Unit 5 Flashcards
Meiosis
cell division for sex cells that makes unique daughters instead of the identical ones made during mitosis
Diploid
two whole sets of chromosomes, one of each is from a different parent
Haploid
only a single set of chromosomes
Meiosis 1
creates two daughter cells that have HALF THE NUMBER OF CHROMOSOMES as the parent cells
Meiosis 2
number of chromosomes DOESN’T change, creates two more daughter cells
Maternal chromosomes
has 23 chromosomes in each egg, these get incorporated into the child which will have 46 total chromosomes
XX
Paternal chromosomes
has 23 chromosomes in each sperm, these get incorporated into the child which will have 46 total chromosomes
XY
Homologous chromosomes
the chromosomes that are paired together, each one is from a parent and they carry similar gene content/information, even if the specifics are slightly different for the different traits.. similar not identical
Crossing over
the exchange of genes between two chromosomes which then makes the chromatids different (chromatids are the two lines that make the x that is the chromosome)
HAPPENS DURING PROPHASE 1 OF MEIOSIS
Recombination
RESULT OF CROSSING OVER
HAPPENS DURING PRO 1
happens when DNA from the mom and dad genes are exchanged to create a new combination for the kid
Genetic diversity
how much genetic variation is there between organisms of the same species
Independent assortment
how genes are distributed is independent - basically the allele for one gamete doesn’t affect the allele received for another gamete
all possible combinations of alleles for each gene is EQUALLY POSSIBLE and likely to occur
Gametes
just any reproductive cells like sperms or eggs
Sexual reproduction vs asexual reproduction
Basically meiosis and mitosis respectively
meiosis - makes unique daughters
mitosis - makes identical daughters
Fertilization
fusion of a sperm and egg cell
Zygote
what is created after fertilization, it is a single cell that is the result of the fusion of a sperm and egg cell
Mendel’s law of segregation
When gametes form, each gene separates so that there is only one allele for each gene
Basically, the organism gives the gamete only ONE copy of one of its genes.
Mendel’s Law of independent assortment
alleles of different genes get sorted into gametes independently of each other
so receiving one allele for a gene doesn’t affect the allele that the gamete receives for other genes.
Allele
one of the two pieces of genetic information that makes up a gene
basically represents the genotype of a specific gene
(Pp or Aa Bb etc.)
Gene
it is information that calls for a specific trait, and it is made up of two alleles (one from each parent )
Dominant
a trait that will be expressed if at least one parent passes it on
Recessive
for it to be expressed both parents would need to pass it on
Genotype
basically what the combination of alleles looks like
homozygous = same alleles
heterozygous = different alleles
Phenotype
the physical properties of an organism, basically how the genotype is shown physically
Wild type vs mutant
wild type - what the phenotype of species would like normally and naturally
mutant - when alleles mutate the species may look different
Monohybrid cross
cross between two organisms that have homozygous genotypes
Dihybrid cross
cross between two organisms that are heterozygous in the same way
Sex-linked
determined by genes that are on the sex chromosomes like XX and XY
Gene linkage
genes closer together are usually linked and get inherited as a unit
Pedigree
a system that is used to analyze the patterns of inheritance, usually of specific traits
Incomplete dominance
Where both alleles are partially expressed
think allele for red and allele for white both being expressed resulting in pink phenotype
Codominance
where both alleles are expressed equally, neither is dominant or recessive
think speckled cats, the two colors are expressed equally
Multiple alleles
the different versions of a trait that exist
like fur color is one gene but there are many different types of alleles
mtDNA (mitochondrial DNA)
circular chromosomes found inside the mitochondria
Non-nuclear inheritance (maternal inheritance of chloroplast and mitochondria)
inheritance of genetic material from DNA found in cytoplasm
Sperm
gametes from the father
Egg
gametes from the mother
Plant ovule
kind of equivalent to eggs in other organisms
Plant pollen
equivalent to the sperm of other organisms
Nondisjunction meiosis 1 vs Meiosis 2
M1: when cells divide during this, there are unusual numbers of chromosomes in the two cells that will then enter m2 (like one chromosome in one cell and three in the other)
M2: receives normal amounts of chromosomes in each of the two cells from m1 but then during division of m2 some chromosomes don’t split so the four daughter cells made from m2 have uneven amounts of chromosomes
