Studied by 7 peoplewho was gregor mendel?
the “father of genetics”
define: chromatin
dna in thin strands
define: chromosome
chromatin coiled around protein forming an X shape
what does a chromosome consist of?
two sister chromatids joined by a centromere
define: gene
a DNA segment that codes for a trait
define: character
an inheritable physical feature
define: trait
a variation of a character
define: allele
a different version of a gene
define: dominant allele
the stronger gene that physically shows on an organism
define: recessive allele
the weaker gene that does not physically show on an organism
define: homozygous
the organism either has two dominant alleles or two recessive alleles
define: heterozygous
the organism has one dominant and one recessive allele
define: phenotype
the physical trait that can be seen
define: genotype
the genetic combination for a trait
define: punnett square
a chart showing possible genetic outcomes for a child
where does the mothers genotype go on a punnett square?
the left side
where does the fathers genotype go on a punnett square?
the top
define: mendels law of segregation
to separate the two alleles of one parent
define: law of independent assortment
chromosomes line up independently from each other so that genes from different chromosomes do not affect each other
when does the law of segregation occur?
during anaphase 1 and 2 of meiosis
when does the law of independent assortment occur?
during metaphase 1 and anaphase 1 of meiosis
define: complete dominance
the dominant allele is only expressed all the way
define: incomplete dominance
both alleles are expressed and blended together
define: codominance
both alleles are expressed and are equally present but separate
define: multiple alleles
when there are multiple versions of the same allele
define: pedigree
a chart showing the family history of a specific trait
what shape are males in pedigrees?
squares
what shape are females in pedigrees?
circles
what does it mean when a shape on a pedigree is shaded in?
that person has the trait
what does a horizontal line between two people mean on a pedigree?
a breeding couple
what does a vertical line between two people mean on a pedigree?
offspring
name a recessive disorder
cystic fibrosis, sickle-cell disease
name a dominant disorder:
dwarfism, huntingtons disease
define: locus
the location of a gene on a chromosome
define: genome
organisms complete dna sequence
define: asexual reproduction
one parent making a clone of itself
name benefits of asexual reproduction
quick reproduction, only one parent needed
name disadvantages of asexual reproduction
no genetic variation, massive death rate
define: sexual reproduction
two parents combining dna resulting in different offspring
name benefits of sexual reproduction
variation in offspring, evolution over time
name disadvantages of sexual reproduction
takes two parents, takes longer
define: somatic cells
regular body cells
how do somatic cells reproduce?
mitosis
define: germ cells
sex cells
how do germ cells reproduce?
meiosis
define: trisomy
too many chromosomes
define: monosomy
too few chromosomes
why are microinsertions and microdeletions hard to see on a microscope?
they’re too small
define: homologous
identical chromosomes
define: heterogous
chromosome pair that is different
does mitosis make haploid or diploid cells?
diploid
does meiosis make haploid or diploid cells?
haploid
define: haploid
having only one set of chromosomes
define: diploid
having two sets of chromosomes
what happens in meiosis 1?
the 46 chromosomes are separated
what phases are in meiosis 1?
interphase, prophase, metaphase, anaphase, telophase
what happens in meiosis 2?
the sister chromatids are separated into four daughter cells
what phases are in meiosis 2?
prophase 2, metaphase 2, anaphase 2, telophase 2, cytokenisis
define: crossover
the male and female chromosomes swapping genes
when does the crossover occur?
prophase 1
what is the purpose of crossover?
genetic variation
how has genetic variation evolved?
prophase 1-crossover, metaphase 1-independent assortment, anaphase 1-law of segragation
define: sex linked gene
genes only passed down through x sex chromosome
is colorblindness dominant or recessive?
recessive
what kind of disorder is colorblindness?
sex linked
is hemophilia recessive or dominant?
recessive
define: karyotype
a picture of all a persons chromosomes
when is karyotype taken?
metaphase
how many pairs of chromosomes do humans have?
23
what is the first step to creating a karyotype?
collect cells and place in petri dish, add cyclin and make cells go into mitosis
what is the second step to creating a karyotype?
allow cells to continue dividing until metaphase, then add chemical to stop mitosis
what is the third step to creating a karyotype?
add dye to chromosomes to stain genes and create banding pattern
what is the fourth step to creating a karyotype?
take picture of chromosomes through microscope
what is the fifth step to creating a karyotype?
cut out chromosomes and arrange them largest to smallest
what is the first step in interpreting a karyotype?
length of chromosomes
what is the second step in interpreting a karyotype?
centromere position
what is the third step in interpreting a karyotype?
banding pattern
what is the fourth step in interpreting a karyotype?
locus of gene
define:
telocentric
define:
acrocentric
define:
submetacentric
define:
metacentric
define: top and short arm of a chromosome
p arm
define: bottom and long arm of a chromosome
q arm
define: aneuploidy
having the wrong number of chromosomes
define: polyploidy
having many extra sets of chromosomes
define: 3N
three sets of each chromosome
define: 4N
four sets of each chromosome
define: part of a chromosome segment is missing
deletion
define: a chromosome segment was copied twice. two genes on the same chromosome and one missing on the other
duplication
define: a chromosome segment is backwards
inversion
define: a chromosome segment is attached to a different autosome; not where it should be
translocation
what is the first stage of mitosis?
interphase
what is the second stage of mitosis?
prophase
what is the third stage of mitosis?
metaphase
what is the fourth stage of mitosis?
anaphase
what is the fifth stage of mitosis?
telophase
what is the sixth stage of mitosis?
cytokenesis
what are the three sub-stages of interphase?
G1, S, G2
what happens in interphase?
growth, copy DNA, self check
Note
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