Unit 4: Heredity Notes

The term agglutination is used to describe what happens to red blood cells when incompatible blood types are mixed

-clumping of red blood cells when complimentary antibodies bind to them -blood clumping=blood clots--> heart attacks, strokes, and infarction

common patterns of recessive traits

-horizontal patterns of inheritance meaning that there usually are multiple affected individuals within a generation -often skips generations so the trait may appear after several generations of unaffected individuals

common characteristics of sex linked recessive gene

-occurs more often in males than in females -often skips generations through female carriers (heterozygote). All of the daughters of affected males are carriers -*Remember to use Xs and Ys to find genotype

complete dominance

-the heterozygote shows the dominant phenotype

common patterns of dominant traits

-vertical patterns of inheritance meaning that there is an infected individual in each generation

Why can people with AB+ blood type receive blood from everyone? (universal recipient)

AB+ blood can receive blood from everyone b/c it does not produce any antibodies that could risk blood clots

What distinguishes a type A red blood cell from a type O red blood cell?

O red blood cells do not have any antigens on its surface

Why can people with O-negative blood type donate blood to everyone? (UNIVERSAL DONOR)

O- blood type can give blood to everyone b/c it has no antigens on the blood cell that the other type bloods' antibodies would attack

A person with type A blood typically would not produce anti-A antibodies. Why is this a benefit to the person?

The body won't attack the type A blood because the A-antibody is complementary to type A blood. Agglutination will occur with the person's own blood

What would happen to a type O patient if he receives type A or type B blood?

Type O blood produces both Anti-A and Anti-B antigens. If blood type O patient receives type A or type B blood, the type O's antigens will attack the type A or B blood and agglutination would occur causing heart attacks and strokes to the patient. Type O blood is recessive, meaning that only type O can be received b/c type O blood does not produce any antigens

pedigree

a family tree that traces the inheritance of traits through many generations

multiple alleles

a gene has 3 or more alleles (versions) --HUMAN ABO BLOOD GROUPS -----in humans, there are four blood types (phenotypes): type A, type B, type AB, and type O -----blood type is controlled by three alleles: A,B, O -----these alleles code for types of carbohydrates that are on the surface of the red blood cells. Allele A codes for A type carbohydrates. Allele B codes for B type carbohydrates. Allele O codes for no carbohydrates -----the O allele is recessive. Two O alleles must be present for the person to have type O blood -----the A and B alleles are codominant. If a person receives an A allele and a B allele, their blood type is type AB. The AB blood cells have both A and B type carbohydrates

plietrophy

a single gene affects more than one trait ---ex: sickle cell anemia-affects the shape of the blood cells, heart damage, brain damage, and weakness

sex-linked genes

genes located on the X chromosome ---Remember organisms have autosomes (chromosomes that do not determine an organism's sex) and sex chromosomes (chromosomes that DO determine an organism's sex) ---Females have XX as their sex chromosomes and males have XY ---Because males have only 1X chromosome, they *only need one recessive allele* to show the recessive phenotype ---A female who has a recessive allele on only one X chromosome will not display the recessive phenotype

carrier

heterozygote for a recessive trait, carry the disease allele but does not have the disease

codominance

heterozygote shows both the "dominant" and "recessive" phenotype ----both alleles act as dominant allele and show up independently (such as with spots) ----Remember co-means together, so in codominance the *heterozygote shows both traits together*

epistasis

one gene impacts the expression of another gene

polygenic traits

one trait controlled by two or more genes ---usually see a lot of possible phenotypes (height, skin, eye color, skin color)

The complementary relationships between antigens and antibodies

the antibody's shape is complementary to the matching antigen-like puzzle pieces

What distinguishes a type A red blood cell from a type B red blood cell?

the antigens and the antibodies produced

environmental effects

the environment can influence the phenotype of an organism

incomplete dominance

the heterozygote displays a phenotype that is a blend of the dominant and recessive phenotype ---one allele is NOT completely dominant over the other. As a result, the "recessive" allele shows through and the *heterozygote is a blend of the two traits*

What happens to red blood cells when they are mixed with complementary antibodies?

they attach themselves to their respective antibodies (ex: if it is a blood type a red blood cell, then A antigens are complementary to it)