Human Growth and Development - Chapter 2 (Part 1)

how much chromosomes does the human body have?

23 pairs (46 chromosomes)

Similarity between humans and every other mammal:

90%

Similarity between humans and chimpanzees

98%

Similarity between two people:

99.5%

x-linked

a gene carried on the x-chromosome

additive genes

a gene that contributes to the phenotype, usually with other additive genes

carrier

a person whose genotype includes a gene that is not expressed in the phenotype and such an unexpressed gene occurs in half the carrier's gametes and thus is passed on to half the carrier's children

dizygotic twins

aka fraternal twins and are twins who are formed when two separate ova are fertilized by two separate sperm are roughly the same time

monozygotic twins

aka identical twins and are twins who originate from one zygote that splits apart very early in development

allele

any of the possible forms of a gene

XY

consists of an X-shaped chromosome from the mother an a Y-shaped chromosome from the father, XY zygotes become males

XX

consists of two X-shaped chromosomes, one each from the mother and the father, XX zygotes become females

chromosome

each molecule of DNA

sons are more likely to have twins than daughters. true or false.

false, daughters are more likely to have twins than sons since they ovulate

dizygotic twins are different from a set of siblings the share the same biological parents. true or false.

false, they are NO different from a set of siblings the share the same biological parents

polymorphic

genes with various alleles

monozygotic twins have the same _______ but slight variations in the ______ due to environmental influences

genotype;phenotype

dominant-recessive pattern

interaction of a pair of genes in such a way that the phenotype reveals the influence of one more than that of the other

DNA

molecule that contains the chemical instructions for cells to manufacture various proteins

females are ___ likely to be carrier of x-linked traits but are ____ likely to express them

more;less

genotype

organism's entire genetic inheritance or genetic potential

zygote

single cell that is formed from the fusing of two gametes, a sperm and an ovum; when egg is fertilized by a sperm

gamete

single individual reproductive cell which is either sperm or ovum that can produce a new individual if it combines with a gamete from the other sex to form a zygote

gene

small section of a chromosome which is the basic unit for transmission of heredity that consists of a string of chemicals that provide instructions for the cell to manufacture certain proteins

copy number variations

small variations, mutations, or repetitions in the base pairs or triplets could make a notable difference in the proteins and in person

the 23rd pair

the chromosome that determines if your male or female

genome

the full set of genes of a certain species

phenotype

the observable characteristics of a person including appearance, personality, intelligence, and all other apparent traits

dizygotic twins have half their genes in common and occur twice as often as monozygotic twins. true or false.

true

monozygotic twins will always be the same gender. true or false.

true

older women are more often to double-ovulate. true or false.

true

vanishing twin phenomenon

when an early sonogram will reveal two developing organisms, but later on only one embryo continues to grow

methylation

when material enhances, transcribes, connects, empowers, silences, regulates, and alters genes

Human Genome Project

• Found "only" about 20,000 - 23,000 genes in humans