General Biology 2 - Genetics

Gregor Johann Mendel

he is the father of genetics, who discovered the basic principles of heredity.

monohybrid cross

it is a cross involving a single trait.

alleles

it refers to one of two or more versions of a gene.

homozygous

fill in the blank.

if the two alleles are the same, the individual is _______________________ for that gene.

heterozygous

fill in the blank.

if the alleles are different, the individual is _______________________.

parental generation

it is a cross of purebred (homozygous) parents.

F₁ (First Filial Generation)

it is the product of the parental generation.

F₂ (Second Filial Generation)

it is the product of the self-fertilization of the products of F1 generation.

genotype

this refers to the genetic make-up.

phenotype

this refers to the physical make-up.

the principle of dominance and recessiveness, law of segregation, law of independent assortment

these are the mendelian principles.

dominant allele

this refers to the expressed trait.

recessive allele

this refers to the masked trait that reappears in the F₂ generation.

The Law of Segregation

this means that a gene pair carries two separate characteristics; the egg and sperm cell carry the hereditary factors that the offspring receives one factor from each parent.

The Principle of Dominance and Recessiveness

this means that one factor in a pair may mask the expression of the other.

dihybrid cross

this is a cross involving two traits.

The Law of Independent Assortment

this is when, during gamete formation, the gene pair assorts independently; the inheritance of one trait is not affected by the inheritance of another trait.

incomplete dominance, codominance, multiple alleles

these are the non-mendelian patterns of inheritance.

incomplete dominance

this states that in the pattern of inheritance, where an intermediate phenotype other than the two parental phenotypes is observed, the dominant allele failed to cover or hide the recessive allele and the offspring does not resemble either of the parents; no allele is completely dominant over the other.

codominance

this means that both alleles are expressed, resulting in the formation of the phenotype or characteristics; the third phenotype is not a blending of the parents traits; rather, both parental traits are displayed.

Iᴬ, Iᴮ, Iᴼ

these are the three common alleles of the human blood group.

Rhesus (Rh) factor

it is an inherited protein found on the surface of red blood cells.

Rh positive

it is the most common blood type.

gene

it is an important segment of deoxyribonucleic acid (DNA) that signifies a unique protein that controls a specific function in the cell; it is capable of storing genetic formation and sometimes can undergo mutation.

DNA (deoxyribonucleic acid)

it is the blueprint of heredity; it is the genetic material that contains all the genetic information responsible in controlling cellular activities within living organisms.

Friedrich Miescher

he first isolated DNA from pus cells in 1869.

X-linked dominant

these are disorders caused by mutations in genes on the X chromosome, one of the two sex chromosomes in each cell.

true

true or false.

a characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons (no male-to-male transmission).

Fragile X syndrome

it is a genetic condition that causes a range of developmental problems, including learning disabilities and cognitive impairment.

carrier

it refers to a female parent possessing one X-linked recessive mutation and means that they will not manifest clinical symptoms of the disorder but will pass on the trait to the next generation.

affected

fill in the blank.

all males possessing an X-linked recessive mutation will be _______________.

Hemophilia A

it is a genetic disorder caused by missing or defective factor VIII, a clotting protein.

factor VIII (FVIII) deficiency

it is the other term for Hemophilia A.

color blindness

it is not a form of blindness, but a deficiency in the way a person sees color.

Y-linked inheritance

it is a trait that never occurs in females and occurs in all male descendants of an affected male.

true

true or false.

the concept of dominant and recessive do not apply to Y-linked traits, as only one allele (on the Y) is ever present in any one (male) individual.

hemizygotes

this refers to males with a single Y- or X-linked allele (only one allele is present).

pedigree chart

this helps trace the phenotypes and genotypes in a family to determine whether people carry recessive alleles.

box

this shape in a pedigree chart represents MALES.

circle

this shape in a pedigree chart represents FEMALES.

shaded shape

this shape in a pedigree chart represents that an individual has the trait.

unshaded shape

this shape in a pedigree chart represents that an individual doesn't have the trait.

half-shaded shape

this shape in a pedigree chart represents that an individual is a carrier.

karyotype

it is a picture of all chromosomes in a cell.

chemicals

these are used to stain chromosomes to produce a pattern of bands on them.

bands

fill in the blank.

in a karyotype, the sizes and locations of the bands are very consistent for each chromosome, but the ___________ differ greatly among different chromosomes.

- shows changes in chromosomes, such as when a person has too many or lacking chromosomes.

- reveals the loss part of a chromosome or deletion.

- used to estimate distances between genes on a chromosome.

- shows the possible location of a gene on a chromosome.

these are the functions of a karyotype.

Turner syndrome

it is a chromosomal condition that alters development in females; women with this condition tend to be shorter than average and are usually unable to conceive a child (infertile) because of an absence of ovarian function.

down syndrome

it is a genetic disorder caused by the presence of all part of a third copy of chromosome 21, it is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability.

trisomy 21 / addition-down syndrome

it is the other term for down syndrome.

3 billion

fill in the blank.

the human DNA consists of ________________ bases, and more than 99% of those bases are the same in all people.

mitochondria (mtDNA), nucleus (nuclear DNA)

these are where DNA is found.

adenine (A), guanine (G), cytosine (C), thymine (T)

these are the four DNA bases.

adenine (A), guanine (G)

these are the purine bases (double ring) in a DNA.

cytosine (C), thymine (T)

these are the pyrimidine bases (sintering) in a DNA.

nucleotide

it is the building block made up of four bases, five carbon sugar deoxyribose, and phospate group.