assessment 1 Flashcards
describe syngamy
the meeting of male and female gametes
are gametes haploid or diploid?
haploid
what is an example of an animal that reproduces externally?
salmon, frogs
what is an example of an animal that reproduces internally?
giraffes, humans
how many copies of each chromosome do haploid cells have?
one copy
what are mammals which lay eggs called + examples?
monotremes, echidnas, platypus
what are the two primary roles of the placenta?
remove waste, supply oxygen and nutrients
what is the purpose of the pouch for marsupials?
so the babies can continue developing after birth
is the umbilical cord two way?
yes, one for waste, one for oxygen + nutrients
what blood vessels are present in the umbilical cord?
two arteries and one vein
where are the follicles located?
in the ovaries
how many follicles reach full maturity each cycle?
one
what does oestrogen promote?
the thickening of the endometrium
what does progesterone do?
stabilises the endometrium
what hormones do follicles release into the bloodstream?
oestrogen
from what does the corpus luteum develop?
the ruptured follicle following ovulation
what does the corpus luteum do?
release oestrogen and progesterone
what happens after the corpus luteum disintegrates at the end?
menstruation occurs, because of the decrease of progesterone and oestrogen
which phase comes first in the menstrual cycle (luteal, follicular)
follicular phase, then the luteal phase
what is GnRH?
gonadotropin-releasing hormone
what does GnRH trigger?
the anterior pituitary gland to release FSH (follicle stimulating hormone) and LH (luteinising hormone)
What does FSH do? (follicle stimulating hormone)
it triggers the growth of follicles in the ovaries
What does LH do? (luteinising hormone)
high concentrations of LH cause the egg to burst out of the mature follicle, the remaining follicle to develop into the corpus luteum
where does the fertilisation of the egg occur? (in humans)
in the fallopian tube
what is the name of the clump of cells which implants itself into the endometrium wall in the uterus?
a blastocyst
what is HCG?
human chorionic gonadotropin
what does HCG do?
it sustains the corpus luteum, allows it to continue secreting progesterone and oestrogen
how is the structure of DNA described as?
a double helix
what backbone does DNA have?
a sugar-phosphate backbone
what is the structure of a nucleotide?
phosphate group, deoxyribose sugar (DNA) OR ribose sugar (RNA), nitrogenous base
what is an example of a prokaryotic organism?
bacteria
what occurs during S phase of the cell cycle?
DNA synthesis, DNA replication
what happens throughout all of interphase?
the cell grows by producing proteins and additional copies of organelles, such as mitochondria
what is the mid-point of a chromosome called?
the centromere
name the four (five ish) stages of mitosis
PMAT, prophase metaphase anaphase telophase, cytokinesis
what is incomplete dominance?
blend of two traits
what is codominance?
when both traits show up together
