genetics test 2 Flashcards
what’s sexual reproduction
two parents create offspring that are unique, not identical to either parent
whats asexual reproduction
one parent produces offspring that are genetically identical to itself-clones
what does sexual reproduction require
sperm and egg
how many chromosomes do body cells have
46
how many chromosomes do gametes have
23
what does 1n+1n=2n represent
23 chromosomes from dad pls 23 from mom make 46 chromosomes
what are gametes made with
meiosis
what is PMAT
prophase, metaphase, anaphase, telephase
homologous chromosomes are separated into how many cells in meiosis
4
what is a haploid
when a cell contains half the number of a full set of chromosomes
what is a diploid
when a cell contains a full set of chromosomes
what is an example of a haploid
gametes
whats a centromere
where the two chromatids of a chromosome are joined together and where spindle fibers attach during cell division
what happens during interphase for meiosis
It’s the resting phase, 1 round of DNA replication
what are the parts of interphase
G1- growth, S- Dna replication, G2- more growth
what happens in prophase 1
spindle fibers begin to form, crossing over occurs
what are homologous chromosomes
chromosomes that contain the same genes, but may have different versions of the same gene
what happens in crossing
chromatids of the homologous cross over one another and are exchanged
why is crossing over important
it adds variation to the chromosome combination and causes the 4 haploids to be unique
what is a tetrad
a pair of two homologous chromosomes .
what happens in metaphase 1
chromosomes move to the middle of the cell
when does independant assortment occur
metaphase 1
what happens in independant assortment
chromosomes line up along the metaphase plate randomly
what does independant assortement help ensure
genetic variation
what happens in anaphase 1
homologous chromosomes are separated and pulled to opposite sides of the cell
what happens in telophase 1
nuclear membrane forms around each cluster chromosomes
what happens in cytokinesis 1
cytoplasm divides to form 2 new daughter cells
what happens in prophase 2
spindles reform and chromosomes become visible
what happens in metaphase 2
chromosomes line up along the center of the cell
what happens in anaphase 2
chromosomes are separated and chromatids move to opposite sides of the cell
what happens in telophase 2
nuclear membrane forms around each cluster of chromosmes
what happens in cytokinesis 2
both cells divide and form 4 haploid daughter cells
how many times does the parent cell divide in meiosis
twice
what are the main 5 chromosomal mutations
deltions, inversion, translocation , non disjunction, duplication
what happens in deletions
piece of chromosome is ost due to breakage
what happens ininversion
chromosome segment breaks off, segment flips around backwards, segment reataches backwards
what happens in duplication
makes it longer when a gene sequence is repeated
what happens in translocation
two chromosomes that aren’t homologous cross over
what happens in non disjunction
failure of chromosome separating that result in gametes having too many or too little chromosomes
what are examples of disorders caused by non-disjunction
down syndrome, turner syndrome, klein felter’s syndrome
whats a monosomie
when theres one one chromosme instead of two in a pir
whats a trysomie
when theres 3 chromosomes instead of 2 in a pair
what happens in down syndrome
a trysomie in the 21st pair of chromosmes
whats a monohybrid cross
crossing only one gene
what a dihybrid cross
crossing two genes
how many alleles does every gene have in mendelian genetics
2
what’s an allele
a diffrent form of a gene
what’s a trait
a characteristic encoded by a gene
what are alleles represented by
ltters
what’s dominant
type of allele that may mask the effect of others
what type of letters are dominant
capital letters
what’s recessive
type of allele that may be masked by others
what type of letters are recessive
lower-case
what’s a genotype
the alleles represented by letters
whats a phenotype
the genotype expressed in a trait
how do you write ratios for a punnet square
don’t simplify
what homozygous
two of the same alleles in a pair
what hetrozygous
two diffrent alleles in a pair
what is incomplete dominance
the blending of traits
example of incomplete dominance
red and white flower make purple
what is codominance
two dominant alleles expressed at the same time
example of codominance
black and orange make black and orange stripes
multiple alleles
when some genes have more than two possible alles
what are the blood types
a, b, ab,o
what do blood types refer to
the diffrent proteins on the surface of red blood cells
which blood type is considered universal
type O
are blood types inherited
yes
what are blood types example of
codiminance and multiple alles
