test 7- heredity Flashcards
gene
a section of DNA that provides the instructions for many making a protein
alleles
different versions of the same gene
homologous chromosomes
the matching chromosomes from our mom and dad
homozygous
2 of the same (ex. AA or aa)
heterozygous
2 different alleles (ex. Aa)
dominant
if present, allele will always have that trait expressed/ seen
recessive
allele will only have that trait expressed when the dominants allele not present
genotype
the actual alleles inherited (ex. genes that code for the flower color such as FF, Ff, or ff)
phenotype
the physical traits/ characteristics seen in an organism (ex. purple flowers)
punnett square
a diagram that shows the probability of inheriting trait from parents with certain genes
monohybrid cross
a cross between two organisms looking at one trait
dihybrid cross
used when finding the possible genotypes of roffspring when considering 2 traits at the same time
law of dominance
a dominant (strong) allele will express itself over a recessive (weak) allele
law of segregation
when chromosomes separate in meiosis, each gamete (egg or sperm) will receive only 1 chromosome from each pair)
law independent assortment
the assortment of chromosomes for 1 trait doesn’t affect the assortment of chromosomes for another
what kind of genotype and phenotype would this be if b was blue and B was brown:
BB
homozygous dominant, brown eyes
what kind of genotype and phenotype would this be if b is blue and B is brown:
bb
homosygous recessive, blue eyes
what kind of genotype and phenotype would this be if b is blue and B is brown:
Bb
heterosygous, brown eyes
how many alleles do you have for one gene?
you have 2 alleles for each gene
where do these alleles come from?
1 from mom and 1 from dad
list mendels three laws of inheritance
-law of dominance
-law of segregatoin
-law of independent assortment
chromosome theory of inheritance
genes are located on the chromosomes and the behavior of the chromosomes during meiosis accounts for inheritance patterns
incomplete dominance
the heterozygous phenotype is somewhere between the 2 homozygous phenotypes, niether allele is dominant or recessive
codominance
both traits are fully and separatley expressed (ex. blood type- AB is fully A and fully B)
multiple alleles
having more than 2 alleles for one gene (ex. alleles for blood type = A, B, and i)
polygenic traits
a trait that produced by two or more genes, usually shows a range in phenotype (ex. height, eye color)
linked genes
genes that are physically located on the same chromosome will be inherited together
epistatsis
when one gene overshadows another gene and blocks the output
carrier
a person that has the gee for a trait or diseas but doesn’t show it
in codominance, what represents the alleles?
two separate letters- ex. A and B
in incomplete dominance, what represents the alleles?
same capital letter, one with a prime- ex. H and H’
what is a real world example for incomplete dominance?
red and white flowers make pink
what is a real world example of codominance?
blood type AB is fully A and fully B
what is real world example of multiple alleles?
blood type- alleles of A, B, and i
what is a real world example of polygenic inheritance?
height
what is a real world example of linked genes?
blonde hair and blue eyes
what inheritance pattern is this: two people have 5 kids with a range of personalities.
polygenic inheritance
what inheritance pattern is this: a black horse and a white horse make a gray horse.
incomplete dominance
what inheritance pattern is this: duchene muscular dystrophy is a disease most common in males.
sex- linked genes
what inheritance pattern is this: red hair and freckles are almost always inherited together.
linked genes
what inheritance pattern is this: a black horse and a white horse make a spotted horse.
codominance
what is the difference between traits inherited on sex chromosomes and traits on autosomes?
sex chromosomes give you your biological sex and sex linked genes while autosomes give you traits that make you who you are and linked genes
mutation
any change in DNA (the order of nucleotide bases/ letters)
mutagen
chemicals that can cause DNA mutations (ex. radiation)
gene mutation
happen during DNA replication and cause a change to the orginal DNA sequence
point mutations
substitute 1 nucleotide for another (ex. sickle cell anemia)
frameshift mutations
the insertion or deletion of a nucleotide (ATTACC–>ATACC)
chromosomal mutation
often happen during meiosis, changing the number or location of genes (ex. Down Syndrome)
duplicaton
changes the size of chromosomes and results in multiple copies of a single gene
translocation
pieces of non-homolgous chromosomes exchange segments (during crossing over)
nondisjunction
chromosomes do not separate correctly during anaphase, resulting in 1 or 3 chromosomes per cell
pedigree
chart used to trace the pheotypes and genotypes in a family to determine whether people carry diseases or not
is a mutation in a somatic cell or gamete worse or why?
gamete because with a somatice cell it will only affect that cell/ part of the body but with the gamete every cell in the offspring’s body will have it
is a gene mutation or chromosome mutation worse and why?
a chromosome mutation because there are many genes on one chromosome so it affects more
what is an example of a mutagen?
cigarette smoke
what is an example of a disorder caused by nondisjunction?
down syndrome
what is an example of a disoreder cause by a gene mutation?
cystic fibrosis
what is an example of a disorder caused by a chromosomal mutation?
turner’s syndrome
