Chapter 11: DNA & RNA Flashcards
exam 1 material
what is transcription?
when the genetic information in DNA is copied into RNA (mRNA, tRNA, rRNA)
what is translation?
information encoded in mRNA directs the addition of amino acids into a sequence to form polypeptides that combine to form proteins
what four criteria must be met for something to be considered genetic material?
- information: must encode the information necessary too make an entire organism
- transmission: must be passed from parent to offspring
- replication: must be copied to be passed from parent to offspring
- variation: must be capable of change to account for the known phenotypic variation in each species
what is the griffith’s experiment?
two strains of streptococcus pneumoniae (one that is rough and is not protected from the immune system and one that is smooth and is protected from the immune system) were injected into two different mice, mouse injected with live type S bacteria died and the bacteria was found in blood, mouse injected with type R survived and had no bacteria in its blood, mouse with heat-killed type S survived with no bacteria in the blood, mouse with live type R and heat-killed type S died and had type S bacteria in its blood, this suggested that something from dead S type was transforming type R into type S
what is the Avery, MacLeod, and McCarty experiment?
type S (immune protected) bacterial cells were placed into lipids, carbohydrates, proteins, and nucleic acids, then DNase, RNase, or protease were used to degrade each of the macromolecules, only the vials that did not degrade the DNA were able to transform type R into type S
what is transformation?
the ability of a molecule to confer new characteristics on an organism that acquires that molecule
what is the Hershey and Chase experiment?
bacteriophage T2 had either its proteins or DNA labeled with radioactive isotopes before being injected into cells, cells were then centrifuged and then examined to find that most of the DNA remained in the cells while the proteins were found outside the cells, this proved that DNA is what is injected into the bacterial cytoplasm during infection, indicating that DNA is the genetic material of viruses
what are the building blocks of chromosomes?
nucleotides are monomers linked together to form polymer strands that then combine to form nucleic acids (DNA and RNA), DNA strands then interact to form a double helix which then folds and interacts with proteins to form chromosomes
what components make up nucleotides?
a phosphate group, a pentose sugar (deoxyribose or ribose), and a nitrogenous base (purines or pyrimidines)
what are the purines and pyrimidines?
purines: adenine and guanine
pyrimidines: thymine, cytosine, and uracil
what are some differences between DNA and RNA?
DNA contains deoxyribose as its sugar, can contain thymine, but never contains uracil
RNA contains ribose as its sugar, never contains thymine, and may contain uracil
what combines to form nucleosides and how are they named?
base + sugar
adenine + ribose = adenosine
adenine + deoxyribose = deoxyadenosine
what forms nucleotides and how are they named?
base + sugar + phosphate(s)
adenosine monophosphate
adenosine diphosphate
adenosine triphosphate
what is the structure of a DNA strand?
nucleotides are covalently linked by a phosphodiester bond (a phosphate connects the 5’ carbon of one sugar to the 3’ carbon of another), the phosphates and sugar molecules form the backbone of the nucleic acid strand while bases face each other and are bonded by a hydrogen bond
what is chargaff’s rule?
percentage of adenine is similar to percentage of thymine and guanine is always similar to cytosine, A + G (purines) bind with T + C (pyrimidines) to ensure a consistent diameter of the helix
