bio quiz Flashcards
During cell division, the DNA in eukaryotic cells nucleus is coiled into compact structures called ______________
chromosomes
what is the middle of a chromosome called?
Centromere
what are the 2 endings of a chromosome called?
sister chromatid
are chromatins condensed or uncondensed
uncondensed
less tightly coiled DNA protein complex
chromatin
chromatin
less tightly coiled DNA protein complex
Human and anima chromosomes are categorized as either ____ chromosomes or _______ chromosomes
sex chromosomes or autosomes chromosomes
What do sex chromosomes do?
define the sex of the individual
what sex is XX?
Female
what sex is XY?
Male
how many sex chromosomes are there
23
how many autosomal chromosomes are there
44
what is a picture of the pairs of chromosomes arranged according to size
karyotype
what are body cells and somatic cells?
diploid
what does diploid mean
there are both chromosomes from each homologous pair
how many pairs do diploid cells have?
23 including a pair of sex chromosomes
what are sex cells?
haploid
what does haploid mean
they contain only one number of each homologous pair
when 2 haploid cells join together what is created?
a diploid cell
what is the division of a prokaryotic cell into two offspring cells
binary fission
how many stages are in binary fission
3
what happens the first stage of binary fission?
DNA replicates
what happens in the second stage of binary fission
DNA moves to opposite ends of the cell
what happens in the 3rd stage of binary fission
Cell splits into 2 new cells
for cell division in the EUKARYOTIC CELL, both the ______ and the ______ divide
nucleus and the cytoplasm
what cell division in eukaryotic cells produces new cells that are identical to the original cell?
Mitosis
what cell division in eukaryotic cells occurs during the formation of gametes?
Meiosis
what cell division in eukaryotic cells divides the chromosome # by half
meiosis
what cell division in eukaryotic cells focuses on growth, development, repair and asexual reproduction
mitosis
what is the time between cell divisions ?
Interphase
how many phases is interphase divided into?
3
what are the 3 phases of interphase
G1, S, G2
what occurs in G1?
cell growth
what occurs in S
DNA replication
what occurs in G2
preparation for cell division and cell growth
what phases do cells go to if they want to exit the cell cycle?
G1 and they enter G0
what is mitosis the division of?
the nucleus
how many phases is mitosis divided into
4
what are the 4 phases of mitosis
(PMAT) Prophase, Metaphase, Anaphase, Telophase
what happens in Prophase
the shortening and tight coiling of DNA into rod shaped chromosomes, they become visible and the nucleus breaks down and centrosomes move to opposite ends
what happens in Metaphase
chromosomes line up in the middle, centrosomes are on opposite sides and spindle fibers
what happens in anaphase
chromatids of each chromosome separate, after they separate they are individual chromosomes
what happens in telophase
chromatids move to opposite ends of the cell, 2 nuclei are formed and nucleus reforms
what is cytokinesis
splitting of the cytoplasm
where is the cleavage furrow in
animal cells
where is the cell plate
only in plant cells due to them being square
what is meiosis
the making of sex cells
diploid cells that divide by meiosis result in how many haploid cells
4
what are the first and second stages of meiosis cell division
Meiosis I and Meiosis II
what is the pairing of homologous chromosomes called?
synapsis
what is each pair of homologous chromosomes called?
tetrad
what is crossing over in meiosis
when genetic info gets exchanged
when does crossing over in meiosis occur
in prophase ! in meiosis
when can meiosis 2 being?
immediately after Meiosis 1
how many haploid cells are in spermatids
4 haploid cells
what is spermatogenesis
the process of making sperm
what is oogenesis
the process of making eggs
what are polar bodies
3 small cells made in oogenesis that disintegrate
1 parent —-> offsprings
offsprings are identical to parent + each other
Asexual reproduction
2 parents —–> offsprings
offsprings different than parent + each other
Sexual reproduction
