Genetics

unit of genetic material, a defined portion of chromosomes that encodes for a particular trait or substance such as hair color, blood type, etc.

the different forms a particular gene can occur in (brown, green, blue)- you have two copies of each gene (one from mom and one from dad) so there are two potential alleles for each

2 identical alleles for a particular gene

2 different alleles for a particular gene

will always be expressed, indicated by a capital letter

will be masked by a dominant gene, can only be expressed if there is no dominant gene present- indicated by a lower case letter

neither masks the other so both are expressed (AB blood type) Incomplete dominance- the traits blend (pink, RW, RR red, WW, white)

the makeup of the genes, which 2 alleles are present

what actually gets expressed-what you “see”

50% blue eyes (bb) 50% brown eyes (Bb) 75% brown eyes- BB or Bb 25% blue eyes- bb

two traits, four results or phenotypes will be seen

are based on what is on the cell surface Type A- A antigen on red blood cell’s (RBCs) surface Type B- B antigen on the surface Type AB- both A and B antigens on the surface Type O- neither A or B antigen on the surface

O is recessive, must be homozygous (OO) A is dominant, can be AA or AO B is dominant, can be BB or BO AB is codominant

Type A-makes antibodies against B, can receive from A or O Type B- makes antibodies against A, can receive from B or O Type AB- can receive from everyone (A, B, or O) Type O- makes antibodies against A and B, can only receive from O, but is a universal donor

a situation where Rh- mother is carrying an Rh+ child. After she is exposed to Rh+ RBCs during the first pregnancy, she may produce IgG antibodies which will cross the placenta and attack fetal RBCs in later pregnancies hemolytic disease of the newborn

generally affects males since they only have on X chromosome, the second X chromosome is always a good back up for females Hemophilia- x-linked disorder, recessive, defect in blood clotting protein Color blindness

2 copies of the bad gene in order for it to be expressed Albinism Sickle cell anemia PKU Cystic fibrosis

a defect in the production of melanin

single amino acid change in the gene that makes hemoglobin, RBCs have sickle shape

Phenylketonuria-enzyme defects leads to the build-up of phenylalanine in the bloodstream and neurological problems

enzyme defect causes the production of abnormal mucus that cause problems in the respiratory and gastrointestinal tract

physical or structural defects in the chromosomes rather than in the genes, often from nondisjunction- where one or more chromosomes pairs do not separate during mitosis or meiosis Trisomy/Polyplodiys- an unusual amount of a particular chromosome Ex: down syndrome (aka trisomy 21), XXY or XYY extra copy of a chromosome Monosomy/anuplodiy- one copy of a chromosome, just an X, example: Turner’s syndrome

the initial step is the splitting the two strands to form a replication fork- it involves the helicase enzymes

synthesis the DNA complementary strand