science topic 3 test Flashcards
what is mitosis
The process of cell division where one parent cell turns into two identical daughter cells
reasons for mitosis
- For growth and development
2.For repair/replacement of cells that die from injury or normal wear and tear
3.for asexual reproduction
Interphase
Cell increases in size
organelles are copied
DNA is copied
* Majority of the cells life is spent in the phase
prophase
DNA condenses into chromosomes and become visible centrioles more to the poles
nucleus and nuclear membrane breakdown
metaphase
Chromosomes line up in the center of the cell
Anaphase
centromeres split,allowing sister chromatids to separate
chromatids move to opposite poles
*phase ends when motion stops
telophase
nuclear membrane reforms
nucleolus reappears
chromosomes unwind back into loose DNA
* Technically the end of mitosis which copies the nucleus
cytokinesis
division of the cytoplasm in the cytoplasm to form two daughter cells
what is meiosis
the process of reducing the number of chromosomes within a specialized cell for the purpose of sexual reproduction.
gametes
sex cells
haploid cells
- One set of chromosomes
-contain half the genetic material to make an organism
(n)
diploid cells
2 sets of chromosomes
- cells have a full set of chromosomes
(2n)
prophase 1
chromosomes are copied
crossing over occurs
crossing-over/recombination
Genes from different chromosomes mix
metaphase 1
Homologous chromosomes line up in the center of the cell
independent assortment occurs
independent assortment
maternal and paternal chromosomes separate
Anaphase 1
homologous chromosomes separate
telophase 1
nuclei reform
cytokinesis 1
cell splits in half
prophase 2
nucleus membrane disappears
new spindle fibers form
centrioles move to the poles
chromosomes are not copied
metaphase 2
chromosomes line up in the center
anaphase 2
chromatids separate
telophase 2
nuclei refoms
cytokinesis 2
cells split in half
what is sexual reproduction
production involving 2 parents,where offspring are genetically unique .
reproduction is the formation for new individuals-important for the survival of the species,but not necessary for the individual organism
what does the reproduction system do
produces,stored,and releases specialized sex cells (gametes) that have half the information needed to make a new organism
Male reproduction system
main function of the make reproduction system is to produce and deliver sperm
FSH and LH cause the testes in males to produce testosterone
testosterone will start to produce male characteristics in puberty
female reproductive system
primary organs are the ovaries which releases eggs an also prepare a woman’s body to nourish a developing embryo
FSH and LH cause the ovaries in females to produce estrogen
estrogen will produce female characteristics in puberty
Steps to sexual reproduction
Meiosis produces gametes
Gametes united to form a diploid zygote
zygote undergoes mitosis to grow
cells differentiate
Differentiate
cells specialize
all cells have the same DNA
each type uses a different part of DNA
Placenta
supplies oxygen and nutrients and removes carbon dioxide and waste from the fetus
maternal and fetal blood do not mix
all transfer happens by diffusion
Plant reproductive system
Plant reproductive organs are found within their flowers perfect flowers have both male and female reproductive parts
imperfect flowers
have either male or female reproductive parts
monoecious plants
have both male and female reproductive organs in the same individual
Dioecious plants
have separate male and female individuals
Pistil
female parts of a plant
-Stigma
-Style
-Ovary
stamen
male parts of a plant
Anther (makes pollen)
filament
Pollination and fertilization
1.pollen must get from the anther to the stigma
2.once on the stigma, a pollen tube grows from the pollen grain down the style to the ovule to deliver sperm to the egg
3.after fertilization the ovary develops into fruit to assist in dispersal
