mitosis, meiosis monohybrid crosses

mitosis

mitosis

somatic cells
2 daughter cells
each cell has 46 chromosomes
diploid (doubled) sets of chromosomes
identical cells

meiosis

gametes
4 daughter cells
each cell has 23 chromosomes
haploid (half) number of chromosomes
genetically diverse

cell cycle

the life of a cycle from its original division from a parent cell until its own division into two daughter cells

4 phases of cell cycle

G1- recognizes
G2- condense chromatid
S- chromatid doubles
mitosis- division of cell

chromosomes

tightly packed coils of DNA molecules

centromere

keeps sister chromatid together in the middle

sister chromatids

original and copy together

interphase

cell gets the response that it is time to divide; only happens with mitosis and meiosis 1 -NOT MEIOSIS 2-

stage G0

when cell is doing its job

stage G1

cells gets ready to divide chromosomes

stage S

DNA synthesize (reproduce) making a copy

stage G2

prepare organelles for two new cells

check point system

three major check points are G1, G2, and mitosis; check points use cyclin and kinase enzymes; if any abnormalities are found, cell will abort

mitosis- prophase

nuclear envelope disappears
chromatid condenses to chromosomes
spindle apparatus forms

mitosis- metaphase

chromosomes line up on the middle equator so sister chromosomes are separated equally

mitosis- anaphase

sister chromosomes pull apart
each chromosome is now called daughter cells
daughter chromosomes move to opposite poles

mitosis- telophase

nuclear envelope reappears
chromosomes turn into chromatid
spindle apparatus disappears

homologous chromosomes

pairs of chromosomes that carry genes that control same inherited characters

synapse

the pairing up of homologous chromosomes

tetrad

when a mother and father chromosome line up creating 4 chromosomes

meiosis 1- prophase

homologous chromosomes find each other creating a tetrad

meiosis 1- metaphase

tetrads line up on equator

meiosis 1- anaphase

homologous chromosomes separate keeping sister chromosomes together

meiosis 1- telophase

results in 2 new haploid daughter cells that are genetically different

meiosis 2- prophase

4 chromatid are in each cell because cells have double chromatid temporarily

meiosis 2- metaphase

chromosomes that are genetically different line up on the equator

meiosis 2- anaphase

sister chromosomes separate

meiosis 2- telophase

results in 4 haploid daughter cells that are genetically different

cell plate

formed to separate plant cells during telophase

genes

units of heredity and are made up of segments of DNA

gametes

sex cells that pass down genes from generation to generation

autosomes

chromosomes 1-22 everyone (has the same ones)

sex chromosomes

XX-female XY- male

diploid

2 copies of chromosomes

haploid

1 copy of chromosomes

homologues

same chromosomes- 1 from mom 1 from dad

stem cells

undifferentiated cells

Gregor Mendel's major discoveries

traits were encoded in units (now called genes)
genes transmitted hereditary information
codominance, independent assortment, and segregation

true breeding

pure bred

hybrid

mutt

P generation

parents

F1 generation

children

F2 generation

grandchildren

alleles

gene pairs (one of each homologous chromosomes)

dominant allele

once dominant allele is present it is always been expressed

recessive allele

only expressed if not masked by a dominant allele

homozygous allele

can be dominant or recessive but both alleles are the same

heterozygous alleles

alleles are different, one dominant one recessive

genotype

the genetic makeup of an individual (DD, Dd, dd)

phenotype

the physical expression of the traits

law of segregation

each gamete carries only one allele because alleles are segregated during anaphase

law of independent assortment

during metaphase 1, chromosomes are assorted randomly

monohybrid cross

one trait to be distributed

test cross

purebred crossed with hybrid

codominant alleles

heterozygotes express both alleles (curly+straight=curly-straight) (type A+ type B = type AB)

incomplete dominance

the heterozygote shows an intermediate trait (curly+straight=wavy)

multiple alleles

genes may exist in more than 2 allele forms

type O

ii

pleitrophy

many outcomes

epistasis

one gene controls many traits

polygenic trait

many traits control one gene

autosomal recessive disorders

the recessive behavior of the alleles causing these conditions occurs because the allele codes for a malfunctioning protein or for no protein at all.

Phenylketonuria

an autosomal 12 mutation that results in the lack of the enzyme the converts phenylketonuria to tyrosine

cystic fibrosis

autosomal 7 disorder where the dene that codes for a chloride ion channel I the cell membrane is defective; causes mucous coats and poor absorption of nutrients

sickle-cell disease

autosomal 11 mutation that causes the shape of the sickle-cell hemoglobin aggregate into long rods that deform RBC into a sickle shape

Huntington's disease

dominant- alleles found on chromosome 4 causes genes to produce abnormal protein that accumulates in neurons- attracting the clumping other essential proteins