test 1 unit 2
what are the different base pair names
adenosine, thymine,guanin and cytosine
properties of eukaryotic DNA
linear shape
has histones/chromatids
DNA condensed into chromosomes
DNA supercoiling using histones
has nucleosomes
properties of prokaryotic DNA
circular shaped
doesnt have histones/chromatids
DNA condenses into chromosomes
DNA supercoiling (but less tight bc no histones
what are genes
sequences of bases located on chromosomes
what do genes do
code for specific proteins
which control traits/charactersistics
what are alleles
different forms of the same gene inherited from parents
this is shown in the letters or genotypes thag produce phenotypes
what is genome
all genetic information of an organism consisting of nucleotide sequences if DNA
includes both coding and non-coding genes
99% of DNA does what
does not code for protein
what is a genotype
an organisms complete set of heritable genes or genetic information
what is a phenotype
an organisms observable characteristics or traits (physical appearance, development, behaviour)
what are the sections of dna (genotype) inside the chromosome that code for smt called
loci or locus if multiple
what is half a chromosome long ways
telomere
what is half a chromosome short ways
chromatids
what is the little middle part of a chromosome called
centromere
what is a homologous chromosome
a pair inside a chromosome
they pair in cell division
some genes are in the same loci
one maternal and one paternal
what is an autosome
homologous or non-sex chromosomes
how many autosomes in human
22 PAIRS
how autosomes ordered
1-22 and 1 is biggest
what is an allosome
sex chromosome
pair of XX or XY (female/male)
who determines the sex of baby
male as passes on either X or Y
what is environmental sex determination
sex of baby can be affected by temp of egg incubated
nucleosome is
histone wrapped in DNA
what is karyotype
image of all an organisms chromosomes
P-arms
the chromosomes short arms (petite)
Q arms
the chromosomes longer arms (not petite)
metacentric meaning
centromere in middle
arms equal length
submetacentric meaning
offset centromere
Q 2x as long
acrocentric meaning
centro very close to one end
very long Q, very short P
telocentric meaning
telo means end
centromere at one end
no p arms
size of chromosome means what
correlates to number of genes
what does a karyotype show
an organised image of the chromosomes stained
this displays the size/shape/position
why do karyotypes
displays abnormalities
what are the abnormalities that a karyotype can outline
change in:
-total # of chromos
-part of one or more chromos
-arrangements of chromos
example of change in # of chromosomes
down syndrome which is example of trisomy (3 chromos instead of 2)
how is extra chromosome written
# of chromos, XX/XY, where extra is
eg 47,XY,+21
examples of changes to part of one or more chromos
turner syndrome (missing allesome)
klinefelt syndrome (extra allesome)
turner syndrome
missing allesome
medical and development issues
written as 46,X0 (zero)
klinefelt syndrome
extra allesome
body type changes such as mixed body types between genders
angelman syndrom
deletion of section/whole chromo
poor motod coordination/development delay
only from maternal
faulty chromo 15
how do chromosomal changes occur
non/disjunction
what is non-disjunction
when gametes have 2 copies of 1 chromo or lack a copy
causes imbalance
occurs during meiosis
abnormalities is autosomes
much more drastic
monosomy
non-variable embryo produced
meaning miscarriage
abnormalities in allesomes
less drastic
monosomy
can produce via offspring (such as klinefelt)
only non-variable type is 0Y bx X chromos are crucial and contain more info
diff types of changes to chromos
duplication
deletion
translocation
example of rearrangment of chromos
angelman syndrome which is deletion
what is deletion
part of chromo is missing
what is duplication
part of chromo is duplucated
what is translocation
one segment of chromo is transferred to another region (part of chromo 18 may be in chromo 5)
which cells are diploid (full set of chromosomes)
stomatic cells
not sex cells (gametes)
which cells are haploid (half set of chromosomes)
gametes (sex cells)
what is crossing over
in meiosis (prophase)
chromatids swap and overlap pieces(from each parent)
exchange chiasma
new combos
what is random assortment
source of genetic variation
homologous pairs randomly line up in middle of cell
diff between meiosis and mitosis
genetically diff haploid (n) cells are produced compares to two diploid (2n) cells in mitosis
what is mandelin genetics
the study of how traits are inherited
largely shown in pea plants as they were cross bread
key principles of mandelin genetics
law of segregation
law of dominance
law of independant assortment
what is the law of segregation
that each organism has two alleles (gene variants)
each segregate during meiosis (each gamete gets one)
what is the law of independant assortment
genes for diff traits assort independantly as gametes form
independant because one trait doesnt affect inheritance of other
what is the law of dominance
some alleles are dominant, some are recessive (dom masks recessive)
what is the law of dominance
how dom alleles mask recessive
what is a carrier
organism that is heterozygous (has a cope of recessive but dont show)
types of dominance
complete
incomplete
codominance
complete dominance
most common
dom masks recessive completely in heterozygous
incomplete dom
neither allele is completely dom
blended/intermediate phenotype (mix)
third pheno beteeen two homozygous forms
"blended inheritance" (traits)
codominance
both alleles fully/equally expressed
neither is dom/recessive
both appear (not blended)
what is a punnett square
a diagram used to predict possible outcomes of genetic cross
how parent alleles combine
helps predict rarios and all possible genotypes
monohybrid cross
genetic cross between two individuals
focuses on one trait
controlled by one gene (w/two alleles)
true breeding
homozygous alleles
multiple alleles
some have more than 2 alleles
such as ABO blood type
ABO blood types
all have mix of two
ABO system depicts mix of dom/recessive
ABO gene
chromosome 9
diff blood tupes form
A and B codom (why AB)
O is recessive
A blood can be
I^AI^A or I^A i
B blood can be
I^BI^B or I^B i
AB blood is
I^AI^B
O blood is
i i
internal enviro factors
hormones
metabolic activity
aging
sex
health care
external enviro factors
nutrition
temp
light exposure
chem/toxin exposure
social enviro (stress)
genotype + enviro is what
phenotype
Epigenetics
study of how cells w/identical genotypes can show didf phenotypes
what is the differences between epigenetics and mandelin
not due to diff base sequences of DNA
are stable in organism
sometimes can be transmitted actoss generations
factors of epigenetics
external to DNA, but acts on it
can turn genes off or on permanently
packaging of epigenetics
may be tight or open
tight=silenced (less expressed)
open =actuve/translated (protein)
how to express silenced
BB. instead of BB
labelling of DNA
like a "tag" (connects)
does not alter gene (but can silence/activate)
what is X-inactivation
when one of XX is deactivated (switching off all genes) caused by tags
this same X stays inactive then
what are imprinted genes
refers to those whose expression affected by parents
small defection on #15 chromo
what does imprinted genes show
if from father its prader will syndrom
if from mother is angelman syndrome
example of chemical action
vinclozdin (commercial fungicide)
interferes wjrh sperm production
inherited several generations
what is a pedigree chart
a representation of a familys genetic lineage (for particular trait)
shaded is has trait (circul is woman) half shaded or shaded a bit is carrier
autosomal dom trait
male/female equally affected
all affected have atleast one affected parent
once gone, gone forever
can be passed mat/paternal
autosomal recessive traits
male/female equally affected actoss large pedigree
unaffected parents can have affected child
if both parents have, child does too
can skip gens
autosomal trauts carriers
both men and women
x linked traits
only heterozygous females can be carriers (males will express bc only one X)
sex-linked inheritance
some genes linked to sex chromosome
Y-linked is possible but uncommon
what differs a monohybrid cross from a dihybrid cross
a dihybrjd cross has two traits instead of one
what does a dihybrid cross help us with
understanding
how genes for diff traits are inherited tigether
linked dihybrid cross meaning
the same chromosome and same locus as they ade not independant
unlinked dihybrid cross meaning
independant traits
shown in a semi colon
eg Aa;Bb
diff loci
how many boxes in a dihybrid cross
16
all combos of the two sets of traits on top and side (eg BBLl means BL, Bl etc)
where linked genes located
on one chromosome
which form a linkage group
how many linkage groups
haploid number of chromosomes