Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
74 Cards in this Set
- Front
- Back
|
how long is DNA in each cell |
2 meters long |
|
|
describe the basic structure of how DNA is stored din the body |
-4 bases complementary paired -2 strands helix -wrap around histones -histone and dna form chromatin -chromatin condensed as chromosome -chromosome packed in nucleus |
|
|
describe a nucleotide |
BASE BINDED TO THE DEOXYRIBOSE SUGAR AND THIS BINDED TO THE PHOSPHATE GROUP |
|
|
what is a homologous pair |
2 chromosomes from each parent found in autosomal cells |
|
|
body cells have how many chromosomes |
46 chromosomes, 23 from mum and 23 from dad |
|
|
what are autosomal chromosomes |
not sex chromosomes |
|
|
how many pairs of autosomal chromosomes do normal human body cells have |
22 |
|
|
what is mitosis for? |
-growth -development -replacement of dead/damaged cells |
|
|
what is the cell cycle |
-interpase -mitosis -cytokinesis |
|
|
what are the stages of interphase and what they do |
-G1 phase growth, normal metabolic roles -S phase DNA replication -G2 phase Prepare for mitosis |
|
|
stages of mitosis |
-prophase -metaphase -anaphase -telophase cytokinesis |
|
|
describe prophase |
-chromosomes condense and become visible -spindle fibres emerge from centrosomes -nuclear evelope breaks and centrosomes move to opposite pols |
|
|
what are centrosomes |
centrosomes are organelles comprised of centrioles made of nanotubules (tubulin protein) -centrosome are replicated during the s phase of interphase -they organise the spindel fibres. |
|
|
what r spindle fibres |
they are proteins structures that pull chromosomes apart furing cell division |
|
|
whats prometaphase |
between prophase and metaphase where the chromosomes condense, kinetochores appear at centromeres and the mitotic spindles attach the the kinetochores |
|
|
describe metaphase |
the chromosomes line up along the centre and each sister chromatid attach to a spindle fiber from opposite poles |
|
|
-describe anaphase |
this is where the sister chromatids pull to opposite poles of the cell |
|
|
-describe telophase |
-the chromosomes arrive at the oppsite end of the cell and the nuclear envelope sarts to form around the set of chromosomes. the mitotic spindles break down but the spindle fibers continue to push the poles apart |
|
|
-describe cytokinesis and the difference between animal and plant cells |
-separation of the two cells, cytoplasm split -animal cell: cleavage furrow seperates the daughter cells -plant cells: precursor to the new cell wall seperated the daughter cells |
|
|
what is meiosis essential for? |
sexual reproduction, turning dipoid cells into haploid cells |
|
|
whats the difference between haploid and diploid |
-haploid have half the number of chromosomes than autosomal somatic. and are found in gametes |
|
|
describe the stages of meiosis. |
starts from diploid to haploid P1 M1 A1 T1 cytokinesis P2 M2 A2 T2 cytokinesis |
|
|
when does crossing over occur |
-prophase 1 |
|
|
describe crossing over (recombination) |
-homologous chromosomes pair up -swap different versions of the same gene |
|
|
what is independent assortment? |
-the arrangement of chromosome in each cell. so the combination of chromosomes that go into each cell |
|
|
when does independent assortment occur |
metaphase 1 and metaphase 2 |
|
|
what is the definition of reproduction |
process where organisms generate new individulas of the same kind |
|
|
what are the 2 forms of reproduction |
-sexual: needs 2 organisms, union of 2 cells -asexual: one organism, single cell, binary fission(bacteria) |
|
|
describe the human reproductive system |
-fully functional after puberty -specialised organs called genitals -female egg is fertilised by male sperm cell |
|
|
where precisely is sperm produced |
walls of the seminiferous tubules which are in the lobules of the testes |
|
|
where are sertoli cells found and what do they do |
sertoli cells regulate spermatogenesis and nourish sperm |
|
|
where are interstitial cells and whta do the do |
they are inbetween seminiferous tubules and they secrete sex hormones |
|
|
describe the sperm anatomy in the three parts head, middle and tail |
head: covered by acrosome and stores enzymes middle piece contains mitochondira tail for movement |
|
|
describe spermogenesis |
-diploid spermatogium MITOSIS -primary spermocyte -MEIOSIS 1 -secondary spermocyte -MEIOSIS 2 -early spematid -late spermatid |
|
|
what oogenesis |
the process of formation of the egg cells. |
|
|
describe the process of oogenesis |
1-2 million primordial follicles at birth, 250 000 at puberty and only 400 mature. each follicle contains an oocyte undergoing meiosis, secondary oocyte and polar body,
the secondary oocyte released from ovary(ovulation) oocyte moves into oviduct |
|
|
describe the process of fertilisation |
sperm enter the oviduct sperm fuses with the egg fertilisation occurs in oviduct to form zygote |
|
|
post ovulation for non pregnant women |
secondary oocyte doesn't complete meiosis secondary oocyte dies soon after ovulation |
|
|
post ovulation for pregnant |
-secondary oocyte fertilised by sperm -fertilised secondary oocyte undergoes meiosis 2 -secondary polar body and zygote -sperm and egg nuclei fused zygote resulting in 46 chromosomes |
|
|
wat are hormones and what are the main types |
-chemical messengers -that promotes communication between cells types of hormones -prostaglandins -pheromones -peptide hormones -steroid hormones |
|
|
prostaglandins |
-local hormones |
|
|
pheromones |
between individuals |
|
|
peptide hormones |
bind to a cell surface receptor on a target cell |
|
|
steroid hormone |
lipids that enter a target cell |
|
|
how do peptide hormones work |
-binds to cell surface receptor -does not enters the target cell -actions mediated by second messenger e.g. Cyclic AMP |
|
|
how to steroid hormones work |
do not bind to the surface receptir. enters the target cell binds to the receptor in the nucleus or cytoplasm |
|
|
what hormones are released by the ovaries |
-oestrogen -progesterone |
|
|
what hormones are released by the testes |
testosterone |
|
|
what hormones involving reproduction that are released by hypothalamus |
gonadotrphin releasing hormones |
|
|
what hormones involving reproduction is released by pituitary. |
gonadotrphic hormones -FSH -LH |
|
|
follicle stimulating hormone (FSH) and Luteinizing hormone are regulated by what machanism |
negative feedback loop |
|
|
what hormones does testosterone regulate |
GnRH and LH |
|
|
what does inhibins produced by sertoli cells regulate |
GnRH FSH |
|
|
what does progesterone do? |
-dilate arteries so uterine blood increases -blood pressure drops -red blood cell increasse -cardiac output increased -relaxes SMC in uterus and arteries |
|
|
what hormone is involved with child birth |
oxytocin |
|
|
what mechanism does oxytocin use |
positive feedback |
|
|
what hormones are involved with menopause |
-ovarian cycle ceases no menstruation for a year -ovaries become unresponsive to FSH and LH |
|
|
what were the 2 main hypothesises of inheritance in the 1800's |
-blending hypothesis: mix genetic material e.g. red and white blend to get pink -particulate hypothesis: traits passed on as discrete unit and maintain their identity |
|
|
which scientist is famous for his contribution to studying inhertiance
|
Gregor Mendel |
|
|
why did mendel choose pea plants |
-grow fast(mature fast) -can grow many at once -large offspring -visable traits -easy and cheap to maintain optimum conditions -can be true breed and it is self fertilised |
|
|
what were the characteristics of the pea plants that mendel was interested in? |
wrinkled or round seed -yellow or green plant |
|
|
what is the F1 generation in a monohybrid cross |
the first generation in a cross between two pure bred peas. Looking at one trait
|
|
|
what theory of inheritance is no longer accepted and how was tbis found |
he blending theory as the monohybrid cross of green and yellow seeds gave NO intermediate yellow/green so blending doesn't occur |
|
|
whats the ratio og a monohybrid cross of the f2 generation(all yellow heterozygous) |
3:1
|
|
|
whats a gene |
Heritable factor he |
|
|
whats an allele
|
the trait |
|
|
genotype |
the genetic make upwhats th |
|
|
whats the phenotype
|
The observed trait |
|
|
w hats homozygous
|
two alleles that comprise of the same genotype |
|
|
whats heterozygous |
two alleles comprised of different genotypes |
|
|
how initially does inhetitance work for heterozygous
|
one gene can mask the effect of another e.g one chromosome has the gene for purple flower and the other has a gene for white flowers the gene for white flowers will produce exzymes that mask the effect of the enzymes of the purple pigment enzyme |
|
|
whats the differecnce between monohybrid and dihybrid crosess |
monohybrid looks at one trait e.g colour. Yy and dihybrid looks at two traits simulanteosly e.g wrinkled,round, and colour. WwYy |
|
|
whats the ratio of a dihybrid cross of the f2 generation |
9:3:3:1 |
|
|
what part of meiosis causes the 9:3:3:1 ratio to occur rather than the 3:1 in dihybrid crosses |
independent assortment |
