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Genetics
CP Bio Genetics
Question | Answer |
---|---|
what does homozygous mean? | two of the same alleles |
what does heterozygous mean? | two different alleles |
what does homozygous dominant mean? | two dominant alleles |
what does homozygous recessive mean? | two recessive alleles |
what is an allele? | a version of a genetic trait |
what is genetics? | the study of inheritance/heredity |
who is the father of modern genetics? | Gregor Mendel |
what is genotype? | the alleles an organism has- the "letters" |
what is phenotype? | the expression of the organism's alleles - the "looks/traits" |
what is a mutation? | a change in the DNA |
are all mutations harmful? | no- some are harmful, some are beneficial and some don't cause any noticeable changes. |
what is another word for regular chromosomes? | autosomes |
what is another phrase for the X and Y chromosome? | sex chromosomes |
how many alleles typically control a trait? | two |
how many alleles control blood type? | three |
when a trait is controlled by more than 2 alleles it is an example of _____ inheritance. | multiple alleles |
what do you call a diagram of several generations of family members that shows the occurrence of certain genetic characteristics? | pedigree |
what do you call a diagram that shows the genotypic and phenotypic outcome of crosses between two organisms? | punnet square |
why do sex-linked diseases show up in males more than females? | females can be a carrier (and not have the disease) but since males only have on X chromosome they cannot be a carrier. They either have the sex-linked disease or they dont |
what gender is XX | female |
what gender is XY | male |
who determines the sex of the child? | dad - he is the only one that can pass down a "y" chromosome |
in a testcross the unknown genotype is crossed with... | a homozygous recessive individual. |
why are testcrosses done? | to determine an unknown dominant genotype |
what is a dihybrid punnett square? | one that shows two traits being tracked |
what is a monohybrid punnett square? | one that shows one trait being tracked |
complete dominance | when heterozygoous and homozygous dominant individuals have the same phenotype |
incomplete dominance | when an individual displays a trait that is intermediate (blended) between the two parents |
codominant | when both alleles for a trait are expressed in a heterozygous individual. |
law of segregation | when the two alleles for the same trait separate when egg/sperm are formed |
law of independent assortment | the alleles of different genes separate independently of one another during the formation of egg/sperm |
germ cell or gamete | egg or sperm |
sex-linked trait | a trait on a sex chromosome |
linked gene | genes that are inherited together (are very close together on a chromosome) |
give an example of linked genes in humans | red hair and freckles |
chromosome map | a map of genes on a chromosome. |
if genes are only a few map units apart then they are probably... | linked genes |
germ-cell mutation | mutations that do not affect the person but occur in their sex cells so they can be passed down to that person's offspring |
somatic-cell mutation | mutations that affect the person but are not passed down to that person's offspring |
give an example of a somatic-cell mutation | some types of skin cancer (you can get from overexposure to the sun) |
deletion mutation | loss of a piece of a chromosome |
inversion mutation | when a chromosome segment breaks off, flips around, and reattaches |
translocation mutation | when pieces of NON-homologous chromosomes break off and reattach to each other |
nondisjunction | when a chromosome fails to separate correctly and one gamete receives an extra copy of a chromosome while the other receives no copy. |
which type of mutation causes down syndrome? | nondisjunction at the 21st chromosome |
point mutation | a change at one single gene |
frameshift mutation | a deletion that causes the entire reading frame a gene to shift and no longer "make sense" |
what type of mutation is a "substitution" | point mutation |
what type of mutation is a "insertion" | frameshift mutation |
pedigree | family tree that can show genetic traits |
polygenic | traits influenced by several genes |
give examples of polygenic traits | eye color, hair color, intelligence, height, skin color... |
what do you call the field of study that looks "above the genome" to see how the environment changes an organism's DNA? | epigenetics |
sex-influenced trait | a trait that is influenced by a gender's hormones |
give an example of a sex-influenced trait | "pattern baldness" is more prevalent in men because they have more testosterone. the testosterone interacts with the gene to produce baldness. |
what are two ways genetic counselors can test a pregnant woman for genetic conditions? | amniocentesis and chorionic villus sampling |
what molecule can turn off and on genes? | methyl groups |
when are some critical times during a person's life that their epigenome might change? | puberty and pregancy |
what are some factors that can cause changes in the epigenome? | stress, diet, exercise, chemicals in the environment. |
are changes in the epigenome reversible? | yes |
how does a mother rat grooming/licking her pups affect the pup's epigenome? | more grooming turns on a gene that is beneficial to mice health. |