Cell/Organism Reproduction Flashcards
Module 7
Cell division occurs for
growth
cell replacement
healing
reproduction
Prokaryotic cells divide by what process
binary fission
these cells divide by mitosis and cytokinesis
Eukaryotic cells
Tow main requirements for cell division
1.) 2 daughter cells must receive full complement of genetic material in the single parent cell
2.) the parent cell must be large enough to divide into two and still contribute sufficient cytoplasmic components to each daughter cell
What are the 6 steps in binary fission
1.) circular bacterial DNA molecule is attached by proteins to inner membrane
2.) DNA replication begins at the specific location and proceeds in 2 directions around the circle
3.) the new DNA molecule is also attached to the inner membrane near where the initial molecule attached
4.) as replication proceeds, the cell elongates symmetrically and separates the DNA attachment sites
5.) cell division begins with the synthesis of a new membrane and wall material at the midpoint
6.) continued synthesis completes the constriction and separates the daughter cells
What is the cell cycle for eukaryotes
1.) M phase
(mitosis and cytokinesis -> parent cell divides into two daughter cells)
2.) g1 phase (gap 1)
3.) s phase (dna synthesis)
4.) g2 phase (gap 2)
interphase is the time between two M phases (therefore from g1-g2)
how long does interphase last for
10-14 hours
What happens during interphase?
preparations for cell division
the number and shapes of chromosomes representative of a species is called its
karyotype
T/F most humans have 46 chromosomes (23 pairs)
true
How many pairs of sex chromosomes are in the human body
1
During the s phase, centromeres become
sister chromatids
what are the 5 stages of mitosis
1.) prophase
- chromosomes condense.
- centrosomes radiate microtubules and migrate to opposite poles
2.) Premetaphase
- microtubules of the mitotic spindle attach to the chromosomes
3.) Metaphase
- chromosomes align in the center of the cell
4.) Anaphase
- sister chromatids separate (becoming individual chromosomes) and travel to opposite poles
5.) telophase
- nuclear envelope re-forms and chromosomes decondense
Meiotic cell division results in how many daughter cells
4
What are the 5 stages of meiosis 1
1.) chromosomes become visible
2.) homologous chromosomes continue to condense and undergo synapsis
3.) once synapsis is done, each pair of homologous chromosomes form a bivalent. each chromosomes consists of 2 sister chromatids
4.) the chromosomes continue to shorten and thicken
5.) the nuclear envelope begins to break down
What are the 5 stages of meiosis 2
1.) Prophase 2
- nuclear envelope breaks down
- chromosomes condense
2.) Prometaphase 2
- spindles attach to kinetochores on chromosomes
3.) Metaphase 2
- chromosomes align in center of cell
4.) Anaphase 2
- sister chromatids separate
5.) Telophase 2 and Cytokinesis
- the nuclear envelope re-forms and cytoplasm divides
What happens during fragmentation
new individuals arise asexually by splitting one of the organisms into pieces which can become a new individual
what happens during parthenogensis
asexual reproduction where the females produce eggs that are not fertilized by males but divide by mitosis and develop into new individuals
what is the two fold cost of sex
John Smith; if an individual reproduces and has 2 offspring asexually, the population will grow ever generation but if it were done sexually, the population size would not grow
what are R strategists
have many offspring without parental investment (external fertilization usually)
what are K strategists
have ew offspring but put a lot of parental investment (internal fertilization usually)
What is gametogensis
formation of gametes. same steps in both male and female but the timing is different
describe the steps in spermatogensis
spermatogonia -> into diploid primary spermatocytes -> secondary spermatocytes -> four haploid spermatids joined by cytoplasmic bridges -> spermatids turn into spermatozoa (mature)
takes 2-3 months
Describe the process of oogenesis
diploid precursor cells (oogonia) from during embryonic development (divide via mitosis)
What is IVF
in vitro fertilization = process where eggs and sperm are brought together in a petri dish and fertilization occurs
describe the development of an embryo
zygote -> two-cell stage -> four-cell stage -> morula -> blastocyst -> embryo
What is a stem cell?
cells able to make other kinds of cells besides it own
what are some promises of stem cells
bone marrow transplants
parkinsons disease
alzheimers diseas
heart failure
diabetes
burns/wounds
spinal cord injury
