosis
what is thef irst stage of mitosis?
parent cell
second stage?
chromosomes become visible in the nucleus
third stage?
chromosomes line up at the equator
fourth stage?
chromatids are pulled apart ro either pole by spindal fibres
fifth stage?
parent cell divides to produce two new cells
how many chromosomes is in a human gamete?
23 chromosomes
what is mitosis the process of?
cell division
what is tranaported from foetus to mother?
carbon dioxides and wastes
what can harm foetul development?
alcohol, tobacco, radiation
where are chromosomes found?
in the nucleus of a cell
what are chromosmes made from?
dna
how many sets of chromosomes does a zygote contain?
two sets
what deos the zygote divide into?
a ball of cells called a embryo and implants into the wall of the uterus
what does the embryo then develop into?
a foetus
what does the placenta allow for the mothet and foetus?
exchange of materials between mother and foetus blood
what is transported from mother to foetus?
glucose and oxygen
how many chromosomes does a human sex cell contain?
23 chromosomes
what another word for sex cells?
gametes
