Unit 2. The Discovery of DNA

DNA

molecule of heredity

Hippocrates (Brick and Mortar Theory)

speculated that there are seeds that containss traits or charcteristics

seeds are found in the semen (men) and womb (women) and the combine and is passed down onto their baby

blood

________ contained materials for building the body

aristotle

according to him, the father provides the form or traits and the mother provides the material substance to accomodate the father’s form

form from father, matter from mother

preformation theory (17th to 18th century)

the sperms contains a miniature human that simply grows larger

homunculus

tiny little human

Jean-Baptiste Lamarck

who proposed the law of use and disuse

law of use and disuse (lamarckcism)

says that organs or sturctures frequently used becomes larger and better while the unused organs shrinks and disappear

organisms develop organs based on needs and the pass it down to the next generation

Theory of Evolution by Natural Selection

by Charles Darwin and Wallace

organisms having more favorable traits have higher chances of survival and are able to pass down their traits to their offsprings

Pangenesis by Charles Darwin

each of our body parts produce tiny particles called “gemmules”

gemmules carey information about that body part

parents’ gemmules combine and are passed down to their offspring

Gregor Mendel

Father of Moden Genetics

Studied inheritance patterns in pea plants

Gregor Mendel

the one who first got it right with heredity

Law of Segregation

Law of Independent Assortment

Law of Dominance

3 Medelian Laws

biomolecules

one time, _____________ became an option for choosing the molecule of herdity

there is something in the dead smooth strain (genetic material) that has been transferred to the rough strain that made it virulent

what is the transforming principle accrdng to griffith

transformation

the change on genotype and phenotype due to assimilation of foreign DNA

Frederick Griffith

proposed the Transformation/ transforming principle

S. pneumoniae

Smooth virulent strain &

Rough ninvirulent strain

bacterium used by Griffith

Ostwald Avery, Colin MacLeod, Maclyn McCarty

tested the 4 biomolecules as candidates for the transforming principle